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  1. The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae, in Mexico City

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    Diaz-Perez Alfonso

    2011-05-01

    Full Text Available Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p

  2. PATOGENITAS CENDAWAN BEAUVERIA BASSIANA TERHADAP LARVA NYAMUK AEDES AEGYPTI DAN CULEX PIPIENS QUINQUEFASCIATUS DI LABORATORIUM

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    Amrul Munif

    2012-09-01

    Full Text Available The capability of Beauveria bassiana fungus to kill mosquito larvae was challenged with Aedes aegypti and Culex pipiens quinquefasciatus in a study conducted at the entomology laboratory of the Health Ecology Research Centre. Cx. p. quinquefeasciatus was more sensitive compared to Ae. aegypti to the B. bassiana strain from Sukamandi (West Java, which is probably due to the mosquitoes behaviour and conidiospore larvacidal effect. Conidia dust application, with a dosage of 2.2 mglliter, to water surface, within 48 hours was able to kill almost all the Cx. p. quinquefasciatus. However a dosage of 4 mglliter was required to kill all the Ae.aegypti. And a dosage of 1.3 mg conidiospore I liter is able to kill 50% Cx. p. quinquefasciatus. It seems that B. bassiana has greater capability to eradicate Cx. p. quinquefasciatus compared to Ae. aegypti

  3. Culex pipiens quinquefasciatus: a potential vector to transmit Zika virus.

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    Guo, Xiao-Xia; Li, Chun-Xiao; Deng, Yong-Qiang; Xing, Dan; Liu, Qin-Mei; Wu, Qun; Sun, Ai-Juan; Dong, Yan-de; Cao, Wu-Chun; Qin, Cheng-Feng; Zhao, Tong-Yan

    2016-09-07

    Zika virus (ZIKV) has become a threat to global health since the outbreak in Brazil in 2015. Although ZIKV is generally considered an Aedes-transmitted pathogen, new evidence has shown that parts of the virus closely resemble Culex-transmitted viruses. Therefore, it is important to evaluate the competence of Culex species for ZIKV to understand their potential as vectors. In this study, female Culex pipiens quinquefasciatus were orally exposed to ZIKV. Mosquito midguts, salivary glands and ovaries were tested for ZIKV to measure infection and dissemination at 2, 4, 6, 8, 12, 16 and 18 days post exposure (pe). In addition, saliva was collected from mosquitoes after infection and infant mice were bitten by infected mosquitoes to measure the transmission ability of Cx. p. quinquefasciatus. The results showed that the peak time of virus appearance in the salivary glands was day 8 pe, with 90% infection rate and an estimated virus titer of 3.92±0.49 lg RNA copies/mL. Eight of the nine infant mice had positive brains after being bitten by infected mosquitoes, which meant that Cx. p. quinquefasciatus could be infected with and transmit ZIKV following oral infection. These laboratory results clearly demonstrate the potential role of Cx. p. quinquefasciatus as a vector of ZIKV in China. Because there are quite different vector management strategies required to control Aedes (Stegomyia) species and Cx. p. quinquefasciatus, an integrated approach may be required should a Zika epidemic occur.

  4. Mom Matters: Diapause Characteristics of Culex pipiens-Culex quinquefasciatus (Diptera: Culicidae) Hybrid Mosquitoes.

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    Meuti, Megan E; Short, Clancy A; Denlinger, David L

    2015-03-01

    Females of the northern house mosquito, Culex pipiens L., are capable of entering an adult overwintering diapause characterized by arrested ovarian development, enhanced stress tolerance, and elevated lipid stores. In contrast, the southern house mosquito, Culex quinquefasciatus Say, lacks this capacity and is therefore unable to survive the harsh winters found in northern regions of North America. These two species are capable of forming fertile hybrids in the United States, yet the diapause characteristics of these hybrids have not been extensively investigated. We crossed Cx. pipiens from Columbus, OH, with Cx. quinquefasciatus from Vero Beach, FL, and reared F1 hybrids from all mothers separately under diapause-inducing, short-day conditions (a photoperiod of 8:16 [L:D] h) at 18°C. Egg follicle length and lipid content were used to assess the diapause status of hybrids. Diapause incidence of hybrids varied widely for progeny from different mothers of the same species, but hybrids with Cx. pipiens mothers were consistently more prone to enter diapause than hybrids that had Cx. quinquefasciatus mothers. Our results suggest a strong maternal influence on the diapause phenotype and that a high percentage (45-75%) of Cx. pipiens-Cx. quinquefasciatus hybrids are capable of entering diapause. This implies that many hybrids can successfully overwinter, leading to a possible widening of the hybrid zone of these two species in North America.

  5. Summary of the symposium Global Perspective on the Culex pipiens Complex in the 21st Century: The Interrelationship of Culex pipiens, quinquefasciatus, molestus and others.

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    Linthicum, Kenneth J

    2012-12-01

    A symposium on the mosquitoes in the Culex pipiens Complex (Pipiens Complex), including Cx. pipiens, Cx. quinquefasciatus, and Cx. molestus, invited 17 of the world's experts on this species Complex to explore the current state of knowledge on the systematic status, speciation, ecology, biology, vector competence, population genetics, endosymbionts, and role in disease transmission of these species in various parts of the world. A Foreword, Introduction, 14 full papers, 3 abstracts and this Summary are published in this special issue of the Journal of the American Mosquito Control Association. A summary of findings, overall conclusions, and research needs will be discussed in relation to mosquito control and interrupting disease transmission caused by these species.

  6. Effects of Forced Egg Retention on the Temporal Progression of West Nile Virus Infection in Culex pipiens quinquefasciatus (Diptera: Culicidae)

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    SMARTT, CHELSEA T.; RICHARDS, STEPHANIE L.; Anderson, Sheri L.; Vitek, Christopher J.

    2010-01-01

    Environmental factors that impact the biology of mosquito vectors can have epidemiological implications. Lack of oviposition sites facilitated by environmental factors such as temperature and drought can often force Culex spp. mosquitoes to retain their eggs. Culex pipiens quinquefasciatus Say were fed blood meals containing West Nile virus (WNV; family Flaviviridae, genus Flavivirus) and either allowed to oviposit or forced to retain their eggs through different time points postinfection (9,...

  7. West Nile virus genetic diversity is maintained during transmission by Culex pipiens quinquefasciatus mosquitoes.

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    Doug E Brackney

    Full Text Available Due to error-prone replication, RNA viruses exist within hosts as a heterogeneous population of non-identical, but related viral variants. These populations may undergo bottlenecks during transmission that stochastically reduce variability leading to fitness declines. Such bottlenecks have been documented for several single-host RNA viruses, but their role in the population biology of obligate two-host viruses such as arthropod-borne viruses (arboviruses in vivo is unclear, but of central importance in understanding arbovirus persistence and emergence. Therefore, we tracked the composition of West Nile virus (WNV; Flaviviridae, Flavivirus populations during infection of the vector mosquito, Culex pipiens quinquefasciatus to determine whether WNV populations undergo bottlenecks during transmission by this host. Quantitative, qualitative and phylogenetic analyses of WNV sequences in mosquito midguts, hemolymph and saliva failed to document reductions in genetic diversity during mosquito infection. Further, migration analysis of individual viral variants revealed that while there was some evidence of compartmentalization, anatomical barriers do not impose genetic bottlenecks on WNV populations. Together, these data suggest that the complexity of WNV populations are not significantly diminished during the extrinsic incubation period of mosquitoes.

  8. The Effect of West Nile Virus Infection on the Midgut Gene Expression of Culex pipiens quinquefasciatus Say (Diptera: Culicidae

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    Chelsea T. Smartt

    2016-12-01

    Full Text Available The interaction of the mosquito and the invading virus is complex and can result in physiological and gene expression alterations in the insect. The association of West Nile virus (WNV and Culex pipiens quinquefasciatus mosquitoes results in measurable changes in gene expression; 22 gene products were shown previously to have altered expression. Sequence analysis of one product, CQ G1A1, revealed 100% amino acid identity to gram negative bacteria binding proteins (CPQGBP in Cx. p. quinquefasciatus, Aedes aegypti (70% and Anopheles gambiae (63% that function in pathogen recognition. CQ G1A1 also was differentially expressed following WNV infection in two populations of Cx. p. quinquefasciatus colonized from Florida with known differences in vector competence for WNV and showed spatial and temporal gene expression differences in midgut, thorax, and carcass tissues. These data suggest gene expression of CQ G1A1 is influenced by WNV infection and the WNV infection-controlled expression differs between populations and tissues.

  9. Effects of forced egg retention on the temporal progression of West Nile virus infection in Culex pipiens quinquefasciatus (Diptera: Culicidae).

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    Smartt, Chelsea T; Richards, Stephanie L; Anderson, Sheri L; Vitek, Christopher J

    2010-02-01

    Environmental factors that impact the biology of mosquito vectors can have epidemiological implications. Lack of oviposition sites facilitated by environmental factors such as temperature and drought can often force Culex spp. mosquitoes to retain their eggs. Culex pipiens quinquefasciatus Say were fed blood meals containing West Nile virus (WNV; family Flaviviridae, genus Flavivirus) and either allowed to oviposit or forced to retain their eggs through different time points postinfection (9, 13, 20, 27 d) at 28 degrees C. Oviposition status did not significantly affect rates of WNV infection (% with virus-positive bodies), dissemination (% with virus-positive legs), or transmission (% with virus-positive saliva) for any of the tested time points. As expected, WNV titers in bodies and legs were significantly (P studies are needed to assess the effects of drought on virus transmission risk and how these interactions affect our interpretation of field data.

  10. Sound and vibration sensitivity of VIIIth nerve fibers in the frogs Leptodactylus albilabris and Rana pipiens pipiens

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, J; Narins, P M

    1993-01-01

    1. Responses of 73 fibers to dorso-ventral vibration were recorded in the saccular and utricular branchlets of Rana pipiens pipiens using a ventral approach. The saccular branchlet contained nearly exclusively vibration-sensitive fibers (33 out of 36) with best frequencies (BFs) between 10 and 70...

  11. 浦东国际机场致倦库蚊和淡色库蚊的调查研究%An investigation of Culex pipiens quinquefasciatus and Culex pipiens pallens in Pudong International Airport

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    曹敏; 何宇平; 李平; 田桢干

    2011-01-01

    Objective To investigate the distribution, seasonal prevalence, diurnal rhythm, bitting and breeding ot Culex pipiens quinquefasciatus and Cx. pipiens pallens in Pudong International Airport. Methods Sample collection was done by means of bednet trap, lamp baited trap, human baited trap, larvae dipping and labor hour method. Results It was found that Cx. pipiens quinquefasciatus and Cx. pipiens pallens were the dominant species of mosquitoes in Pudong International Airport, which were harmful to human health from April to November. The findings from the lamp baited trap showed a slope-shaped curve for the seasonal fluctuation of the insects, beginning in April, peaking from May to June and declining gradually from October and disappearing at the end of November. The bednet trap revealed that the insects were active predominantly in the evening and at night, with peak activity seen 1-4 h after the sunset and little movement during the day. The human baited trap indicated that the peak time of bitting was at 21:00 o'clock, with a maximum frequency of 42 times/15 min). The number of mosquitos that entered each room was highest from 19:00 to 21:00 with the highest burglary rate being 9 mosquitos per 15 min. The larvae were mainly breeding in still sewage or clean water in ponds, pools, bottomlands, ditches and containers, etc. Conclusion Cx. pipiens quinquefasciatus and Cx. pipiens pallens are common human-biting species in Pudong International Airport. The data on the seasonal prevalence, diurnal rhythm, bitting and breeding of Cx. pipiens quinquefasciatus and Cx. pipiens pallens contribute to the prevention and control of the insects and related vector-borne diseases.%目的 了解致倦库蚊和淡色库蚊在浦东机场的分布与活动规律.方法 帐诱法、灯诱法、人诱法、捞勺法和人工小时法.结果 致倦库蚊和淡色库蚊是浦东国际机场的优势蚊种,4-11月均有危害;灯诱法调查,季节消长呈坡型,蚊虫于4月出现,5-6

  12. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae.

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    Minghui Zhao

    Full Text Available Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1 was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A. Analysis of the correlation between mutation frequencies and resistance levels (LC50 suggests that two point mutations, G247S (r2 = 0.732, P = 0.065 and A328S (r2 = 0.891, P = 0.016, are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036. And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045 resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  13. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae).

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    Zhao, Minghui; Dong, Yande; Ran, Xin; Wu, Zhiming; Guo, Xiaoxia; Zhang, Yingmei; Xing, Dan; Yan, Ting; Wang, Gang; Zhu, Xiaojuan; Zhang, Hengduan; Li, Chunxiao; Zhao, Tongyan

    2014-01-01

    Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1) was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A). Analysis of the correlation between mutation frequencies and resistance levels (LC50) suggests that two point mutations, G247S (r2 = 0.732, P = 0.065) and A328S (r2 = 0.891, P = 0.016), are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036). And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045) resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  14. Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

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    Atyame, Célestine M.; Pasteur, Nicole; Dumas, Emilie; Tortosa, Pablo; Tantely, Michaël Luciano; Pocquet, Nicolas; Licciardi, Séverine; Bheecarry, Ambicadutt; Zumbo, Betty; Weill, Mylène; Duron, Olivier

    2011-01-01

    The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands. PMID:22206033

  15. Trap effects of different physical and chemical attractants on Culex pipiens quinquefasciatus%不同物理、化学因子对致倦库蚊的引诱效果研究

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    谷依露; 高小峰; 杨晓菁; 葛台明

    2012-01-01

    Objective To observe the trap effects of several different physical and chemical attractants on adult Culex pipiens quinquefasciatus, providing better designs of new mosquito trap devices. Methods The "Y" - tube olfactometer was used to measure the trap effects of seven chemicals (urea, lactic acid, glycerol, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and nonyl aldehyde) and two physical attractants (sound and visible light) on adult Cx. Pipiens quinquefasciatus. The number of individuals attracted by the tested attractants was calculated and compared among the groups. Results Chemical attractants including urea (10 mg/L), lactic acid (1000 mg/L), hexadecanoic acid (10 mg/L), nonyl aldehyde (0.1 mg/L) and physical attractants including 150 Hz sinus tone and 380 nm visible light had better mosquito trap effects. Conclusion The chemical and physical attractants mentioned above can be introduced to the design of mosquito trap devices to improve the efficiency of mosquito control.%目的 研究不同物理、化学因子对致倦库蚊的引诱效果,以更好地设计改进新一代灭蚊器.方法 使用Y形嗅觉测试仪测定化学因子(尿素、乳酸、丙三醇、十二烷酸、十四烷酸、十六烷酸、壬醛)以及物理因子(声波和可见光)对致倦库蚊成虫的引诱作用;将致倦库蚊成虫逐只放入Y形嗅觉测试仪,统计飞入处理端的个体数,通过比较得出对致倦库蚊具有较好引诱效果的物理、化学因子.结果 对致倦库蚊具有较高引诱率的化学因子有尿素(10 mg/L)、乳酸(1000 mg/L)、十六烷酸(10 mg/L)和壬醛(0.1 mg/L);物理因子中150 Hz的正弦波和380 nm的可见光分别对致倦库蚊具有较高引诱率.结论 可将上述引诱效果较佳的物理、化学因子引入到灭蚊器的设计生产中,以提高灭蚊效率.

  16. The Culex pipiens complex in the Mississippi River basin: identification, distribution, and bloodmeal hosts.

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    Savage, Harry M; Kothera, Linda

    2012-12-01

    Members of the Culex pipiens complex are the primary vectors of St. Louis encephalitis virus and West Nile virus in the Mississippi River basin (MRB). The Cx. pipiens complex in the MRB is composed of 4 taxa: Cx. p. pipiens form pipiens, Cx. p. quinquefasciatus, hybrids between Cx. p. pipiens f. pipiens and Cx. p. quinquefasciatus, and Cx. p. pipiens form molestus. Three studies on bloodmeal hosts with large sample sizes have been conducted on members of the Cx. pipiens complex in the MRB including 1 each on Cx. p. quinquefasciatus from Louisiana, Cx. p. pipiens-quinquefasciatus hybrids from Tennessee, and Cx. p. pipiens from Illinois. The top 8 bloodmeal hosts from each of the 3 sites accounted for 68-92% of bloodmeals. Only 14 species accounted for the top 8 bloodmeal hosts at each of the 3 sites. The most often utilized bloodmeal hosts for members of the Culex pipiens complex within the MRB are the American robin, Northern cardinal, human, raccoon, common grackle, house sparrow, mourning dove, dog, Northern mockingbird, blue jay, opossum, domestic horse, house finch and European starling. Human feeding varied widely among sites from 1% to 15.7% of bloodmeals. The proportion of bloodmeals taken on humans is an important epidemiological variable and future studies are needed to define the primary genetic and environmental factors that influence host utilization by members of the Cx. pipiens complex.

  17. Avaliação da sensibilidade de adultos de Culex quinquefasciatus Say a inseticidas químicos de contato Evaluation of the sensitivity of the adult Culex quinquefasciatus Say to chemical insecticides

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    Carlos Fernando S. de Andrade

    1990-08-01

    Full Text Available A sensibilidade de adultos do pernilongo doméstico Culex quinquefasciatus a 5 inseticidas químicos foi avaliada sob condições de laboratório pelo critério de Tempo Letal Mediano (TL50. Foram utilizados o organofosforado Malathion e quatro piretróides: Bifenthrin, Deltamethrin, Esfenvalerate e Alfamethrin. Foi sugerida uma técnica simples e eficiente para se avaliar adultos de um dia de idade incluindo 5 repetições para cada tratamento. Os resultados obtidos mostraram ser o método bastante adequado para avaliações rotineiras. Não ocorreu resistência a esses 5 princípios ativos, na população natural de Culex quinquefasciatus estudada.The sensitivity of the adult house mosquito Culex quinquefasciatus to 5 chemical insecticides was evaluated under laboratory condictions, based on the Median Lethal Time (LT50 criterion. The organophosphorous Malathion and four pyrethroids: Bifenthrin, Deltamethrin, Esfenvalerate and Alfamethrin were utilized. An easy and efficient technique was suggested for the testing of one-day-old adults, including five repetitions for each treatment. The results revealed the full adequacy of this method for routine use. Further, no resistance to the 5 chemical compounds was detected among this natural population of Cx. quinquefasciatus.

  18. Effects of latitude and longitude on the population structure of Culex pipiens s.l., vectors of West Nile virus in North America.

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    Edillo, Frances; Kiszewski, Anthony; Manjourides, Justin; Pagano, Marcello; Hutchinson, Michael; Kyle, Andrew; Arias, Jorge; Gaines, David; Lampman, Richard; Novak, Robert; Foppa, Ivo; Lubelcyzk, Charles; Smith, Robert; Moncayo, Abelardo; Spielman, Andrew

    2009-11-01

    We assessed the structure and latitudinal selection that might result in sensitivities to critical day-lengths that trigger diapause between Culex pipiens populations distributed along North-South and East-West axes in eastern North America. Strong population structure between Cx. p. pipiens and Cx. p. quinquefasciatus existed. Among Cx. p. pipiens, a 100-km increase in the latitudinal change resulted in an increased square root of F(ST) by 0.002. A 100-km increase in the longitudinal change caused an increased square root of F(ST) by 0.035. A lack of latitudinal influence on the structure between Cx. p. pipiens populations suggests a uniform signal using the 12 microsatellite markers, which might increase the risk of West Nile virus (WNV) transmission toward northern areas because of longer breeding season, extend host-seeking period, and larger population size. Northern Cx. p. pipiens may have undergone additional generations before diapause is triggered, magnifying population size when WNV amplification is peaking.

  19. UJI COBA STRAIN LOKAL BACILLUS THURINGIENSIS H-14 YANG DITUMBUHKAN DALAM MEDIA AIR KELAPA TERHADAP JENTIK NYAMUK ANOPHELES ACONITUS DAN CULEX PIPIENS QUINQUEFASCIATUS PERANGKAP SENTINEL DI KOLAM KOTAMADIA SALATIGA

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    Blondie Ch. P.

    2012-09-01

    Full Text Available An investigation was conducted on Bacillus thuringiensis H-14 local strain grown in coconut water media and Tryptose Phosphate Broth (TPB. The two media were tested against Anopheles aconitus and Culex p. quinquefasciatus mosquito larvae in the Vector Control Research Station laboratory and in Sentinel traps village Kauman Kidul pool, Salatiga. The pathogenicity test on B. thuringiensis H-14 local strain grown in coconut water and TPB against An. aconitus and Cx. p. quinquefasciatus larvae in the laboratory was done according to WHO procedure. This was conducted to determine the LC50 and LC90 which is counted according to the probit analysis. The pathogenicity test result of B. thuringiensis H-14 local strain cultured in coconut water against An. aconitus and Cx. p. quinquefasciatus larvae at 24 hours of exposure, showed the LC50 were 0,04 ml/100ml and 0,10 ml/100ml with LC90 were 0,15 ml/100ml and 0,20 ml/100ml respectively. The pathogenicity test at 48 hours of exposure showed the LC50 were 0,01 ml/100ml and 0,02 ml/100ml with LC90 were 0,04 ml/100 ml and 0,13 ml/100 ml respectively. The pathogenicity test result o/B. thuringiensis H-14 local strain cultured in TPB media against An. aconitus and Cx. p. quinquefasciatus larvae at 24 hours exposure, showed the LC50 were 0,05 ml/100 ml and 0,06 ml/100 ml with LC90 were 0,20 ml/100 ml and 0,15 ml/100 ml respectively. The pathogenicity test at 48 hours of exposure showed the LC50 were 0,02 ml/100 ml and 0,03 ml/100ml with LC90 were 0,10 ml/100 ml and 0,08 ml/100ml respectively. The field trial showed the patogenicity test result of B. thuringiensis H-14 local strain cultured in coconut water media against An. aconitus larvae at Sentinel trap in r icefield pools, showed a mortality of more than 50% for 4 days at the 0,15 ml/100 ml (LC90 aplication dosage. The pathogenicity against Cx. p. quinquefasciatus larvae at Sentinel trap was more than 50% for 3 days at the 0,20 ml/100 ml (LC90 aplication

  20. [Sensitivity and specificity of prick skin test with two concentrations of standardized extract of Culex quinquefasciatus in allergic children].

    Science.gov (United States)

    Castro-Almarales, Raúl Lázaro; Álvarez-Castelló, Mirta; Ronquillo-Díaz, Mercedes; Rodríguez-Canosa, José S; González-León, Mayda; Navarro-Viltre, Bárbara I; Betancourt-Mesia, Daniel; Enríquez-Domínguez, Irene; Reyes-Zamora, Mary Carmen; Oliva-Díaz, Yunia; Mateo-Morejón, Maytee; Labrada-Rosado, Alexis

    2016-01-01

    Antecedentes: las opciones diagnósticas de las reacciones inmunológicas a la picadura del mosquito son limitadas. En Cuba, las reacciones mediadas por IgE más frecuentes son por picadura de Culex quinquefasciatus. Objetivo: determinar la sensibilidad y especificidad de la prueba cutánea por punción con dos dosis del extracto estandarizado en unidades de nitrógeno proteico (UNP) de Culex quinquefasciatus (BIOCEN, Cuba). Material y método: estudio analítico efectuado en 100 niños entre 2 y 15 años de edad: 50 pacientes atópicos con antecedentes de alergia a la picadura de mosquito e IgE sérica específica positiva a Culex quinquefasciatus y 50 pacientes atópicos sin antecedentes de alergia a la picadura de mosquito e IgE sérica específica negativa a Culex quinquefasciatus. La prueba cutánea por punción se realizó por duplicado en los antebrazos de los pacientes. Las dosis investigadas fueron 100 y 10 UNP/mL. Resultados: en la prueba cutánea por punción con el extracto de mayor concentración se obtuvo un tamaño del área del habón de 22.09 mm2 y con la menor concentración de 8.19 mm2; una diferencia estadísticamente significativa (p=0.001, prueba t de Student). La prueba cutánea positiva se correlacionó en el 100% de los pacientes con la existencia de IgE específica. La prueba con ambas dosis mostró 94% de especificidad y 88% de sensibilidad. Conclusión: la alta coincidencia en el resultado de la prueba cutánea nos muestra que puede sustituirse la concentración del extracto a 100 UNP/mL por la de menor concentración, sin perder confiabilidad en el diagnóstico de sensibilización al mosquito Culex quinquefasciatus, utilizando ese método in vivo.

  1. “BIRD BITING” MOSQUITOES AND HUMAN DISEASE: A REVIEW OF THE ROLE OF CULEX PIPIENS COMPLEX MOSQUITOES IN EPIDEMIOLOGY

    Science.gov (United States)

    Farajollahi, Ary; Fonseca, Dina M.; Kramer, Laura D.; Kilpatrick, A. Marm

    2011-01-01

    The transmission of vector-borne pathogens is greatly influenced by the ecology of their vector, which is in turn shaped by genetic ancestry, the environment, and the hosts it feeds on. One group of vectors, the mosquitoes in the Culex pipiens complex, play key roles in the transmission of a range of pathogens including several viruses such as West Nile and St. Louis encephalitis viruses, avian malaria (Plasmodium spp.), and filarial worms. The Cx. pipiens complex includes Cx. pipiens pipiens with two forms, pipiens and molestus, Cx. pipiens pallens, Cx. quinquefasciatus, Cx. australicus, and Cx. globocoxitus. While several members of the complex have limited geographic distributions, Cx. pipiens pipiens and Cx. quinquefasciatus are found in all known urban and sub-urban temperate and tropical regions, respectively, across the world, where they are often principal disease vectors. In addition, hybrids are common in areas of overlap. Although gaps in our knowledge still remain, the advent of genetic tools has greatly enhanced our understanding of the history of speciation, domestication, dispersal, and hybridization. We review the taxonomy, genetics, evolution, behavior, and ecology, of members of the Cx. pipiens complex and their role in the transmission of medically important pathogens. The adaptation of Cx. pipiens complex mosquitoes to human-altered environments led to their global distribution through dispersal via humans and, combined with their mixed feeding patterns on birds and mammals (including humans), increased the transmission of several avian pathogens to humans. We highlight several unanswered questions that will increase our ability to control diseases transmitted by these mosquitoes. PMID:21875691

  2. A Pictorial Key for Culex pipiens Complex (Diptera: Culicidae In Iran

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    Hossein Dehghan

    2016-01-01

    Full Text Available Background: The aim of this study was to design pictorial key and taxonomic literature of Culex pipiens complex in Iran.Methods: Larvae were collected using standard dipping methods in 13 randomly selected areas of Bushehr, Hame­dan, Kerman, Khorasan-e-Razavi, Khuzistan, Mazandaran, Tehran, Sistan and Baluchistan and Yazd Provinces from April 2009 to October 2010. The data were analyzed using SPSS Ver. 11.5.Results: Culex pipiens larvae were identified based on the Seta 1 of the abdominal segments III–IV in north and central parts of Iran. This diagnostic character had some variation among the Cx. quinquefasciatus collected from south of the country. The identification value of intersection of costa, subcosta and bifurcation of R2+3 of female veins, was calculated as 90–100 % for Cx. pipiens. This diagnostic character was varied among the Cx. quinquefas­ciatus specimens. The male genitalia found as the main characters to distinguish of Cx. quinquefasciatus from Cx. pipiens.Conclusion: It is necessary more studies on the behavior and genetic variations of Cx. pipiens complex in Iran.

  3. Distribution of the members of the Pipiens Assemblage in the sympatric area from Argentina: which is where and when?

    Science.gov (United States)

    Cardo, María V; Rubio, Alejandra; Junges, Melania; Vezzani, Darío; Carbajo, Aníbal E

    2016-01-01

    Given their medical and veterinary relevance, the members of the Pipiens Assemblage are a worldwide target of ecological research. The distribution of Culex pipiens s.s. and Cx. quinquefasciatus converge in Buenos Aires, Argentina, where hybrids have been detected. Each member of the assemblage exhibits a distinct eco-physiological behaviour that can affect its efficiency in pathogen transmission. Our aim was to identify the environmental drivers for the spatio-temporal distribution of each member, focusing on latitudinal and urbanisation gradients. Immatures of mosquitoes were surveyed in artificial containers found within 11 public cemeteries, raised up to the adult stage and identified by their male genitalia. The distribution of each member was associated with the environment in a Generalized Linear Model. The variable accounting for most of the heterogeneity was latitude; Cx. quinquefasciatus was collected more frequently at northern cemeteries, whereas Cx. pipiens and hybrids were more likely at the southern extreme. The urbanisation gradient was also associated with the occurrence of Cx. quinquefasciatus and hybrids at the high and low end, respectively. Other relevant variables were cemetery total area, the proportion with graves and the presence of plastic flowers in the containers. The spatial distribution of the members of the Pipiens Assemblage within the sympatric region in South America is driven by environmental features. The information presented herein provides essential baseline data for surveillance programs and control activities. PMID:27783720

  4. Identification of genes involved in pyrethroid-, propoxur-, and dichlorvos- insecticides resistance in the mosquitoes, Culex pipiens complex (Diptera: Culicidae).

    Science.gov (United States)

    Li, Chun-xiao; Guo, Xiao-xia; Zhang, Ying-mei; Dong, Yan-de; Xing, Dan; Yan, Ting; Wang, Gang; Zhang, Heng-duan; Zhao, Tong-yan

    2016-05-01

    Culex pipiens pallens and Cx. p. quinquefasciatus are important vectors of many diseases, such as West Nile fever and lymphatic filariasis. The widespread use of insecticides to control these disease vectors and other insect pests has led to insecticide resistance becoming common in these species. In this study, high throughout Illumina sequencing was used to identify hundreds of Cx. p. pallens and Cx. p. quinquefasciatus genes that were differentially expressed in response to insecticide exposure. The identification of these genes is a vital first step for more detailed investigation of the molecular mechanisms involved in insecticide resistance in Culex mosquitoes.

  5. Characterization of Culex pipiens Complex (Diptera: Culicidae) Populations in Colorado, USA Using Microsatellites

    Science.gov (United States)

    Kothera, Linda; Godsey, Marvin S.; Doyle, Michael S.; Savage, Harry M.

    2012-01-01

    Mosquitoes such as those in the Culex pipiens complex are important vectors of disease. This study was conducted to genetically characterize Cx. pipiens complex populations in the state of Colorado, USA, and to determine the number of genetic clusters represented by the data. Thirteen populations located among four major river basins were sampled (n = 597 individuals) using a panel of 14 microsatellites. The lowest-elevation sites had the highest Expected Heterozygosity (HE) values (range 0.54–0.65). AMOVA results indicated the presence of statistically significant amounts of variation within each level when populations were analyzed as one group or when they were grouped either by river basin or by their position on the east or west side of the Rocky Mountains. Most pairwise FST values were significant via permutation test (range 0–0.10), with the highest values from comparisons with Lamar, in southeast CO. A neighbor joining tree based on Cavalli–Sforza and Edwards’s chord distances was consistent with the geographic locations of populations, as well as with the AMOVA results. There was a significant isolation by distance effect, and the cluster analysis resolved five groups. Individuals were also assayed with an additional microsatellite marker, Cxpq78, proposed to be monomorphic in Cx. pipiens but polymorphic in the closely related but biologically distinct species Cx. quinquefasciatus. Low frequencies (≤3%) of Cx. quinquefasciatus alleles for this marker were noted, and mostly confined to populations along the Interstate 25 corridor. Pueblo was distinct in that it had 10% Cx. quinquefasciatus alleles, mostly of one allele size. The degree of population genetic structure observed in this study is in contrast with that of Cx. tarsalis, the other major vector of WNV in the western U.S., and likely reflects the two species’ different dispersal strategies. PMID:23094068

  6. Acute toxicity of furazolidone on Artemia salina, Daphnia magna, and Culex pipiens molestus larvae

    Energy Technology Data Exchange (ETDEWEB)

    Macri, A.; Stazi, A.V.; Dojmi di Delupis, G.

    1988-10-01

    As a result of evidence of the ecotoxicity of nitrofurans, the acute toxicity of furazolidone was tested in vivo on two aquatic organisms, Artemia salina and Daphnia magna, which are both crustaceans. Toxicity studies were also performed on larvae of Culex pipiens molestus. Results indicated a significant toxicity of the compound on Culex pipiens and Daphnia magna, while Artemia salina proved to be the least sensitive.

  7. The Morphological Variations of Culex pipiens Larvae (Diptera: Culicidae in Yazd Province, Central Iran

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    H Dehghan

    2010-12-01

    Full Text Available "nAbstract "nBackground: Culex pipiens complex shows variations in morphological and biological characters including differ­ent biological forms and has medical and veterinary importance. Because of having morphological variations, some­times it is not easy to separate this species from Cx. quinquefasciatus and Cx. torrentium. The aim of this study was to  identify the  Culex pipiens complex species in order to use in control programs in the future. "nMethods: This study was carried out in two randomly selected rural villages in Yazd County, eastern Iran using dip­ping technique from April to October 2009. The data were analyzed using SPSS software version 16. "nResults: Average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2.43 and 5.14, respectively. Siphon/Saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. In our study, only 4 specimens had single seta 1 on segments III and VI (2.5% and the remaining beard double seta (97.5%. The maximum 3-6 branches seta 1a-S and 1b-S (95% were observed on siphon. "nConclusion: More populations of Culex pipiens from different areas of Iran need to be studied to gain complete informa­tion about the taxonomy and ecology of the species in the country. "n  "nKeywords: Culex pipiens complex, larvae, taxonomy, Iran

  8. Midgut barrier imparts selective resistance to filarial worm infection in Culex pipiens pipiens.

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    Michelle L Michalski

    Full Text Available Mosquitoes in the Culex pipiens complex thrive in temperate and tropical regions worldwide, and serve as efficient vectors of Bancroftian lymphatic filariasis (LF caused by Wuchereria bancrofti in Asia, Africa, the West Indies, South America, and Micronesia. However, members of this mosquito complex do not act as natural vectors for Brugian LF caused by Brugia malayi, or for the cat parasite B. pahangi, despite their presence in South Asia where these parasites are endemic. Previous work with the Iowa strain of Culex pipiens pipiens demonstrates that it is equally susceptible to W. bancrofti as is the natural Cx. p. pipiens vector in the Nile Delta, however it is refractory to infection with Brugia spp. Here we report that the infectivity barrier for Brugia spp. in Cx. p. pipiens is the mosquito midgut, which inflicts internal and lethal damage to ingested microfilariae. Following per os Brugia exposures, the prevalence of infection is significantly lower in Cx. p. pipiens compared to susceptible mosquito controls, and differs between parasite species with <50% and <5% of Cx. p. pipiens becoming infected with B. pahangi and B. malayi, respectively. When Brugia spp. mf were inoculated intrathoracically to bypass the midgut, larvae developed equally well as in controls, indicating that, beyond the midgut, Cx. p. pipiens is physiologically compatible with Brugia spp. Mf isolated from Cx. p. pipiens midguts exhibited compromised motility, and unlike mf derived from blood or isolated from the midguts of Ae. aegypti, failed to develop when inoculated intrathoracically into susceptible mosquitoes. Together these data strongly support the role of the midgut as the primary infection barrier for Brugia spp. in Cx. p. pipiens. Examination of parasites recovered from the Cx. p. pipiens midgut by vital staining, and those exsheathed with papain, suggest that the damage inflicted by the midgut is subcuticular and disrupts internal tissues. Microscopic studies

  9. Winter biology of Culex pipiens quinquefasciatus say, (Diptera: Culicidae from Córdoba, Argentina

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    Walter R Almirón

    1996-10-01

    Full Text Available Adult cohorts and immature stages were kept under field conditions during the autumn and winter of three consecutive years. Survival, oviposition and development time from egg to adult were considered. The adult cohorts were studied under three experimental conditions: unfed cohorts, cohorts fed with sugar solution ansd cohorts fed with both sugar solution and blood (chicken. Female longevity showed significant differences among the three treatments. Females of unfed cohorts lived up to three weeks; females fed with sugar solution survived until six weeks, while those fed both with sugar and blood lived at most fourteen weeks; after the blood intake eggs were laid. In the immature stages, the highest relative mortality rates occurred during the egg and larval stages. Total pre-adult mortality varied between 59.09 and 89.71%. The developmental duration from egg to adult was between 43-62 days; there were no differences among results obtained for the three years.

  10. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

    Science.gov (United States)

    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

    Wolbachia pipientis, a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia-mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens, and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus, we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia-mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

  11. Multiple Insecticide Resistances in the Disease Vector Culex p. Quinquefasciatus from Western Indian Ocean

    Science.gov (United States)

    Pocquet, Nicolas; Milesi, Pascal; Makoundou, Patrick; Unal, Sandra; Zumbo, Betty; Atyame, Célestine; Darriet, Frédéric; Dehecq, Jean-Sébastien; Thiria, Julien; Bheecarry, Ambicadutt; Iyaloo, Diana P.; Weill, Mylène; Chandre, Fabrice; Labbé, Pierrick

    2013-01-01

    Several mosquito-borne diseases affect the Western Indian Ocean islands. Culex pipiens quinquefasciatus is one of these vectors and transmits filariasis, Rift Valley and West Nile viruses and the Japanese encephalitis. To limit the impact of these diseases on public health, considerable vector control efforts have been implemented since the 50s, mainly through the use of neurotoxic insecticides belonging to Organochlorines (OC), Organophosphates (OP) and pyrethroids (PYR) families. However, mosquito control failures have been reported on site, and they were probably due to the selection of resistant individuals in response to insecticide exposure. In this study, we used different approaches to establish a first regional assessment of the levels and mechanisms of resistance to various insecticides. Bioassays were used to evaluate resistance to various insecticides, enzyme activity was measured to assess the presence of metabolic resistances through elevated detoxification, and molecular identification of known resistance alleles was investigated to determine the frequency of target-site mutations. These complementary approaches showed that resistance to the most used insecticides families (OC, OP and PYR) is widespread at a regional scale. However, the distribution of the different resistance genes is quite heterogeneous among the islands, some being found at high frequencies everywhere, others being frequent in some islands and absent in others. Moreover, two resistance alleles displayed clinal distributions in Mayotte and La Réunion, probably as a result of a heterogeneous selection due to local treatment practices. These widespread and diverse resistance mechanisms reduce the capacity of resistance management through classical strategies (e.g. insecticide rotation). In case of a disease outbreak, it could undermine the efforts of the vector control services, as only few compounds could be used. It thus becomes urgent to find alternatives to control populations

  12. 淡色库蚊幼虫对7种杀虫剂的敏感性和抗性调查%Survey on the sensitivity and resistance of Culex pipiens pallens larva to seven kinds of insecticide

    Institute of Scientific and Technical Information of China (English)

    陈志龙; 陈东亚; 刘慧; 杨维芳; 褚宏亮; 刘大鹏; 张爱军; 徐燕; 孙俊

    2011-01-01

    Objective To investigate the resistance of Culex pipiens pallens larva to insecticides in Jiangsu Province and provide scientific evidence for control. Methods Larva immersion method. Results The lab population was the most susceptive with LC50 of 0.001 3 mg/L to deltamethrin, 0.003 8 mg/L to beta -cypermethrin, 0.027 7 mg/L to permethrin, 0. 181 3 mg/L to esbiothrin,0. 018 3 mg/L to DDVP, 0.096 8 mg/L to propoxur and 0. 000 4 mg/L to temephos. The highest resistance ratio of insecticide was 200 in Nanjing, Xuzhou, Lianyungang and Wuxi. Conclusion In Jiangsu Province C. pipens pallens have developed different resistance to DDVP, temephos, deltamethrin, beta - cypermethrin and propoxur. It is necessary to use the result of survey to prevent the resistance from developing.%目的 为了解江苏省淡色库蚊幼虫对卫生杀虫剂的敏感性和抗药性发生发展状况进行生物学抗性调查.方法 幼虫浸渍法.结果 实验室淡色库蚊幼虫对溴氰菊酯、高效氯氰菊酯、氯菊酯、生物丙烯菊酯、敌敌畏、残杀威和双硫磷幼虫敏感性LC50分别为0.001 3、0.003 8、0.027 7,0.181 3、0.018 3、0.096 8、0.000 4 mg/L.南京、徐州、连云港和无锡等地蚊虫幼虫抗性分别是敏感品系的数倍到200倍不等.结论 江苏省淡色库蚊幼虫对敌敌畏、双硫磷、溴氰菊酯、高效氯氰菊酯和残杀威等杀虫剂均产生不同程度的抗性.抗性调查的结果为指导江苏省蚊虫防治以及合理使用卫生杀虫剂提供科学依据.

  13. Asymmetric introgression between sympatric molestus and pipiens forms of Culex pipiens (Diptera: Culicidae in the Comporta region, Portugal

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    Côrte-Real Ana R

    2009-11-01

    Full Text Available Abstract Background Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground, a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group. Results Autogeny and stenogamy was evaluated in the F1 progeny of 145 individual Cx. pipiens females. Bayesian clustering analysis based on the genotypes of 13 microsatellites revealed two distinct genetic clusters that were highly correlated with the alternative traits that define pipiens and molestus. Admixture analysis yielded hybrid rate estimates of 8-10%. Higher proportions of admixture were observed in pipiens individuals suggesting that more molestus genes are being introgressed into the pipiens form than the opposite. Conclusion Both physiological/behavioural and genetic data provide evidence for the sympatric occurrence of molestus and pipiens forms of Cx. pipiens in the study area. In spite of the significant genetic differentiation between forms, hybridisation occurs at considerable levels. The observed pattern of asymmetric

  14. Emergence of resistance and resistance management in field populations of tropical Culex quinquefasciatus to the microbial control agent Bacillus sphaericus.

    Science.gov (United States)

    Mulla, Mir S; Thavara, Usavadee; Tawatsin, Apiwat; Chomposri, Jakkrawarn; Su, Tianyun

    2003-03-01

    In recent years, highly potent mosquitocidal strains of the microbial agent Bacillus sphaericus (Bsph) have been isolated and developed for the control of mosquito larvae around the world. Laboratory selection experiments with the most active strains and their use in large-scale operational mosquito control programs resulted in the emergence of resistance in larvae of the Culex pipiens complex. This generated great concern among vector control agencies around the world, who feared reduced efficacy of this highly active larvicidal agent. To address this issue, the current studies were started to find practical strategies for controlling resistant mosquitoes and more importantly to develop resistance management strategies that would prevent or delay development of resistance. We initiated field studies in 3 low-income communities in Nonthaburi Province, Thailand. In 1 of the communities, larvae of Culex quinquefasciatus that were highly resistant (>125,000-fold) to Bsph strain 2362 were successfully controlled with applications of Bacillus thuringiensis var. israelensis (Bti) alone or in combination with Bsph. To prevent or delay resistance to Bsph, 2 other sites were selected, 1 treated with Bsph 2362 alone and the other treated with a mixture of Bsph 2362 and Bti. Mosquitoes treated with Bsph 2362 alone showed some resistance by the 9th treatment and almost complete failure of control occurred by the 17th treatment. After 9 treatments with the mixture over a 9-month period at another site, no noticeable change in susceptibility to Bsph was detected. During this period, the site treated with Bsph alone required 19 treatments, whereas the site treated with mixtures took only 9 treatments because of slower resurgence of larvae at the site treated with the mixture than at the site treated with Bsph alone. This is the 1st field evidence for delay or prevention of resistance to microbial agents in larval Cx. quinquefasciatus by using mixtures of Bti and Bsph. Further

  15. Efficacy of female Culex quinquefasciatus with entomopathogenic fungus Fusarium pallidoroseum.

    Science.gov (United States)

    Mohanty, Suman Sundar; Raghavendra, Kamaraju; Rai, Usha; Dash, Aditya Prasad

    2008-06-01

    This study was conducted to isolate and identify natural entomopathogenic fungi from female Culex quinquefasciatus and to test their adulticidal activity. Field-collected female C. quinquefasciatus died early and were placed on a Saboraud's dextrose agar plates for growth and isolation of natural entomopathogenic fungi. The plates were maintained in an incubator at 24+/-2 degrees C for 3 days. Four fungal species were isolated in two genera namely, Aspergillus and Fusarium. The identified fungal species were A. niger, A. flavus, A. nidulans var acristatus (ITCC-6327.04), and F. pallidoroseum (ITCC-6324.06). Adult bioassays were carried out using spore-impregnated paper in WHO-holding tubes. F. pallidoroseum was found to be more effective than the others. Exposure of C. quinquefasciatus to spores of A. flavus and A. niger for 4 h caused 5.53% and 5.51% mortality in the mosquitoes within a week, respectively. All the female C. quinquefasciatus were killed within 4 days of exposure to F. pallidoroseum at a concentration of 1.11 x 10(10) conidia per m2. Significant difference of longevity was observed between the F. pallidoroseum-treated C. quinquefasciatus and control mosquitoes. The LT50 of F. pallidoroseum was 2.08 days for 4 h exposure to C. quinquefasciatus. Results of the present study confirm that F. pallidoroseum is one of the alternative biological control agents of adult mosquitoes.

  16. Repellent activity of five essential oils against Culex pipiens.

    Science.gov (United States)

    Erler, F; Ulug, I; Yalcinkaya, B

    2006-12-01

    Essential oils extracted from the seeds of anise (Pimpinella anisum), dried fruits of eucalyptus (Eucalyptus camaldulensis), dried foliage of mint (Mentha piperita) and basil (Ocimum basilicum) and fresh foliage of laurel (Laurus nobilis) were tested for their repellency against the adult females of Culex pipiens. All essential oils showed repellency in varying degrees, eucalyptus, basil and anise being the most active.

  17. Avian host-selection by Culex pipiens in experimental trials.

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    Jennifer E Simpson

    Full Text Available Evidence from field studies suggests that Culex pipiens, the primary mosquito vector of West Nile virus (WNV in the northeastern and north central United States, feeds preferentially on American robins (Turdus migratorius. To determine the contribution of innate preferences to observed preference patterns in the field, we conducted host preference trials with a known number of adult female C. pipiens in outdoor cages comparing the relative attractiveness of American robins with two common sympatric bird species, European starling, Sternus vulgaris and house sparrow, Passer domesticus. Host seeking C. pipiens were three times more likely to enter robin-baited traps when with the alternate host was a European starling (n = 4 trials; OR = 3.06; CI [1.42-6.46] and almost twice more likely when the alternative was a house sparrow (n = 8 trials; OR = 1.80; CI = [1.22-2.90]. There was no difference in the probability of trap entry when two robins were offered (n = 8 trials. Logistic regression analysis determined that the age, sex and weight of the birds, the date of the trial, starting-time, temperature, humidity, wind-speed and age of the mosquitoes had no effect on the probability of a choosing a robin over an alternate bird. Findings indicate that preferential feeding by C. pipiens mosquitoes on certain avian hosts is likely to be inherent, and we discuss the implications innate host preferences may have on enzootic WNV transmission.

  18. Experimental investigation of the susceptibility of Italian Culex pipiens mosquitoes to Zika virus infection.

    Science.gov (United States)

    Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia

    2016-09-01

    We investigated the susceptibility of an Italian population of Culex pipiens mosquitoes to Zika virus (ZIKV) infection, tested in parallel with Aedes aegypti, as a positive control. We analysed mosquitoes at 0, 3, 7, 10, 14, 20 and 24 days after an infectious blood meal. Viral RNA was detected in the body of Cx. pipiens up to three days post-infection, but not at later time points. Our results indicate that Cx. pipiens is not susceptible to ZIKV infection.

  19. Experimental investigation of the susceptibility of Italian Culex pipiens mosquitoes to Zika virus infection

    Science.gov (United States)

    Boccolini, Daniela; Toma, Luciano; Di Luca, Marco; Severini, Francesco; Romi, R; Remoli, Maria Elena; Sabbatucci, Michela; Venturi, Giulietta; Rezza, Giovanni; Fortuna, Claudia

    2016-01-01

    We investigated the susceptibility of an Italian population of Culex pipiens mosquitoes to Zika virus (ZIKV) infection, tested in parallel with Aedes aegypti, as a positive control. We analysed mosquitoes at 0, 3, 7, 10, 14, 20 and 24 days after an infectious blood meal. Viral RNA was detected in the body of Cx. pipiens up to three days post-infection, but not at later time points. Our results indicate that Cx. pipiens is not susceptible to ZIKV infection. PMID:27605056

  20. Culex pipiens forms and urbanization: effects on blood feeding sources and transmission of avian Plasmodium.

    Science.gov (United States)

    Martínez-de la Puente, Josué; Ferraguti, Martina; Ruiz, Santiago; Roiz, David; Soriguer, Ramón C; Figuerola, Jordi

    2016-12-08

    The wide spread mosquito Culex pipiens pipiens have two forms molestus and pipiens which frequently hybridize. The two forms have behavioural and physiological differences affecting habitat requirements and host selection, which may affect the transmission dynamic of Cx. p. pipiens-borne diseases. During 2013, blood engorged Cx. p. pipiens mosquitoes were captured in urban, rural and natural areas from Southern Spain. In 120 mosquitoes, we identified the blood meal origin at vertebrate species/genus level and the mosquito form. The presence and molecular lineage identity of avian malaria parasites in the head-thorax of each mosquito was also analysed. Mosquitoes of the form pipiens were more frequently found in natural than in urban areas. The proportion of Cx. pipiens form molestus and hybrids of the two forms did not differ between habitat categories. Any significant difference in the proportion of blood meals on birds between forms was found. Birds were the most common feeding source for the two forms and their hybrids. Among mammals, dogs and humans were the most common hosts. Two Plasmodium and one Haemoproteus lineages were found in mosquitoes, with non-significant differences between forms. This study supports a differential distribution of Cx. p. pipiens form pipiens between urban and natural areas. Probably due to the similar feeding sources of both mosquito forms and their hybrids here, all of them may frequently interact with avian malaria parasites playing a role in the transmission of Plasmodium.

  1. Mitotic activity in dorsal epidermis of Rana pipiens.

    Science.gov (United States)

    Garcia-Arce, H.; Mizell, S.

    1972-01-01

    Study of statistically significant rhythms of mitotic division in dorsal epidermis of frogs, Rana pipiens, exposed to a 12:12 light:dark environment for 14 days. The results include the findings that (1) male animals have a primary period of 22 hr in summer and 18 hr in winter, (2) female animals have an 18 hr period, and (3) parapinealectomy and blinding abolish the rhythm.

  2. Cloning and characterization of two glutathione S-transferases from pyrethroid resistant Culex pipiens

    Science.gov (United States)

    Samra, Aman I; Kamita, Shizuo G; Yao, Hong-Wei; Cornel, Anthony J; Hammock, Bruce D

    2013-01-01

    BACKGROUND The Marin strain of Culex pipiens Say is a pyrethroid-resistant population that was collected in Marin County, California, in 2001 and subsequently maintained in the laboratory under regular permethrin exposure. RESULTS In this study, two genes, CpGSTd1 and CpGSTd2, encoding glutathione S-transferase (GST) were cloned from Cx. pipiens Marin. Phylogenetic analysis of the deduced amino acid sequences, CpGSTD1 and CpGSTD2, of these genes indicated that they belong to the Delta class of insect GSTs. The nucleotide and deduced amino acid sequences of CpGSTd1 and CpGSTd2 were 59% and 48% identical, respectively. CpGSTD1 and CpGSTD2 were expressed in Escherichia coli and purified by affinity chromatography. The recombinant GSTs exhibited unique selectivity towards the general GST substrates CDNB and DCNB, and also differed in their sensitivity to known inhibitors of GSTs. CpGSTD1 exhibited peroxidase activity with cumene hydroperoxide, while CpGSTD2 appeared to lack this activity. CpGSTD1 was able to metabolize DDT, while DDT metabolism by CpGSTD2 was not detectable. CpGSTD1 and CpGSTD2 showed no detectable metabolism of permethrin. Gene expression of CpGSTd1 and CpGSTd2 in Marin mosquitoes was elevated by about 2-fold in comparison to that found in a pyrethroid-sensitive mosquito strain. CONCLUSION Our results indicated that CpGSTD1 and CpGSTD2 have unique biochemical characteristics but they did not appear to play major roles in permethrin resistance in Marin mosquitoes. PMID:22290868

  3. Host choice and West Nile virus infection rates in blood-fed mosquitoes, including members of the Culex pipiens complex, from Memphis and Shelby County, Tennessee, 2002-2003.

    Science.gov (United States)

    Savage, Harry M; Aggarwal, Deepak; Apperson, Charles S; Katholi, Charles R; Gordon, Emily; Hassan, Hassan K; Anderson, Michael; Charnetzky, Dawn; McMillen, Larry; Unnasch, Emily A; Unnasch, Thomas R

    2007-01-01

    The source of bloodmeals in 2,082 blood-fed mosquitoes collected from February 2002 through December 2003 in Memphis and surrounding areas of Shelby County, Tennessee were determined. Members of the genus Culex and Anopheles quadrimaculatus predominated in the collections. Members of the Cx. pipiens complex and Cx. restuans were found to feed predominately upon avian hosts, though mammalian hosts made up a substantial proportion of the bloodmeals in these species. No significant difference was seen in the host class of bloodmeals in mosquitoes identified as Cx. pipiens pipiens, Cx. p. quinquefasciatus, or hybrids between these two taxa. Anopheles quadrimaculatus and Cx. erraticus fed primarily upon mammalian hosts. Three avian species (the American Robin, the Common Grackle, and the Northern Cardinal) made up the majority of avian-derived bloodmeals, with the American Robin representing the most frequently fed upon avian host. An analysis of these host feeding data using a modification of a transmission model for Eastern Equine encephalitis virus suggested that the American Robin and Common Grackle represented the most important reservoir hosts for West Nile virus. A temporal analysis of the feeding patterns of the dominant Culex species did not support a shift in feeding behavior away from robins to mammals late in the summer. However, a significant degree of temporal variation was noted in the proportion of robin-derived bloodmeals when the data were analyzed by semi-monthly periods throughout the summers of 2002 and 2003. This pattern was consistent with the hypothesis that the mosquitoes were preferentially feeding upon nesting birds.

  4. Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon

    Directory of Open Access Journals (Sweden)

    Osta Mike A

    2012-07-01

    Full Text Available Abstract Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the

  5. Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon

    Science.gov (United States)

    2012-01-01

    Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester) and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the Ester2 allele, which exhibits

  6. Larvicidal activity of leguminous seeds and grains against Aedes aegypti and Culex pipiens pallens.

    Science.gov (United States)

    Jang, Young-Su; Baek, Bong-Rae; Yang, Young-Cheol; Kim, Moo-Key; Lee, Hoi-Seon

    2002-09-01

    Larvicidal activity of methanol extracts of 26 leguminous seeds and 20 grains against early 4th-stage larvae of Aedes aegypti and Culex pipiens pallens was examined. At 200 ppm of the extracts from Cassia obtusifolia, Cassia tora, and Vicia tetrasperma, more than 90% mortality was obtained in larvae of Ae. aegypti and Cx. pipiens pallens. Extract of C. tora gave 86.7 and 100% mortality in the larvae of Ae. aegypti and Cx. pipiens pallens at 40 ppm but 59.2 and 78.3% mortality against larvae of Ae. aegypti and Cx. pipiens pallens at 20 ppm, respectively. At 40 ppm, extract of C. obtusifolia caused 51.4 and 68.5% mortality of the 4th-stage larvae of Ae. aegypti and Cx. pipiens pallens, respectively. Larvicidal activity of extract of C obtusifolia was significantly reduced when used at 20 ppm. Further studies of these plants as possible agents for mosquito control are warranted.

  7. Toxicities of Organophosphate and Carbamat Insecticide Against Culex quinquefasciatus Mosquito Larvae

    OpenAIRE

    Endang Puji Astuti; Yuneu Yuliasih; Titin Delia; Marliah Santi

    2009-01-01

    Culex quinquefasciatus mosquito is increasing problem of public health, being the vector responsible for West Nile Virus and Filariasis. Chlorpirifos (Organofosfat) and Metonil (Carbamat) were known to posses insecticide activity against insect. The study was aimed to examine effectiveness of Klorpirifos and Metonil as larvicide against C. quinquefasciatus larval. Chlorpirifos a significantly higher larvicidal activity against 3th-4th instar larvae of C. quinquefasciatus than Metonil. The lar...

  8. Identification and Expression Profile of Multiple Genes in Response to Magnesium Exposure in Culex quinquefasciatus Larvae

    Science.gov (United States)

    2010-11-01

    reaction. Target transcripts up/downregulated by magnesium included Cx. quinquefasciatus troponin C, isocitrate dehydrogenase , allergen, cytochrome b5...partial mRNA, length 1,421 nt: 1146Ð767, nt: 1187Ð720 1AB-5 ref XM_001844978.1 Cx. quinquefasciatus isocitrate dehydrogenase partial mRNA, length 1,303...XM_001845150.1 Cx. quinquefasciatus aldehyde dehydrogenase , mRNA, length 1,499 nt: 927Ð1274 1B-10 ref XM_001841858.1 Cx. quinquefasciatus isocitrate

  9. Plasmodium relictum (lineages pSGS1 and pGRW11): complete synchronous sporogony in mosquitoes Culex pipiens pipiens.

    Science.gov (United States)

    Kazlauskienė, Rita; Bernotienė, Rasa; Palinauskas, Vaidas; Iezhova, Tatjana A; Valkiūnas, Gediminas

    2013-04-01

    Plasmodium relictum is a widespread invasive agent of avian malaria, responsible for acute, chronic and debilitating diseases in many species of birds. Recent PCR-based studies revealed astonishing genetic diversity of avian malaria parasites (genus Plasmodium), with numerous genetic lineages deposited in GenBank. Many studies addressed distribution and evolutionary relationships of avian Plasmodium lineages, but information about patterns of development of different lineages in mosquito vectors remains insufficient. Here we present data on sporogonic development of 2 widespread mitochondrial cytochrome b lineages (cyt b) of P. relictum (pSGS1 and pGRW11) in mosquito Culex pipiens pipiens. Genetic distance between these lineages is 0.2%; they fall in a well-supported clade in the phylogenetic tree. Three P. relictum strains were isolated from common crossbill (Loxia curvirostra, lineage pSGS1), domestic canary (Serinus canaria domestica, pSGS1) and house sparrow (Passer domesticus, pGRW11). These strains were multiplied in domestic canaries and used as donors of malarial gametocytes to infect C. p. pipiens. Mosquitoes were allowed to take blood meal on infected canaries and then dissected on intervals to study development of sporogonic stages. All 3 strains developed synchronously and completed sporogony in this vector, with infective sporozoites reported in the salivary glands on the day 14 after infection. Ookinetes, oocysts and sporozoites of all strains were indistinguishable morphologically. This study shows that patterns of sporogonic development of the closely related lineages pSGS1 and pGRW11 and different strains of the lineage pSGS1 of P. relictum are similar indicating that phylogenetic trees based on the cyt b gene likely can be used for predicting sporogonic development of genetically similar avian malaria lineages in mosquito vectors. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Lectin Activity in Gut Extract of Culex pipiens.

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-06-01

    Full Text Available The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens.Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  11. Lectin Activity in Gut Extract of Culex pipiens

    Science.gov (United States)

    Koosha, Mona; Abai, Mohammad Reza; Abolhasani, Mandan; Charedar, Soroor; Basseri, Hamid Reza

    2013-01-01

    Background: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. Methods: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and unfed) were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups). Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+) glucose, D (+) galactose, D (+) mannose, D (−) fructose, D (−) arabinose, L (−) fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin. Results: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose. Conclusion: The secretion of hemagglutinins (lectins or lectin-like molecules) in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins. PMID:23785692

  12. Acid exposure is an immune disruptor in adult Rana pipiens.

    Science.gov (United States)

    Vatnick, Itzick; Andrews, Jaime; Colombo, Matthew; Madhoun, Hareth; Rameswaran, Muthuramanan; Brodkin, Marc A

    2006-01-01

    Acidic environments are physiological stressors for amphibians. The objective of the present study was to document the effect of an acidic environment on innate immune system function under controlled experimental conditions in Rana pipiens. We developed an in vivo assay, by injecting a suspension of 1-microm fluorescent beads in fluid thioglycollate, to induce peritonitis. The number of peritoneal exudate leukocytes and their phagocytic activity did not increase with thioglycollate injection when frogs were exposed to pH 5.5 compared to when frogs were exposed to pH 7.0. An environment of pH 5.5 disrupted the inflammatory response of frogs compared to an environment of pH 7.0; at pH 5.5, more nonphagocytic leukocytes and fewer highly phagocytic leukocytes were found compared to those in frogs exposed to pH 7.0. Frogs stimulated by thioglycollate injection and exposed to pH 5.5 had a 50% increase in cells that did not exhibit phagocytosis and a 4- to 10-fold reduction in the number of highly phagocytic cells. This is evidence that acid exposure functions as an immune disruptor in adult R. pipiens under laboratory conditions.

  13. Efficacy of fipronil combined with permethrin commercial spot on (Effitix) preventing Culex pipiens from feeding on dogs.

    Science.gov (United States)

    Franc, Michel; Lienard, Emmanuel; Jacquiet, Philippe; Bonneau, Stephane; Bouhsira, Emilie

    2015-06-01

    A controlled clinical trial was carried out to assess the adulticidal and anti-feeding effectiveness of a spot-on combining fipronil and permethrin (Effitix, Virbac, Carros, France) in preventing Culex pipiens from feeding on dogs. Twelve dogs with equal sensitivity to mosquitoes were included in the study and divided into two groups of six dogs: an untreated control group and a group treated with Effitix. All dogs were challenged with 80 females C. pipiens for 90 ± 5 min on days -7, 1, 7, 14, 21, and 28 (day 0 being treatment day). The number of engorged, dead, and live mosquitoes was determined after each exposure to treated and untreated dogs. Dead mosquitoes were also counted 24 h after exposure. The anti-feeding effect of the spot-on formulation was 100, 99.5, 97.7, 98.3, and 96.7% on days 1, 7, 14, 21, and 28, respectively. The mortality effect was 66.6, 55.9, 38, 17.2, and 12.3% on days 1, 7, 14, 21, and 28, respectively. At each challenge point, the mortality and anti-feeding effects on mosquitoes were significantly different between the control and treated group (p < 0.05). The results indicate that a combination of permethrin and fipronil could be used as an effective mosquito control strategy in dogs and is therefore recommended for use in a dirofilariasis prevention program.

  14. Identification of differentially expressed microRNAs in Culex pipiens and their potential roles in pyrethroid resistance.

    Science.gov (United States)

    Hong, Shanchao; Guo, Qin; Wang, Weijie; Hu, Shengli; Fang, Fujin; Lv, Yuan; Yu, Jing; Zou, Feifei; Lei, Zhentao; Ma, Kai; Ma, Lei; Zhou, Dan; Sun, Yan; Zhang, Donghui; Shen, Bo; Zhu, Changliang

    2014-12-01

    Pyrethroids are the major class of insecticides used for mosquito control. Excessive and improper use of insecticides, however, has resulted in pyrethroid resistance, which has become a major obstacle for mosquito control. The development of pyrethroid resistance is a complex process involving many genes, and information on post-transcription regulation of pyrethroid resistance is lacking. In this study, we extracted RNA from mosquitoes in various life stages (fourth-instar larvae, pupae, male and female adult mosquitoes) from deltamethrin-sensitive (DS) and resistant (DR) strains. Using illumina sequencing, we obtained 13760296 and 12355472 reads for DS-strains and DR-strains, respectively. We identified 100 conserved miRNAs and 42 novel miRNAs derived from 21 miRNA precursors in Culex pipiens. After normalization, we identified 28 differentially expressed miRNAs between the two strains. Additionally, we found that cpp-miR-71 was significant down regulated in female adults from the DR-strain. Based on microinjection and CDC Bottle Bioassay data, we found that cpp-miR-71 may play a contributing role in deltamethrin resistance. The present study provides the firstly large-scale characterization of miRNAs in Cu. pipiens and provides evidence of post-transcription regulation. The differentially expressed miRNAs between the two strains are expected to contribute to the development of pyrethroid resistance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Toxicities of Organophosphate and Carbamat Insecticide Against Culex quinquefasciatus Mosquito Larvae

    Directory of Open Access Journals (Sweden)

    Endang Puji Astuti

    2009-06-01

    Full Text Available Culex quinquefasciatus mosquito is increasing problem of public health, being the vector responsible for West Nile Virus and Filariasis. Chlorpirifos (Organofosfat and Metonil (Carbamat were known to posses insecticide activity against insect. The study was aimed to examine effectiveness of Klorpirifos and Metonil as larvicide against C. quinquefasciatus larval. Chlorpirifos a significantly higher larvicidal activity against 3th-4th instar larvae of C. quinquefasciatus than Metonil. The larval mortality was observed after 24-h exposure. The LC95 value of Chlorpirifos and Metonil were 3,139 mg/lt and 9,045 mg/lt, against C. quinquefasciatus. The mixed of both insecticide was LC95 value 2,823 mg/lt. The result of this study suggested that Chlorpirifos more effective larvicide against C. quinquefasciatus than Metonil.

  16. The Developmental Effects Of A Municipal Wastewater Effluent On The Northern Leopard Frog, Rana pipiens

    Science.gov (United States)

    Wastewater effluents are complex mixtures containing a variety of anthropogenic compounds, many of which are known endocrine disruptors. In order to characterize the development and behavorial effects of such a complex mixture, northern leopard frogs, Rana pipiens, were e...

  17. Genetic diversity of Wolbachia endosymbionts in Culex quinquefasciatus from Hawai`i, Midway Atoll, and Samoa

    Science.gov (United States)

    Atkinson, Carter T.; Watcher-Weatherwax, William; Lapointe, Dennis

    2016-01-01

    Incompatible insect techniques are potential methods for controlling Culex quinquefasciatus and avian disease transmission in Hawai‘i without the use of pesticides or genetically modified organisms. The approach is based on naturally occurring sperm-egg incompatibilities within the Culex pipiens complex that are controlled by different strains of the bacterial endosymbiont Wolbachia pipientis (wPip). Incompatibilities can be unidirectional (crosses between males infected with strain A and females infected with strain B are fertile, while reciprocal crosses are not) or bidirectional (reciprocal crosses between sexes with different wPip strains are infertile). The technique depends on release of sufficient numbers of male mosquitoes infected with an incompatible wPip strain to suppress mosquito populations and reduce transmission of introduced avian malaria (Plasmodium relictum) and Avipoxvirus in native forest bird habitats. Both diseases are difficult to manage using more traditional methods based on removal and treatment of larval habitats and coordination of multiple approaches may be needed to control this vector. We characterized the diversity of Wolbachia strains in C. quinquefasciatus from Hawai‘i, Kaua‘i, Midway Atoll, and American Samoa with a variety of genetic markers to identify compatibility groups and their distribution within and between islands. We confirmed the presence of wPip with multilocus sequence typing, tested for local genetic variability using 16 WO prophage genes, and identified similarities to strains from other parts of the world with a transposable element (tr1). We also tested for genetic differences in ankyrin motifs (ank2 and pk1) which have been used to classify wPip strains into five worldwide groups (wPip1–wPip5) that vary in compatibility with each other based on experimental crosses. We found a mixture of both widely distributed and site specific genotypes based on presence or absence of WO prophage and transposable

  18. Dieldrin-resistance in Culex pipiens fatigans in Malaya

    Science.gov (United States)

    Wharton, R. H.

    1958-01-01

    Resistance to insecticides in Culex pipiens fatigans has already been reported from two areas in Malaya. In Penang two years' use of BHC as a larvicide resulted in the development of a strain which was found to have acquired a tenfold resistance to BHC, and also to dieldrin to which it had not been exposed. In Singapore, when larval control became unsatisfactory after 6 months' use of a dieldrin emulsion, laboratory experiments confirmed that active resistance to dieldrin had developed. The present observations report the finding of two further dieldrin-BHC resistant strains of C. p. fatigans in Malaya, but differ from the previous reports in that resistance, in one strain at least, was developed as a result of house-spraying with dieldrin against adult mosquitos. In this strain resistance to dieldrin was about 100 times in both adults and larvae, resistance to gamma-BHC in larvae was about 20 times, while resistance to DDT was slight. PMID:13536808

  19. The Culex pipiens complex in continental Portugal: distribution and genetic structure.

    Science.gov (United States)

    Gomes, Bruno; Parreira, Ricardo; Sousa, Carla A; Novo, Maria T; Almeida, António P G; Donnelly, Martin J; Pinto, João

    2012-12-01

    Portugal is a southern European country that displays favorable ecological conditions for the establishment of West Nile virus (WNV) transmission cycles. Competent mosquito vector species are present throughout the country. Among the species with reported cases of WNV isolation in Portugal, Culex pipiens is the most ubiquitous and abundant mosquito. This species exhibits two biological forms with differences in host preferences. The molestus form has a greater tendency to feed upon humans and other mammals whereas the pipiens form prefers avian hosts. In northern latitudes, both forms are physically separated, with molestus occupying underground habitats and pipiens being found aboveground. However, the warmer climatic conditions of southern regions such as Portugal may favor the sympatric occurrence of both forms hence promoting interform hybridization. Genetic introgression between molestus and pipiens forms may result in a higher propensity for admixed populations to serve as bridge-vectors of WNV between humans and birds. Here we revise our present knowledge on the distribution, role in WNV transmission and genetic structure of the Cx. pipiens complex in continental Portugal. We focus on recent findings of sympatric molestus and pipiens populations that display considerable levels of hybridization and discuss the epidemiological repercussions of this occurrence.

  20. Lectin Activity in Gut Extract of Culex Pipiens

    Directory of Open Access Journals (Sweden)

    Mona Koosha

    2013-03-01

    Full Text Available Background: The role of lectins is important in interaction between pathogens and mosquito vectors. This study was performed to identify agglutinin activities of protein molecules on the midgut of Culex pipiens. Methods: Culex pipiens was reared in insectray condition and the midguts of males and females (blood fed and un­fed were dissected separately in Tris-HCl buffer. The extracts of midguts were applied for hemagglutinin assay against red blood cells of rabbit, mouse, rat, dog, horse, sheep, guinea pig, cow, human (A, B, AB, O groups. Then, the RBCs with relatively high agglutinin activity were chosen for carbohydrate inhibition assay. D (+ glucose, D (+ galactose, D (+ mannose, D (- fructose, D (- arabinose, L (- fucose, lactose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, sialic acid were used to specify carbohydrate binding lectin.Results: The highest agglutinin activities were found against sheep and rabbits RBCs. Sexual diversity of agglutinin activities was observed among midgut extraction of males and females. In addition, variation in agglutinin activity of blood fed and unfed female mosquitoes were detected. The lectin activity was inhibited highly with glucose, galactose, fucose and fructose but less inhibitor activities was observed by arabinose, N-acetyl-D-galactosamine, n-acetyl-d-glucosamine, lactose and mannose.Conclusion: The secretion of hemagglutinins (lectins or lectin-like molecules in the digestive system depends on the type of food in the gut. This suggests that emptying of the gut in preparation for protein rich food probably starts the secretion of hemagglutinins.

  1. Midgut Microbial Community of Culex quinquefasciatus Mosquito Populations from India

    Science.gov (United States)

    Chandel, Kshitij; Mendki, Murlidhar J.; Parikh, Rasesh Y.; Kulkarni, Girish; Tikar, Sachin N.; Sukumaran, Devanathan; Prakash, Shri; Parashar, Brahma D.; Shouche, Yogesh S.; Veer, Vijay

    2013-01-01

    The mosquito Culex quinquefasciatus is a ubiquitous species that serves as a major vector for west nile virus and lymphatic filariasis. Ingestion of bloodmeal by females triggers a series of physiological processes in the midgut and also exposes them to infection by these pathogens. The bacteria normally harbored in the midgut are known to influence physiology and can also alter the response to various pathogens. The midgut bacteria in female Cx. quinquefasciatus mosquitoes collected over a large geographical area from India was studied. Examination of 16S ribosomal DNA amplicons from culturable microflora revealed the presence of 83 bacterial species belonging to 31 bacterial genera. All of these species belong to three phyla i.e. Proteobacteria, Firmicutes and Actinobacteria. Phylum Proteobacteria was the most dominant phylum (37 species), followed by Firmicutes (33 species) and Actinobacteria (13 species). Phylum Proteobacteria, was dominated by members of γ-proteobacteria class. The genus Staphylococcus was the largest genus represented by 11 species whereas Enterobacter was the most prevalent genus and recovered from all the field stations except Leh. Highest bacterial prevalence was observed from Bhuj (22 species) followed by Nagrota (18 species), Masimpur (18 species) and Hathigarh (16 species). Whereas, least species were observed from Leh (8 species). It has been observed that individual mosquito harbor extremely diverse gut bacteria and have very small overlap bacterial taxa in their gut. This variation in midgut microbiota may be one of the factors responsible for variation in disease transmission rates or vector competence within mosquito population. The present data strongly encourage further investigations to verify the potential role of the detected bacteria in mosquito for the transmission of lymphatic filariasis and west nile virus. To the best of our knowledge this is the first study on midgut microbiota of wild Cx. quinquefasciatus from over a

  2. Catepsinas B vitelolíticas de Culex quinquefasciatus.

    OpenAIRE

    Alexandre Santos de Moura

    2014-01-01

    Apesar de Culex quinquefasciatus ser um eficiente vetor de doenças tais como a filariose linfática, febre do Nilo Ocidental e outras várias neuroviroses, poucas pesquisas sobre sua fisiologia têm sido conduzidas. Como em todos os animais ovíparos, o desenvolvimento embrionário dos mosquitos depende da degradação dos nutrientes armazenados no ovo, sendo a catepsina B uma protease que tem sido identificada e caracterizada em vários insetos como envolvida nesta função. Neste trabalho identificam...

  3. Dynamics of Aedes aegypti and Culex quinquefasciatus in septic tanks.

    Science.gov (United States)

    Mackay, Andrew J; Amador, Manuel; Diaz, Annette; Smith, Josh; Barrera, Roberto

    2009-12-01

    Aedes aegypti and Culex quinquefasciatus were found in large numbers emerging from septic tanks in southern Puerto Rico during the dry season. Previous studies suggested that Ae. aegypti uses subterranean aquatic habitats only during dry periods when surface containers do not have water. This research investigated whether septic tanks are alternative aquatic habitats that this mosquito uses during unfavorable times of the year, or whether Ae. aegypti uses this aquatic habitat throughout the year. To assess temporal change, exit traps were used to collect mosquitoes emerging from septic tanks in Playa/Playita, southern Puerto Rico, from November 2006 to October 2007. We also investigated the hypotheses that (1) the production of Ae. aegypti in septic tanks was larger than in surface containers and (2) adult mosquitoes emerging from septic tanks were larger than those emerging from surface containers. This study demonstrated that unsealed septic tanks produced large numbers of Ae. aegypti and Cx. quinquefasciatus throughout the year, without any significant relationship with rainfall. The number of adult Ae. aegypti emerging per day from septic tanks in each community was 3 to 9 times larger than those produced in surface containers. It was also demonstrated that Ae. aegypti emerging from septic tanks were significantly larger than those emerging from surface container habitats. It is recommended that dengue prevention programs include regular inspection and maintenance of septic tanks in communities lacking sewerage.

  4. Evaluation of Insecticide Resistance and Biochemical Mechanisms in a Population of Culex quinquefasciatus (Diptera: Culicidae from São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Bracco José Eduardo

    1999-01-01

    Full Text Available To establish an insecticidal resistance surveillance program, Culex quinquefasciatus mosquitoes from São Paulo, Brazil, were colonized (PIN95 strain and analyzed for levels of resistance. The PIN95 strain showed low levels of resistance to organophosphates [malathion (3.3-fold, fenitrothion (11.2-fold] and a carbamate [propoxur (3.0-fold]. We also observed an increase of 7.4 and 9.9 in a and b esterase activities, respectively, when compared with the reference IAL strain. An alteration in the sensitivity of acetylcholinesterase to insecticide inhibition was also found in the PIN95 mosquitoes. The resistant allele (Ace.1R, however, was found at low frequencies (0.12 and does not play an important role in the described insecticide resistance. One year later, Cx. quinquefasciatus mosquitoes were collected (PIN96 strain at the same site and compared to the PIN95 strain. The esterase activity patterns observed for the PIN96 strain were similar to those of the PIN95 mosquitoes. However the occurrence of the Ace.1R allele was statistically higher in the PIN96 strain. The results show that esterase-based insecticide resistance was established in the PIN95 Cx. quinquefasciatus population and that an acethylcholinesterase based resistant mechanism has been selected for. A continuous monitoring of this phenomenon is fundamental for rational mosquito control and insecticide application programs.

  5. Testing of UK Populations of Culex pipiens L. for Schmallenberg Virus Vector Competence and Their Colonization.

    Directory of Open Access Journals (Sweden)

    Robyn Manley

    Full Text Available Schmallenberg virus (SBV, an arboviral pathogen of ruminants, emerged in northern Europe during 2011 and has subsequently spread across a vast geographic area. While Culicoides biting midges (Diptera: Ceratopogonidae have been identified as a biological transmission agent of SBV, the role of mosquitoes (Diptera: Culicidae as potential vectors has not been defined beyond small-scale field collections in affected areas. Culex pipiens L. are one of the most widespread mosquitoes in northern Europe; they are present on farms across the region and have previously been implicated as vectors of several other arboviruses. We assessed the ability of three colony lines of Cx. pipiens, originating from geographically diverse field populations, to become fully infected by SBV using semi-quantitative real-time RT-PCR (sqPCR.Two colony lines of Cx. pipiens were created in the UK ('Brookwood' and 'Caldbeck' from field collections of larvae and pupae and characterised using genetic markers. A third strain of Cx. pipiens from CVI Wageningen, The Netherlands, was also screened during experiments. Intrathoracic inoculation of the Brookwood line resulted in infections after 14 days that were characterised by high levels of RNA throughout individuals, but which demonstrated indirect evidence of salivary gland barriers. Feeding of 322 individuals across the three colony lines on a membrane based infection system resulted in no evidence of full dissemination of SBV, although infections did occur in a small proportion of Cx. pipiens from each line.This study established two novel lines of Cx. pipiens mosquitoes of UK origin in the laboratory and subsequently tested their competence for SBV. Schmallenberg virus replication and dissemination was restricted, demonstrating that Cx. pipiens is unlikely to be an epidemiologically important vector of the virus in northern Europe.

  6. Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil.

    Science.gov (United States)

    Barbosa, Rosângela Maria Rodrigues; Regis, Lêda Narcisa

    2011-06-01

    The use of attractants and larvicides in oviposition traps is of practical interest for the surveillance and control of urban mosquitoes. In addition to increasing the safety of the traps, this combination is essential for an attract-and-kill control strategy based on trapping mosquito eggs. The combination of Bacillus thuringiensis var. israelensis (Bti) and grass infusion (GI) vs. GI alone were tested for their ability to attract in paired BR-OVT traps in the backyards of 10 houses in Recife, Brazil, for a period of 45 days. Results show that females prefer to oviposit in traps containing Bti (363 compared with 251 egg rafts over 45 days). Results from a one-year trial on the efficacy of BR-OVT traps loaded with GI and Bti as a sampling tool to monitor temporal fluctuations in the population densities of Culex quinquefasciatus in an urban environment are also reported. From December 2006-January 2007, one trap per home was installed and maintained for 348 consecutive days in 134-151 houses located in three urban blocks. Throughout the one-year field trial a total of 43,151 Culex egg rafts were collected in the traps. The data show that BR-OVT loaded with GI and Bti is sensitive enough to demonstrate continuous reproductive activity of Cux. quinquefasciatus in the study area throughout the year and to monitor temporal fluctuations in population density.

  7. Monitoring temporal fluctuations of Culex quinquefasciatus using oviposition traps containing attractant and larvicide in an urban environment in Recife, Brazil

    Directory of Open Access Journals (Sweden)

    Rosângela Maria Rodrigues Barbosa

    2011-06-01

    Full Text Available The use of attractants and larvicides in oviposition traps is of practical interest for the surveillance and control of urban mosquitoes. In addition to increasing the safety of the traps, this combination is essential for an attract-and-kill control strategy based on trapping mosquito eggs. The combination of Bacillus thuringiensis var. israelensis (Bti and grass infusion (GI vs. GI alone were tested for their ability to attract in paired BR-OVT traps in the backyards of 10 houses in Recife, Brazil, for a period of 45 days. Results show that females prefer to oviposit in traps containing Bti (363 compared with 251 egg rafts over 45 days. Results from a one-year trial on the efficacy of BR-OVT traps loaded with GI and Bti as a sampling tool to monitor temporal fluctuations in the population densities of Culex quinquefasciatus in an urban environment are also reported. From December 2006-January 2007, one trap per home was installed and maintained for 348 consecutive days in 134-151 houses located in three urban blocks. Throughout the one-year field trial a total of 43,151 Culex egg rafts were collected in the traps. The data show that BR-OVT loaded with GI and Bti is sensitive enough to demonstrate continuous reproductive activity of Cux. quinquefasciatus in the study area throughout the year and to monitor temporal fluctuations in population density.

  8. Modeled response of the West Nile virus vector Culex quinquefasciatus to changing climate using the dynamic mosquito simulation model

    Science.gov (United States)

    Morin, Cory W.; Comrie, Andrew C.

    2010-09-01

    Climate can strongly influence the population dynamics of disease vectors and is consequently a key component of disease ecology. Future climate change and variability may alter the location and seasonality of many disease vectors, possibly increasing the risk of disease transmission to humans. The mosquito species Culex quinquefasciatus is a concern across the southern United States because of its role as a West Nile virus vector and its affinity for urban environments. Using established relationships between atmospheric variables (temperature and precipitation) and mosquito development, we have created the Dynamic Mosquito Simulation Model (DyMSiM) to simulate Cx. quinquefasciatus population dynamics. The model is driven with climate data and validated against mosquito count data from Pasco County, Florida and Coachella Valley, California. Using 1-week and 2-week filters, mosquito trap data are reproduced well by the model ( P climate projection data generated by the National Center for Atmospheric Research CCSM3 general circulation model, we applied temperature and precipitation offsets to the climate data at each location to evaluate mosquito population sensitivity to possible future climate conditions. We found that temperature and precipitation shifts act interdependently to cause remarkable changes in modeled mosquito population dynamics. Impacts include a summer population decline from drying in California due to loss of immature mosquito habitats, and in Florida a decrease in late-season mosquito populations due to drier late summer conditions.

  9. The arbovirus vector Culex torrentium is more prevalent than Culex pipiens in northern and central Europe.

    Science.gov (United States)

    Hesson, J C; Rettich, F; Merdić, E; Vignjević, G; Ostman, O; Schäfer, M; Schaffner, F; Foussadier, R; Besnard, G; Medlock, J; Scholte, E-J; Lundström, J O

    2014-06-01

    Two species of arbovirus vector, Culex torrentium and Culex pipiens (Diptera: Culicidae), occur in several European countries, but difficulties in their accurate identification and discrimination have hampered both detailed and large-scale distribution and abundance studies. Using a molecular identification method, we identified to species 2559 larvae of Cx. pipiens/torrentium collected from 138 sites in 13 European countries ranging from Scandinavia to the Mediterranean coast. In addition, samples of 1712 males of Cx. pipiens/torrentium collected at several sites in the Czech Republic were identified to species based on the morphology of their hypopygia. We found that the two species occur together in large areas of Europe, and that Cx. torrentium dominates in northern Europe and Cx. pipiens dominates south of the Alps. The transition in dominance occurs in central Europe, where both species are roughly equally common. There was a strong correlation between the length of the growing season at different sites and occurrences of the two species. As the growing season increases, the proportion and detection of Cx. torrentium decrease, whereas those of Cx. pipiens increase. The present findings have important consequences for the interpretation of the results of studies on major enzootic and link-vectors of mosquito-borne bird-associated viruses (i.e. Sindbis, West Nile and Usutu viruses), especially in central Europe and Scandinavia.

  10. The potential of cladocerans as controphic competitors of the mosquito Culex pipiens.

    Science.gov (United States)

    Duquesne, Sabine; Kroeger, Iris; Kutyniok, Magdalene; Liess, Matthias

    2011-05-01

    This study assesses the potential of cladocerans as competitors for controlling the oviposition and larval abundances of mosquitoes. Control of mosquito larvae involving the use of antagonists has focused mostly on predators. We hypothesized that cladoceran competitors have a strong potential to control larval populations of some species of mosquitoes that can be early colonizers of newly-filled waterbodies, and should be less efficient competitors. To test this hypothesis, the establishment and development of larval populations of wild Culex pipiens were investigated in outdoor microcosms varying in terms of Daphnia magna populations. When the population was well established (i.e., high densities of D. magna), oviposition was fully inhibited and there was consequently no mosquito larvae. When the population was more recently established (i.e., lower densities of D. magna), oviposition and larval development of Cx. pipiens occurred. In the absence of D. magna, oviposition, larval biomass, and abundance of Cx. pipiens reached high values. In this situation, conspecifics were inhibiting further oviposition of Cx. pipiens. Based on these results, we suggest that competing zooplankton species, such as D. magna, could be used for the control of mosquito species such as Cx. pipiens. This approach could be beneficial for the management of wetlands.

  11. Culex pipiens and Culex restuans mosquitoes harbor distinct microbiota dominated by few bacterial taxa.

    Science.gov (United States)

    Muturi, Ephantus J; Kim, Chang-Hyun; Bara, Jeffrey; Bach, Elizabeth M; Siddappaji, Madhura H

    2016-01-13

    Mosquitoes host diverse microbial communities that influence many aspects of their biology including reproduction, digestion, and ability to transmit pathogens. Unraveling the composition, structure, and function of these microbiota can provide new opportunities for exploiting microbial function for mosquito-borne disease control. MiSeq® sequencing of 16S rRNA gene amplicons was used to characterize the microbiota of adult females of Culex pipiens L. and Cx. restuans Theobald collected from nine study sites in central Illinois. Out of 195 bacterial OTUs that were identified, 86 were shared between the two mosquito species while 16 and 93 OTUs were unique to Cx. pipiens and Cx. restuans, respectively. The composition and structure of microbial communities differed significantly between the two mosquito species with Cx. restuans hosting a more diverse bacterial community compared to Cx. pipiens. Wolbachia (OTU836919) was the dominant bacterial species in Cx. pipiens accounting for 91% of total microbiota while Sphingomonas (OTU817982) was the dominant bacterial species in Cx. restuans accounting for 31% of total microbiota. Only 3 and 6 OTUs occurred in over 60% of individuals in Cx. pipiens and Cx. restuans, respectively. There was little effect of study site on bacterial community structure of either mosquito species. These results suggest that the two mosquito species support distinct microbial communities that are sparsely distributed between individuals. These findings will allow investigations of the role of identified microbiota on the spatial and temporal heterogeneity in WNV transmission and their potential application in disease control.

  12. Screening of twenty five plant extracts for larvicidal activity against Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Samuel Tennyson; K John Ravindran; S Arivoli

    2012-01-01

    Objective: To determine the larvicidal activity of twenty five plant extracts against Culex quinquefasciatus (Cx. quinquefasciatus). Methods: The larvicidal activity was determined against the third instar larvae of Cx. quinquefasciatus at 1 000 ppm concentration. Larval mortality was assessed after 24 and 48 h. Results: The hexane extracts of Cleistanthus collinus (C. collinus) and Murraya koeingii (M. koeingii) plants showed 100 percent mortality at 24 h bioassay followed by diethyl ether, dichloromethane and ethyl acetate extracts of C. collinus, Leucas aspera (L. aspera), Hydrocotyle javanica (H. javanica), M. koeingii, Sphaeranthus indicus (S. indicus) and Zanthoxylum limonella (Z. limonella) after 48 h exposure. Conclusions: The results indicate larvicidal activity against Cx. quinquefasciatus and further investigations are needed to elucidate this activity against a wide range of all stages of mosquito species and also the active ingredients of the extract responsible for larvicidal activity should be identified.

  13. Repellent effect of Lagenaria siceraria extracts against Culex pipiens.

    Science.gov (United States)

    Hassan, Mostafa I; Fouda, Mohamad A; Hammad, Kotb M; Tanani, Mohamad A; Shehata, Ahmed Z

    2014-04-01

    Ethanolic, acetone and petroleum ether extracts from leaves and stems of Lagenaria siceraria (Cucurbitaceae) were screened for their repellency effect against Culex pipiens L. mosquito. The repellent action of the present plant extracts were varied depending on the plant parts and the dose of extract. The petroleum ether extract of leaves showed the same repellency percent (100%) of commercial formulation, N. N.diethyl toulamide (DEET) at the higher dose (3.33 mg/cm2), while petroleum ether extract from stems exhibiting the repellent action (89.6%) at the same dose, respectively. Ethanolic extracts of leaves and stems exhibited the lowest repellent activity as it recorded (81.3% and 69.1%) at (6.67 mg/cm2), respectively. Results of this study may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection measure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  14. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus (Diptera: Culicidae)

    OpenAIRE

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality, deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus. Methods: Serial dilutions (0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules (WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in c...

  15. Transmission of West Nile virus by Culex quinquefasciatus say infected with Culex Flavivirus Izabal.

    Directory of Open Access Journals (Sweden)

    Rebekah J Kent

    Full Text Available BACKGROUND: The natural history and potential impact of mosquito-specific flaviviruses on the transmission efficiency of West Nile virus (WNV is unknown. The objective of this study was to determine whether or not prior infection with Culex flavivirus (CxFV Izabal altered the vector competence of Cx. quinquefasciatus Say for transmission of a co-circulating strain of West Nile virus (WNV from Guatemala. METHODS AND FINDINGS: CxFV-negative Culex quinquefasciatus and those infected with CxFV Izabal by intrathoracic inoculation were administered WNV-infectious blood meals. Infection, dissemination, and transmission of WNV were measured by plaque titration on Vero cells of individual mosquito bodies, legs, or saliva, respectively, two weeks following WNV exposure. Additional groups of Cx. quinquefasciatus were intrathoracically inoculated with WNV alone or WNV+CxFV Izabal simultaneously, and saliva collected nine days post inoculation. Growth of WNV in Aedes albopictus C6/36 cells or Cx. quinquefasciatus was not inhibited by prior infection with CxFV Izabal. There was no significant difference in the vector competence of Cx. quinquefasciatus for WNV between mosquitoes uninfected or infected with CxFV Izabal across multiple WNV blood meal titers and two colonies of Cx. quinquefasciatus (p>0.05. However, significantly more Cx. quinquefasciatus from Honduras that were co-inoculated simultaneously with both viruses transmitted WNV than those inoculated with WNV alone (p = 0.0014. Co-inoculated mosquitoes that transmitted WNV also contained CxFV in their saliva, whereas mosquitoes inoculated with CxFV alone did not contain virus in their saliva. CONCLUSIONS: In the sequential infection experiments, prior infection with CxFV Izabal had no significant impact on WNV replication, infection, dissemination, or transmission by Cx. quinquefasciatus, however WNV transmission was enhanced in the Honduras colony when mosquitoes were inoculated simultaneously with

  16. Functional response analysis of Anisops sardea (Hemiptera: Notonectidae) against Culex quinquefasciatus in laboratory condition

    OpenAIRE

    Rajendra Prasad Mondal; Anupam Ghosh; Subhasis Bandyopadhyay; Goutam Chandra

    2014-01-01

    Background & objectives: Culex quinquefasciatus is the principal vector of lymphatic filariasis (LF). Application of alternative vector control methodologies are aimed at reduction of mosquito breeding sites and biting activity through the use of biological control methods. In the present study, functional response of aquatic Hemipteran backswimmer, Anisops sardea was assessed against Cx. quinquefasciatus larvae in laboratory bioassay. Methods: The functional respons of A. sardea was ass...

  17. Lysinibacillus sphaericus S-layer protein toxicity against Culex quinquefasciatus.

    Science.gov (United States)

    Lozano, Lucía C; Ayala, Juan A; Dussán, Jenny

    2011-10-01

    The main toxicity mechanism of Lysinibacillus sphaericus, which is used in the control of mosquitoes, is its binary toxin produced during sporulation; additionally the Mtx1, Mtx2 and Mtx 3 toxins are expressed in vegetative cells. Mosquito larvicidal potency of the S-layer protein that is expressed in vegetative cells has been determined. The protein is similar to other S-layer proteins of mosquitocidal L. sphaericus strains. The LC50 values of the S-layer protein of the L. sphaericus OT4b25, OT4b26, and III(3)7 strains against third-instar larvae of Culex quinquefasciatus were 8.7, 24 and 0.68 μg/ml, respectively. To our knowledge this is the first study showing the mosquito larvicidal potency of the S-layer protein from Lysinibacillus sphaericus.

  18. European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus

    Science.gov (United States)

    Desprès, Philippe

    2017-01-01

    Background Japanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5. Findings After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease. Conclusions In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds. PMID:28085881

  19. European Aedes albopictus and Culex pipiens Are Competent Vectors for Japanese Encephalitis Virus.

    Science.gov (United States)

    de Wispelaere, Mélissanne; Desprès, Philippe; Choumet, Valérie

    2017-01-01

    Japanese encephalitis virus (JEV) is the causative agent of Japanese encephalitis, the leading cause of viral encephalitis in Asia. JEV transmission cycle involves mosquitoes and vertebrate hosts. The detection of JEV RNA in a pool of Culex pipiens caught in 2010 in Italy raised the concern of a putative emergence of the virus in Europe. We aimed to study the vector competence of European mosquito populations, such as Cx. pipiens and Aedes albopictus for JEV genotypes 3 and 5. After oral feeding on an infectious blood meal, mosquitoes were dissected at various times post-virus exposure. We found that the peak for JEV infection and transmission was between 11 and 13 days post-virus exposure. We observed a faster dissemination of both JEV genotypes in Ae. albopictus mosquitoes, when compared with Cx. pipiens mosquitoes. We also dissected salivary glands and collected saliva from infected mosquitoes and showed that Ae. albopictus mosquitoes transmitted JEV earlier than Cx. pipiens. The virus collected from Ae. albopictus and Cx. pipiens saliva was competent at causing pathogenesis in a mouse model for JEV infection. Using this model, we found that mosquito saliva or salivary glands did not enhance the severity of the disease. In this study, we demonstrated that European populations of Ae. albopictus and Cx. pipiens were efficient vectors for JEV transmission. Susceptible vertebrate species that develop high viremia are an obligatory part of the JEV transmission cycle. This study highlights the need to investigate the susceptibility of potential JEV reservoir hosts in Europe, notably amongst swine populations and local water birds.

  20. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    National Research Council Canada - National Science Library

    Flávia P. Morais de Medeiros; Maria Alice Varjal de Melo Santos; Leda Regis; Eugênia M. Maranhão Rios; Pedro J. Rolim Neto

    2005-01-01

    ...; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae...

  1. Ontogeny and distribution of cells in B lineage in the American leopard frog, Rana pipiens.

    Science.gov (United States)

    Zettergren, L D

    1982-01-01

    Two-color immunofluorescence techniques were used in order to trace the development and distribution of cells expressing immunoglobulin in Rana pipiens. Evidence is provided which suggests that (i) embryo-larval urogenital tissues are sites of generation of cells in B lineage, (ii) during ontogeny, there is a sequential expression of immunoglobulin isotypes on B cell surfaces, (iii) larvae are able to produce the full range of immunoglobulin clases found in adults, and (iv) at least two subpopulations of lymphocytes exist in Rana pipiens, sIg+ and sIg-; thymocytes and presumably peripheral T cells lack conventional surface immunoglobulin. Some ontogenetic and phylogenetic implications are discussed.

  2. Energetic cost of insecticide resistance in Culex pipiens mosquitoes.

    Science.gov (United States)

    Rivero, A; Magaud, A; Nicot, A; Vézilier, J

    2011-05-01

    The extensive use of insecticides to control vector populations has lead to the widespread development of different mechanisms of insecticide resistance. Mutations that confer insecticide resistance are often associated to fitness costs that prevent them from spreading to fixation. In vectors, such fitness costs include reductions in preimaginal survival, adult size, longevity, and fecundity. The most commonly invoked explanation for the nature of such pleiotropic effects of insecticide resistance is the existence of resource-based trade-offs. According to this hypothesis, insecticide resistance would deplete the energetic stores of vectors, reducing the energy available for other biological functions and generating trade-offs between insecticide resistance and key life history traits. Here we test this hypothesis by quantifying the energetic resources (lipids, glycogen, and glucose) of larvae and adult females of the mosquito Culex pipiens L. resistant to insecticides through two different mechanisms: esterase overproduction and acetylcholinesterase modification. We find that, as expected from trade-off theory, insecticide resistant mosquitoes through the overproduction of esterases contain on average 30% less energetic reserves than their susceptible counterparts. Acetylcholinesterase-modified mosquitoes, however, also showed a significant reduction in energetic resources (20% less). We suggest that, in acetylcholinesterase-modified mosquitoes, resource depletion may not be the result of resource-based trade-offs but a consequence of the hyperactivation of the nervous system. We argue that these results not only provide a mechanistic explanation for the negative pleiotropic effects of insecticide resistance on mosquito life history traits but also can have a direct effect on the development of parasites that depend on the vector's energetic reserves to fulfil their own metabolic needs.

  3. Distribution and postbreeding environmental relationships of Northern leopard frogs (Rana [Lithobates] pipiens) in Washington

    Science.gov (United States)

    Germaine, S.S.; Hays, D.W.

    2009-01-01

    Northern leopard frogs (Rana [Lithobates] pipiens) are considered sensitive, threatened, or endangered in all western states and western Canadian provinces. Historically present in eastern Washington in 6 major river drainages, leopard frogs are now only known to occur at 2 localized areas in the Crab Creek drainage in Grant County. During the summers of 2002-2005, we surveyed both areas to document extent of leopard frog distributions and to describe habitat and vertebrate community characteristics associated with leopard frog site occupancy. At Gloyd Seeps, 2 juvenile leopard frogs were observed in a total of 8.2 person-days of searching along a 5-km stream reach. At Potholes Reservoir, we surveyed 243 wetland sites in 7 management units known to have been occupied by leopard frogs during the 1980s. We confirmed leopard frog presence at only 87 sites (36%) in 4 management units. Site occupancy models for individual ponds indicated that, compared to unoccupied sites, occupied sites had slightly greater pond depths, less tall emergent vegetation, more herbaceous vegetative cover, and fewer neighboring ponds containing nonnative predatory fish. Models developed at the 1-km2 scale indicated that occupied areas had greater average midsummer pond depths, fewer ponds occupied by bullfrogs (Rana [Lithobates] catesbeiana) and carp (Cyprinus carpio), and more herbaceous vegetation surrounding ponds. The Gloyd Seeps population now appears defunct, and the Potholes Reservoir population is in sharp decline. Unless management actions are taken to reduce nonnative fish and bullfrogs and to enhance wetland vegetation, leopard frogs may soon be extirpated from both sites and possibly, therefore, from Washington.

  4. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    El-Akhal, Fouad; Guemmouh, Raja; Ez Zoubi, Yassine; El Ouali Lalami, Abdelhakim

    2015-01-01

    Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens. PMID:26640701

  5. High Insecticides Resistance in Culex pipiens (Diptera: Culicidae from Tehran, Capital of Iran

    Directory of Open Access Journals (Sweden)

    Yaser Salim-Abadi

    2016-10-01

    Full Text Available Background: During recent years transmission of Dirofilaria immitis (dog heart worm by Culex pipiens and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of Cx. pipiens collected from capital city of Tehran, Iran.Methods: Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard  methods were used for evaluating the susceptibility status of Cx. pipiens from Tehran moreover  For comparison susceptibility status a Laboratory strain also was used.  Bioassay data were ana­lyzed using Probit program. The lethal time for 50% and 90% mortality (LT50 and LT90 values were calculated from regression line.Results: The susceptibility status of lab strain of Cx. pipiens revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT50=36 seconds and DDT with LT50=3005 seconds had the least and most LT50s. Field population was resistance to all tested insecticides and DDT yielded no mortality.Conclusion: Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control.

  6. Effectiveness of seven mosquito larvicides against the West Nile vector Culex pipiens (L. in Saudi Arabia

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    Jazem Abdullah Mahyoub

    2016-05-01

    Full Text Available Objective: To explore the effects of different chemical larvicides, bioinsecticides and insect growth regulators against the West Nile vector Culex pipiens (Diptera: Culicidae (Cx. pipiens in Saudi Arabia. Methods: We tested seven commercial mosquito larvicides, including classic cyfluthrin, diazinon and propoxur, bioinsecticides Bactilarvae and Tracer 24%, and insect growth regulators Baycidal and Sumilarv. LC50 and LC90 values were calculated in laboratory conditions using probit analysis. Results: Concerning chemical insecticides, the highest larval mortality was observed for diazinon, with LC50 = 0.352 3 mg/L, followed by propoxur and cyfluthrin. The bacterial insecticide Tracer was more effective than Bactilarvae (LC50 = 0.008 7 mg/L and 0.011 7 mg/L, respectively by 1.37 folds. Furthermore, Cx. pipiens larvae were more susceptible to insect growth regulators Baycidal (IC50 = 0.0004 mg/L if compared to Sumilarv (IC50 = 0.0029 mg/L by 7.25 folds. Conclusions: Overall, this research added basic knowledge about the effectiveness of seven mosquito larvicides with different mechanisms of action as potential candidates for the control programs of Cx. pipiens mosquito populations in Saudi Arabia.

  7. Pattern formation in artificially activated ectoderm (Rana pipiens and Ambystoma punctatum)

    NARCIS (Netherlands)

    Nieuwkoop, P.D.

    1963-01-01

    Presumptive ectoneuroderm of late blastulae or early gastrulae of Rana pipiens was partially activated by short-lasting disaggregation in Ca-free Holtfreter or Niu-Twitty solutions and subsequent reaggregation in normal solutions. The explants usually became dumbbell shaped and consisted respectivel

  8. Larvicidal Activity of Nerium oleander against Larvae West Nile Vector Mosquito Culex pipiens (Diptera: Culicidae

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    Fouad El-Akhal

    2015-01-01

    Full Text Available Background. Outbreaks of the West Nile virus infection were reported in Morocco in 1996, 2003, and 2010. Culex pipiens was strongly suspected as the vector responsible for transmission. In the North center of Morocco, this species has developed resistance to synthetic insecticides. There is an urgent need to find alternatives to the insecticides as natural biocides. Objective. In this work, the insecticidal activity of the extract of the local plant Nerium oleander, which has never been tested before in the North center of Morocco, was studied on larval stages 3 and 4 of Culex pipiens. Methods. Biological tests were realized according to a methodology inspired from standard World Health Organization protocol. The mortality values were determined after 24 h of exposure and LC50 and LC90 values were calculated. Results. The extract had toxic effects on the larvae of culicid mosquitoes. The ethanolic extract of Nerium oleander applied against the larvae of Culex pipiens has given the lethal concentrations LC50 and LC90 in the order of 57.57 mg/mL and 166.35 mg/mL, respectively. Conclusion. This investigation indicates that N. oleander could serve as a potential larvicidal, effective natural biocide against mosquito larvae, particularly Culex pipiens.

  9. Mitochondrial DNA analyses reveal low genetic diversity in Culex quinquefasciatus from residential areas in Malaysia.

    Science.gov (United States)

    Low, V L; Lim, P E; Chen, C D; Lim, Y A L; Tan, T K; Norma-Rashid, Y; Lee, H L; Sofian-Azirun, M

    2014-06-01

    The present study explored the intraspecific genetic diversity, dispersal patterns and phylogeographic relationships of Culex quinquefasciatus Say (Diptera: Culicidae) in Malaysia using reference data available in GenBank in order to reveal this species' phylogenetic relationships. A statistical parsimony network of 70 taxa aligned as 624 characters of the cytochrome c oxidase subunit I (COI) gene and 685 characters of the cytochrome c oxidase subunit II (COII) gene revealed three haplotypes (A1-A3) and four haplotypes (B1-B4), respectively. The concatenated sequences of both COI and COII genes with a total of 1309 characters revealed seven haplotypes (AB1-AB7). Analysis using tcs indicated that haplotype AB1 was the common ancestor and the most widespread haplotype in Malaysia. The genetic distance based on concatenated sequences of both COI and COII genes ranged from 0.00076 to 0.00229. Sequence alignment of Cx. quinquefasciatus from Malaysia and other countries revealed four haplotypes (AA1-AA4) by the COI gene and nine haplotypes (BB1-BB9) by the COII gene. Phylogenetic analyses demonstrated that Malaysian Cx. quinquefasciatus share the same genetic lineage as East African and Asian Cx. quinquefasciatus. This study has inferred the genetic lineages, dispersal patterns and hypothetical ancestral genotypes of Cx. quinquefasciatus.

  10. Adulticidal efficacy of Delonix elata against filariasis vector mosquito, Culex quinquefasciatus (Diptera: Culicidae

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    Mohan Rajeswary

    2014-09-01

    Full Text Available Objective: To evaluate the adulticidal activity and toxicity of different solvent crude extracts of Delonix elata (D. elata against filariasis vector mosquito Culex quinquefasciatus (Cx. quinquefasciatus. Methods: The adulticidal activities of crude hexane, benzene, ethyl acetate, chloroform and methanol leaf and seed extracts of D. elata were assayed for their toxicity against vector mosquito Cx. quinquefasciatus. Bioassay was carried out by WHO method for determination of adulticidal activity against mosquitoes. The adult mortality was observed after 24 h of exposure. Results: All extracts showed moderate adulticidal effects; however, the highest adult mortality was found in methanol extract of D. elata leaf against the adults of Cx. quinquefasciatus with the LC50 and LC90 values at 197.28 and 347.45mg/L, respectively. Conclusions: These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This study provides first report on the mosquito adulticidal activity of D. elata plant extracts against filariasis vector mosquito, Cx. quinquefasciatus.

  11. Adulticidal efficacy of Delonix elata against filariasis vector mosquito, Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Mohan Rajeswary; Marimuthu Govindarajan

    2014-01-01

    Objective: To evaluate the adulticidal activity and toxicity of different solvent crude extracts of Delonix elata (D. elata) against filariasis vector mosquito Culex quinquefasciatus (Cx. quinquefasciatus). Methods: The adulticidal activities of crude hexane, benzene, ethyl acetate, chloroform and methanol leaf and seed extracts of D. elata were assayed for their toxicity against vector mosquitoCx. quinquefasciatus. Bioassay was carried out by WHO method for determination of adulticidal activity against mosquitoes. The adult mortality was observed after 24 h of exposure. Results: All extracts showed moderate adulticidal effects; however, the highest adult mortality was found in methanol extract of D. elata leaf against the adults of Cx. quinquefasciatus with the LC50 and LC90 values at 197.28 and 347.45mg/L, respectively.Conclusions:These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of mosquitoes. This study provides first report on the mosquito adulticidal activity of D. elata plant extracts against filariasis vector mosquito, Cx. quinquefasciatus.

  12. Vector competence of Culex quinquefasciatus say from different regions of Brazil to Dirofilaria immitis

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    Ahid Silvia Maria Mendes

    2000-01-01

    Full Text Available The vector competence of Culex quinquefasciatus from five localities in Brazil to Dirofilaria immitis was evaluated experimentally. Females from each locality were fed on an infected dog (~ 6 microfilariae/µl blood. A sample of blood fed mosquitoes were dissected approximately 1 h after blood meal. These results demonstrated that all had ingested microfilariae (mean, 4.8 to 24.6 microfilariae/mosquito. Fifteen days after the infected blood meal, the infection and infective rates were low in all populations of Cx. quinquefasciatus. The mean number of infective larvae detected in the head and proboscis of these mosquitoes was 1-1.5. The vector efficiency, the number of microfilariae ingested/number of infective larvae, was low for all populations of Cx. quinquefasciatus. However, the survival rate for all populations was high (range 50-75%. The survival rate of Aedes aegypti assayed simultaneously for comparison was low (24.7%, while the vector efficiency was much higher than for Cx. quinquefasciatus. These data suggest that the vector competence of all assayed populations of Cx. quinquefasciatus to D. immitis in Brazil is similar and that this species is a secondary vector due to its low susceptibility. Nevertheless, vector capacity may vary between populations due to differences in biting frequency on dogs that has been reported in Brazil.

  13. Synergism between permethrin and propoxur against Culex quinquefasciatus mosquito larvae.

    Science.gov (United States)

    Corbel, V; Chandre, F; Darriet, F; Lardeux, F; Hougard, J-M

    2003-06-01

    To see if synergism occurs between carbamate and pyrethroid insecticides, we tested permethrin and propoxur as representatives of these two classes of compounds used for mosquito control. Larvicidal activity of both insecticides was assessed separately and together on a susceptible strain of the mosquito Culex quinquefasciatus (Diptera: Culicidae) by two methods. When mixed at a constant ratio (permethrin : propoxur 1 : 60 based on LC50) and tested at serial concentrations to plot dose/mortality regression, significant synergy occurred between them (co-toxicity coefficient = 2.2), not just an additive effect. For example, when the mixture gave 50% mortality, the same concentrations of permethrin and propoxur alone would have given merely 2 x 1% mortality. When a sublethal dose (LC0) of permethrin or propoxur was added to the other (range LC10-LC95), synergism occurred up to the LC80 level. Synergistic effects were attributed to the complementary modes of action by these two insecticide classes acting on different components of nerve impulse transmission. Apart from raising new possibilities for Culex control, it seems appropriate to consider using such mixtures or combinations for insecticide-treated mosquito nets in situations with insecticide-resistant Anopheles malaria vectors.

  14. Oviposition Attractancy of Bacterial Culture Filtrates: response of Culex quinquefasciatus

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    S Poonam

    2002-04-01

    Full Text Available Oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. In the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of Culex quinquefasciatus. When their oviposition active indices (OAI were studied, the culture filtrates of Bacillus cereus and Pseudomonas fluorescens exhibited oviposition attractancy (OAI = >0.3 at 100 ppm and the OAI were respectively 0.70 and 0.47. Culture filtrates of B. thuringiensis var. israelensis (wild type, B. t. var. israelensis (mutant and B. sphaericus showed attractancy at 2000 ppm with OAI of respectively 0.71, 0.59 and 0.68. However, the OAI of B. megaterium as well as Azospirillum brasilense was 0.13 (at 2000 ppm, which was less than 0.3 required to be considered them as attractants. When the oviposition attractancy of the bacterial culture filtrates were compared with that of a known oviposition attractant, p-cresol (at 10 ppm, the culture filtrates of B. t. var. israelensis (wild type and B. cereus were found to be more active than p-cresol, respectively with 64.2 and 54.3% oviposition.

  15. Efectos de la competencia larval en los mosquitos de contenedores artificiales, Aedes aegypti y Culex pipiens (Diptera: Culicidae en condiciones semi-controladas

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    Analía FRANCIA

    2011-01-01

    Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artificiales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (δ estimada según un censo previo de A. aegypti y C. pipiens. Se realizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.

  16. A first note on Japanese encephalitis virus isolation from Culex quinquefasciatus Say in Northern West Bengal.

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    V. Thenmozhi

    2014-03-01

    Full Text Available Japanese encephalitis (JE is endemic in many parts of India including the state of West Bengal. In West Bengal, the first major outbreaks of JE occurred in the districts of Bankura and Burdwan in 1973. The Culex vishnui subgroup of mosquitoes has been implicated as major vectors of JE. However in India, JE virus (JEV has been isolated from 16 species of mosquitoes. During September 2011, JE cases were reported from four districts -Jalpaiguri, Darjeeling, Dinajpur and Cooch Behar of West Bengal (North. Adult mosquitoes were collected, identified, pooled and screened for JEV using antigen capture ELISA. Out of 279 mosquito pools tested, one pool of Cx. pseudovishnui and three pools of Cx. quinquefasciatus were found positive for JEV. The ELISA positive pools were further confirmed as JEV by insect bioassay (Toxo-IFA. Two pools of Cx. quinquefasciatus were confirmed as JEV. This represents the first report of JEV isolation from Cx. quinquefasciatus in West Bengal.

  17. Culex quinquefasciatus from Rio de Janeiro Is Not Competent to Transmit the Local Zika Virus.

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    Rosilainy Surubi Fernandes

    2016-09-01

    Full Text Available The Americas have suffered a dramatic epidemic of Zika since May in 2015, when Zika virus (ZIKV was first detected in Brazil. Mosquitoes belonging to subgenus Stegomyia of Aedes, particularly Aedes aegypti, are considered the primary vectors of ZIKV. However, the rapid spread of the virus across the continent raised several concerns about the transmission dynamics, especially about potential mosquito vectors. The purpose of this work was to assess the vector competence of the house mosquito Culex quinquefasciatus from an epidemic Zika area, Rio de Janeiro, Brazil, for local circulating ZIKV isolates.Culex quinquefasciatus and Ae. aegypti (positive control of ZIKV infection from Rio de Janeiro were orally exposed to two ZIKV strains isolated from human cases from Rio de Janeiro (Rio-U1 and Rio-S1. Fully engorged mosquitoes were held in incubators at 26 ± 1°C, 12 h:12 h light:dark cycle and 70 ± 10% humidity. For each combination mosquito population-ZIKV strain, 30 specimens were examined for infection, dissemination and transmission rates, at 7, 14 and 21 days after virus exposure by analyzing body (thorax plus abdomen, head and saliva respectively. Infection rates were minimal to completely absent in all Cx. quinquefasciatus-virus combinations and were significantly high for Ae. aegypti. Moreover, dissemination and transmission were not detected in any Cx. quinquefasciatus mosquitoes whatever the incubation period and the ZIKV isolate. In contrast, Ae. aegypti ensured high viral dissemination and moderate to very high transmission.The southern house mosquito Cx. quinquefasciatus from Rio de Janeiro was not competent to transmit local strains of ZIKV. Thus, there is no experimental evidence that Cx. quinquefasciatus likely plays a role in the ZIKV transmission. Consequently, at least in Rio, mosquito control to reduce ZIKV transmission should remain focused on Ae. aegypti.

  18. Culex quinquefasciatus from Rio de Janeiro Is Not Competent to Transmit the Local Zika Virus

    Science.gov (United States)

    Ferreira-de-Brito, Anielly; de Miranda, Rafaella Moraes; Barbosa da Silva, Keli Antunes; de Castro, Marcia Gonçalves; Raphael, Lidiane M. S.; Failloux, Anna-Bella; Bonaldo, Myrna C.; Lourenço-de-Oliveira, Ricardo

    2016-01-01

    Background The Americas have suffered a dramatic epidemic of Zika since May in 2015, when Zika virus (ZIKV) was first detected in Brazil. Mosquitoes belonging to subgenus Stegomyia of Aedes, particularly Aedes aegypti, are considered the primary vectors of ZIKV. However, the rapid spread of the virus across the continent raised several concerns about the transmission dynamics, especially about potential mosquito vectors. The purpose of this work was to assess the vector competence of the house mosquito Culex quinquefasciatus from an epidemic Zika area, Rio de Janeiro, Brazil, for local circulating ZIKV isolates. Methodology/Principal Findings Culex quinquefasciatus and Ae. aegypti (positive control of ZIKV infection) from Rio de Janeiro were orally exposed to two ZIKV strains isolated from human cases from Rio de Janeiro (Rio-U1 and Rio-S1). Fully engorged mosquitoes were held in incubators at 26 ± 1°C, 12 h:12 h light:dark cycle and 70 ± 10% humidity. For each combination mosquito population—ZIKV strain, 30 specimens were examined for infection, dissemination and transmission rates, at 7, 14 and 21 days after virus exposure by analyzing body (thorax plus abdomen), head and saliva respectively. Infection rates were minimal to completely absent in all Cx. quinquefasciatus-virus combinations and were significantly high for Ae. aegypti. Moreover, dissemination and transmission were not detected in any Cx. quinquefasciatus mosquitoes whatever the incubation period and the ZIKV isolate. In contrast, Ae. aegypti ensured high viral dissemination and moderate to very high transmission. Conclusions/Significance The southern house mosquito Cx. quinquefasciatus from Rio de Janeiro was not competent to transmit local strains of ZIKV. Thus, there is no experimental evidence that Cx. quinquefasciatus likely plays a role in the ZIKV transmission. Consequently, at least in Rio, mosquito control to reduce ZIKV transmission should remain focused on Ae. aegypti. PMID

  19. Bionomics of Culex quinquefasciatus within urban areas of Rio de Janeiro, Southeastern Brazil

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    Mariana Rocha David

    2012-10-01

    Full Text Available OBJECTIVE: To evaluate density, parity rates, daily survival and longevity of natural populations of Culex quinquefasciatus in three neighborhoods with distinct socio-economic and infrastructure profiles. METHODS: Mosquito collections of the Culex quinquefasciatus species were performed weekly during two four month periods, from August to November 2008 (spring and March to June 2009 (fall, in a favela (slum, a suburban area and a middle class area of Rio de Janeiro, Southeastern Brazil. Collections were performed with backpack aspirators, in 20 randomly selected houses in each area per week, during 15-20 minutes per house. Ovaries were removed from captured females and classified as initial, intermediary or final stage. Furthermore, females were dissected for determination of parity based on the condition of the tracheal system. Mosquito survival rate and longevity were estimated on a per month basis for each neighborhood. RESULTS: We collected a total of 2,062 Culex quinquefasciatus, but monthly vector density was not correlated with temperature and rainfall. We dissected the ovaries of 625 Culex quinquefasciatus, and overall, there was a higher proportion of nulliparous females during the dryer months, while gravid females were more frequent in rainy months. In the middle class neighborhood, the parity rate reached up to 93.75% with survivorship of 0.979. Lower parity and survival rates were obtained in the suburban area (as low as 36.4% parity and 0.711 daily survival. Up to 84.7% of Culex quinquefasciatus females could survive the eight day period needed to complete West Nile Virus incubation. CONCLUSIONS: The survival rate of Culex quinquefasciatus varied significantly between the neighborhoods. This suggests that vectorial capacity and disease transmission risk may vary greatly between different urban areas, which is potentially useful information for vector control programs.

  20. Repellency and toxicity of aromatic plant extracts against the mosquito Culex pipiens molestus (Diptera: Culicidae).

    Science.gov (United States)

    Traboulsi, Abdallah F; El-Haj, Samih; Tueni, Marie; Taoubi, Khalil; Nader, Natalie Abi; Mrad, Abir

    2005-06-01

    The insecticidal activities of essential oil extracts from leaves, flowers and roots of aromatic plants against fourth-instar larvae of the mosquito Culex pipiens molestus Forskal were determined. Extracts of Foeniculum vulgare Mill were the most toxic, followed by those of Ferula hermonis Boiss, Citrus sinensis Osbeck, Pinus pinea L, Laurus nobilis L and Eucalyptus spp with LC50 values of 24.5, 44.0, 60.0, 75.0, 117.0 and 120.0 mg litre(-1), respectively. Combination tests between the LC50 and the maximum sub-lethal concentration (MSLC) were determined. Over 20 major components were identified in extracts from each plant species tested. Five essential oils and nine pure components were studied for their repellency against mosquito bites. Terpineol and 1,8-cineole were the most effective against Culex pipiens molestus bites offering complete protection for 1.6 and 2 h, respectively.

  1. Decreased Flight Activity in Culex pipiens (Diptera: Culicidae) Naturally Infected With Culex flavivirus.

    Science.gov (United States)

    Newman, Christina M; Anderson, Tavis K; Goldberg, Tony L

    2016-01-01

    Insect-specific flaviviruses (ISFVs) commonly infect vectors of mosquito-borne arboviruses. To investigate whether infection with an ISFV might affect mosquito flight behavior, we quantified flight behavior in Culex pipiens L. naturally infected with Culex flavivirus (CxFV). We observed a significant reduction in the scotophase (dark hours) flight activity of CxFV-positive mosquitoes relative to CxFV-negative mosquitoes, but only a marginal reduction in photophase (light hours) flight activity, and no change in the circadian pattern of flight activity. These results suggest that CxFV infection alters the flight activity of naturally infected Cx. pipiens most dramatically when these vectors are likely to be host seeking and may therefore affect the transmission of medically important arboviruses.

  2. Wolbachia Endobacteria in Natural Populations of Culex pipiens of Iran and its Phylogenetic Congruence

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    Mohsen Karami

    2016-01-01

    Full Text Available Background: Wolbachia are common intracellular bacteria that infect different groups of arthropods including mos­quitoes. These bacteria modify host biology and may induce feminization, parthenogenesis, male killing and cyto­plasmic incompatibility (CI. Recently Wolbachia is being nominated as a bio-agent and paratransgenic candidate to control mosquito borne diseases.Methods: Here we report the results of a survey for presence, frequency, and phylogenetic congruence of these en­dosymbiont bacteria in Culex pipiens populations in Northern, Central, and Southern parts of Iran using nested-PCR amplification of wsp gene.Results: Wolbachia DNA were found in 227 (87.3% out of 260 wild-caught mosquitoes. The rate of infection in adult females ranged from 61.5% to 100%, while in males were from 80% to 100%. The Blast search and phyloge­netic analysis of the wsp gene sequence revealed that the Wolbachia strain from Iranian Cx. pipiens was identical to the Wolbachia strains of supergroup B previously reported in members of the Cx. pipiens complex. They had also identical sequence homology with the Wolbachia strains from a group of distinct arthropods including lepidopteran, wasps, flies, damselfly, thrips, and mites from remote geographical areas of the world.Conclusion: It is suggested that Wolbachia strains horizontally transfer between unrelated host organisms over evo­lutionary time. Also results of this study indicates that Wolbachia infections were highly prevalent infecting all Cx. pipiens populations throughout the country, however further study needs to define Wolbachia inter-population repro­ductive incompatibility pattern and its usefulness as a bio-agent control measure.

  3. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes

    OpenAIRE

    Tranchida, María C.; Micieli, María V.; Arnaldo Maciá; García, Juan J.

    2009-01-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops ur...

  4. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes

    OpenAIRE

    C. Tranchida, María; V. Micieli, María; Maciá, Arnaldo; J. García, Juan

    2008-01-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops ur...

  5. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  6. An impossible journey? The development of Plasmodium falciparum NF54 in Culex quinquefasciatus.

    Science.gov (United States)

    Knöckel, Julia; Molina-Cruz, Alvaro; Fischer, Elizabeth; Muratova, Olga; Haile, Ashley; Barillas-Mury, Carolina; Miller, Louis H

    2013-01-01

    Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species-among them culicines (Culex spp., Aedes spp.)-present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito's immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito's blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph.

  7. Chemical ecology of the behaviour of the filariasis mosquito Culex quinquefasciatus Say

    NARCIS (Netherlands)

    Mboera, L.E.G.

    1999-01-01

    Culex quinquefasciatus is an important vector of urban bancroftian filariasis in the tropical world. Despite its public health importance, much of its olfactory mediated behaviour is poorly understood. Studies on resource-location behaviour, in particular the role of semiochemicals in its behaviour,

  8. Enzymatic characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus say (Diptera: Culicidae.

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    Van Lun Low

    Full Text Available BACKGROUND: There has been no comprehensive study on biochemical characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus. To fill this void in the literature, a nationwide investigation was performed to quantify the enzyme activities, thereby attempting to characterize the potential resistance mechanisms in Cx. quinquefasciatus in residential areas in Malaysia. METHODOLOGY/PRINCIPAL FINDINGS: Culex quinquefasciatus from 14 residential areas across 13 states and one federal territory were subjected to esterases, mixed function oxidases, glutathione-S-transferase and insensitive acetylcholinesterase assays. Enzyme assays revealed that α-esterases and β-esterases were elevated in 13 populations and 12 populations, respectively. Nine populations demonstrated elevated levels of mixed function oxidases and glutathione-S-transferase. Acetylcholinesterase was insensitive to propoxur in all 14 populations. Activity of α-esterases associated with malathion resistance was found in the present study. In addition, an association between the activity of α-esterases and β-esterases was also demonstrated. CONCLUSIONS/SIGNIFICANCE: The present study has characterized the potential biochemical mechanisms in contributing towards insecticide resistance in Cx. quinquefasciatus field populations in Malaysia. Identification of mechanisms underlying the insecticide resistance will be beneficial in developing effective mosquito control programs in Malaysia.

  9. Larvicidal activity of some Euphorbiaceae plant extracts against Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Rahuman, A Abdul; Gopalakrishnan, Geetha; Venkatesan, P; Geetha, Kannappan

    2008-04-01

    Larvicidal activity of ethyl acetate, butanol, and petroleum ether extracts of five species of Euphorbiaceae plants, Jatropha curcas, Pedilanthus tithymaloides, Phyllanthus amarus, Euphorbia hirta, and Euphorbia tirucalli, were tested against the early fourth instar larvae of Aedes aegypti L. and Culex quinquefasciatus (Say). The larval mortality was observed after 24 h of exposure. All extracts showed low larvicidal effects; however, the highest larval mortality was found in petroleum ether extract. The LC50 value of petroleum ether extracts of J. curcas, P. tithymaloides, P. amarus, E. hirta, and E. tirucalli were 8.79, 55.26, 90.92, 272.36, and 4.25 ppm, respectively, against A. aegypti and 11.34, 76.61, 113.40, 424.94, and 5.52 ppm, respectively, against C quinquefasciatus. Of the various ratios tested, the petroleum ether extracts of J. curcas and E. tirucalli were observed to be more efficient than the other plant extracts. It is, therefore, suggested that E. tirucalli can be applied as an ideal potential larvicide against A. aegypti and C. quinquefasciatus. This is an ideal ecofriendly approach for the control of the dengue vector, A. aegypti, and the lymphatic filariasis vector, C. quinquefasciatus.

  10. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  11. Chemical ecology of the behaviour of the filariasis mosquito Culex quinquefasciatus Say

    NARCIS (Netherlands)

    Mboera, L.E.G.

    1999-01-01

    Culex quinquefasciatus is an important vector of urban bancroftian filariasis in the tropical world. Despite its public health importance, much of its olfactory mediated behaviour is poorly understood. Studies on resource-location behaviour, in particular the role of

  12. Functional response analysis of Anisops sardea (Hemiptera: Notonectidae) against Culex quinquefasciatus in laboratory condition.

    Science.gov (United States)

    Mondal, Rajendra Prasad; Ghosh, Anupam; Bandyopadhyay, Subhasis; Chandra, Goutam

    2014-10-01

    Culex quinquefasciatus is the principal vector of lymphatic filariasis (LF). Application of alternative vector control methodologies are aimed at reduction of mosquito breeding sites and biting activity through the use of biological control methods. In the present study, functional response of aquatic Hemipteran backswimmer, Anisops sardea was assessed against Cx. quinquefasciatus larvae in laboratory bioassay. The functional respons of A. sardea was assessed against III(rd) instar larvae of Cx. quinquefasciatus. Respective handling times and coefficient of attack rates were determined by a non linear polynomeal regression equation. The results of rates of predation in variable prey densities exhibited a 'linear rise to plateau curve', associated with 'Type -II' functional response. The logistic regression estimated a significant negative linear parameter (P(1) <0) which also supported the same observation. Associated 'attack rates' and 'handling times' were also calculated using the Holling Disc Equation. The results of present experiments indicate that A. sardea can be used as a biocontrol agent against the larval forms of Cx. quinquefasciatus in temporarily available breeding places of mosquito with relatively clear water. However, a detailed field study has to be done to confirm these findings.

  13. Functional response analysis of Anisops sardea (Hemiptera: Notonectidae against Culex quinquefasciatus in laboratory condition

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    Rajendra Prasad Mondal

    2014-01-01

    Interpretation & conclusions: The results of present experiments indicate that A. sardea can be used as a biocontrol agent against the larval forms of Cx. quinquefasciatus in temporarily available breeding places of mosquito with relatively clear water. However, a detailed field study has to be done to confirm these findings.

  14. SR450 and Superhawk XP applications of Bacillus thuringiensis israelensis de Barjac against Culex quinquefasciatus Say

    Science.gov (United States)

    Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) de Barjac against Culex quinquefasciatus Say. Bacillus thuringiensis israelensis was applied at m...

  15. Application site and mosquito age influences malathion- and permethrin-induced mortality in Culex quinquefasciatus

    Science.gov (United States)

    Concentrations of malathion and permethrin typical in droplets generated from ultra-low volume and low volume applications were evaluated for efficacy against multiple-aged Culex quinquefasciatus Say, using a topical bioassay. Although during mosquito control operations insecticide droplets will imp...

  16. The impact of weather conditions on Culex pipiens and Culex restuans (Diptera: Culicidae) abundance: a case study in Peel Region.

    Science.gov (United States)

    Wang, Jiafeng; Ogden, Nick H; Zhu, Huaiping

    2011-03-01

    Mosquito populations are sensitive to long-term variations in climate and short-term variations in weather. Mosquito abundance is a key determinant of outbreaks of mosquito-borne diseases, such as West Nile virus (WNV). In this work, the short-term impact of weather conditions (temperature and precipitation) on Culex pipiens L.-Culex restuans Theobald mosquito abundance in Peel Region, Ontario, Canada, was investigated using the 2002-2009 mosquito data collected from the WNV surveillance program managed by Ontario Ministry of Health and Long-Term Care and a gamma-generalized linear model. There was a clear association between weather conditions (temperature and precipitation) and mosquito abundance, which allowed the definition of threshold criteria for temperature and precipitation conditions for mosquito population growth. A predictive statistical model for mosquito population based on weather conditions was calibrated using real weather and mosquito surveillance data, and validated using a subset of surveillance data. Results showed that WNV vector abundance on any one day could be predicted with reasonable accuracy from relationships with mean degree-days >9 degrees C over the 11 preceding days, and precipitation 35 d previously. This finding provides optimism for the development of weather-generated forecasting for WNV risk that could be used in decision support systems for interventions such as mosquito control.

  17. Complex spatial dynamics maintain northern leopard frog (Lithobates pipiens) genetic diversity in a temporally varying landscape

    Science.gov (United States)

    Mushet, David M.; Euliss, Ned H.; Chen, Yongjiu; Stockwell, Craig A.

    2013-01-01

    In contrast to most local amphibian populations, northeastern populations of the Northern Leopard Frog (Lithobates pipiens) have displayed uncharacteristically high levels of genetic diversity that have been attributed to large, stable populations. However, this widely distributed species also occurs in areas known for great climatic fluctuations that should be reflected in corresponding fluctuations in population sizes and reduced genetic diversity. To test our hypothesis that Northern Leopard Frog genetic diversity would be reduced in areas subjected to significant climate variability, we examined the genetic diversity of L. pipiens collected from 12 sites within the Prairie Pothole Region of North Dakota. Despite the region's fluctuating climate that includes periods of recurring drought and deluge, we found unexpectedly high levels of genetic diversity approaching that of northeastern populations. Further, genetic structure at a landscape scale was strikingly homogeneous; genetic differentiation estimates (Dest) averaged 0.10 (SD = 0.036) across the six microsatellite loci we studied, and two Bayesian assignment tests (STRUCTURE and BAPS) failed to reveal the development of significant population structure across the 68 km breadth of our study area. These results suggest that L. pipiens in the Prairie Pothole Region consists of a large, panmictic population capable of maintaining high genetic diversity in the face of marked climate variability.

  18. Isolation and identification of α-proteobacteria from Culex pipiens (Diptera Culicidae) larvae.

    Science.gov (United States)

    Tranchida, M C; Riccillo, P M; Rodriguero, M S; García, J J; Micieli, M V

    2012-01-01

    A survey of drainage ditches in suburban areas of La Plata, Buenos Aires province, Argentina for pathogens of Culex pipiens larvae was conducted from 2003 to 2006. C. pipiens larvae of opaque, white color were found in several of those field collections. When the white larvae were dissected and observed by phase-contrast microscopy in wet-mount preparations, the presence of bacteria, located in the hemocoel, was recorded. Laboratory experiments were performed to elucidate the pathway for transmission of this pathogen. Although approaches involving traditional culturing had failed to reveal the identity of the new microorganism present, molecular techniques to identify the pathogen in the studies reported here were successful. The partial sequence of the 16S-rRNA gene constitutes a powerful tool for the detection of new isolates from the hemocoele of C. pipiens larvae. These bacteria were characterized as belonging to the genus Novispirillum. In spite of the genus's wide distribution in different aquatic environments, information related to the parasitic relationship of Novispirillum spp. to aquatic insects is scarce, and this association has not been described in other mosquito species. This report constitutes the first documentation of Novispirillum spp. as a pathogen for mosquito larvae. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENS

    Institute of Scientific and Technical Information of China (English)

    Hai-qunCao; Yong-deYue; Zhen-huaPeng; Ri-maoHua; FengTang

    2004-01-01

    The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them,the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24h of 30.65mg/L,53.94mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively.The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of bamboo.

  20. Evaluation of released malathion and spinosad from chitosan/alginate/gelatin capsules against Culex pipiens larvae

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    Badawy MEI

    2016-09-01

    Full Text Available Mohamed EI Badawy,1 Nehad EM Taktak,2 Osama M Awad,2 Souraya A Elfiki,2 Nadia E Abou El-Ela2 1Department of Pesticide Chemistry and Technology, Faculty of Agriculture, 2Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria, Egypt Abstract: Efficacy of spinosad and malathion loaded in eco-friendly biodegradable formulations was evaluated for controlling Culex pipiens larvae. Malathion (organophosphorus larvicide and spinosad (naturally derived insecticide were loaded on chitosan/alginate/gelatin capsules. Capsules were characterized by size measurement, scanning electron microscopy, Fourier transform infrared spectroscopy, and water uptake. In vitro release kinetics of the larvicides was studied in the running and stagnant water. Biochemical studies on the larvae treated with technical and formulated insecticides were also demonstrated. The results indicated that the released spinosad was active for a long time up to 48 and 211 days in the running and stagnant water, respectively. However, the capsules loaded with malathion showed larvicidal activity for 20 and 27 days in the running and stagnant water, respectively. Technical and formulated malathion and spinosad had an inhibition effect on acetylcholinesterase, carboxylesterase, and glutathione S-transferase. The results proved that the prepared capsules consisting of biodegradable polymers containing larvicides could be effective as controlled-release formulation against C. pipiens larvae for a long period. Keywords: chitosan capsules, larvicide, controlled-release formulation, swelling, mosquitocidal activity, Culex pipiens, biochemical study

  1. In vitro Mosquito Larvicidal Activity of Marine Algae Against the Human Vectors, Culex quinquefasciatus (Say and Aedes aegypti (Linnaeus (Diptera: Culicidae

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    Akbar Idhayadhulla

    2011-01-01

    Full Text Available A total of twenty marine algae were collected from the rocky intertidal and subtidal regions of the southwest coast of India and extracted in methanol. The extracts were evaluated for larvicidal activity against the second and third instar larvae of the human vector mosquito Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae. Analysis on the activity profile of the above marine algae indicated that the early stage larvae were very sensitive to seven seaweed extracts that had been tested. Among the seven marine algae, Lobophora variegata was highly potential, showing LD50 value of 70.38 and 79.43 g mL-1 on the 2nd instar larvae of A. aegypti and C. quinquefasciatus respectively. The rank of larvicidal potency in highly active algae in the descending order is as follows: Lobophora variegata (Dictyotaceae>Spatoglossum asperum (Dictyotaceae>Stoechospermum marginatum (Dictyotaceae>Sargassum wightii (Sargassaceae >Acrosiphonia orientalis (Acrosiphoniaceae>Centroceras clavulatum (Ceramiacea>Padina tetrastromatica (Dictyotaceae. This is the first report that envisaged the mosquito larvicidal efficacy of L. variegata from the Indian coast. Therefore, this marine alga could be recognized as a potential resource of natural insecticide and can be developed to replace synthetic insecticides in future.

  2. Measurement of the susceptibility of Culex pipiens pallens and Musca domestica to common insecticides in urban Henan province%河南省两市区蚊蝇对常用杀虫剂敏感性测定

    Institute of Scientific and Technical Information of China (English)

    刘吉起; 张玉勤; 唐振强; 郭祥树; 赵旭东

    2011-01-01

    Objective To determine the susceptibility of Culex pipiens pollens and Musca domestica to common insecticides in Henan province. Methods The dipping method and the topical application method were used to measure the susceptibility of Cx. Pipiens pollens and M. Domestica to commonly used insecticides. Results In Zhumadian city, the resistance ratio of Cx. Pipiens pollens to common insecticides was 1.36-67.37, and Cx. Pipiens pollens had the highest resistance to deltamethrin. The resistance ratio of M. Domestica was 6.36 to greater than 443.39, and M. Domestica had the highest resistance to propoxur. In Nanyang city, the resistance ratio of Cx. Pipiens pollens was 1.33-40.26, and Cx. Pipiens pollens had the highest resistance to beta-cypermethrin. The resistance ratio of M. Domestica was 6.34 to greater than 443.39, and M. Domestica had the highest resistance to propoxur. Conclusion Cx. Pipiens pollens populations in investigated cities were still sensitive to temephos and fenobucarb but resistant to deltamethrin and beta-cypermethrin. M. Domastica had developed different resistances to all insecticides. It is important to use insecticides appropriately to prevent the development of resistance in mosquitoes and houseflies.%目的 了解河南省淡色库蚊和家蝇对常用卫生杀虫剂的敏感性.方法 淡色库蚊采用幼虫浸渍法,家蝇采用点滴法进行测定.结果 驻马店市城区淡色库蚊对供试杀虫剂相对抗性倍数为1.36~67.37倍,其中溴氰菊酯的抗性倍数最高;家蝇对供试杀虫剂相对抗性倍数为6.36~>443.39倍,其中残杀威的抗性倍数最高.南阳市城区淡色库蚊对供试杀虫剂相对抗性倍数为1.33~40.26倍,其中高效氯氰菊酯的抗性倍数最高;家蝇对供试杀虫剂相对抗性倍数为6.34~>443.39倍,其中残杀威的抗性倍数最高.结论驻马店和南阳市城区的淡色库蚊对双硫磷和仲丁威保持相对敏感,对溴氰菊酯和高效氯氰菊酯产生

  3. Evaluation of the pyrrole insecticide chlorfenapyr for the control of Culex quinquefasciatus Say.

    Science.gov (United States)

    Raghavendra, K; Barik, T K; Bhatt, R M; Srivastava, H C; Sreehari, U; Dash, A P

    2011-04-01

    Culex quinquefasciatus Say (Diptera: Culicidae) is a widely distributed mosquito vector species in India and also in other tropical regions of the world. This species is implicated in the transmission of lymphatic filariasis in many countries. This species is reported to be widely resistant to insecticides of different classes in current use. In the present study, bio-efficacy of chlorfenapyr, an insecticide of pyrrole class with a novel mode of action was tested for the control of Cx. quinquefasciatus. Studies were performed to determine the diagnostic dosage; residual efficacy on different artificially fabricated substrates, namely wood, mud, mud+lime, cement and cement+distemper; to assess cross-resistance with different insecticides; and synergism/antagonism using piperonyl butoxide (PBO). A dosage of 5.0% chlorfenapyr was determined as diagnostic dosage with 2 h exposure and 48 h holding period for assessing the susceptibility of mosquitoes. The residual efficacy was observed up to 34 weeks on wood and mud+lime substrates while on other substrates, it was about 15 weeks at a dosage of 400mg a.i./m(2). Laboratory-reared strains of Cx. quinquefasciatus showed cross-resistance, whereas field-collected mosquitoes showed absence of cross-resistance to chlorfenapyr. Potentiation bioassays showed antagonistic effect of PBO to chlorfenapyr toxicity owing to the involvement of oxidases in the initial step of a conversion of pro-insecticide chlorfenapyr to toxic form CL 303268. The present study results have shown that chlorfenapyr can be a potential insecticide for the control of multiple insecticide resistant strains of Cx. quinquefasciatus. However, in countries where indoor residual spray (IRS) is not targeted for the control of this species, like in India, chlorfenapyr used in IRS for the control of malaria vectors in rural and peri-urban areas can additionally provide control of Cx. quinquefasciatus also. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Behavioural response of female Culex pipiens pallens to common host plant volatiles and synthetic blends.

    Science.gov (United States)

    Yu, Bao-Ting; Ding, Yan-Mei; Mo, Jian-Chu

    2015-11-17

    Most mosquito species need to obtain sugar from host plants. Little is known about the chemical cues that Culex pipiens pallens use during their orientation to nectar host plants. In this study, we investigated the behavioural responses of female Cx. pipiens pallens to common floral scent compounds and their blends. Behavioural responses of female Cx. pipiens pallens to 18 individual compounds at different concentrations were determined in the olfactometer bioassays. A synthetic blend composed of behaviourally active compounds was formulated, and its attractiveness to mosquitoes was tested. Several most attractive compounds constituted a reduced blend, and its attractiveness was tested against the solvent and the full blend, respectively. Mosquito response in the olfactometer was analyzed by comparing the percentages of mosquitoes caught in the two arms by χ(2) test (observed versus expected). Fifteen of the 18 compounds were attractive to female Cx. pipiens pallens in the dose-dependent bioassays, with the exception of β-pinene, acetophenone and nonanal. (68.00 ± 2.49) % mosquitoes responded to the full blend composed of these 15 compounds on their optimal doses when tested against the solvent, with the preference index at 46.11 ± 3.57. Six individual compounds whose preference indices were over 40 constituted the reduced blend, and it attracted (68.00 ± 1.33) % mosquitoes when tested against the solvent while its preference index was 42.00 ± 3.54. When tested against the full blend simultaneously in the olfactometer, the reduced blend could attract (45.00 ± 2.69) % of released mosquitoes, which was as attractive as the full blend. Our results demonstrate that female Cx. pipiens pallens is differentially attracted by a variety of compounds at different concentrations. Alteration of the concentration strongly affects the attractiveness of the synthetic blend. Several floral scent volatiles might be the universal olfactory cues for various

  5. Juvenile hormone (JH esterase of the mosquito Culex quinquefasciatus is not a target of the JH analog insecticide methoprene.

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    Shizuo G Kamita

    Full Text Available Juvenile hormones (JHs are essential sesquiterpenes that control insect development and reproduction. JH analog (JHA insecticides such as methoprene are compounds that mimic the structure and/or biological activity of JH. In this study we obtained a full-length cDNA, cqjhe, from the southern house mosquito Culex quinquefasciatus that encodes CqJHE, an esterase that selectively metabolizes JH. Unlike other recombinant esterases that have been identified from dipteran insects, CqJHE hydrolyzed JH with specificity constant (k(cat/K(M ratio and V(max values that are common among JH esterases (JHEs. CqJHE showed picomolar sensitivity to OTFP, a JHE-selective inhibitor, but more than 1000-fold lower sensitivity to DFP, a general esterase inhibitor. To our surprise, CqJHE did not metabolize the isopropyl ester of methoprene even when 25 pmol of methoprene was incubated with an amount of CqJHE that was sufficient to hydrolyze 7,200 pmol of JH to JH acid under the same assay conditions. In competition assays in which both JH and methoprene were available to CqJHE, methoprene did not show any inhibitory effects on the JH hydrolysis rate even when methoprene was present in the assay at a 10-fold higher concentration relative to JH. Our findings indicated that JHE is not a molecular target of methoprene. Our findings also do not support the hypothesis that methoprene functions in part by inhibiting the action of JHE.

  6. Efectos de la competencia larval en los mosquitos de contenedores artificiales, Aedes aegypti y Culex pipiens (Diptera: Culicidae en condiciones semi-controladas Effects of larval competition between the container mosquitoes, Aedes aegypti and Culex pipiens (Diptera: Culicidae in semi-controlled conditions

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    Analía Francia

    2011-12-01

    Full Text Available Las larvas de los mosquitos Aedes aegypti (Linneo y Culex pipiens Linneo pueden criar conjuntamente en pequeños contenedores artificiales de agua, se genera así una competencia interespecífica y/o intraespecífica. El objetivo de este trabajo fue comparar la magnitud relativa de la competencia intra e interespecífica en A. aegypti y C. pipiens, generada durante el desarrollo larval en contenedores artifi ciales. Las variables medidas como respuesta fueron la supervivencia y el tiempo de desarrollo larval, y la biomasa total producida en estado de pupa. Se criaron larvas de ambos mosquitos en neumáticos de automóvil con agua declorinada y hojarasca. Se introdujeron larvas recién eclosionadas de acuerdo a la densidad (5 estimada según un censo previo de A. aegypti y C. pipiens. Serealizaron los siguientes tratamientos agregando larvas de: (1 A. aegypti hasta alcanzar δ A. aegypti determinada según el censo previo, (2 C. pipiens hasta δ C. pipiens del censo previo, (3 A. aegypti hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo, (4 C. pipiens hasta alcanzar la suma de δ A. aegypti y δ C. pipiens del censo previo y (5 A. aegypti y C. pipiens hasta δ A. aegypti y δ C. pipiens del censo previo. Las tres variables medidas fueron afectadas por los tratamientos, excepto la supervivencia y la biomasa producida por C. pipiens. Aedes aegypti fue más alterada por la competencia intraespecífica que por la competencia interespecífica. En C. pipiens, la competencia interespecífica superó en sus efectos a la competencia intraespecífica. Existió asimetría competitiva, ya que C. pipiens fue más afectada por A. aegypti que lo contrario.Larvae of Aedes aegypti (Linneo and Culex pipiens Linneo may develop together in small artificial water containers, promoting inter- and/or intra-specific competition. Our aim was to compare the relative importance of interspecific and intraspecific competition in both species during

  7. Immature Aedes mosquitoes colonize Culex quinquefasciatus breeding sites in neighborhoods in the municipality of Olinda, State of Pernambuco

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    Suzane Alves dos Santos

    2014-12-01

    Full Text Available Introduction The present study shows the colonization of Aedes mosquitoes in breeding sites specific for Culex quinquefasciatus in neighborhoods in the municipality of Olinda. Methods Samples were collected between May 2011 and June 2012 from breeding sites positive for Cx. quinquefasciatus by using a ladle and manual suction pump. Results Aedes aegypti (0.12%, Aedes albopictus (0.03%, and Cx. quinquefasciatus (99.8% were found across the breeding sites. Conclusions The presence of Aedes ssp. in several Cx. quinquefasciatus breeding sites with a heavy load of organic material demonstrates the need to review the concepts and methods used for treatment, as the use of specific larvicide for breeding sites of Culex.

  8. Larvivorous activity of Poecilia reticulata against Culex quinquefasciatus larvae in a polluted water drain in Hardwar, India.

    Science.gov (United States)

    Dua, Virendra K; Pandey, A C; Rai, Swapnil; Dash, A P

    2007-12-01

    The efficacy of the larvivorous fish Poecilia reticulata against mosquito larvae was monitored in a drain at Bharat Heavy Electricals Limited, Hardwar, India. The water was polluted and the water flow was in some way impeded. Poecilia reticulata failed to feed on Culex quinquefasciatus larvae in this drain. Laboratory experiments also confirmed the inefficacy of P. reticulata as a predator of Cx. quinquefasciatus larvae during the first 24 h. Significant differences in the efficacy of P. reticulata against Cx. quinquefasciatus were recorded between polluted water and drinking water. Poecilia reticulata preferred to feed on other available food present in the polluted water rather than on Cx. quinquefasciatus larvae. This was verified by the identification of plankton in the gut content of the fish and by the high density of plankton present in the polluted water.

  9. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L.(Diptera: Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S.Alrefaei; Marcello Nicoletti; Hui Wei; Angelo Canale; Giovanni Benelli

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L.(Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia.Methods: The tested conventional insecticides were Actikil and Pesgard, while the nonconventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photomicroscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains.Results: Cx. pipiens were more susceptible to Pesgard(LC50: 0.045 and 0.032 mg/L)than Actikil(0.052 and 0.038 mg/L) and Bacilod(0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin synthesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained(concentration which to inhibit the emergence of 50% of mosquito adults), the compound Dudim(0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal(0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively.Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  10. Insecticide susceptibility in larval populations of the West Nile vector Culex pipiens L. (Diptera:Culicidae) in Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Al Thabiani Aziz; Angelo Canale; Giovanni Benelli; Jazem Abdullah Mahyoub; Hasibur Rehman; Shalini Saggu; Kadarkarai Murugan; Chellasamy Panneerselvam; Majed Salum S Alrefaei; Marcello Nicoletti; Hui Wei

    2016-01-01

    Objective: To investigate the susceptibility to some conventional and non-conventional insecticides in laboratory and field larval populations of the West Nile vector Culex pipiens L. (Cx. pipiens), the dominant species in Jeddah Province, Saudi Arabia. Methods: The tested conventional insecticides were Actikil and Pesgard, while the non-conventional ones were Bacilod, Dudim and Baycidal. Probit analysis and photo-microscopical observations were carried out to shed light on acute toxicity in laboratory and field Cx. pipiens strains. Results: Cx. pipiens were more susceptible to Pesgard (LC50: 0.045 and 0.032 mg/L) than Actikil (0.052 and 0.038 mg/L) and Bacilod (0.129 and 0.104 mg/L), for the field and laboratory strains, respectively. Results showed that treatments with the chitin syn-thesis inhibitor Dudim and Baycidal evoked morphological effects similar to those induced by other insect growth regulators. According to IC50 values obtained (concen-tration which to inhibit the emergence of 50%of mosquito adults), the compound Dudim (0.000 3 and 0.000 1 mg/L) was more effective against Cx. pipiens L. mosquitoes than Baycidal (0.000 4 and 0.000 3 mg/L) for both the field and laboratory strains, respectively. Conclusions: Our results provide baseline data to enhance control programs and orient public health decisions on the selection of pesticides against mosquito vectors in Saudi Arabia.

  11. Larvicidal activity of a toxin from the seeds of Jatropha curcas Linn. against Aedes aegypti Linn. and Culex quinquefasciatus Say.

    Science.gov (United States)

    Chanthakan, Nuchsuk; Nuanchawee, Wetprasit; Sittiruk, Roytrakul; Sunanta, Ratanapo

    2012-06-01

    The larvicidal effects of the crude protein extract and purified toxin, Jc-SCRIP, from the seed coat of Jatropha curcas Linn. against the third instar larvae of mosquitoes, Aedes aegypti Linn. and Culex quinquefasciatus Say, were investigated. This test compared the effects of the purified toxin with crude protein extracts from seed kernels of J. curcas and Ricinus communis. At various concentrations of purified toxin and crude protein extract, the larval mortality of both Ae. aegypti and Cx. quinquefasciatus were positively correlated with increased exposure time. The larvae of Cx. quinquefasciatus were more susceptible to the toxin and both extracts than the larvae of Ae. aegypti. After 24 hours of exposure, the extract showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 3.89 mg/ml and 0.0575 mg/ml, respectively. The toxin, Jc-SCRIP, showed larvicidal activity against Ae. aegypti and Cx. quinquefasciatus with (LC50) values of 1.44 mg/ml and 0.0303 mg/ ml, respectively. These results indicated that the crude protein extract and Jc-SCRIP were more toxic to the third instar larvae of Cx. quinquefasciatus than that of Ae. aegypti. The potent larvicidal activities of the seed coat extract and the Jc-SCRIP toxin from J. curcas suggest that they may be used as bioactive agents to control the mosquito population.

  12. Mosquito larvicidal and ovicidal activity of puffer fish extracts against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Samidurai, Kaliyaperumal; Mathew, Nisha

    2013-03-01

    The extracts of liver (LE), ovary (OE), skin (SE) and muscle (ME) tissues of four species of puffer fishes viz., Arothron hispidus, Lagocephalus inermis, Lagocephalus scleratus and Chelonodon patoca were evaluated against larvae and eggs of three mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. The LC50 values were 1194.26, 1382.73 (LE); 1421.42, 1982.73 (OE); 7116.86, 15038.98 (ME) and 10817.8 ppm (SE) for An. stephensi and Cx. quinquefasciatus respectively for A. hispidus. In the case of L. inermis, the LC50 values were 1163.83, 1556.1 and 2426.38 (LE); 1653.53, 2734.74 (OE); 6067.47 (ME) and 10283.04 ppm (SE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. The LC50 values were 1509.98, 1608.69 (LE) and 1414.9, 2278.69 ppm (OE) for An. stephensi and Cx. quinquefasciatus respectively for the extracts of L. scleratus. In the case C. patoca extracts the LC50 values were 1182.29, 1543.00, 2441.03 (LE) and 1076.13, 2582.11 ppm (OE) for An. stephensi, Cx. quinquefasciatus and Ae. aegypti respectively. OE and LE of all puffer fishes exhibited zero percent egg hatchability from 600 to 1000 ppm against eggs of An. stephensi and Cx. quinquefasciatus. This study shows that puffer toxins are effective in killing the larvae and eggs of mosquitoes.

  13. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan M; Mathivanan T; Elumalai K; Krishnappa K; Anandan A

    2011-01-01

    Objective: To determine the ovicidal and repellent activities of methanol leaf extract ofErvatamia coronaria (E. coronaria) and Caesalpinia pulcherrima (C. pulcherrima) against Culex quinquefasciatus (Cx. quinquefasciatus), Aedes aegypti (Ae. aegypti) and Anopheles stephensi (An. stephensi). Methods: The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions. The hatch rates were assessed 48 h after treatment. The repellent efficacy was determined against three mosquito species at three concentrations viz., 1.0, 2.5 and 5.0 mg/cm2 under the laboratory conditions.Results:The crude extract of E. coronaria exerted zero hatchability (100% mortality) at 250, 200 and 150 ppm for Cx. quinquefasciatus, Ae. aegypti and An. stephensi, respectively. The crude extract of C. pulcherrima exerted zero hatchability (100% mortality) at 375, 300 and 225 ppm for Cx. quinquefasciatus, Ae. aegypti and An. Stephensi, respectively. The methanol extract of E. coronaria found to be more repellenct than C. pulcherrima extract. A higher concentration of 5.0 mg/cm2 provided 100% protection up to 150, 180 and 210 min against Cx. quinquefasciatus, Ae.aegypti and An. stephensi, respectively. The results clearly showed that repellent activity was dose dependent. Conclusions: From the results it can be concluded the crude extracts of E. coronaria and C. pulcherrima are an excellent potential for controlling Cx. quinquefasciatus, Ae. aegypti and An. stephensi mosquitoes.

  14. Larvicidal and repellent activity of tetradecanoic acid againstAedes aegypti (Linn.) andCulex quinquefasciatus (Say.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Sivakumar R; Jebanesan A; Govindarajan M; Rajasekar P

    2011-01-01

    Objective:To investigate the larvicidal and repellent efficacy of tetradecanoic acid against Aedes aegypti (Ae. aegypti) L. andCulex quinquefasciatus (Cx. quinquefasciatus) Say (Diptera: Culicidae).Methods: Larvicidal efficacy of tetradecanoic acid was tested at various concentrations against the early third instar larvae of Ae. aegypti andCx. quinquefasciatus. The repellent activity was determined against two mosquito species at three concentrations viz.,1.0,2.5 and5.0 ppm under the laboratory conditions.Results: The tetradecanoic acid was found to be more effective againstCx. quinquefasciatus thanAe. aegypti larvae. TheLC50values were14.08 ppm and25.10 ppm, respectively. Tetradecanoic acid showed lesser repellency againstAe. aegypti andCx. quinquefasciatus. The highest repellency was observed in higher concentration of5.0 mg/cm2provided100% protection up to60 and 90 min againstAe. aegypti andCx. quinquefasciatusrespectively.Conclusions: From the results it can be concluded the tetradecanoic acid is a potential for controlling Cx. quinquefasciatus andAe. aegypti mosquitoes.

  15. Vector competence of Aedes aegypti (L.) and Culex quinquefasciatus (Say) for Dirofilaria immitis (Leidy).

    Science.gov (United States)

    Tiawsirisup, Sonthaya; Nithiuthai, Suwannee

    2006-01-01

    This study was performed to examine the vector competence of Aedes aegypti and Culex quinquefasciatus for Dirofilaria immitis. Eleven individual experiments were conducted in this study. Nonthaburi and Udon Thani strains of Ae. aegypti were allowed to feed on infected dogs that had 5,750 and 4,600 microfilariae (mW) per ml of blood, respectively. Three groups of Bangkok-strain Cx. quinquefasciatus were allowed to feed on dogs that had 4,800, 5,200, and 5,850 mf per ml of blood. Six groups of Liverpool-strain Ae. aegypti were allowed to feed on dogs with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood. Three to 4% of Nonthaburi-strain, and 0-6% of Udon Thani-strain Ae. aegypti became infected and had infective-stage larvae (L3) of D. immitis in their probosces. Zero to 1 and 7% of Bangkok-strain Cx. quinquefasciatus had L3 in their probosces after taking blood meals with 4,800 and 5,850 mf per ml of blood, respectively. The percent-infected Liverpool-strain Ae. aegypti with L3 in their probosces were 3-12, 0-12, 10, 16, 7-19, and 0-21 after taking blood meals with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood, respectively, when tested at different post-blood-feeding days. This study showed both Ae. aegypti and Cx. quinquefasciatus from Thailand can become vectors for D. immitis; however, Liverpool-strain Ae. aegypti are more likely to be competent vectors for D. immitis than Ae. aegypti and Cx. quinquefasciatus from Thailand. The percent infection rates of Ae. aegypti and Cx. quinquefasciatus with D. immitis in the field in Thailand need to be investigated, to confirm the role of these mosquitoes in the life cycle of D. immitis in nature.

  16. Toxicity of the conventional energetics TNT and RDX relative to new insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

    Science.gov (United States)

    Stanley, Jacob K; Lotufo, Guilherme R; Biedenbach, James M; Chappell, Pornsawan; Gust, Kurt A

    2015-04-01

    An initiative within the US military is targeting the replacement of traditional munitions constituents with insensitive munitions to reduce risk of accidental detonation. The purpose of the present study was to comparatively assess toxicity of the traditional munitions constituents 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) with the new insensitive munitions constituents 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO). The following exposure durations were performed with Rana pipiens (leopard frog) tadpoles: TNT and DNAN, 96 h and 28 d; RDX, 10 d and 28 d; NTO, 28 d. The 96-h 50% lethal concentration (LC50) values and 95% confidence intervals for TNT and DNAN were 4.4 mg/L (4.2 mg/L, 4. 7 mg/L) and 24.3 mg/L (21.3 mg/L, 27.6 mg/L), respectively. No significant impacts on survival were observed in the 10-d exposure to RDX up to 25.3 mg/L. Effects on tadpole swimming distance were observed with a lowest-observed-effect concentration (LOEC) of 5.9 mg/L RDX. In the 28-d exposures, the LOECs for survival for TNT, DNAN, and NTO were 0.003 mg/L, 2.4 mg/L, and 5.0 mg/L, respectively. No significant mortality was observed in the RDX chronic 28-d exposure up to the highest treatment level tested of 28.0 mg/L. Neither tadpole developmental stage nor growth was significantly affected in any of the 28-d exposures. Rana pipiens were very sensitive to chronic TNT exposure, with an LOEC 3 orders of magnitude lower than those for insensitive munitions constituents DNAN and NTO.

  17. Prevalence of the pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of northern leopard frogs, Rana pipiens

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    Govindarajulu Purnima

    2010-03-01

    Full Text Available Abstract Background Emerging infectious diseases threaten naïve host populations with extinction. Chytridiomycosis, an emerging infectious disease of amphibians, is caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd and has been linked to global declines in amphibians. Results We monitored the prevalence of Bd for four years in the Northern leopard frog, Rana pipiens, which is critically imperiled in British Columbia (BC, Canada. The prevalence of Bd initially increased and then remained constant over the last three years of the study. Young of the year emerging from breeding ponds in summer were rarely infected with Bd. Some individuals cleared their Bd infections and the return rate between infected and uninfected individuals was not significantly different. Conclusions The BC population of R. pipiens appears to have evolved a level of resistance that allows it to co-exist with Bd. However, this small population of R. pipiens remains vulnerable to extinction.

  18. Larvicidal activity of Cyclamen (Myrsinaceae) extracts against the larvae of West Nile virus vector Culex pipiens L. (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Emre Oz; Samed Koc; Olcay Dinc Dusen; Ramazan Mammadov; Huseyin Cetin

    2013-01-01

    Objective: To evaluate the larvicidal activity of the tuber extracts isolated from two species of Cyclamen (Cyclamen mirabile Hildebr. and Cyclamen alpinum Dammann ex. Sprenger) against Culex pipiens L. (Diptera: Culicidae). Methods: Twenty young (first-second) or older (third-fourth) instars of the Culex pipiens were exposed to various concentrations (100 to 1 000 ppm) of the extracts. Mortality was recorded after 12-, 24-, 48-, 72- and 96-h of exposure. Results: We determined that the young larval stages were more susceptible to the extracts in comparison with the older larval stages. A comparison of LC50 and LC90 values has shown that Cyclamen mirabile was more active than Cyclamen alpinum. Conclusions: This study is the first to report on the larvicidal activity of the extracts of Cyclamen species against Culex pipiens. More studies are needed to isolate and identify the active components involved, their mode of action, and effects on other mosquito and pest species.

  19. Proteolytic profiling and comparative analyses of active trypsin-like serine peptidases in preimaginal stages of Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Borges-Veloso Andre

    2012-06-01

    Full Text Available Abstract Background The mosquito Culex quinquefasciatu s, a widespread insect in tropical and sub-tropical regions of the world, is a vector of multiple arboviruses and parasites, and is considered an important risk to human and veterinary health. Proteolytic enzymes play crucial roles in the insect physiology including the modulation of embryonic development and food digestion. Therefore, these enzymes represent important targets for the development of new control strategies. This study presents zymographic characterization and comparative analysis of the proteolytic activity found in eggs, larval instars and pupae of Culex quinquefasciatus. Methods The proteolytic profiles of eggs, larvae and pupa of Cx. quinquefasciatus were characterized by SDS-PAGE co-polymerized with 0.1% gelatin, according to the pH, temperature and peptidase inhibitor sensitivity. In addition, the proteolytic activities were characterized in solution using 100 μM of the fluorogenic substrate Z-Phe-Arg-AMC. Results Comparison of the proteolytic profiles by substrate-SDS-PAGE from all preimaginal stages of the insect revealed qualitative and quantitative differences in the peptidase expression among eggs, larvae and pupae. Use of specific inhibitors revealed that the proteolytic activity from preimaginal stages is mostly due to trypsin-like serine peptidases that display optimal activity at alkaline pH. In-solution, proteolytic assays of the four larval instars using the fluorogenic substrate Z-Phe-Arg-AMC in the presence or absence of a trypsin-like serine peptidase inhibitor confirmed the results obtained by substrate-SDS-PAGE analysis. The trypsin-like serine peptidases of the four larval instars were functional over a wide range of temperatures, showing activities at 25°C and 65°C, with an optimal activity between 37°C and 50°C. Conclusion The combined use of zymography and in-solution assays, as performed in this study, allowed for a more detailed analysis of the

  20. Competence of Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus Mosquitoes as Zika Virus Vectors, China

    Science.gov (United States)

    Liu, Zhuanzhuan; Zhou, Tengfei; Lai, Zetian; Zhang, Zhenhong; Jia, Zhirong; Zhou, Guofa; Williams, Tricia; Xu, Jiabao; Gu, Jinbao; Zhou, Xiaohong; Lin, Lifeng; Yan, Guiyun

    2017-01-01

    In China, the prevention and control of Zika virus disease has been a public health threat since the first imported case was reported in February 2016. To determine the vector competence of potential vector mosquito species, we experimentally infected Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus mosquitoes and determined infection rates, dissemination rates, and transmission rates. We found the highest vector competence for the imported Zika virus in Ae. aegypti mosquitoes, some susceptibility of Ae. albopictus mosquitoes, but no transmission ability for Cx. quinquefasciatus mosquitoes. Considering that, in China, Ae. albopictus mosquitoes are widely distributed but Ae. aegypti mosquito distribution is limited, Ae. albopictus mosquitoes are a potential primary vector for Zika virus and should be targeted in vector control strategies. PMID:28430562

  1. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina against Aedes aegypti and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Raimundo Wagner Souza Aguiar

    Full Text Available This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult and Aedes albopictus (C6/36 cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min and in contact with cultured insect cells (C6/36 induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  2. Insecticidal and repellent activity of Siparuna guianensis Aubl. (Negramina) against Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Aguiar, Raimundo Wagner Souza; dos Santos, Suetonio Fernandes; da Silva Morgado, Fabricio; Ascencio, Sergio Donizeti; de Mendonça Lopes, Magnólia; Viana, Kelvinson Fernandes; Didonet, Julcemar; Ribeiro, Bergmann Morais

    2015-01-01

    This study investigated the toxic effects of essential oils isolated from Siparuna guianensis against Aedes aegypti, Culex quinquefasciatus (eggs, larvae, pupae, and adult) and Aedes albopictus (C6/36) cells. The oviposition-deterring activity, egg viability, and repellence activity in the presence of different essential oils concentrations were determined. The essential oils showed high toxicity to all developmental stages of A. aegypti and C. quinquefasciatus. Furthermore, the oils also showed high repellent activity towards the adult stage of mosquitoes (0.025 to 0.550 μg/cm2 skin conferred 100% repellence up to 120 min) and in contact with cultured insect cells (C6/36) induced death possibly by necrosis. The results presented in this work show the potential of S. guianensis essential oils for the development of an alternative and effective method for the natural control of mosquitoes in homes and urban areas.

  3. Multiple mutations and mutation combinations in the sodium channel of permethrin resistant mosquitoes, Culex quinquefasciatus

    Science.gov (United States)

    Li, Ting; Zhang, Lee; Reid, William R.; Xu, Qiang; Dong, Ke; Liu, Nannan

    2012-10-01

    A previous study identified 3 nonsynonymous and 6 synonymous mutations in the entire mosquito sodium channel of Culex quinquefasciatus, the prevalence of which were strongly correlated with levels of resistance and increased dramatically following insecticide selection. However, it is unclear whether this is unique to this specific resistant population or is a common mechanism in field mosquito populations in response to insecticide pressure. The current study therefore further characterized these mutations and their combinations in other field and permethrin selected Culex mosquitoes, finding that the co-existence of all 9 mutations was indeed correlated with the high levels of permethrin resistance in mosquitoes. Comparison of mutation combinations revealed several common mutation combinations presented across different field and permethrin selected populations in response to high levels of insecticide resistance, demonstrating that the co-existence of multiple mutations is a common event in response to insecticide resistance across different Cx. quinquefasciatus mosquito populations.

  4. Repellent activity of herbal essential oils against Aedes aegypti (Linn. and Culex quinquefasciatus (Say.

    Directory of Open Access Journals (Sweden)

    Duangkamon Sritabutra

    2013-08-01

    Full Text Available Objective: To determine the mosquito repellent activity of herbal essential oils against female Aedes aegypti and Culex quinquefasciatus. Methods: On a volunteer’s forearm, 0.1 mL of each essential oil was applied to 3 cm伊10 cm of exposed skin. The protection time was recorded for 3 min after every 30 min. Results: Essential oil from clove oil in olive oil and in coconut oil gave the longest lasting period of 76.50 min and 96.00 min respectively against Aedes aegypti. The citronella grass oil in olive oil, citronella grass oil in coconut oil and lemongrass oil in coconut oil exhibited protection against Culex quinquefasciatus at 165.00, 105.00, and 112.50 min respectively. Conclusions: The results clearly indicated that clove, citronella and lemongrass oil were the most promising for repellency against mosquito species. These oils could be used to develop a new formulation to control mosquitoes.

  5. PENGARUH RADIASI SINAR GAMMA Co-60 TERHADAP STERILITAS DAN PERKEMBANGAN EMBRIO CULEX QUINQUEFASCIATUS

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    Riyani Setiyaningsih

    2015-05-01

    Full Text Available AbstrakTeknik Serangga Mandul merupakan teknik pengendalian vektor yang ramah lingkungan dan spesifi target. Aplikasi Teknik Serangga Mandul dalam pengendalian Cx quinquefasciatus belum pernah dilakukan di Indonesia, sehingga perlu uji pendahuluan sebelum aplikasi ke alam. Penelitian bertujuanmenentukan dosis optimal iradiasi sinar gamma Co-60 yang dapat mensterilkan dan berpengaruh terhadap perkembangan embrio Culex quinquefasciatus. Pupa jantan diradiasi dengan sinar gamma pada dosis 50 Gy, 50 Gy, 60 Gy, dan 70 Gy. Radiasi di lakukan di BATAN Jakarta. Nyamuk jantan yang muncul dari pupa kemudian di kawinkan dengan betina normal. Hasil perkawinan diamati sterilitas telur dan perkembangan embrio. Hasil penelitian menunjukkan sinar gamma Co-60 dosis 40 Gy, 50 Gy, 60 Gy, dan 70 Gy menyebabkan sterilitas telur yang dihasilkan 20,919%, 48,995%, 89,48%, dan 100%.Perlakuan dosis 40 Gy menghasilkan telur steril dengan 29,39% mengandung embrio dan 70,66% tidak mengandung embrio. Perlakuan dosis 50 Gy menghasilkan telur steril dengan 16,71% mengandung embrio dan 86,56% tidak mengandung embrio. Perlakuan dosis 60 Gy 9,35% telur steril mengandungembrio dan 90,64% tidak mengandung embrio. Perlakukan dosis 70 Gy 100 % telur yang dihasilkan steril dan tidak mengandung embrio. Dosis optimal yang dapat mensterilkan dan berpengaruh terhadap perkembangan embrio Culex quinquefasciatus adalah dosis 70 Gy.Kata kunci : Teknik Serangga Mandul, Culex quinquefasciatus dan sterilitasAbstractSterile Insect Tecnique is a vector control techniques that are environmentally safe and specifi targets. SIT application in the control of Cx quinquefasciatus has never been done in Indonesia, so we need a preliminary test before application to the nature. The aim of the study are to determine the optimal dose of gamma Co-60 radiation to sterilize and effect develop of embrio Culex quinquefasciatus. Male pupae radiated with gamma rays at a dose of 50 Gy, 50 Gy, 60 Gy, and 70 Gy

  6. Phylogenetic relationships of leopard frogs (Rana pipiens complex) from an isolated coastal mountain range in southern Sonora, Mexico.

    Science.gov (United States)

    Pfeiler, E; Markow, T A

    2008-10-01

    Mitochondrial DNA sequence data from the control region and 12S rRNA in leopard frogs from the Sierra El Aguaje of southern Sonora, Mexico, together with GenBank sequences, were used to infer taxonomic identity and provide phylogenetic hypotheses for relationships with other members of the Rana pipiens complex. We show that frogs from the Sierra El Aguaje belong to the Rana berlandieri subgroup, or Scurrilirana clade, of the R. pipiens group, and are most closely related to Rana magnaocularis from Nayarit, Mexico. We also provide further evidence that Rana magnaocularis and R. yavapaiensis are close relatives.

  7. Application Site and Mosquito Age Influences Malathion- and Permethrin-Induced Mortality in Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Aldridge, Robert L; Kaufman, Phillip E; Bloomquist, Jeffrey R; Gezan, Salvador A; Linthicum, Kenneth J

    2017-09-06

    Concentrations of malathion and permethrin typical in droplets generated from ultra-low-volume and low-volume applications used to control mosquito populations were evaluated for efficacy against multiple-aged Culex quinquefasciatus Say (Diptera: Culicidae), using a topical bioassay. Although insecticide droplets will impinge on many exoskeletal body regions and a range of ages of mosquitoes in a population, traditional mosquito topical bioassays focus pesticide application to the mesothoracic pleural or dorsal regions across an average mosquito age (e.g., 3-7 d). Our results document nonuniform insecticide sensitivity across body regions at ages not previously assessed in mosquitoes (teneral and 14-d old). We expect our findings to influence the topical bioassay process, illustrating the difference in mosquito body regions and ages that ultimately may explain insecticide effectiveness wherever droplets impinge upon the mosquito body during field control applications. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  8. An impossible journey? The development of Plasmodium falciparum NF54 in Culex quinquefasciatus.

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    Julia Knöckel

    Full Text Available Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species-among them culicines (Culex spp., Aedes spp.-present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito's immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito's blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph.

  9. Comparison of Biological Attributes of Culex quinquefasciatus (Diptera: Culicidae) Populations from India

    OpenAIRE

    Gokhale, Mangesh D.; Mandar S Paingankar; Dhaigude, Sachin D.

    2013-01-01

    Understanding the population dynamics of mosquito populations through life table analysis and insecticide susceptibility is important to assess the likely impact of vector control strategies as well as to aid the design of novel interventions. Variation in the life tables and other biological data was compared for two populations of Culex quinquefasciatus Say 1823 from geographically isolated regions, Gorakhpur and Pune from India. Under a standardized rearing regime and constant laboratory c...

  10. Mitotic-chromosome-based physical mapping of the Culex quinquefasciatus genome.

    Science.gov (United States)

    Naumenko, Anastasia N; Timoshevskiy, Vladimir A; Kinney, Nicholas A; Kokhanenko, Alina A; deBruyn, Becky S; Lovin, Diane D; Stegniy, Vladimir N; Severson, David W; Sharakhov, Igor V; Sharakhova, Maria V

    2015-01-01

    The genome assembly of southern house mosquito Cx. quinquefasciatus is represented by a high number of supercontigs with no order or orientation on the chromosomes. Although cytogenetic maps for the polytene chromosomes of this mosquito have been developed, their utilization for the genome mapping remains difficult because of the low number of high-quality spreads in chromosome preparations. Therefore, a simple and robust mitotic-chromosome-based approach for the genome mapping of Cx. quinquefasciatus still needs to be developed. In this study, we performed physical mapping of 37 genomic supercontigs using fluorescent in situ hybridization on mitotic chromosomes from imaginal discs of 4th instar larvae. The genetic linkage map nomenclature was adopted for the chromosome numbering based on the direct positioning of 58 markers that were previously genetically mapped. The smallest, largest, and intermediate chromosomes were numbered as 1, 2, and 3, respectively. For idiogram development, we analyzed and described in detail the morphology and proportions of the mitotic chromosomes. Chromosomes were subdivided into 19 divisions and 72 bands of four different intensities. These idiograms were used for mapping the genomic supercontigs/genetic markers. We also determined the presence of length polymorphism in the q arm of sex-determining chromosome 1 in Cx. quinquefasciatus related to the size of ribosomal locus. Our physical mapping and previous genetic linkage mapping resulted in the chromosomal assignment of 13% of the total genome assembly to the chromosome bands. We provided the first detailed description, nomenclature, and idiograms for the mitotic chromosomes of Cx. quinquefasciatus. Further application of the approach developed in this study will help to improve the quality of the southern house mosquito genome.

  11. Profiles of Amino Acids and Acylcarnitines Related with Insecticide Exposure in Culex quinquefasciatus (Say)

    Science.gov (United States)

    Martin-Park, Abdiel; Gomez-Govea, Mayra A.; Lopez-Monroy, Beatriz; Treviño-Alvarado, Víctor Manuel; Torres-Sepúlveda, María del Rosario; López-Uriarte, Graciela Arelí; Villanueva-Segura, Olga Karina; Ruiz-Herrera, María del Consuelo; Martinez-Fierro, Margarita de la Luz; Delgado-Enciso, Ivan; Flores-Suárez, Adriana E.; White, Gregory S.; Martínez de Villarreal, Laura E.; Ponce-Garcia, Gustavo; Black, William C.; Rodríguez-Sanchez, Irám Pablo

    2017-01-01

    Culex quinquefasciatus Say is a vector of many pathogens of humans, and both domestic and wild animals. Personal protection, reduction of larval habitats, and chemical control are the best ways to reduce mosquito bites and, therefore, the transmission of mosquito-borne pathogens. Currently, to reduce the risk of transmission, the pyrethroids, and other insecticide groups have been extensively used to control both larvae and adult mosquitoes. In this context, amino acids and acylcarnitines have never been associated with insecticide exposure and or insecticide resistance. It has been suggested that changes in acylcarnitines and amino acids profiles could be a powerful diagnostic tool for metabolic alterations. Monitoring these changes could help to better understand the mechanisms involved in insecticide resistance, complementing the strategies for managing this phenomenon in the integrated resistance management. The purpose of the study was to determine the amino acids and acylcarnitines profiles in larvae of Cx. quinquefasciatus after the exposure to different insecticides. Bioassays were performed on Cx. quinquefasciatus larvae exposed to the diagnostic doses (DD) of the insecticides chlorpyrifos (0.001 μg/mL), temephos (0.002 μg/mL) and permethrin (0.01 μg/mL). In each sample, we analyzed the profile of 12 amino acids and 31 acylcarnitines by LC-MS/MS. A t-test was used to determine statistically significant differences between groups and corrections of q-values. Results indicates three changes, the amino acids arginine (ARG), free carnitine (C0) and acetyl-carnitine (C2) that could be involved in energy production and insecticide detoxification. We confirmed that concentrations of amino acids and acylcarnitines in Cx. quinquefasciatus vary with respect to different insecticides. The information generated contributes to understand the possible mechanisms and metabolic changes occurring during insecticide exposure. PMID:28085898

  12. Efficacy of two formulations of the bioinsecticide spinosad against Culex quinquefasciatus in India.

    Science.gov (United States)

    Sadanandane, C; Boopathi Doss, P S; Jambulingam, P; Zaim, M

    2009-03-01

    Spinosad 12% suspension concentrate (SC) and 0.5% granular (G) formulations were tested against Culex quinquefasciatus immatures at 3 dosages--50, 100, and 150 mg active ingredient (AI)/m2--in cesspits, street drains, and disused wells in comparison with temephos 1% G at 1 part per million. The 2 formulations reduced the density of pupae of Cx. quinquefasciatus by 80-100% for 7-14 days in cesspits, 7-18 days in drains, and 33-69 days in disused wells at the 3 dosages tested. The 12% SC and 0.5% G formulations were equally effective in suppressing the larval and pupal populations of Cx. quinquefasciatus in all the habitats treated. At 100 mg AI/m2 in drains and cesspits, the efficacy of spinosad 0.5% G was greater than that of temephos (1% G) and that of spinosad 12% SC was comparable to that of temephos (1% G) applied to the 2 habitats. In disused wells, both the formulations lasted longer than temephos. Based on the small-scale trial, the rate of 150 mg AI/m2 of spinosad was selected for field application to cesspits and drains and 50 mg AI/m2 for application to disused wells. The efficacy observed in medium-scale trials was in agreement with that of small-scale trials. The trial showed that the 2 formulations of spinosad can be used for larval control of Cx. quinquefasciatus, at 50 mg AI/m2, applied at weekly intervals to cesspits and street drains and at monthly intervals to disused wells. At the higher dose of 150 mg AI/m2, the 2 formulations were effective in suppressing the pupal population for 2 wk in cesspits and street drains and for 2 months in disused wells.

  13. Natural vertical transmission of ndumu virus in Culex pipiens (Diptera: Culicidae) mosquitoes collected as larvae.

    Science.gov (United States)

    Lutomiah, Joel; Ongus, Juliette; Linthicum, Kenneth J; Sang, Rosemary

    2014-09-01

    Ndumu virus (NDUV) is a member of the family Togaviridae and genus Alphavirus. In Kenya, the virus has been isolated from a range of mosquito species but has not been associated with human or animal morbidity. Little is know about the transmission dynamics or vertebrate reservoirs of this virus. NDUV was isolated from two pools of female Culex pipiens mosquitoes, IJR37 (n = 18) and IJR73 (n = 3), which were collected as larvae on 15 April 2013 from two dambos near the village of Marey, Ijara District, Garissa County, Kenya, and reared to adults and identified to species. These results represent the first field evidence of vertical transmission of NDUV among mosquitoes.

  14. Native Argentinean cyclopoids (Crustacea: Copepoda) as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae) mosquitoes.

    Science.gov (United States)

    Tranchida, María C; Micieli, María V; Maciá, Arnaldo; García, Juan J

    2009-12-01

    Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis biological control agents for mosquitoes.

  15. Neem oil (Azadirachta indica) nanoemulsion--a potent larvicidal agent against Culex quinquefasciatus.

    Science.gov (United States)

    Anjali, C H; Sharma, Yamini; Mukherjee, Amitava; Chandrasekaran, Natarajan

    2012-02-01

    Nanoemulsion composed of neem oil and non-ionic surfactant Tween 20, with a mean droplet size ranging from 31.03 to 251.43 nm, was formulated for various concentrations of the oil and surfactant. The larvicidal effect of the formulated neem oil nanoemulsion was checked against Culex quinquefasciatus. O/W emulsion was prepared using neem oil, Tween 20 and water. Nanoemulsion of 31.03 nm size was obtained at a 1:3 ratio of oil and surfactant, and it was found to be stable. The larger droplet size (251.43 nm) shifted to a smaller size of 31.03 nm with increase in the concentration of Tween 20. The viscosity of the nanoemulsion increased with increasing concentration of Tween 20. The lethal concentration (LC50) of the nanoemulsion against Cx. quinquefasciatus was checked for 1:0.30, 1:1.5 and 1:3 ratios of oil and surfactant respectively. The LC50 decreased with droplet size. The LC50 for the ratio 1:3 nanoemulsions was 11.75 mg L(-1). The formulated nanoemulsion of 31.03 nm size was found to be an effective larvicidal agent. This is the first time that a neem oil nanoemulsion of this droplet size has been reported. It may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. Copyright © 2011 Society of Chemical Industry.

  16. Oviposition responses of gravid Culex quinquefasciatus and Culex tarsalis to bulrush (Schoenoplectus acutus) infusions.

    Science.gov (United States)

    Du, Y; Millar, J G

    1999-12-01

    Laboratory bioassays demonstrated that fermented infusions of dried bulrushes (Schoenoplectus acutus) strongly attracted and stimulated oviposition by gravid female Culex quinquefasciatus and Culex tarsalis. The responses of the 2 species varied with the concentration and method of preparation of the infusions, with responses generally increasing with increasing concentration. No major differences were found in the responses of either species to infusions prepared with bulrushes alone, or with bulrushes plus lactalbumin hydrolysate and brewer's yeast. Infusions remained more attractive than distilled water controls to both species for up to 8 wk. Field tests corroborated the results from the laboratory bioassays. Culex quinquefasciatus, Cx. tarsalis, and Cx. stigmatosoma egg rafts were collected from water pan traps baited with bulrush infusions. A few Culiseta incidens eggs also were collected. In multiple-choice tests using gravid female or egg traps, Cx. quinquefasciatus preferred the most concentrated bulrush infusions, whereas Cx. tarsalis preferred intermediate concentrations. Female Cx. stigmatosoma and Culiseta incidens also were attracted. Overall, these results may provide new leads towards developing synthetic chemical baits to attract bloodfed mosquitoes.

  17. Bacillus thuringiensis isolates entomopathogenic for Culex quinquefasciatus (Diptera: Culicidae and Anticarsia gemmatalis (Lepidoptera: Noctuidae

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    V. Gobatto

    Full Text Available Samples of the Bacillus thuringiensis (Bt were collected from soil and insects. Eight isolates were selected from rural soil, 15 from urban soil and 11 from insects. These were evaluated for entomopathogenicity against larvae of Anticarsia gemmatalis and Culex quinquefasciatus. The pathogenicity tests showed that a higher percentage of isolates were active against A. gemmatalis (60% compared to C. quinquefasciatus (31%. Probit analysis (LC50 indicated that against A. gemmatalis four of the isolates presented values similar to the reference strain against A. gemmatalis, while against C. quinquefasciatus one isolate showed an LC50 similar to the reference strain (IPS-82. SDS-PAGE characterisation of two isolates showed a 27 kDa protein fraction related to the Bt subspecies israelensis cytolytic toxin (cyt gene. One 130 kDa protein, possibly related to the Bt crystal inclusions (cry1 gene, was identified in the other two isolates, which were more toxic for lepidoptera; another isolate presented a protein of 100 kDa. Some new local Bt isolates had similar LC50 probit values to the reference strains.

  18. Vector competence of Kenyan Culex zombaensis and Culex quinquefasciatus mosquitoes for Rift Valley fever virus.

    Science.gov (United States)

    Turell, M J; Lee, J S; Richardson, J H; Sang, R C; Kioko, E N; Agawo, M O; Pecor, J; O'Guinn, M L

    2007-12-01

    Rift Valley fever (RVF) continues to be a significant problem in Kenya as well as in Egypt, Yemen, and Saudi Arabia. In order to determine the ability of Kenyan mosquitoes to transmit RVF virus (RVFV), we collected mosquitoes in the Lake Naivasha region of Kenya and evaluated them for their potential to transmit RVFV under laboratory conditions. After feeding on a hamster (Mesocricetus auratus) with a viremia of 10(9.7) plaque-forming units of virus/ml of blood, Culex zombaensis were highly susceptible to infection with RVFV, with 89% becoming infected. In contrast, Cx. quinquefasciatus that were fed on the same hamsters were marginally susceptible, with only 20% becoming infected. Differences in percentages of mosquitoes that developed a disseminated infection were equally disparate, with 55% and 8%, for Cx. zombaensis and Cx. quinquefasciatus, respectively. Forty-eight percent of the Cx. zombaensis with a disseminated infection that fed on a susceptible hamster transmitted virus by bite, indicating a moderate salivary gland barrier. However, the presence of a salivary gland barrier could not be determined for Cx. quinquefasciatus because none of the 18 mosquitoes that took a 2nd blood meal had a disseminated infection. These studies illustrate the need to identify the ability of individual mosquito species to transmit RVFV so that correct decisions can be made concerning the application of appropriate control measures during an outbreak.

  19. Synergistic effect of Croton caudatus (fruits) and Tiliacora acuminata (flowers) extracts against filarial vector Culex quinquefasciatus

    Institute of Scientific and Technical Information of China (English)

    Someshwar Singha; Siddharthasankar Banerjee; Goutam Chandra

    2011-01-01

    Objective:To investigate the synergistic effect of crude and solvent extract of Croton caudatus (C. caudatus ) (fruits) and Tiliacora acuminata (T. acuminata) (flowers) against the larval form of Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Crude and solvent [chloroform:methanol (1:1 v/v), benzene and ethyl acetate] extracts of two plants, C. caudatus (fruits) and T. acuminata (flowers) were examined separately against filarial vector Cx. quinquefasciatus larvae with gradually increasing concentration i.e. from 0.1%to 0.5%of crude extract and 25 ppm to 75 ppm of solvent extracts. To observe the synergistic effect, if any, extracts of these two plant parts were mixed at different concentrations and treated against mosquito larvae. Phytochemical analyses of extracts of both the plant parts were carried out. Results: In a 72-h bioassay experiment with plant extracts, highest mortalities were recorded at 0.5% (crude) and 75 ppm (solvent) concentration for fruits of C. caudatus and flowers of T. acuminata individually. For synergistic effect, only 0.2%of the mixture of these two crude extracts and 75 ppm concentration of chloroform:methanol (1:1 v/v) and ethyl acetate extracts showed 100%mortality after 24 h and 48 h of exposure respectively. Conclusions:In the field of mosquito control, insecticides of plant origin may serve as suitable alternative to the toxic chemicals. Some secondary metabolites in combination may be responsible for better larvicidal activity.

  20. Population dynamics of Culex quinquefasciatus filaria vector in Raipur City of Chhattisgarh State.

    Science.gov (United States)

    Dixit, Vandana; Gupta, A K; Kataria, Om; Prasad, G B K S

    2002-09-01

    Indoor resting Culex quinquefasciatus were collected from 17 localities of Raipur City using aspirator tube between 06.00 and 08.00 hrs. at monthly intervals for over a period of 12 months. Mosquitoes were also collected using animal and human baits. A total of 4973 C. quinquefasciatus were collected in 176 man hours from different locations of Raipur City with a mean density of 28.26 pmh. The vector was recorded throughout the year with higher densities during the months of March (44.29 pmh), February (41.29 pmh), August (38.58 pmh) and April (37.17 pmh). The lower densities were recorded during July (17.05 pmh), September (16.82 pmh) and November (16.64 pmh). The Gudhyari and Amanaka localities recorded the highest and lowest densities of C. quinquefasciatus respectively. No significant relationship was observed between the density variation of the vector and variation in temperature and/or humidity in the study region.

  1. Laboratory development of permethrin resistance and cross-resistance pattern of Culex quinquefasciatus to other insecticides.

    Science.gov (United States)

    Ramkumar, Govindaraju; Shivakumar, Muthugoundar S

    2015-07-01

    Resistance of mosquitoes to insecticides is a growing concern in India. Since only a few insecticides are used for public health and limited development of new molecules is expected in the next decade, maintaining the efficacy of control programs mostly relies on resistance management strategies. Developing such strategies requires a deep understanding of factors influencing resistance together with characterizing the mechanisms involved. Among factors likely to influence insecticide resistance in mosquitoes, agriculture and urbanization have been implicated but rarely studied in detail. In the present study, we evaluate the permethrin resistance and cross-resistance pattern of several insecticides in Culex quinquefasciatus mosquitoes. After 10 generation of selection with permethrin, the LC50 value for both larvae and adult Cx. quinquefasciatus was increased by 17.3- and 17.1-folds compared with susceptible strain. Detoxification enzyme profiles and native PAGE electrophoresis of esterase isoenzyme further revealed that esterase and CytP450 may be involved in permethrin resistance (PerRes) strain compared with susceptible strain. In addition to cross-resistance, study revealed that high resistance to cypermethrin (RR = 6.3, 8.8-folds). This study provided important information for understanding permethrin resistance and facilitating a better strategy for the management of resistance. These studies conclude that a strong foundation for further study of permethrin resistance mechanisms observed in Cx. quinquefasciatus mosquitoes.

  2. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus Organophosphorous and carbamate resistence in a population of Culex quinquefasciatus

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    José Eduardo Bracco

    1997-04-01

    Full Text Available Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente, mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively to this insect population is reported. The results show the need to develop an insecticide management program. The suscetibility to permethrin (pyretroid suggests the possibility of using this class of insecticide shoul the need for replacement of the insecticide in use arise.

  3. Insecticidal and genotoxic activity of Psoralea corylifolia Linn. (Fabaceae) against Culex quinquefasciatus Say, 1823.

    Science.gov (United States)

    Dua, Virendra K; Kumar, Arvind; Pandey, Akhilesh C; Kumar, Sandeep

    2013-02-04

    Indiscriminate use of synthetic insecticides to eradicate mosquitoes has caused physiological resistance. Plants provide a reservoir of biochemical compounds; among these compounds some have inhibitory effect on mosquitoes. In the present study the larvicidal, adulticidal and genotoxic activity of essential oil of Psoralea corylifolia Linn. against Culex quinquefasciatus Say was explored. Essential oil was isolated from the seeds of P. corylifolia Linn. Larvicidal and adulticidal bioassay of Cx. quinquefasciatus was carried out by WHO method. Genotoxic activity of samples was determined by comet assay. Identification of different compounds was carried out by gas chromatography- mass spectrometry analysis. LC50 and LC90 values of essential oil were 63.38±6.30 and 99.02±16.63 ppm, respectively against Cx. quinquefasciatus larvae. The LD50 and LD90 values were 0.057±0.007 and 0.109±0.014 mg/cm2 respectively against adult Cx. quinquefasciatus,. Genotoxicity of adults was determined at 0.034 and 0.069 mg/cm2. The mean comet tail length was 6.2548±0.754 μm and 8.47±0.931 μm and the respective DNA damage was significant i.e. 6.713% and 8.864% in comparison to controls. GCMS analysis of essential oil revealed 20 compounds. The major eight compounds were caryophyllene oxide (40.79%), phenol,4-(3,7-dimethyl-3-ethenylocta-1,6-dienyl) (20.78%), caryophyllene (17.84%), α-humulene (2.15%), (+)- aromadendrene (1.57%), naphthalene, 1,2,3,4-tetra hydro-1,6-dimethyle-4-(1-methyl)-, (1S-cis) (1.53%), trans- caryophyllene (0.75%), and methyl hexadecanoate (0.67%). Essential oil obtained from the seeds of P. corylifolia showed potent toxicity against larvae and adult Cx. quinquefasciatus. The present work revealed that the essential oil of P. corylifolia could be used as environmentally sound larvicidal and adulticidal agent for mosquito control.

  4. Effects of agricultural pesticides on the immune system of Xenopus laevis and Rana pipiens

    Energy Technology Data Exchange (ETDEWEB)

    Christin, M.S.; Menard, L.; Gendron, A.D.; Ruby, S.; Cyr, D.; Marcogliese, D.J.; Rollins-Smith, L.; Fournier, M

    2004-03-30

    Over the last 30 years, there have been mass declines in diverse geographic locations among amphibian populations. Multiple causes have been suggested to explain this decline. Among these, environmental pollution is gaining attention. Indeed, some chemicals of environmental concern are known to alter the immune system. Given that amphibians are frequently exposed to agricultural pesticides, it is possible that these pollutants alter their immune system and render them more susceptible to different pathogens. In this study, we exposed two frog species, Xenopus laevis and Rana pipiens, for a short period of time to a mixture of pesticides (atrazine, metribuzine, endosulfan, lindane, aldicarb and dieldrin) representative in terms of composition and concentrations to what it is found in the environment of the southwest region of the province of Quebec. The pesticides were known to be present in surface water of many tributaries of the St. Lawrence River (Quebec, Canada). Our results demonstrate that the mixture of pesticides could alter the cellularity and phagocytic activity of X. laevis and the lymphocyte proliferation of R. pipiens. Taken together, these results indicate that agricultural pesticides can alter some aspects of the immune response in frogs and could contribute to their global decline by rendering them more susceptible to certain infections.

  5. Suppression of allatotropin simulates reproductive diapause in the mosquito Culex pipiens.

    Science.gov (United States)

    Kang, David S; Denlinger, David L; Sim, Cheolho

    2014-05-01

    The cessation of juvenile hormone (JH) production is a key endocrine event that halts ovarian development and hence initiates diapause in females of the mosquito, Culex pipiens. The shutdown in endocrine activity of the corpora allata (CA), the source of JH, was manifested in the smaller size of CA in females reared under short daylengths (diapause) compared to those reared under long daylengths (nondiapause), as well as in low expression of the mRNA encoding allatotropin, the neuropeptide that promotes JH biosynthesis in the CA. Genes encoding both allatotropin and allatostatin were identified in C. pipiens, but only expression levels of allatotropin differed in the two types of females. Knockdown of allatotropin mRNA using RNA interference in females programmed for nondiapause resulted in a cessation of ovarian development akin to diapause. This arrest in development could be reversed with an application of JH. Our results thus suggest that suppression of allatotropin is a critical link in regulating the shutdown of the CA during diapause.

  6. Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.

    Science.gov (United States)

    Shi, Linna; Hu, Hongxia; Ma, Kai; Zhou, Dan; Yu, Jing; Zhong, Daibin; Fang, Fujin; Chang, Xuelian; Hu, Shengli; Zou, Feifei; Wang, Weijie; Sun, Yan; Shen, Bo; Zhang, Donghui; Ma, Lei; Zhou, Guofa; Yan, Guiyun; Zhu, Changliang

    2015-01-01

    Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs). However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.

  7. Efficiency of Colocasia esculenta leaves extract and histopathological effects on Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    El-Monairy, Olfat M

    2015-04-01

    This study evaluated the toxicity of Colocasia esculenta leaves extract on 3rd, 4th instars larvae and pupae of Culex pipiens. Bioassays showed that the 3rd instar larvae was the most susceptible to the different concentrations of extract, where the LC50 after 48 hr. post-exposure was 79.41, 109.65 & 141.25 for the 3rd, 4th instars larvae and pupal stage respectively. The histo-pathological effects of C. esculenta leaves extract on midgut regions and gastric caeca of the 3rd instar larvae were studied. When larvae were treated with 100 ppm of C. esculenta extract, all larvae developed dramatic pathological lesions especially Malpighian tubules were extensively affected. The midgut cells showed morphological deviation from normal ones, through slightly apical degenerated (lysis) of epithelial cells. The epithelial cells with extensive cellular microvilli were shrinkage, the nuclei showed pyknotic characteristic and the peritrophic membrane was appeared discontinuation in compared to control. When the 3rd larval instar was exposed to extract 400 ppm, the epithelial cells, adipose fabric and muscles were extensively affected. Also, the gastric caeca was affected obviously. These observation and alterations in cells of Cx. pipiens larvae are related to the dangerous effect of C. esculent leaves extract.

  8. The morphological variations of Culex pipiens (Diptera:Culicidae) in central Iran

    Institute of Scientific and Technical Information of China (English)

    Hossein Dehghan; Javid Sadraei; Seyed Hassan Moosa-Kazemi

    2011-01-01

    Objective:To determine the variations in morphological characters of Culex pipiens complex and identify the species complex. Methods:A study was carried out from April to October 2009 in Yazd Province, Iran. This study was performed in two randomly selected rural villages in Yazd County using different sampling methods such as larval collection, hand catch, pyrethrum space spray, light trap, and pit shelter collections. The data were analyzed using SPSS software Ver. 16. ANOVA and Tukey's post-hoc test was used to compare the ratios of the samples. Results:The average of the DV/D ration was 0.090±0.007 and the range was 0-0.33. The average D/V ratio was 1.07±0.02, with maximum 1.6 and minimum 0.6. The costa and subcosta intersection were observed beyond the bifurcation of R2+3 in most of the specimens. The bifurcations of R2+3 and M1+3 veins were not on one direction in all samples. The range of the R-Cell/R2+3 ratio was 2.42-7.91. The average ratio of cross wing was 2.25±0.04 with a range of 1.36-3.70. Conclusions:More populations of Culex pipiens from different areas of Iran need to be studied to gain complete information about the taxonomy and ecology of the species.

  9. Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.

    Directory of Open Access Journals (Sweden)

    Linna Shi

    Full Text Available Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs. However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.

  10. The Arrival of the Northern House Mosquito Culex pipiens (Diptera: Culicidae) on Newfoundland's Avalon Peninsula.

    Science.gov (United States)

    Chaulk, Andrew C; Carson, Kate P; Whitney, Hugh G; Fonseca, Dina M; Chapman, Thomas W

    2016-11-01

    Culex pipiens L., the northern house mosquito, is the primary vector of West Nile virus to humans along the east coast of North America and thus the focus of much study. This species is an urban container-breeding mosquito whose close contact with humans and flexibility in host choice has led to its classification as a "bridge vector"; that is, it is thought to move zoonotic diseases to humans from vertebrate reservoirs. While this invasive species is now well documented in its established range, which expanded in 2001 to include Canada, the existence of populations of this species along the fringes of its range are less well known. Here we report, using morphological and genetic techniques, the existence of two locations where Cx. pipiens exists in Newfoundland in both expected and unexpected sites based on projected habitat suitability on the island. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Wolbachia induces male-specific mortality in the mosquito Culex pipiens (LIN strain.

    Directory of Open Access Journals (Sweden)

    Jason L Rasgon

    Full Text Available BACKGROUND: Wolbachia are maternally inherited endosymbionts that infect a diverse range of invertebrates, including insects, arachnids, crustaceans and filarial nematodes. Wolbachia are responsible for causing diverse reproductive alterations in their invertebrate hosts that maximize their transmission to the next generation. Evolutionary theory suggests that due to maternal inheritance, Wolbachia should evolve toward mutualism in infected females, but strict maternal inheritance means there is no corresponding force to select for Wolbachia strains that are mutualistic in males. METHODOLOGY/PRINCIPAL FINDINGS: Using cohort life-table analysis, we demonstrate that in the mosquito Culex pipiens (LIN strain, Wolbachia-infected females show no fitness costs due to infection. However, Wolbachia induces up to a 30% reduction in male lifespan. CONCLUSIONS/SIGNIFICANCE: These results indicate that the Wolbachia infection of the Culex pipiens LIN strain is virulent in a sex-specific manner. Under laboratory situations where mosquitoes generally mate at young ages, Wolbachia strains that reduce male survival could evolve by drift because increased mortality in older males is not a significant selective force.

  12. Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb. Benth. (Fabaceae against Culex quinquefasciatus Say (Diptera: Culicidae

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    Govindarajan Marimuthu

    2014-04-01

    Full Text Available Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobium dulce (P. dulce against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005. The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx. quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions. Results: The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC 50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce. Conclusions: From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  13. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae

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    Marimuthu Govindarajan

    2014-03-01

    Full Text Available Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi (An. stephensi, Aedes aegypti (Ae. aegypti and Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions: From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  14. Mosquito larvicidal and ovicidal properties of Pithecellobium dulce (Roxb.) Benth. (Fabaceae) against Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan Marimuthu; Rajeswary Mohan

    2014-01-01

    Objective: To assess the larvicidal and ovicidal potential of the crude hexane, benzene, chloroform, ethyl acetate and methanol solvent extracts from the medicinal plant, Pithecellobiumdulce (P. dulce) against filariasis vector mosquito, Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five early third instar larvae of Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol of WHO (2005). The larval mortality was observed after 24 h of treatment. The ovicidal activity was determined against Cx.quinquefasciatus mosquito eggs to various concentrations ranging from 100-750 mg/L under the laboratory conditions.Results:The methanol extract of the leaves and seed of P. dulce was the most effective against the larvae with LC50 and LC90 values 164.12 mg/L, 214.29 mg/L, 289.34 mg/L and 410.18 mg/L being observed after 24 h of exposure. The efficacy of methanol was followed by that of the ethyl acetate, chloroform, benzene and hexane extracts. The mean percent hatchability of the egg rafts were observed after 48 h of treatment. About 100% mortality was observed at 500 mg/L for leaf and 750 mg/L for seed methanol extracts of P. dulce.Conclusions:From the results, it can be concluded that the larvicidal and ovicidal effect of P. dulce against Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  15. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus

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    Anjali Rawani

    2012-06-01

    Full Text Available Objective: To evaluate the larvicide and biting deterrency activity of bud of Polianthes tuberosa (P. tuberosa against Culex quinquefasciatus (Cx. quinquefasciatus and Anopheles stephensi (An. stephensi. Methods: Crude and solvent extract [ethyl acetate, chloroform: methanol (1:1, v/v, acetone] of fresh, mature, bud of P. tuberosa was tested against Cx. quinquefasciatus and An. stephensi. The repellent activity tested by chloroform: methanol (1:1, v/v solvent extract against both mosquito species. The appropriate lethal concentrations at 24 h for chloroform: methanol (1:1, v/v extract was also studied on non target organisms such as Toxorhynchites larvae, Diplonychus annulatum and Chironomus circumdatus. Results: In a 72 h bioassay experiment, 0.5 % crude extract showed the highest mortality and chloroform: methanol (1:1, v/v solvent extract showed the highest mortality, the maximum (P < 0.05 mortality was recorded at a concentration of 60 mg/L. The chloroform: methanol (1:1, v/v solvent extract provide 4 h protection against Cx. quinquefasciatus and 5 h against An. stephensi from biting. Conclusions: Both crude and chloroform: methanol (1:1, v/v extract showed efficient activity against Cx. quinquefasciatus, so it could be used as a mosquito larvicide agent. There is no change in the activity of non-target organism so, it is safe to use.

  16. Potential larvicidal and pupacidal activities of herbal essential oils against Culex quinquefasciatus say and Anopheles minimus (Theobald).

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    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-11-01

    The larvicidal and pupacidal effects of eight herbal essential oils were tested against third instar (L3), fourth instar (L4), and pupal stages of Culex quinquefasciatus and Anopheles minimus. Probit analysis was used to analyze the data. The larval mortality was recorded at 1, 5, 10, 30, and 60 minutes, and 24 hours. Pupal mortality was also recorded at 24 hours intervals for 96 hours when completed mortality was achieved. Citronella grass oil #2 (Cymbopogon nardus) proved to have the greatest toxicity against 3rd instar Cx. quinquefasciatus and An. minimus with LT50 at 1.2 and <0.2 minute, respectively. It exhibited a high level of effectiveness against 4th instar Cx. quinquefasciatus (LT50 at 5.1 minutes) and An. minimus (LT50 at 0.9 minute). Regarding pupacidal activity, Cx. quinquefasciatus and An. minimus pupae were susceptible to Lemon grass oil (LT50 at 1.2 hours) and Citronella grass oil #1 (LT50 at 0.6 hour), respectively. These oils had larvicidal and pupacidal activities with 100% mortality against L3, L4 and pupal stage Cx. quinquefasciatus at 10 minutes, 30 minutes and 24 hours. They also caused 100% mortality of An. minimus at 5 minutes (L3, L4), and 24 hours (pupal stage).

  17. Evaluation of four sampling techniques for surveillance of Culex quinquefasciatus (Diptera: Culicidae) and other mosquitoes in African rice agroecosystems.

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    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Muriu, Simon; Jacob, Benjamin; Mbogo, Charles M; John, Githure; Novak, Robert

    2007-05-01

    Field studies were conducted in a rice, Oryza sativa L., agroecosystem in Mwea Kenya to compare the efficiency of CO2-baited Centers for Disease Control (CDC) light traps against nonbaited CDC light traps and gravid traps against oviposition traps in outdoor collection of Culex quinquefasciatus Say (Diptera: Culicidae) and other mosquitoes. Collectively, 21 mosquito species from the genera Culex, Anopheles, Mansonia, Ficalbia, and Aedes were captured during the 10-wk study period. Cx. quinquefasciatus was the predominant species in all trap types with proportions ranging from 57% in the nonbaited CDC light traps to 95% in the gravid traps. Significantly higher numbers of Cx. quinquefasciatus and Culex annulioris Theobald were collected in the CO2-baited CDC light traps than in the nonbaited CDC light traps, but the numbers of other mosquito species, including malaria vectors Anopheles arabiensis Patton and Anopheles funestus Giles did not differ significantly between the two trap types. More Cx. quinquefasciatus females were collected in grass infusion-baited gravid traps than egg rafts of this species in oviposition traps containing the same infusion. Although most mosquitoes captured in CO,-baited and nonbaited CDC light traps were unfed, most of those collected in gravid traps were gravid. From these findings, it is concluded that at least in the rice-growing area of Mwea Kenya, CO2-baited CDC light traps in conjunction with gravid traps can be used in monitoring of Cx. quinquefasciatus both for control and disease surveillance.

  18. Effects of heavy metals on population growth and metallothionein gene expression in the mosquito Culex quinquefasciatus, from Calcutta, India

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sagartirtha; Duttagupta, Asish K.; Mal, Tarun K

    2004-01-01

    Major water bodies in and around the city of Calcutta (India) receive heavy metal contaminated effluents from industries, households, and vehicular traffic through sewage or drainage. We quantified concentrations of Cu, Zn, and Cd from three water bodies at Kalighat, Tangra, and VIP Road, respectively. The concentrations of these heavy metals were significantly greater in the summer than in monsoon when heavy downpours resulted in reduced metal concentrations. Concentrations of metals in the mosquito Culex quinquefasciatus also reflected such seasonal fluctuations. Hatchability and survivorship of C. quinquefasciatus significantly differed among the sites and were reduced significantly from the control. Exposure to heavy metals also induced MT-gene expression in C. quinquefasciatus, likely helping them to survive in the water bodies stressed with heavy metals. MT-gene activity demonstrated significant variation among sites and seasons with the highest activity in the summer in the VIP Road population. This study suggests that C. quinquefasciatus could be used as an ecological indicator of heavy metal pollution by monitoring its MT-gene expression. - The mosquito, Culex quinquefasciatus, might be useful as an indicator of trace metals.

  19. Mosquito larvicidal properties of Impatiens balsamina (Balsaminaceae) against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan; Mohan Rajeswary

    2014-01-01

    Objective: To assess the larvicidal potential of the crude benzene, chloroform, ethyl acetate and methanol solvent extracts of the medicinal plant Impatiens balsamina against Anopheles stephensi(An. stephensi), Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus). Methods: Twenty five third instar larvae of An. stephensi, Ae. aegypti and Cx. quinquefasciatus were exposed to various concentrations and were assayed in the laboratory by using the protocol recommended by WHO. The larval mortality was observed after 24 h of treatment. Results: Among extracts tested, the highest larvicidal activity was observed in leaf methanol extract of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 values 98.04, 119.68, 125.06 and 172.93, 210.14, 220.60 mg/L, respectively. Conclusions:From the results it can be concluded that the larvicidal effect of Impatiens balsamina against An. stephensi, Ae. aegypti and Cx. quinquefasciatus make this plant product promising as an alternative to synthetic insecticide in mosquito control programs.

  20. Oviposition preferences of Culex restuans and Culex pipiens (Diptera: Culicidae) for selected infusions in oviposition traps and gravid traps.

    Science.gov (United States)

    Jackson, Bryan T; Paulson, Sally L; Youngman, Roger R; Scheffel, Sabra L; Hawkins, Belinda

    2005-12-01

    Field studies were conducted in southwestern Virginia to determine the ovipositional preferences of Culex restuans and Culex pipiens by using ovitraps and gravid traps baited with selected infusions. For the ovitrap collections, 4 different infusions (manure, hay, grass, and rabbit chow) were used. Significant differences among infusions were detected on most sample dates for both species. For 3 of the first 4 wk of collections, the manure infusion collected significantly more Cx. restuans than all the other infusions. The hay and grass infusions collected the majority of the egg rafts during weeks 5-9. Cx. pipiens egg rafts were absent from the first 3 wk of collections. Of the remaining 6 wk, 4 showed significant differences in attractiveness of infusions, with the hay and grass infusions preferred by Cx. pipiens. Two infusions, manure and hay, were used for the gravid trap experiment and both Cx. restuans and Cx. pipiens data were combined for analysis. Only the first 2 wk showed significance, with manure being preferred over hay in both weeks. In later collections, the relative attractiveness of the hay infusion increased. A seasonal shift in infusion preference may be related to incubation temperature during preparation of the infusions. New infusions were prepared each week and incubation was done outside. Increased attractiveness of the hay infusion coincided with higher average temperatures in July and August. Hay infusion was very effective for trapping both Cx. pipiens and Cx. restuans in southwestern Virginia and is more convenient to use than manure. However, cool outside temperatures in the early season may interfere with the fermentation process and thus incubation should be done for a longer time or brought indoors.

  1. Insecticidal, repellent and oviposition-deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Prajapati, Veena; Tripathi, A K; Aggarwal, K K; Khanuja, S P S

    2005-11-01

    Essential oils extracted from 10 medicinal plants were evaluated for larvicidal, adulticidal, ovicidal, oviposition-deterrent and repellent activities towards three mosquito species; Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. The essential oils of Juniperus macropoda and Pimpinella anisum were highly effective as both larvicidal and ovicidal. The essential oil of P. anisum showed toxicity against 4th instar larvae of A. stephensi and A. aegypti with equivalent LD95 values of 115.7 microg/ml, whereas it was 149.7 microg/ml against C. quinquefasciatus larvae. Essential oils of Zingiber officinale and Rosmarinus officinalis were found to be ovicidal and repellent, respectively towards the three mosquito species. The essential oil of Cinnamomum zeylanicum resulted into highest repellent (RD95) values of 49.6, 53.9 and 44.2 mg/mat against A. stephensi, A. aegypti and C. quinquefasciatus, respectively apart from oviposition-deterrent potential.

  2. Mosquitocidal activity of Polygala arvensis Willd against Aedes aegypti (Linn., Anopheles stephensi (Liston. and Culex quinquefasciatus (Say. (Diptera: Culicidae

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    M. Deepa

    2014-12-01

    Full Text Available To determine the larvicidal, ovicidal and repellent activities of benzene and methanol extract of Polygala arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus Twenty five 3rd instar larvae of selected mosquitoes species were exposed to various concentrations (60-300 ppm and were assayed in the laboratory by using the protocol of WHO 2005; the 24 h LC50 values of the P. Arvensis leaf extract was determined following Probit analysis. The ovicidal activity was determined against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus exposed to variousconcentrations were tested under laboratory conditions and the hatch rates were assessed 120hrs post treatment. The repellent efficacy was determined against selected mosquitoes at three concentrations viz., 1.0, 2.0 and 3.0 mg/cm2 under the laboratory conditions. The LC50 and LC90 values of benzene and methanol extract of P. arvensis against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus larvae in 24 h were 75.32, 88.26, 82.46, 58.21, 46.37, 42.68 and 260.48, 275.26, 251.39, 208.45, 189.82 and 130.44 ppm, respectively. It has been noticed that the higher concentrations of P. arvensis extractspossesses strong ovicidal activity at 200 ppm concentration against Ae. aegypti, An. stephensi and C. quinquefasciatus, no egg hatchability was recorded. In the same way, methanol extracts showed maximum ovicidal activity followed by benzene extract against selected vector mosquitoes. In repellent activity, among two extracts tested P. arvensis methanol extract had strong repellent action against selected mosquitoes as it provided 100% protection against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus for 280min. From the results it can be concluded the P. arvensis extract was an excellent potential for controlling Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus mosquitoes.

  3. Larvicidal, oviposition, and ovicidal effects of Artemisia annua (Asterales: Asteraceae) against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Cheah, Shao-Xiong; Tay, Jia-Wei; Chan, Lai-Keng; Jaal, Zairi

    2013-09-01

    This study focuses on the larvicidal, oviposition, and ovicidal effects of a crude extract of Artemisia annua against Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus. Dried cells of Artemisia annua from cell suspension cultures were extracted using hexane. The extract showed moderate larvicidal effects against mosquitoes. At 24-h post treatment, the LC50 values for Anopheles sinensis, Aedes aegypti, and Culex quinquefasciatus were recorded as 244.55, 276.14, and 374.99 ppm, respectively. The percentage mortality of larvae was directly proportional to the tested concentration. Anopheles sinensis was found to be the most susceptible species, whereas Culex quinquefasciatus was the most tolerant to the Artemisia annua extract. The results indicated that the Artemisia annua extract showed concentration-dependent oviposition deterrent activity and had a strong deterrent effect. At 500 ppm, the percentage effective repellency was more than 85% compared with the control group for all the species, with oviposition activity index values of -0.94, -0.95, and -0.78 for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. In the ovicidal assay, the percentage hatchability of eggs after treatment with 500 ppm of Artemisia annua extract was significantly lower than the control, with values of 48.84 ± 4.08, 38.42 ± 3.67, and 79.35 ± 2.09% for Aedes aegypti, Anopheles sinensis, and Culex quinquefasciatus, respectively. Artemisia annua was found to be more effective against Aedes aegypti and Anopheles sinensis compared with Culex quinquefasciatus. This study indicated that crude extract of A. annua could be a potential alternative for use in vector management programs.

  4. EFIKASI LARVASIDA BERBAHAN AKTIF BENZOYL PHENIL UREA SEBAGAI INSECT GROWTH REGULATOR TERHADAP LARVA Culex quinquefasciatus DI LABORATORIUM

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    Siti Alfiah

    2014-06-01

    Full Text Available This study was conducted to determine the efficacy of an insect growth regulator (IGRbenzoyl phenil urea against Culex quinquefasciatus larvae, laboratory scale trial. The researchused seven concentrations of IGR, were evaluated 0,5 ; 1 ; 2 ; 2,5 ; 3 and 5 ppm and untreatedcontrol, using 4 replications (20 larvae each. The result showed that 0,5 ppm of the benzoylphenil urea could kill more 90% of Cx. quinquefasciatus larvae in 5 days, while concentrations 1; 2 ; 2,5 and 3 ppm in 4 days, and concentration 5 ppm in 3 days. The result was also revealedthat LC50 and LC90 0,57 and 23,2 ppm. Mosquito larvae mortalities were showed statisticallydifferent among concentrations (p < 0,05.Key words : Efficacy, benzoyl phenil urea, Culex quinquefasciatus Penelitian untuk mengetahui efikasi insect growth regulator (IGR benzoyl phenil ureaterhadap larva Culex quinquefasciatus telah dilakukan. Penelitian menggunakan 7 konsentrasipengujian yaitu 0,5 ppm, 1 ppm, 2 ppm, 2,5 ppm, 3 ppm, 5 ppm dan kontrol. Setiap konsentrasimenggunakan 4 kali pengulangan. Hasil menunjukkan bahwa larvasida benzoyl phenil ureamembunuh lebih dari 90% larva Cx. quinquefasciatus dengan konsentrasi 0,5 ppm dalam 5 hari,konsentrasi 1 ; 2 ; 2,5 dan 3 ppm dalam waktu 4 hari dan konsentrasi 5 ppm dalam waktu 3 hari.Konsentrasi yang diperlukan untuk membunuh 50% (LC50 dan 90% (LC90 larva uji adalah 0,57ppm dan 23,2 ppm. Uji analisis varian memberikan hasil bahwa ada perbedaan bermaknakematian larva antar konsentrasi pada taraf nyata 5%.Kata kunci : Efikasi, benzoyl phenil urea, Culex quinquefasciatus

  5. Macrocyclops albidus (Copepoda: cyclopidae) for the Biocontrol of Aedes albopictus and Culex pipiens in Italy.

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    Veronesi, Rodolfo; Carrieri, Marco; Maccagnani, Bettina; Maini, Stefano; Bellini, Romeo

    2015-03-01

    The aim of our study was to assess the potential of Macrocyclops albidus as a biological control agent against the 1st and 2nd instars of Culex pipiens and Aedes albopictus. Under laboratory conditions of prey saturation (50 1st instars/copepod), an average of 58.98% of Cx. pipiens and 54.99% of Ae. albopictus larvae were killed by 1 copepod in 24 h. Trials run in big drums containing 200 liters of water showed that the M. albidus population, inoculated in April, efficiently controlled the mosquito population for the entire season. The predator was particularly effective against Ae. albopictus, as only 2 larvae of this species were found in the treated drums, compared to 814 larvae in untreated control drums throughout the study period. No difference was observed in the control efficacy between the 2 initial densities of copepods used. The reduction in Ae. albopictus density in the drums with 100 and 500 M. albidus with respect to the control drums was 99.90 ± 0.35% and 100.0 ± 0.0%, respectively. For Cx. pipiens, the reduction in density was 88.69 ± 13.51% and 84.65% in drums inoculated with 100 and 500 copepods, respectively. Macrocyclops albidus populations survived through the winter and continued to keep the mosquito population under control during the 2008 season. The M. albidus population developed very well both in drums placed in sunny and shaded areas and proved to be tolerant to both high (summer) and low (winter) temperatures. Trials performed on M. albidus survival in catch basins showed that after a few weeks, the copepod population dramatically decreased and subsequently disappeared. The main problem for copepod survival in catch basins seemed to be the low oxygen tension and accumulation of toxic substances, rather than copepods being flushed out in heavy rainfall episodes. During the period when copepods were present, they maintained the mosquito population under control; their partial disappearance from the catch basins, however, would

  6. Seasonal dynamics of insecticide resistance, multiple resistance, and morphometric variation in field populations of Culex pipiens.

    Science.gov (United States)

    Taskin, Belgin Gocmen; Dogaroglu, Taylan; Kilic, Sercan; Dogac, Ersin; Taskin, Vatan

    2016-05-01

    Resistance to insecticides that impairs nervous transmission has been widely investigated in mosquito populations as insecticides are crucial to effective insect control. The development of insecticide resistance is also of special interest to evolutionary biologists since it represents the opportunity to observe the genetic consequences of a well-characterized alteration in the environment. Although the frequencies of resistance alleles in Culex pipiens populations against different groups of insecticides have been reported, no detailed information is available on the relative change in these allele frequencies over time. In this study, we collected mosquitoes of the Cx. pipiens complex from six locations in three seasons in the Aegean region of Turkey and examined the i) seasonal variations in resistance to four different chemical classes of insecticides, ii) seasonal fluctuations in frequencies of resistance-associated target-site mutations of the three genes (ace-1, kdr, and Rdl), and iii) potential seasonal variations in wing morphometric characters that may be modified in resistant mosquitoes. Our bioassay results indicated the presence of different levels of resistance to all tested insecticides for all three seasons in all locations. The results of the PCR-based molecular analysis revealed low frequencies of mutations in ace-1 and Rdl that are associated with resistance to malathion, bendiocarb, and dieldrin and no obvious seasonal changes. In contrast, we detected high frequencies and striking seasonal changes for two kdr mutations associated with resistance to DDT and pyrethroids. In addition, the evaluation of the field populations from all seasons in terms of the combinations of polymorphisms at four resistance-associated mutations did not reveal the presence of insects that are resistant to all pesticides. Results from the morphological analysis displayed a similar pattern for both wings and did not show a clear separation among the samples from the

  7. Differential expression of salivary proteins between susceptible and insecticide-resistant mosquitoes of Culex quinquefasciatus.

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    Innocent Djegbe

    Full Text Available BACKGROUND: The Culex quinquefasciatus mosquito, a major pest and vector of filariasis and arboviruses in the tropics, has developed multiple resistance mechanisms to the main insecticide classes currently available in public health. Among them, the insensitive acetylcholinesterase (ace-1(R allele is widespread worldwide and confers cross-resistance to organophosphates and carbamates. Fortunately, in an insecticide-free environment, this mutation is associated with a severe genetic cost that can affect various life history traits. Salivary proteins are directly involved in human-vector contact during biting and therefore play a key role in pathogen transmission. METHODS AND RESULTS: An original proteomic approach combining 2D-electrophoresis and mass spectrometry was adopted to compare the salivary expression profiles of two strains of C. quinquefasciatus with the same genetic background but carrying either the ace-1(R resistance allele or not (wild type. Four salivary proteins were differentially expressed (>2 fold, P<0.05 in susceptible (SLAB and resistant (SR mosquito strains. Protein identification indicated that the D7 long form, a major salivary protein involved in blood feeding success, presented lower expression in the resistant strain than the susceptible strain. In contrast, three other proteins, including metabolic enzymes (endoplasmin, triosephosphate isomerase were significantly over-expressed in the salivary gland of ace-1(R resistant mosquitoes. A catalogue of 67 salivary proteins of C. quinquefasciatus sialotranscriptome was also identified and described. CONCLUSION: The "resistance"-dependent expression of salivary proteins in mosquitoes may have considerable impact on biting behaviour and hence on the capacity to transmit parasites/viruses to humans. The behaviour of susceptible and insecticide-resistant mosquitoes in the presence of vertebrate hosts and its impact on pathogen transmission urgently requires further

  8. Differential expression of salivary proteins between susceptible and insecticide-resistant mosquitoes of Culex quinquefasciatus.

    Science.gov (United States)

    Djegbe, Innocent; Cornelie, Sylvie; Rossignol, Marie; Demettre, Edith; Seveno, Martial; Remoue, Franck; Corbel, Vincent

    2011-03-23

    The Culex quinquefasciatus mosquito, a major pest and vector of filariasis and arboviruses in the tropics, has developed multiple resistance mechanisms to the main insecticide classes currently available in public health. Among them, the insensitive acetylcholinesterase (ace-1(R) allele) is widespread worldwide and confers cross-resistance to organophosphates and carbamates. Fortunately, in an insecticide-free environment, this mutation is associated with a severe genetic cost that can affect various life history traits. Salivary proteins are directly involved in human-vector contact during biting and therefore play a key role in pathogen transmission. An original proteomic approach combining 2D-electrophoresis and mass spectrometry was adopted to compare the salivary expression profiles of two strains of C. quinquefasciatus with the same genetic background but carrying either the ace-1(R) resistance allele or not (wild type). Four salivary proteins were differentially expressed (>2 fold, Pmosquito strains. Protein identification indicated that the D7 long form, a major salivary protein involved in blood feeding success, presented lower expression in the resistant strain than the susceptible strain. In contrast, three other proteins, including metabolic enzymes (endoplasmin, triosephosphate isomerase) were significantly over-expressed in the salivary gland of ace-1(R) resistant mosquitoes. A catalogue of 67 salivary proteins of C. quinquefasciatus sialotranscriptome was also identified and described. The "resistance"-dependent expression of salivary proteins in mosquitoes may have considerable impact on biting behaviour and hence on the capacity to transmit parasites/viruses to humans. The behaviour of susceptible and insecticide-resistant mosquitoes in the presence of vertebrate hosts and its impact on pathogen transmission urgently requires further investigation. All proteomic data will be deposited at PRIDE (http://www.ebi.ac.uk/pride/).

  9. Larvicidal activity of Dregea volubilis and Bombax malabaricum leaf extracts against the filarial vector Culex quinquefasciatus

    Institute of Scientific and Technical Information of China (English)

    Emdad Hossain; Anjali Rawani; Goutam Chandra; Subhash C Mandal; Jayanta Kumar Gupta

    2011-01-01

    Objective: To analyze the larvicidal activity of two plant leaf powder and leaf-extracts, Dregea volubilis and Bombax malabaricum against Culex quinquefasciatus. Methods: The larvicidal bioassay was done for powdered leaves of Dregea volubilis and Bombax malabaricum individually and their methanol extracts against first-, second-, third-and fourth-instar larval forms of Culex quinquefasciatus. Mortality rate was recorded after 24, 48 and 72 h of post-exposure. LC50 and LC90 values were calculated at different time intervals for third instar larvae. Results:All the graded concentration (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) of powdered leaves showed significant (P<0.05) larval mortality. The mortality rate was higher in 50 ppm doses of methanolic extracts of both the plants against Culex quinquefaciatus. The corresponding LC50 values were 56.97 ppm and 48.85 ppm, respectively after 24 h of exposure. There is no mortality of non-target organism such as Chironomous circumdatus, Oreochromis niloticus niloticus and Diplonichus annulatum within 72 h of post exposure to 0.1%, 0.2%, 0.3%crude powdered leaves and methanolic extracts of both the two individual plants under the laboratory condition. The results of preliminary qualitative phytochemical analysis of both the plants revealed the presence of many bioactive principles such as steroids, tannins, flavonoids, triterpenoids, saponins, etc. that may be responsible for their bio-control potentiality. Conclusions:The results have shown potential and eco-friendly use of both plant extracts against larva of Culex quinquefasciatus for the first time.

  10. Pterodon emarginatus oleoresin-based nanoemulsion as a promising tool for Culex quinquefasciatus (Diptera: Culicidae) control.

    Science.gov (United States)

    Oliveira, Anna E M F M; Duarte, Jonatas L; Cruz, Rodrigo A S; Souto, Raimundo N P; Ferreira, Ricardo M A; Peniche, Taires; da Conceição, Edemilson C; de Oliveira, Leandra A R; Faustino, Silvia M M; Florentino, Alexandro C; Carvalho, José C T; Fernandes, Caio P

    2017-01-03

    Preparation of nanoformulations using natural products as bioactive substances is considered very promising for innovative larvicidal agents. On this context, oil in water nanoemulsions develop a main role, since they satisfactorily disperse poor-water soluble substances, such as herbal oils, in aqueous media. Pterodon emarginatus, popularly known as sucupira, has a promising bioactive oleoresin. However, to our knowledge, no previous studies were carried out to evaluate its potential against Culex quinquefasciatus, the main vector of the tropical neglected disease called lymphatic filariasis or elephantiasis. Thus, we aimed to investigate influence of different pairs of surfactants in nanoemulsion formation and investigate if a sucupira oleoresin-based nanoemulsion has promising larvicidal activity against this C. quinquefasciatus. We also evaluated morphological alteration, possible mechanism of insecticidal action and ecotoxicity of the nanoemulsion against a non-target organism. Among the different pairs of surfactants that were tested, nanoemulsions obtained with polysorbate 80/sorbitan monooleate and polysorbate 80/sorbitan trioleate presented smallest mean droplet size just afterwards preparation, respectively 151.0 ± 2.252 and 160.7 ± 1.493 nm. They presented high negative zeta potential values, low polydispersity index (algae Chlorella vulgaris at low concentration (25 mg/L). Our results suggest that optimal nanoemulsions may be prepared with different surfactants using a low cost and low energy simple method. Moreover, this prototype proved to be effective against C. quinquefasciatus, being considered an ecofriendly novel nanoproduct that can be useful in integrated control programs of vector control.

  11. Detection of Wolbachia endobacteria in Culex quinquefasciatus by Gimenez staining and confirmation by PCR

    Directory of Open Access Journals (Sweden)

    M. Muniaraj, R. Paramasivan, I.P. Sunish, N. Arunachalam, T. Mariappan, S. Victor Jerald Leo & K.J. Dhananjeyan

    2012-12-01

    Full Text Available Background & objectives: Wolbachia are common intracellular bacteria that are found in arthropods and nematodes.These endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, includingthe induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-eggincompatibility. Since they can also move horizontally across species boundaries, Wolbachia is gaining importancein recent days as it could be used as a biological control agent to control vector mosquitoes or for paratransgenicapproaches. However, the study of Wolbachia requires sophisticated techniques such as PCR and cell culturefacilities which cannot be affordable for many laboratories where the diseases transmitted by arthropod vectorsare common. Hence, it would be beneficial to develop a simple method to detect the presence of Wolbachia inarthropods.Method: In this study, we described a method of staining Wolbachia endobacteria, present in the reproductivetissues of mosquitoes. The reliability of this method was compared with Gram staining and PCR based detection.Results: The microscopic observation of the Gimenez stained smear prepared from the teased ovary of wildcaught and Wolbachia (+ Cx. quinquefasciatus revealed the presence of pink coloured pleomorphic cells ofWolbachia ranging from cocci, comma shaped cells to bacillus and chain forms. The ovaries of Wolbachia (–cured mosquito did not show any cell. Although Gram’s staining is a reliable differential staining for the otherbacteria, the bacterial cells in the smears from the ovaries of wild caught mosquitoes did not take the stain properlyand the cells were not clearly visible. The PCR amplified product from the pooled remains of wild caught andWolbachia (+ Cx. quinquefasciatus showed clear banding, whereas, no banding was observed for the negativecontrol (distilled water and Wolbachia (– Cx. quinquefasciatus.Interpretation & conclusion: The

  12. Residential characteristics aggravating infestation by Culex quinquefasciatus in a region of Northeastern Brazil

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    Juliana Cavalcanti Correia

    2012-12-01

    Full Text Available OBJECTIVE: Analyse how basic sanitation conditions, water supply and housing conditions affect the concentration of Culex quinquefasciatus METHODS: Populations of C. quinquefasciatus in 61 houses in the municipality of Olinda, PE, were monitored between October 2009 and October 2010. Observations were carried out in homes without the presence of preferred breeding sites in order to identify characteristics that may be aggravating factors for the development of the mosquito. Five aggravating factors were analysed: vegetation cover surrounding the home, number of residents/home, water storage, sewage drainage and water drainage. These characteristics were analysed in terms of presence or absence and as indicators of the degree of infestation, which was estimated through monitoring the concentration of eggs (oviposition traps - BR-OVT and adults (CDC light traps. RESULTS: Sewage drainage to a rudimentary septic tank or to the open air was the most frequent aggravating factor in the homes (91.8%, although the presence of vegetation was the only characteristic that significantly influenced the increase in the number of egg rafts (p = 0.02. The BR-OVT achieved positive results in 95.1% of the evaluations, with the presence of at least one egg raft per month. A total of 2,366 adults were caught, with a mosquito/room/night ratio of 32.9. No significant difference was found in the number of mosquitoes caught in the homes. CONCLUSIONS: Although the sanitation and water supply influence the population density of C. quinquefasciatus, residence features that are not usually considered in control measures can be aggravating factors in sustaining the mosquito population.

  13. Larval Habitat Substrates Could Affect the Biology and Vectorial Capacity of Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Shah, Rizwan Mustafa; Ali, Qasim; Alam, Mehboob; Shad, Sarfraz Ali; Majeed, Shahid; Riaz, Muhammad; Binyameen, Muhammad

    2017-05-01

    Culex quinquefasciatus Say is an important disease vector throughout much of the world. Experiments were conducted to determine the effects of different larval habitat substrates on the fitness and biting efficiency of Cx. quinquefasciatus adults. Our findings indicate that the development time (egg to adult) of larvae reared in irrigation water was 8.63 d while that of larvae reared in distilled water was 17.10 d (Effect size = 0.95). However, the rate of adult emergence was similar for all the tested treatments. Furthermore, the mean weight of an egg raft varied between larval habitats: distilled water (1.83 mg), rainfall water (1.25 mg), irrigation water (1.52 mg), and sewerage water (2.52 mg) (Effect size = 0.91). But, the fecundity (eggs per female) and hatchability (%) were statistically similar in all the rearing mediums (Effect size = 0.79). Longevity of females in all the tested populations did not differ significantly (Effect size = 0.91). The mean relative growth rates of larvae reared in tap water (0.80) and distilled water (0.86) habitats were lower than growth rates in all other rearing habitats (Effect size = 0.96). The intrinsic rate of natural increase in tap water (0.27) and irrigation water (0.35) was significantly higher than that in distilled water (0.09) and sewerage water (0.16) (Effect size = 0.84). Adults reared in rain water had the highest biting efficiency among all the tested populations. These results provide useful information for the management of Cx. quinquefasciatus. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Bioaccumulation kinetics of the conventional energetics TNT and RDX relative to insensitive munitions constituents DNAN and NTO in Rana pipiens tadpoles.

    Science.gov (United States)

    Lotufo, Guilherme R; Biedenbach, James M; Sims, Jerre G; Chappell, Pornsawan; Stanley, Jacob K; Gust, Kurt A

    2015-04-01

    The manufacturing of explosives and their loading, assembling, and packing into munitions for use in testing on training sites or battlefields has resulted in contamination of terrestrial and aquatic sites that may pose risk to populations of sensitive species. The bioaccumulative potential of the conventional explosives 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and of the insensitive munitions (i.e., less shock sensitive) compound 2,4-dinitroanisole (DNAN) were assessed using the Northern leopard frog, Rana pipiens. Trinitrotoluene entering the organism was readily biotransformed to aminodinitrotoluenes, whereas no transformation products were measured for RDX or DNAN. Uptake clearance rates were relatively slow and similar among compounds (1.32-2.19 L kg(-1) h(-1) ). Upon transfer to uncontaminated water, elimination rate was very fast, resulting in the prediction of fast time to approach steady state (5 h or less) and short elimination half-lives (1.2 h or less). A preliminary bioconcentration factor of 0.25 L kg(-1) was determined for the insensitive munitions compound 3-nitro-1,2,4-trizole-5-one (NTO) indicating negligible bioaccumulative potential. Because of the rapid elimination rate for explosives, tadpoles inhabiting contaminated areas are expected to experience harmful effects only if under constant exposure conditions given that body burdens can rapidly depurate preventing tissue concentrations from persisting at levels that may cause detrimental biological effects.

  15. Current susceptibility status of Malaysian Culex quinquefasciatus (Diptera: Culicidae) against DDT, propoxur, malathion, and permethrin.

    Science.gov (United States)

    Low, V L; Chen, C D; Lee, H L; Lim, P E; Leong, C S; Sofian-Azirun, M

    2013-01-01

    A nationwide investigation was carried out to determine the current susceptibility status of Culex quinquefasciatus Say populations against four active ingredients representing four major insecticide classes: DDT, propoxur, malathion, and permethrin. Across 14 study sites, both larval and adult bioassays exhibited dissimilar trends in susceptibility. A correlation between propoxur and malathion resistance and between propoxur and permethrin resistance in larval bioassays was found. The results obtained from this study provide baseline information for vector control programs conducted by local authorities. The susceptibility status of this mosquito should be monitored from time to time to ensure the effectiveness of current vector control operations in Malaysia.

  16. Effect of ivermectin on the larvae of Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Malongo, Bernard B.; Simonsen, Paul E.

    2016-01-01

    Background: Ivermectin is used extensively globally for treatment of helminthic and ectoparasitic infections in animals and humans. The effect of excreted ivermectin on non-target organisms in aquatic and terrestrial environments has been increasingly reported. Due to its low water solubility...... and adsorption to sediments, the ivermectin exposure-risk to aquatic organisms dwelling in different strata of water bodies varies. This study assessed the survival of larvae of Anopheles gambiae Giles and Culex quinquefasciatus Say, when exposed to low concentrations of ivermectin under laboratory conditions...

  17. Effects of exposure to ultraviolet light on the development of Rana pipiens, the northern leopard frog

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.J.; Wofford, H.W. [Union Univ., Jackson, TN (United States)

    1996-10-01

    The increase in ultraviolet light intensity levels due to ozone depletion recently has been linked to the decline in amphibian population. In this experiment, eggs and larvae of Rana pipiens were subjected to differing amounts of ultraviolet radiation to determine the effects of ultraviolet light on the development of amphibian tadpoles. The total length, length of body without tail, and maximum width of each specimen was recorded for a month of the tadpoles` development, including several measurements after the ultraviolet exposures were concluded. It was found that ultraviolet exposure significantly reduced the size of the organisms in comparison with the control group in all three measured areas. Ultraviolet radiation altered the health and appearance of the exposed organisms and was lethal at large amounts. This experiment showed that ultraviolet radiation could cause many problems in developing amphibians. By slowing their development and physically weakening predation, thus contributing to a decline in overall population levels.

  18. Correlation between carboxylesterase alleles and insecticide resistance in Culex pipiens complex from China

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    Liu Yangyang

    2011-12-01

    Full Text Available Abstract Background In China, large amounts of chemical insecticides are applied in fields or indoors every year, directly or indirectly bringing selection pressure on vector mosquitoes. Culex pipiens complex has evolved to be resistant to all types of chemical insecticides, especially organophosphates, through carboxylesterases. Six resistant carboxylesterase alleles (Ester were recorded previously and sometimes co-existed in one field population, representing a complex situation for the evolution of Ester genes. Results In order to explore the evolutionary scenario, we analyzed the data from an historical record in 2003 and a recent investigation on five Culex pipiens pallens populations sampled from north China in 2010. Insecticide bioassays showed that these five populations had high resistance to pyrethroids, medium resistance to organophosphates, and low resistance to carbamates. Six types of Ester alleles, EsterB1, Ester2, Ester8, Ester9, EsterB10, and Ester11 were identified, and the overall pattern of their frequencies in geographic distribution was consistent with the report seven years prior to this study. Statistical correlation analysis indicated that Ester8 and Ester9 positively correlated with resistance to four insecticides, and EsterB10 to one insecticide. The occurrences of these three alleles were positively correlated, while the occurrence of EsterB1 was negatively correlated with Ester8, indicating an allelic competition. Conclusion Our analysis suggests that one insecticide can select multiple Ester alleles and one Ester allele can work on multiple insecticides. The evolutionary scenario of carboxylesterases under insecticide selection is possibly "one to many".

  19. Cutaneous transport of Ca2+ in the frog Rana pipiens: significance and specificity.

    Science.gov (United States)

    Stiffler, D F; Eskandari, S; Dejbakhsh, S

    1997-04-01

    Rana pipiens were divided into four groups: controls; hypocalcemic frogs, depleted of salts by acclimation to deionized water; hypercalcemic frogs, calcium-loaded by the introduction of 40 mumol calcium gluconate; and frogs exposed to the potential competing ions Mg2+, Sr2+, and Ba2+. All groups displayed calcium influx that was proportional to external [Ca2+]; however, the group acclimated to deionized water also displayed hypocalcemia (P 0.3 mM) external [Ca2+]. Ca2+ efflux was depressed in hypocalcemic frogs, and thus net Ca2+ flux shifted from net loss in control frogs to net uptake in hypocalcemic frogs. Hypocalcemia also resulted in increased skin Ca2+ deposits which may be related to a decreased Ca2+ (and other ions) permeability as a consequence of the acclimation to deionized water. Another group of frogs was Ca(2+)-loaded by injecting calcium gluconate: Sodium gluconate controls did not significantly alter Ca2+ fluxes. The frogs that received calcium gluconate treatments became hypercalcemic (P < 0.01) and did not display significant changes in calcium fluxes, nor did they show significant changes in skin calcium deposits. We conclude that hypocalcemia leads to regulatory responses that stimulate active Ca2+ transport in Rana pipiens skin and possibly inhibits cutaneous and renal efflux. We also conclude that hypercalcemia does not alter calcium fluxes across skin. The ions from Group IIA of the Periodic Table of Elements had little effect on Ca2+ fluxes at concentrations ranging from 0.5-4.0 mM; neither Sr2+ or Ba2+ affected Ca2+ influx. The only divalent ion tested that influenced Ca2+ was Mg2+, which significantly inhibited Ca2+ influx but only at 4.0 mM or eight times the external [Ca2+]. We conclude, therefore, that the Ca2+ transport mechanism is fairly specific for Ca2+ within Group IIA.

  20. Larvicidal Activity of Cassia occidentalis (Linn. against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

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    Deepak Kumar

    2014-01-01

    Full Text Available Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn. against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn. belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn. was observed at 200 and 300 ppm (parts per million. The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn. is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn. has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control.

  1. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin.

    Science.gov (United States)

    N'Guessan, Raphael; Boko, Pelagie; Odjo, Abiba; Knols, Bart; Akogbeto, Martin; Rowland, Mark

    2009-04-01

    To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Eight-week trial conducted in experimental huts. Indoor residual spraying killed 82.9% of An. gambiae overall (mean mortality: 79.5%) compared to 53.5% overall (mean mortality: 61.7%) in the hut containing the lower dosed ITN. Analysis of data on a fortnightly basis showed high levels of mosquito mortality and blood-feeding inhibition during the first few weeks after treatment. Control of C. quinquefasciatus by the IRS and ITN interventions showed a similar trend to that of An. gambiae and though the average level of mortality was lower it was still much higher than with pyrethroid treatments against this population. Chlorfenapyr's reputation for being rather slow acting was evident particularly at lower dosages. The treatments showed no evidence of excito-repellent activity in this trial. Chlorfenapyr has the potential to control pyrethroid resistant populations of A. gambiae. There is a need to develop long-lasting formulations of chlorfenapyr to prolong its residual life on nets and sprayed surfaces. On nets it could be combined with a contact irritant pyrethroid to give improved protection against mosquito biting while killing pyrethroid-resistant mosquitoes that come into contact with the net.

  2. A rapid knockdown effect of Penicillium citrinum for control of the mosquito Culex quinquefasciatus in Thailand.

    Science.gov (United States)

    Maketon, Monchan; Amnuaykanjanasin, Alongkorn; Kaysorngup, Achirayar

    2014-02-01

    Twenty local isolates of entomopathogenic fungi were determined for control of the larvae and adults of Culex quinquefasciatus. In a laboratory experiment, a Penicillium sp. CM-010 caused 100% mortality of third-instar larvae within 2 h using a conidial suspension of 1 × 10⁶ conidia ml⁻¹. Its LC₅₀ was 3 × 10⁵ conidia ml⁻¹, and the lethal time (LT₅₀) was 1.06 h. Cloning and sequencing of its internal transcribed spacer region indicated that this Penicillium species is Penicillium citrinum (100% identity in 434 bp). Mortality of the adult was highest with Aspergillus flavus CM-011 followed with Metarhizium anisopliae CKM-048 from 1 × 10⁹ conidia ml⁻¹. P. citrinum CM-010 at 1 × 10⁶ conidia ml⁻¹ killed 100% larvae within 2 h while Bacillus thuringiensis var. israelensis at 5 ITU ml⁻¹ required 24 h. This P. citrinum CM-010 also greatly reduced survival of C. quinquefasciatus larvae in an unreplicated field test. Light and transmission electron micrographs showed that the fungal conidia were ingested by the larvae and deposited in the gut. The metabolite patulin was produced by P. citrinum CM-010 instead of citrinin.

  3. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes.

    Science.gov (United States)

    Huang, Yan-Jang S; Hettenbach, Susan M; Park, So Lee; Higgs, Stephen; Barrett, Alan D T; Hsu, Wei-Wen; Harbin, Julie N; Cohnstaedt, Lee W; Vanlandingham, Dana L

    2016-10-01

    During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America.

  4. Larvicidal Activity of Cassia occidentalis (Linn.) against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

    Science.gov (United States)

    Kumar, Deepak; Chawla, Rakesh; Dhamodaram, P.; Balakrishnan, N.

    2014-01-01

    Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn.) against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn.) belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn.) was observed at 200 and 300 ppm (parts per million). The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn.) is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn.) has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control. PMID:24688786

  5. Alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides.

    Science.gov (United States)

    Alves, Stênio Nunes; Serrão, José Eduardo; Melo, Alan Lane

    2010-08-01

    This study describes morphological alterations in the fat body and midgut of Culex quinquefasciatus larvae following exposure to different insecticides. To this end, both third and fourth instars of C. quinquefasciatus larvae were exposed for 30 and 60 min to organophosphate (50 ppb), pyrethroids (20 and 30 ppb), and avermectin derivates (1.5 and 54 ppb). Following incubation, pH measurements of the larvae gut were recorded. The fat body and midgut were also analyzed by light and transmission electron microscopy. These studies demonstrate a decrease in the pH of the larvae anterior midgut following exposure to all of the tested insecticides. Histochemical tests revealed a strong reaction for neutral lipids in the control group and a marked decrease in the group exposed to cypermethrin. Furthermore, a weak reaction with acidic lipids in larvae exposed to deltamethrin, temephos, ivermectin and abamectin was also observed. Insecticide-exposed larvae also exhibited cytoplasm granule differences, relative to control larvae. Finally, we noted a small reduction in microvilli size in the apex of digestive cells, although vesicles were found to be present. The destructive changes in the larvae were very similar regardless of the type of insecticide analyzed. These data suggest that alterations in the fat body and midgut are a common response to cellular intoxication.

  6. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes

    Science.gov (United States)

    Huang, Yan-Jang S.; Park, So Lee; Higgs, Stephen; Barrett, Alan D. T.; Hsu, Wei-Wen; Harbin, Julie N.; Cohnstaedt, Lee W.; Vanlandingham, Dana L.

    2016-01-01

    During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV) has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII) with clade b of GI (GI-b). Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b), GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America. PMID:27706157

  7. Use of floating layers of polystyrene beads to control populations of the filaria vector Culex quinquefasciatus.

    Science.gov (United States)

    Curtis, C F; Malecela-Lazaro, M; Reuben, R; Maxwell, C A

    2002-12-01

    Floating layers of polystyrene beads suffocate mosquito larvae and pupae and inhibit egg laying. The layers are very durable in breeding sites with water contained within walls, as in wet pit latrines and soakage pits. In some areas such pits constitute an important breeding site for Culex quinquefasciatus. Trials have been conducted in communities in Zanzibar, Tanzania, and in Tamil Nadu, India, where such mosquito populations were the vectors of Wuchereria bancrofti. In each case, treatment of all the pits with polystyrene beads was integrated with mass treatment of the people with antifilarial drugs-in Zanzibar in 1988 with diethylcarbamazine (DEC) and in India in the 1990s with DEC plus ivermectin. The results were compared with those in communities with the mass drug treatment alone and with control communities with neither treatment. The polystyrene-bead treatments greatly and sustainably reduced the vector populations. Comparison of the communities after drug treatment ceased showed that this form of vector control contributed markedly to the prevention of a resurgence of filarial infection. Where Cx. quinquefasciatus breeding in pits form a major component of the vector population, use of polystyrene-bead layers could assist considerably in the process of eliminating lymphatic filariasis by mass drug administration.

  8. Larvicidal activity of essential extract of Rosmarinus officinalis against Culex quinquefasciatus.

    Science.gov (United States)

    Yu, Jing; Liu, Xiang-Yi; Yang, Bin; Wang, Jie; Zhang, Fu-Qiang; Feng, Zi-Liang; Wang, Chen-Zhu; Fan, Quan-Shui

    2013-03-01

    Constituents in rosemary (Rosmarinus officinalis) have been shown to have larvicidal activity against invertebrates. In order to explore the properties of crude extract of rosemary further, we studied the chemical composition and its activity against dichlorodiphenyltrichloroethane (DDT)-susceptible, DDT-resistant, and field strains of Culex quinquefasciatus larvae. The major components of R. officinalis were found to be eucalyptol and camphor, with relative percentages of 10.93% and 5.51%, respectively. Minor constituents included limonene, (+)-4-carene, isoborneol, 1-methyl-4-(1-methylethylidene)-cyclohexene, and pinene. The median lethal concentration (LC50) values of the essential oil of R. officinalis against DDT-susceptible, DDT-resistant, and field strains of larvae of Cx. quinquefasciatus were 30.6, 26.4, and 38.3 mg/liter, respectively. The single median lethal dose (LD50) in Kunming mice was 4752 mg/kg. Essential oils from R. officinalis may, therefore, provide an effective natural plant product for use in mosquito prevention and control.

  9. Laboratory and field evaluation of an oviposition trap for Culex quinquefasciatus(Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Rosângela MR Barbosa

    2007-06-01

    Full Text Available An ovitrap (BR-OVT based on physical and chemical stimuli for attracting gravid Culex quinquefasciatus (Diptera: Culicidae females was developed and evaluated under laboratory and field conditions. Attractants were assayed using alternative chamber bioassays prior to being used in the BR-OVT oviposition trap. A significant preference of gravid females for sites containing conspecific egg rafts was observed, as a response to the natural oviposition pheromone, as well as for sites treated with the synthetic pheromone erythro-6-acetoxy-5-hexadecanolide. Five- to 20-day old grass infusion was strongly attractive to gravid females for laying eggs. On the other hand, entomopathogenic Bacillus sphaericus (Bs did not influence the choice of an oviposition site when used in combination with grass infusion and can therefore be used as a larvicide in ovitraps. Results from field trials showed that the BR-OVT with grass infusion and with or without Bs works as a preferred oviposition site for Cx. quinquefasciatus. The BR-OVT was more effective for egg collection when placed indoors and comparison with the number of egg rafts laid in cesspits over 40 days indicates that this very simple ovitrap may be a useful tool for monitoring populations of the most important of the vectors of bancroftian filariasis.

  10. Entomopathogenic fungus generated Nanoparticles for enhancement of efficacy in Culex quinquefasciatus and Anopheles stephensi

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    N. SONI, S. PRAKASH

    2012-05-01

    Full Text Available Objective: To evaluate to efficacy of silver and gold generated larvicide with the help of entomopathogenic fungus Chrysosporium tropicum against the Culex quinquefasciatus and Anopheles stephensi larvae. Methods: The silver and gold nanoparticles were quantified and observed by the Micro-scan reader and X-ray diffraction technique. The micrographs of silver and gold nanoparticles were obtained by the Transmission electron microscope and Scanning electron microscope. The larvicidal efficacy was then performed at six different log concentrations by the probit analysis. Results: The characterization study confirmed the spherical shaped and sized (20-50 and 2-15 nm of silver and gold nanoparticles. The all larval stages of Cx. quinquefasciatus were found more susceptible to the synthesized silver nanoparticles. Whereas, the larvae of An. stephensi were found more susceptible to larvicide synthesized with gold nanoparticles. Conclusions: The results suggested that the silver and gold nanoparticles generated by the entomopathogenic fungus C. tropicum is an environmentally safer and greener approach for mosquito control and new possibility in vector control strategy.

  11. Mosquito larvicidal activity of Rauvolfia serpentina L. seeds against Culex quinquefasciatus Say

    Institute of Scientific and Technical Information of China (English)

    Dipanwita Das; Goutam Chandra

    2012-01-01

    Objective:To establish the larvicidal activities, if any of solvent extracts of Rauvolfia serpentina (R. serpentina) L. seeds against Culex quinquefasciatus (Cx. quinquefasciatus) Say, 1823 as target species. Methods:Seeds of R. serpentina were extracted with five solvents graded according to the polarity [viz. petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol] continuing one after another with the same seeds. Results:Mortality rate with petroleum ether extract was significantly higher than other extracts. The mortality rates of late 3rd instar larvae were 50.33±5.51, 10.00±1.00, 0.00±0.00, 21.33±1.53 and 0.00±0.00 in 100 ppm concentration of petroleum ether, benzene, ethyl acetate, acetone and absolute alcohol respectively, after 24 h of exposure period. Conclusions:Results of this study show that petroleum ether extract of R. serpentina seed may be considered as a potent source of mosquito larvicidal agent.

  12. Insecticidal activity of isobutylamides derived from Piper nigrum against adult of two mosquito species, Culex pipiens pallens and Aedes aegypti.

    Science.gov (United States)

    Park, Il-Kwon

    2012-01-01

    The insecticidal activity of Piper nigrum fruit-derived piperidine alkaloid (piperine) and N-isobutylamide alkaloids (pellitorine, guineensine, pipercide and retrofractamide A) against female adults of Culex pipiens pallens and Aedes aegypti was examined. On the basis of 24-h LD(50) values, the compound most toxic to female C. pipiens pallens was pellitorine (0.4 µg/♀) followed by guineensine (1.9 µg/♀), retrofractamide A (2.4 µg/♀) and pipercide (3.2 µg/♀). LD(50) value of chlorpyrifos was 0.03 µg/♀. Against female A. aegypti, the insecticidal activity was more pronounced in pellitorine (0.17 µg/♀) than in retrofractamide A (1.5 µg/♀), guineensine (1.7 µg/♀), and pipercide (2.0 µg/♀). LD(50) value of chlorpyrifos was 0.0014 µg/♀.

  13. Sampling gravid Culex quinquefasciatus (Diptera: Culicidae) in Tanzania with traps baited with synthetic oviposition pheromone and grass infusions

    NARCIS (Netherlands)

    Mboera, L.E.G.; Takken, W.; Mdira, K.Y.; Pickett, J.A.

    2000-01-01

    The effectiveness of traps baited with (5R,6S)-6-acetoxy-5-hexadecanolide (the synthetic oviposition pheromone) and grass infusions in sampling a population of gravid Culex quinquefasciatus Say was conducted in Muheza, Northeast Tanzania. A counterflow geometry (CFG) trap baited with pheromone and s

  14. Synthesis of eco-friendly silver nanoparticles from Morinda tinctoria leaf extract and its larvicidal activity against Culex quinquefasciatus.

    Science.gov (United States)

    Kumar, K Ramesh; Nattuthurai, N; Gopinath, Ponraj; Mariappan, Tirupathi

    2015-02-01

    Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, chikungunya and Japanese encephalitis, and they accounted for global mortality and morbidity with increased resistance to common insecticides. The aim of this study was to investigate the larvicidal potential of the acetone leaf extracts of Morinda tinctoria and synthesized silver nanoparticles against third instar larvae of Culex quinquefasciatus Say (Diptera: Culicidae). Nanoparticles are being used in many commercial applications. It was found that aqueous silver ions can be reduced by aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Synthesized AgNPs were characterized by ultraviolet-visible (UV-vis) spectroscopy, Atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) analysis. The synthesized silver nanoparticles have also been tested against the third instar larvae of C. quinquefasciatus. The leaf extract and the AgNPs high mortality values were 50 % lethal concentration (LC50) = 8.088 and 1.442 ppm against C. quinquefasciatus, respectively. The results recorded from ultraviolet-visible spectroscopy, atomic force microscopy and Fourier transform infrared spectroscopy support the biosynthesis and characterization of silver nanoparticles. These results suggest that the leaf extract of M. tinctoria and synthesis of AgNPs have the potential to be used as an ideal eco-friendly approach for the control of C. quinquefasciatus. By this approach, it is suggestive that this rapid synthesis of nanoparticles would be proper for developing a biological process for mosquito control.

  15. Effectivity of Sugar-Apple (Annona squamosa Seed Extract with a Different Length of Storage against Culec quinquefasciatus Larvae

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    Heni Prasetyowati

    2012-06-01

    Full Text Available Synthetic insecticide have been used to control Culex quinquefasciatus, but the prolonged usage of synthetic insecticide has a bad impact on the environment and may caused resistance. Sugar apple’s (Annona squamosa seeds which contain alkaloid can be used as an alternative insecticide that was safe for environment. This research aims is to know the effect of sugar apple’s seeds with different length of storage as C. quinquefasciatus larvacide. This research was an experimental study with a randomized controlled trial group design approach. The test material was an extract of sugar apple’s seeds which have been kept for 0, 1, 2, and 3 week with LC50 (0,47 ppm was used. Each treatment used 25 C. quinquefasciatus larvae from third instar larvae stage and replicated five times. After exposed for 24 hours, dead larvae counted. The result confirmed that the extract of sugar apple’s seeds which has been stored in 0, 1, 2, and 3 week did not showed any significant different on larvae mortality. Extract of sugar apple’s seeds which have been stored in 0, 1, 2, and 3 week have an equal activity as Culex quinquefasciatus larvicide.

  16. Ovicidal and larvicidal activities of some plant extracts against Aedes aegypti L. and Culex quinquefasciatus Say (Diptera: Culicidae

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    Rajiv Gandhi Munusamy

    2016-06-01

    Full Text Available Objective: To evaluate the ovicidal and larvicidal activities of hexane, chloroform and methanol extracts of Gymnema sylvestre, Scilla peruvina, Rubia cordifolia (R. cordifolia and Elytraria acaulis roots against the eggs and larvae of Aedes aegypti L. (Ae. aegypti and Culex quinquefasciatus Say (Cx. quinquefasciatus at different concentrations of 62.5, 125, 250 and 500 mg/L. Methods: The plant materials were shade dried in the laboratory for one week and then coarsely powdered. The root powder of each plant (500 g was sequentially soaked in hexane, chloroform and methanol for 96 h with intermittent shaking. After 96 h, the solution was filtered and the filtrate was concentrated under reduced pressure by using rotary vacuum evaporator. All the crude extracts thus obtained were stored in air tight glass vials and Petri dishes. Results: The ovicidal activity results showed that the methanol extract of R. cordifolia root was the most potent compared to other with 82.40% and 70.40% activity against the eggs of Cx. quinquefasciatus and Ae. aegypti, respectively, at 500 mg/L concentration similarly, methanol extract of R. cordifolia root also recorded the highest larvicidal activity with LC50 and LC90 values of 95.69, 347.96 mg/L against Cx. quinquefasciatus and 102.23, 350.20 mg/L against Ae. aegypti larvae, respectively. Conculsions: Hence, methanol extract of R. cordifolia root can be probed further for effective biological control of mosquitoes.

  17. Variation in the number and position of siphonal setae in Culex quinquefasciatus from Key West and Vero Beach, Florida, USA.

    Science.gov (United States)

    Rey, Jorge R; O'Meara, George F; O'Oonnell, Sheila M; Darsie, Richard F

    2006-09-01

    Variations in diagnostic siphonal characters of Culex quinquefasciatus larvae collected in Key West and Vero Beach, FL, are described. We observed specimens with 3, 4, and 5 sets of siphonal setae and also observed frequent variation in the insertion point of the proximal and subapical setae.

  18. Mosquito repellent properties of Delonix elata (L. gamble (Family: Fabaceae against filariasis vector, Culex quinquefasciatus Say. (Diptera: Culicidae

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    Marimuthu Govindarajan

    2014-02-01

    Full Text Available Objective: To determine the repellent activity of hexane, ethyl acetate, benzene, chloroform and methanol extract of Delonix elata (D. elata leaf and seed against Culex quinquefasciatus (Cx. quinquefasciatus. Methods: Evaluation was carried out in a net cage (45 cm伊30 cm伊25 cm containing 100 blood starved female mosquitoes of Cx. quinquefasciatus. Repellent activity was carried out in the laboratory conditions according to the WHO 2009 protocol. Plant crude extracts of D. elata were applied at 1.0, 2.5, and 5.0 mg/cm2 separately in the exposed fore arm of study subjects. Ethanol was used as the sole control. Results: In this study, the applied plant crude extracts were observed to protect against mosquito bites. There were no allergic reactions experienced by the study subjects. The repellent activity of the extract was dependent on the strength of the extract. Among the tested solvents, the leaf and seed methanol extract showed the maximum efficacy. The highest concentration of 5.0 mg/cm2 provided over 150 min and 120 min protection, respectively. Conclusions: Crude extracts of D. elata exhibit the potential for controlling Cx. quinquefasciatus, the mosquito vector of filariasis.

  19. Efficacy of a Mosaic Long-Lasting Insecticide Net, PermaNet 3.0, against Wild Populations of Culex quinquefasciatus in Experimental Huts in Togo

    OpenAIRE

    Dery, Dominic B; Ketoh, Guillaume K.; Chabi, Joseph; Apetogbo, George; Glitho, Isabelle A.; Baldet, Thierry; Hougard, Jean-Marc

    2013-01-01

    PermaNet 3.0 was evaluated against Culex quinquefasciatus in experimental huts in Lomé. Endpoints were deterrence, exophily, blood feeding inhibition, and mortality. Insecticide susceptibility of Culex quinquefasciatus was assessed with permethrin (1%), DDT (4%), bendiocarb (0.1%), deltamethrin (0.5%, 0.05%), carbosulfan (0.4%), and chlorpyrifos methyl (0.4%). Total of 1,223 Cx. quinquefasciatus females were collected. PermaNet 3.0 unwashed deterred 16.84% Culex mosquitoes. After 20 washes, i...

  20. Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

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    Kweka Eliningaya J

    2012-02-01

    Full Text Available Abstract Background The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between An. gambiae s.s. and Cx. quinquefasciatus on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions. Methods Experiments were set up with three combinations; Cx. quinquefasciatus alone (single species treatment, An. gambiae s.s. alone (single species treatment; and An. gambiae s.s. with Cx. quiquefasciatus (co-habitation treatment in different densities in semi field situation. Results The effect of co-habitation of An. gambiae s.s. and Cx. quinquefasciatus was found to principally affect three parameters. The wing-lengths (a proxy measure of body size of An. gambiae s.s. in co-habitation treatments were significantly shorter in both females and males than in An. gambiae s.s single species treatments. In Cx. quinquefasciatus, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both An. gambiae s.s. and Cx. quinquefasciatus. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co

  1. Influence of warming tendency on Culex pipiens population abundance and on the probability of West Nile fever outbreaks (Israeli Case Study: 2001-2005).

    Science.gov (United States)

    Paz, Shlomit; Albersheim, Iris

    2008-03-01

    Climate change and West Nile fever (WNV) are both subjects of global importance. Many mosquitoes and the diseases they carry, including West Nile virus (WNV), are sensitive to temperature increase. The current study analyzes the lag correlations between weather conditions (especially air temperature) and 1) Culex pipiens mosquito population abundance, and 2) WNF frequency in humans, between 2001 and 2005 in Israel. These 5 years follow a long period with a documented tendency for temperature increase in the hot season in the country. Monthly anomalies of minimum and maximum temperatures, relative seasonal rainfall contribution, mosquito samplings (hazard level), and WNF cases (hospital admission dates and patients' addresses) were analyzed. Logistic regression was calculated between the climatic data and the mosquito samples, as Spearman correlations and Pearson cross-correlations were calculated between daily temperature values (or daily precipitation amounts) and the hospital admission dates. It was found that the disease appearance reflects the population distribution, while the risk tends to escalate around the metropolis characterized by an urban heat island. Positive anomalies of the temperature during the study period appear to have facilitated the mosquito abundance and, consequently, the disease emergence in humans. An important finding is the potential influence of extreme heat in the early spring on the vector population increase and on the disease's appearance weeks later. Awareness of such situations at the beginning of the spring may help authorities to reduce the disease risk before it becomes a real danger.

  2. Evaluation of Some Plant Fruit Extracts for the Control of West Nile Virus Vector Culex pipiens (Diptera: Culicidae)

    Science.gov (United States)

    Koc, Samed; Evren, Ozay Hasan; Cetin, Huseyin

    2016-01-01

    Background: The extracts of different parts of plants were found very effective against various pests. The aim of this research was to determine the insecticidal activity of fruit methanol extracts obtained from Melia azedarach (Meliaceae), Phoenix theophrasti (Arecaceae), Styphnolobium japonicum (Fabaceae) and Pyracantha coccinea (Rosaceae) against the larvae of Culex pipiens (Diptera: Culicidae). Methods: The fruits of test plants were collected from the Campus of Akdeniz University, Antalya, Turkey in 2013. A series of concentrations of the extracts ranging from 62.5–1000 ppm were tested against second instar larvae. Results: Only the extracts of Me. azedarach and Ph. theoprasti showed significant larvicidal activity against Cx. pipiens and the LC50 values of these extracts were found to be 169.48 and 220.60 ppm, respectively. This is the first research investigating the insecticidal or larvicidal activity of Ph. theophrasti, St. japonicum and Py. coccinea extracts on mosquitoes. Conclusion: The methanol extract of fruits of Me. azedarach and Ph. theophrasti showed significantly higher larvicidal activity against Cx. pipiens. PMID:28032112

  3. Evolutionary genomics of Culex pipiens: global and local adaptations associated with climate, life-history traits and anthropogenic factors.

    Science.gov (United States)

    Asgharian, Hosseinali; Chang, Peter L; Lysenkov, Sergey; Scobeyeva, Victoria A; Reisen, William K; Nuzhdin, Sergey V

    2015-07-07

    We present the first genome-wide study of recent evolution in Culex pipiens species complex focusing on the genomic extent, functional targets and likely causes of global and local adaptations. We resequenced pooled samples of six populations of C. pipiens and two populations of the outgroup Culex torrentium. We used principal component analysis to systematically study differential natural selection across populations and developed a phylogenetic scanning method to analyse admixture without haplotype data. We found evidence for the prominent role of geographical distribution in shaping population structure and specifying patterns of genomic selection. Multiple adaptive events, involving genes implicated with autogeny, diapause and insecticide resistance were limited to specific populations. We estimate that about 5-20% of the genes (including several histone genes) and almost half of the annotated pathways were undergoing selective sweeps in each population. The high occurrence of sweeps in non-genic regions and in chromatin remodelling genes indicated the adaptive importance of gene expression changes. We hypothesize that global adaptive processes in the C. pipiens complex are potentially associated with South to North range expansion, requiring adjustments in chromatin conformation. Strong local signature of adaptation and emergence of hybrid bridge vectors necessitate genomic assessment of populations before specifying control agents.

  4. Potential of biologically active plant oils to control mosquito larvae (Culex pipiens, Diptera: Culicidae) from an Egyptian locality.

    Science.gov (United States)

    Khater, Hanem Fathy; Shalaby, Afaf Abdel-Salam

    2008-01-01

    The insecticidal effect of six commercially available plant oils was tested against 4th larval instars of Culex pipiens. Larvae were originally collected from Meit El-Attar, Qalyubia Governorate, Egypt, and then reared in the laboratory until F1 generation. The LC50 values were 32.42, 47.17, 71.37, 83.36, 86.06, and 152.94 ppm for fenugreek (Trigonella foenum-grecum), earth almond (Cyperus esculentus), mustard (Brassica compestris), olibanum (Boswellia serrata), rocket (Eruca sativa), and parsley (Carum ptroselinum), respectively. The tested oils altered some biological aspects of C. pipiens, for instance, developmental periods, pupation rates, and adult emergences. The lowest concentrations of olibanum and fenugreek oils caused remarkable prolongation of larval and pupal durations. Data also showed that the increase of concentrations was directly proportional to reduction in pupation rates and adult emergences. Remarkable decrease in pupation rate was achieved by mustard oil at 1000 ppm. Adult emergence was suppressed by earth almond and fenugreek oils at 25 ppm. In addition, the tested plant oils exhibited various morphological abnormalities on larvae, pupae, and adult stages. Consequently, fenugreek was the most potent oil and the major cause of malformation of both larval and pupal stages. Potency of the applied plant oils provided an excellent potential for controlling C. pipiens.

  5. Identification of Culex pipiens complex mosquitoes in a hybrid zone of West Nile virus transmission in Fresno County, California.

    Science.gov (United States)

    McAbee, Rory D; Green, Emily N; Holeman, Jodie; Christiansen, Julie; Frye, Niki; Dealey, Katherine; Mulligan, F Steve; Brault, Aaron C; Cornel, Anthony J

    2008-02-01

    Culex pipiens sensu lato mosquitoes were collected from 24 gravid traps (mid-June to mid-October, 2005) in Fresno County, CA. Captured gravid females were allowed to oviposit before sibling species identification by Ace.2 PCR and detection of West Nile virus (WNV) RNA by RT-PCR were performed on the mother and her offspring. Of the 442 Cx. pipiens s.l. female mosquitoes collected, 88 were positive for WNV viral RNA (peaked in August) with no significant differences among complex members or habitat. Vertical transmission was detected in 4 out of 20 families originating from WNV-positive mothers, however, in only a small number of offspring from each family. Out of 101 families that had PCR-based maternal and offspring identifications, the offspring from 15 families produced inexplicable amplicon patterns, suggesting ambiguities in the PCR assay identifications. Male genitalia (DV/D ratio) and Ace.2 PCR identifications revealed numerous discrepancies in our ability to accurately determine the identity of Cx. pipiens complex members in the hybrid zone of Fresno County.

  6. Ankyrin repeat domain-encoding genes in the wPip strain of Wolbachia from the Culex pipiens group

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    Parkhill Julian

    2007-09-01

    Full Text Available Abstract Background Wolbachia are obligate endosymbiotic bacteria maternally transmitted through the egg cytoplasm that are responsible for several reproductive disorders in their insect hosts, such as cytoplasmic incompatibility (CI in infected mosquitoes. Species in the Culex pipiens complex display an unusually high number of Wolbachia-induced crossing types, and based on present data, only the wPip strain is present. Results The sequencing of the wPip strain of Wolbachia revealed the presence of 60 ankyrin repeat domain (ANK encoding genes and expression studies of these genes were carried out in adult mosquitoes. One of these ANK genes, pk2, is shown to be part of an operon of three prophage-associated genes with sex-specific expression, and is present in two identical copies in the genome. Another homolog of pk2 is also present that is differentially expressed in different Cx. pipiens group strains. A further two ANK genes showed sex-specific regulation in wPip-infected Cx. pipiens group adults. Conclusion The high number, variability and differential expression of ANK genes in wPip suggest an important role in Wolbachia biology, and the gene family provides both markers and promising candidates for the study of reproductive manipulation.

  7. Comparative efficacies of permethrin-, deltamethrin- and alpha-cypermethrin-treated nets, against Anopheles arabiensis and Culex quinquefasciatus in northern Tanzania.

    Science.gov (United States)

    Mosha, F W; Lyimo, I N; Oxborough, R M; Matowo, J; Malima, R; Feston, E; Mndeme, R; Tenu, F; Kulkarni, M; Maxwell, C A; Magesa, S M; Rowland, M W

    2008-06-01

    Mosquito nets treated with permethrin, deltamethrin or alpha-cypermethrin at 25 mg/m(2) were evaluated in experimental huts in an area of rice irrigation near Moshi, in northern Tanzania. The nets were deliberately holed to resemble worn nets. The nets treated with permethrin offered the highest personal protection against Anopheles arabiensis (61.6% reduction in fed mosquitoes) and Culex quinquefasciatus (25.0%). Deltamethrin and alpha-cypermethrin provided lower personal protection against An. arabiensis (46.4% and 45.6%, respectively) and no such protection against Cx. quinquefasciatus. Permethrin performed poorly in terms of mosquito mortality, however, killing only 15.2% of the An. arabiensis and 9.2% of the Cx. quinquefasciatus exposed to the nets treated with this pyrethroid (after correcting for control mortality). The alpha-cypermethrin and deltamethrin performed marginally better, with respective mortalities of 32.8% and 33.0% for An. arabiensis and 19.4% and 18.9% for Cx quinquefasciatus. The poor killing effect of permethrin was confirmed in a second trial where a commercial, long-lasting insecticidal net based on this pyrethroid (Olyset) produced low mortalities in both An. arabiensis (11.8%) and Cx. quinquefasciatus (3.6%). Anopheles arabiensis survivors collected from the verandahs of the experimental huts and tested on 0.75%-permethrin and 0.05%-deltamethrin papers, in World Health Organization susceptibility kits, showed mortalities of 96% and 100%, respectively. The continued use of permethrin-treated nets is recommended for personal protection against An. arabiensis. In control programmes that aim to interrupt transmission of pathogens by mosquitoes and/or manage pyrethroid resistance in such vectors, a combination of a pyrethroid and another insecticide with greater killing effect should be considered.

  8. Comparative mosquito repellency of essential oils against Aedes aegypti (Linn.), Anopheles dirus (Peyton and Harrison) and Culex quinquefasciatus (Say)

    Institute of Scientific and Technical Information of China (English)

    Siriporn Phasomkusolsil; Mayura Soonwera

    2011-01-01

    Objective: To assess the repellency to female Aedes aegypti (Ae. aegypti), Anopheles dirus (An. dirus) and Culex quinquefasciatus (Cx. quinquefasciatus) of seven essential oils using two treatment methods. Methods: Topical applications of three dose concentrations (0.02, 0.10 and 0.21 mg/cm2) were made on the forearms of volunteers. Dose-response study and protection time study were employed in the experiment. Results: In the dose-response test, Cymbopogon citratus (C. citratus), Cymbopogon nardus (C. nardus), Syzygium aromaticum (S. aromaticum) and Ocimum basilicum (O. basilicum) exhibited a high repellency against Ae. aegypti with ED50 at < 0.045 mg/cm2, whereas C. citratus, C. nardus and S. aromaticum showed repellency against An. dirus with ED50 at <0.068 mg/cm2. Furthermore, the essential oils of C. citratus, C. nardus, S. aromaticum, O.basilicum and Cananga odorata gave strong effective dose (ED 50) values at <0.003 mg/cm2 when tested against Cx. quinquefasciatus. For testing by arm in cage method, at 0.21 mg/cm2, protection time of C. citratus gave the longest lasting period against three mosquito species, 72 min for Ae. aegypti, 132 min for An. dirus and 84 min for Cx. quinquefasciatus. In addition, the two essential oils exhibited moderate repellency against Ae. aegypti, An. dirus and Cx. quinquefasciatus, at 60, 90 and 78 min with C. nardus, and 54, 96 and 72 min with S. aromaticum, respectively. Conclusions: The percentage repellency increased when the concentration of essential oils increased. In contrast, biting rates decreased when the concentration of essential oils increased.C. citratus exhibited high efficiency for the protection time and the percentage of biting deterrent against all of 3 mosquito species.

  9. Ovicidal and repellent activities of botanical extracts against Culex quinquefasciatus,Aedes aegypti and Anopheles stephensi(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Govindarajan; M; Mathivanan; T; Elumalai; K; Krishnappa; K; Anandan; A

    2011-01-01

    Objective:To determine the ovicidal and repellent activities of methanol leaf extract of Ervatamia coronaria(E.coronaria) and Caeslpinia pulckerrima(C.pulcherrima) against Culex quinquefasciatus(Cx.quinquefasciatus),Aedes aegypti(Ae.aegypti) and Anopheles stephensi(An. stephensi).Methods:The ovicidal activity was determined against three mosquito species at various concentrations ranging from 50-450 ppm under the laboratory conditions.The hatch rates were assessed 48 h after treatment.The repellent efficacy was determined against three mosquito species at three concentrations viz.,1.0,2.5 and 5.0 mg/cm under the laboratory conditions. Results:The crude extract of E.coronaria exerted zero hatchability(100%mortality) at 250.200 and 150 ppm for Cx.quinqitefasciatus,Ae.aegypti and An.stephensi,respectively.The crude extract of C.pulchenima exerted zero hatchability(100%mortality) at 375.300 and 225 ppm for Cx.quinquefasciatus,Ae.aegypti and An.Stephensi,respectively.The methanol extract of E. coronaria found to be more repellenct than C.pukherrima extract.A higher concentration of 5.0 mg/cm~2 provided 100%protection up to 150.180 and 210 min against Cx.quinquefasciatus,Ae. aegypti and An.stephensi,respectively.The results clearly showed that repellent activity was dose dependent.Conclusions:From the results it can be concluded the crude extracts of E.coronaria and C.pukherrima are an excellent potential for controlling Cx.quinquefasciatus,Ae.aegypti and An.stephensi mosquitoes.

  10. Host-feeding patterns of Culex pipiens and other potential mosquito vectors (Diptera: Culicidae) of West Nile virus (Flaviviridae) collected in Portugal.

    Science.gov (United States)

    Osório, Hugo Costa; Zé-Zé, Líbia; Alves, Maria João

    2012-05-01

    The host blood-feeding patterns of mosquito vectors affects the likelihood of human exposure to zoonotic pathogens, including West Nile Virus (family Flaviviridae, genus Flavivirus, WNV). In Portugal, data are unavailable regarding the blood-feeding habits of common mosquito species, including Culex pipiens L., considered the primary vector of WNV to humans. The sources of bloodmeals in 203 blood-fed mosquitoes of nine species collected from June 2007 to November 2010 in 34 Portuguese counties were analyzed by sequencing cytochrome-b partial fragments. Cx. pipiens was the most common species collected and successfully analyzed (n = 135/78). In addition, blood-fed females of the following species were analyzed: Ochlerotatus caspius Pallas (n = 20), Culex theileri Theobald (n = 16), Anopheles maculipennis s.l. Meigen (n = 10), Culiseta longiareolata Macquart (n = 7), Aedes aegypti L. (n = 6), Culex perexiguus Theobald (n = 3), Culiseta annulata Schrank (n = 3), and Ochlerotatus detritus Haliday (n = 3). The Cx. pipiens mosquitoes fed predominantly on birds (n = 55/78, 70.5%), with a high diversity of avian species used as hosts, although human blood was identified in 18 specimens (18/78, 23.1%). No significant differences were found between the host-feeding patterns of blood-fed Cx. pipiens collected in residential and nonresidential habitats. The occurrence of human derived blood meals and the presence of a mix avian-human bloodmeal accordingly suggest this species as a potential vector of WNV. Therefore, in Portugal, Cx. pipiens may play a role both in the avian-to-avian enzootic WNV cycle and in the avian-to-mammal transmission. In this context, the identity of Cx. pipiens (considering the forms molestus and pipiens) and the potential consequence on feeding behavior and WNV transmission are discussed.

  11. Mosquitocidal toxins of spore forming bacteria: recent advancement

    African Journals Online (AJOL)

    Administrator

    Some mosquito species (Culex pipiens pipiens, C. quinquefasciatus) which had been susceptible to Bs .... Sporulation of these Bs strains in a liquid culture medium was studied ... within a genus, a serotype or even within the same serotype.

  12. Larvicidal activity of extracts from Ammi visnaga Linn. (Apiaceae) seeds against Culex quinquefasciatus Say. (Diptera: Culicidae).

    Science.gov (United States)

    Pavela, Roman; Vrchotová, Naděžda; Tříska, Jan

    2016-06-01

    Efficacies of the Ammi visnaga seeds extract and a majority of substances on larval Culex quinquefasciatus mortality in various development stages including pupae were studied. The effect of exposure time on larval mortality was also studied. The effect of sublethal concentrations or short exposure times on further larval development and subsequent fecundity in adults were studied as well. Lethal doses of the extract were estimated for the 2nd, 3rd and 4th instar of C. quinquefasciatus (LC50 for 18, 23 and 180 mg L(-1), respectively). The majority of furanochromenes, khellin and visnagin, were identified by analysing the extract. Khellin was significantly more effective compared to visnagin, whose LC50 was estimated at 8, 10 and 41 mg L(-1) for the 2nd, 3rd and 4th instar larvae. Khellin showed very fast efficacy on mortality for the 3rd instar larvae in a concentration of 100 mg L(-1). Fifty percent mortality was determined 30 min after application, a time which was considerably shorter compared to the extract (113 min) or visnagin (169 min). The effect of the application of lethal concentrations on C. quinquefasciatus larval mortality was studied. The least number of adults were hatched after application of the extract and khellin (41.8% and 37.9%, respectively), less than after visnagin application (46.7%) or in the control (94.2%). LC50 application caused lower fecundity in the hatched adults, lower hatchability of the eggs, and also very low natality, more than 77% lower for khellin compared to the control. A short exposure, corresponding to our estimated LT30, caused no significant acute toxicity in the larvae (until 24 h) for the extract or visnagin (4.3% and 11.5%, respectively); however, 18 min of action from khellin caused a 54.3% mortality rate of the larvae within 24 h.

  13. Efficient induction of spawning of Northern leopard frogs (Lithobates pipiens) during and outside the natural breeding season

    Science.gov (United States)

    2013-01-01

    Background Amphibian declines are now recognized globally. It is also well known that many anurans do not reproduce easily in captivity, especially when held over long periods, or if they require hibernation before breeding. A simple method to induce spawning and subsequent development of large numbers of healthy tadpoles is therefore required to meet research and conservation goals. Methods The method is based on simultaneous injection of both female and male leopard frogs, Lithobates pipiens (formerly called Rana pipiens) with a cocktail of a gonadotropin-releasing hormone agonist (GnRH-A) and a dopamine antagonist. We call this the AMPHIPLEX method, which is derived from the combination of the words amphibian and amplexus. Following injection, the animals are thereby induced, and perform amplexus and natural fertilization under captive conditions. Results We tested combinations of a GnRH agonist with 2 different dopamine antagonists in L. pipiens in the breeding season. The combination of des-Gly10, D-Ala6, Pro-NHEt9-GnRH (0.4 micrograms/g body weight; GnRH-A) with metoclopramide hydrochloride (10 micrograms/g body weight; MET) or domperidone (DOM) were equally effective, producing 89% and 88% successful spawning, respectively. This yielded more than 44,000 eggs for the 16/18 females that ovulated in the GnRH-A+MET group, and more than 39,000 eggs for the 15/17 females that ovulated in the GnRH-A+DOM group. We further tested the GnRH-A+MET in frogs collected in the wild in late autumn and hibernated for a short period under laboratory conditions, and report a low spawning success (43%). However, GnRH-A priming 24 hours prior to injections of the GnRH-A+MET cocktail in animals hibernated for 5–6 weeks produced out-of-season spawning (89%) and fertilization (85%) comparable to those we observed for in-season spawning. Assessment of age and weight at metamorphosis indicated that L. pipiens tadpoles resulting from out-of-season spawning grew normally and

  14. Effects of microcosm scaling and food resources on growth and survival of larval Culex pipiens

    Directory of Open Access Journals (Sweden)

    Paradise Christopher J

    2001-08-01

    Full Text Available Abstract Background We used a simple experimental design to test for the effects of microcosm scaling on the growth and survival of the mosquito, Culex pipiens. Microcosm and mesocosm studies are commonly used in ecology, and there is often an assumption that scaling doesn't affect experimental outcomes. The assumption is implicit in the design; choice of mesocosms may be arbitrary or based on convenience or cost. We tested the hypothesis that scale would influence larvae due to depth and surface area effects. Larvae were predicted to perform poorly in microcosms that were both deep and had small openings, due to buildup of waste products, less exchange with the environment, and increased competition. To determine if the choice of scale affected responses to other factors, we independently varied leaf litter quantity, whose effects on mosquitoes are well known. Results We found adverse effects of both a lower wall surface area and lower horizontal surface area, but microcosm scale interacted with resources such that C. pipiens is affected by habitat size only when food resources are scarce. At low resource levels mosquitoes were fewer, but larger, in microcosms with smaller horizontal surface area and greater depth than in microcosms with greater horizontal surface area and shallower depth. Microcosms with more vertical surface area/volume often produced larger mosquitoes; more food may have been available since mosquitoes browse on walls and other substrates for food. Conclusions The interaction between habitat size and food abundance is consequential to aquatic animals, and choice of scale in experiments may affect results. Varying surface area and depth causes the scale effect, with small horizontal surface area and large depth decreasing matter exchange with the surrounding environment. In addition, fewer resources leads to less leaf surface area, and the effects of varying surface area will be greater under conditions of limiting resources

  15. Native Argentinean cyclopoids (Crustacea: Copepoda as predators of Aedes aegypti and Culex pipiens (Diptera: Culicidae mosquitoes

    Directory of Open Access Journals (Sweden)

    María C Tranchida

    2009-12-01

    Full Text Available Copepods from La Plata, Argentina were investigated to characterize the local community of larvivorous copepods inhabiting mosquito breeding sites and to identify new predator species of the mosquitoes which occur in artificial containers, Aedes aegypti and Culex pipiens. Diversity of larvivorous cyclopoids was highest in permanent pools. Predation by sex and age, selectivity on mosquito species, and daily predation rate during five days were studied for Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus and Mesocyclops longisetus. Female copepods presented the highest predatory capacity. No predatory preference for mosquito species was found. According to overall predation potential, copepods were ranked as follows: D. uruguayensis Se hizo una prospección de copépodos en La Plata, Argentina, con los objetivos de caracterizar la comunidad local de copépodos larvívoros en sitios de cría de mosquitos, e identificar nuevas especies depredadoras de los mosquitos de contenedores artificiales Aedes aegypti y Culex pipiens. La diversidad de ciclopoides larvívoros fue máxima en charcos permanentes. Se examinó la depredación por sexos y edad, la selectividad por especies de mosquito, y la tasa de depredación diaria durante cinco días en Acanthocyclops robustus, Diacyclops uruguayensis, Macrocyclops albidus y Mesocyclops longisetus. Los copépodos hembra presentaron la capacidad depredadora más alta. No se encontró preferencia por alguna especie de mosquito. De acuerdo al potencial de depredación en general, los copépodos se ordenan así: D. uruguayensis < A. robustus < M. albidus < M. longisetus. También se evaluó la tolerancia a la desecación del hábitat y la capacidad de resistir en agua de contenedores artificiales. D. uruguayensis y A. robustus sobrevivieron en condiciones de sequía, pero D. uruguayensis presentó menor supervivencia en agua de floreros de cementerio. M. albidus no sobrevivió condiciones de

  16. Evaluation of factors for rapid development of Culex quinquefasciatus in belowground stormwater treatment devices.

    Science.gov (United States)

    Harbison, Justin E; Metzger, Marco E; Walton, William E; Hu, Renjie

    2009-12-01

    Water samples from 11 belowground stormwater treatment Best Management Practices (BMPs) were evaluated for their capacity to support rapid development of the West Nile virus (WNV) mosquito vector, Culex quinquefasciatus. The observed minimum development time from egg to pupa ranged from six to over 30 days. Concentrations of potential food resources (total suspended solids and the particulate organic matter in water samples) were significantly correlated to development times. In addition, the rate of immature mosquito development was both site-dependent and variable in time, suggesting that factors favorable to rapid development were strongly influenced by watershed characteristics and seasonal changes in temperature. Measured temperatures in belowground BMPs suggest that these structures may remain amenable to WNV virus activity longer each year than sites aboveground.

  17. Laboratory assessment of indigenous plant extracts for anti-juvenile hormone activity in Culex quinquefasciatus.

    Science.gov (United States)

    Saxena, R C; Dixit, O P; Sukumaran, P

    1992-07-01

    Of 15 plants tested, five plant extracts showed anti-juvenile hormone-like activity against laboratory colonised late fourth instar larvae and adult female mosquitoes. Petroleum ether extract of Eichhornia crassipes and acetone extracts of Ageratum conyzoides, Cleome icosandra, Tagetes erectes and Tridax procumbens showed growth inhibitory (P less than 0.001) and juvenile hormone mimicing activity to the treated larvae of C. quinquefasciatus.. Larval pupal intermediates, demalanised pupae, defective egg rafts and adult with deformed flight muscles were few noticeable changes. Biting behaviour was observed to be affected only in Ageratum, Cleome and Tridax extracts (P less than 0.001). Loss of fecundity was observed in the treated mosquitoes but no sterilant effects could be seen. Adults, obtained from larvae exposed to the plant extracts produced significantly shorter egg-rafts (P less than 0.005) than in control.

  18. Larvicidal activity of synthetic disinfectants and antibacterial soaps against mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A

    2013-01-01

    Seven commercial synthetic disinfectant and antibacterial soap products were evaluated as mosquito larvicides against Culex quinquefasciatus Say in the laboratory. Three aerosol disinfectant products, at 0.01% concentration resulted in 58-76% mortality of laboratory-reared fourth instar mosquito larvae at 24 h posttreatment. Four antibacterial soap products at 0.0001% concentration resulted in 88-100% larval mortality at 24 h posttreatment. The active ingredient of the antibacterial soap products, triclosan (0.1%) resulted in 74% larval mortality. One of the antibacterial soap products, Equate caused the highest mosquito larval mortality in the laboratory. Equate antibacterial soap at the application rate of 0.000053 ppm resulted in 90% mortality of the introduced fourth instar larvae of Cx. quinquesfasicatus in the outdoor pools. In laboratory and field bioassays, the antibacterial soap resulted in significant larval mosquito mortality.

  19. Larvicidal activity of Lawsonia inermis and Murraya exotica leaves extract on filarial vector, Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    K. Dass

    2014-06-01

    Full Text Available Extensive use of synthetic and chemical insecticides to control mosquitoes result in environment hazards and development of resistance in vector species. This research work is about an alternative mosquito control method that is considered as safe to environment and non-target species and also bio-degradable. Hence an attempt was made to study the larvicidal effect of the extract of Lawsonia inermis and Murraya exotica leaves on III and IV instar larva and pupa of Culex quinquefasciatus. The LC50 value of Murraya exotica for III and IV instar larvae and pupae is 135.539 ppm, 154.361 ppm and 178.571 ppm respectively. Likewise for Lawsonia inermis it is 139.057 for III instar, 163.630 for IV instar and 188.151 for the pupa. Of these, two plants Murraya exotica plant extract is more effective than the Lawsonia inermis.

  20. Dispersal of Culex quinquefasciatus (Diptera: Culicidae) in a Hawaiian rain forest

    Science.gov (United States)

    Lapointe, D.A.

    2008-01-01

    Introduced mosquito-borne pathogens avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox virus (Avipoxvirus) have been implicated in the past extinctions and declines of Hawaiian avifauna and remain significant obstacles to the recovery and restoration of endemic Hawaiian birds. Effective management of avian disease will require extensive mosquito control efforts that are guided by the local ecology of the vector Culex quinquefasciatus Say (Diptera: Culicidae). During October and November 1997 and September through November 1998 five mark-release-recapture experiments with laboratory-reared Cx. quinquefasciatus were conducted in a native rain forest on Hawaii Island. Of the overall 66,047 fluorescent dye-marked and released females, 1,192 (1.8%) were recaptured in 43-52 CO2-baited traps operated for 10-12-d trapping periods. Recaptured mosquitoes were trapped in all directions and at distances up to 3 km from the release site. The cumulative mean distance traveled (MDTs) over the trapping period ranged from a high of 1.89 km after 11 d (September 1998) to a low of 0.81 km after 11 d (November 1998). Released mosquitoes moved predominately in a downwind direction and they seemed to use forestry roads as dispersal corridors. Applying an estimated MDT of 1.6 km to a geographical information system-generated map of the Hakalau Forest National Wildlife Refuge clearly demonstrated that the effective refuge area could be reduced 60% by mosquitoes infiltrating into managed refuge lands. These findings should have significant implications for the design of future refuges and development of effective mosquito-borne avian disease control strategies.

  1. Ovicidal activity of neem products (azadirachtin) against Culex tarsalis and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Su, T; Mulla, M S

    1998-06-01

    Bioactive compounds contained in the seed kernel and other parts of the neem tree (Azadirachta indica A. Juss) have been found to show insecticidal activities and other effects in many species of insects. These activities include antifeedancy, growth regulation, fecundity suppression, male sterility, oviposition repellency, changes in biological fitness such as loss of flying ability, immunodepression, enzyme inhibition, splitting of biological rhythms, and so forth. We investigated the ovicidal effects of various formulations of azadrirachtin (AZ) against the mosquitoes Culex tarsalis Coquillett and Culex quinquefasciatus Say. The formulations tested were wettable powder Azad WP10, emulsifiable concentrate Azad EC4.5, and technically pure AZ. The ovicidal activity of the test neem products was influenced by concentration of AZ, age of the egg rafts, and age of the neem preparations. Other factors such as formulation and mosquito species were also involved in the degree of ovicidal activity. When the egg rafts were deposited directly in fresh neem suspension and left there for 4 h before transfer to untreated water, 1 ppm of AZ produced almost 100% mortality in eggs. When egg rafts aged for 0, 4, 8, 12, and 24 h were exposed to 10 ppm neem suspensions for 36 h, the ovicidal activity was only attained in the egg rafts deposited directly (0 h old) in the neem suspension, not in those with ages of 4-24 h. On aging, depending on the formulations and mosquito species, the neem suspensions at 1 ppm completely lost ovicidal activity within 7-20 days. The egg rafts of Cx. quinquefasciatus were more susceptible to the test neem products than those of Cx. tarsalis. The formulated neem products were more persistent and effective than the technical AZ. The wettable powder (WP) formulation was slightly more persistent and effective than the emulsifiable concentrate (EC). The ovicidal activity of the neem products against mosquitoes from the current research clearly demonstrated

  2. Differential Infectivities among Different Japanese Encephalitis Virus Genotypes in Culex quinquefasciatus Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Yan-Jang S Huang

    2016-10-01

    Full Text Available During the last 20 years, the epidemiology of Japanese encephalitis virus (JEV has changed significantly in its endemic regions due to the gradual displacement of the previously dominant genotype III (GIII with clade b of GI (GI-b. Whilst there is only limited genetic difference distinguishing the two GI clades (GI-a and GI-b, GI-b has shown a significantly wider and more rapid dispersal pattern in several regions in Asia than the GI-a clade, which remains restricted in its geographic distribution since its emergence. Although previously published molecular epidemiological evidence has shown distinct phylodynamic patterns, characterization of the two GI clades has only been limited to in vitro studies. In this study, Culex quinquefasciatus, a known competent JEV mosquito vector species, was orally challenged with three JEV strains each representing GI-a, GI-b, and GIII, respectively. Infection and dissemination were determined based on the detection of infectious viruses in homogenized mosquitoes. Detection of JEV RNA in mosquito saliva at 14 days post infection indicated that Cx. quinquefasciatus can be a competent vector species for both GI and GIII strains. Significantly higher infection rates in mosquitoes exposed to the GI-b and GIII strains than the GI-a strain suggest infectivity in arthropod vectors may lead to the selective advantage of previously and currently dominant genotypes. It could thus play a role in enzootic transmission cycles for the maintenance of JEV if this virus were ever to be introduced into North America.

  3. Resistance in the mosquito, Culex quinquefasciatus, and possible mechanisms for resistance.

    Science.gov (United States)

    Xu, Qiang; Liu, Huqi; Zhang, Lee; Liu, Nannan

    2005-11-01

    Two mosquito strains of Culex quinquefasciatus (Say), MAmCq(G0) and HAmCq(G0), were collected from Mobile and Huntsville, Alabama, respectively. MAmCq(G0) and HAmCq(G0) were further selected in the laboratory with permethrin for one and three generations, respectively. The levels of resistance to permethrin in MAmCq(G1) (after one-generation selection) and HAmCq(G3) (after three-generation selection) increased rapidly. Resistance to permethrin in MAmCq(G1) and HAmCq(G3) was partially suppressed by piperonyl butoxide (PBO), S,S,S-tributylphosphorotrithioate (DEF) and diethyl maleate (DEM), inhibitors of cytochrome P450 monooxygenases, hydrolases and glutathione S-transferases (GST), respectively, suggesting these three enzyme families are important in conferring permethrin resistance in both strains. A substitution of leucine to phenylalanine (L to F) resulting from a single nucleotide polymorphism (SNP), termed the kdr mutation, in the para-homologous sodium channel gene has been reported as a very common mutation associated with pyrethroid resistance of insects. A 341-bp sodium channel gene fragment, where the kdr mutation resides, was generated by PCR from genomic DNAs of Cx. quinquefasciatus strains. We found that the kdr mutation was present in both permethrin-selected and unselected HAmCq and MAmCq mosquito populations, suggesting that the kdr mutation plays the role in permethrin resistance. There was no significant change in the frequency and heterozygosity of the A to T SNP for the kdr allele between permethrin-selected and unselected MAmCq and HAmCq mosquitoes, indicating that other mechanisms are involved in the evolution of resistance in mosquitoes selected by permethrin in the laboratory. Copyright 2005 Society of Chemical Industry.

  4. Density and survival rate of Culex quinquefasciatus at Parque Ecológico do Tietê, São Paulo, Brazil.

    Science.gov (United States)

    Laporta, Gabriel Z; Sallum, Maria Anice M

    2008-03-01

    Parity rate, gonotrophic cycle length, and density of a Culex quinquefasciatus female population was estimated at the Parque Ecológico do Tietê (PET), São Paulo, Brazil. Adult Cx. quinquefasciatus females were collected from vegetation along the edges of a polluted drainage canal with the use of a battery-powered backpack aspirator from September to November 2005 and from February to April 2006. We examined 255 Cx. quinquefasciatus ovaries to establish the parity rate of 0.22 and determined the gonotrophic cycle length under laboratory conditions to be 3 and 4 days. From these data, we calculated the Cx. quinquefasciatus survival rate to be 0.60 and 0.68 per day. Density of the Cx. quinquefasciatus female (5.71 females per m2) was estimated based on a population size of 28,810 individuals divided by the sampled area of 5,040 m2. Results of all experiments indicate medium survivorship and high density of the Cx. quinquefasciatus female population. This species is epidemiologically relevant in the PET area and should be a target of the vector control program of São Paulo municipality.

  5. Repellent activity of Eucalyptus and Azadirachta indica seed oil against the filarial mosquito Culex quinquefasciatus Say (Diptera:Culicidae) in India

    Institute of Scientific and Technical Information of China (English)

    Shyamapada Mandal

    2011-01-01

    Objective: To evaluate the repellent activity of Eucalyptus and Azadirachta indica (A. indica) seed oil against filarial mosquito Culex quinquefasciatus (Cx. quinquefasciatus) from Purulia district of the West Bengal state, India. Methods: The repellent activity of Eucalyptus and A. indica seed oils (using coconut oil base) against Cx. quinquefasciatus mosquito were evaluated in indoor conditions. Three concentrations, 0%, 50% and 100% (v/v) of both the agents were considered in the studies. The protection percentage was determined, and the protection time was recorded. Results: The test oils showed excellent repellent action against Cx. quinquefasciatus. The A. indica seed oil provided 90.26% and 88.83% protection, and the Eucalyptus oil 93.37% and 92.04%, at concentrations 50% and 100% (v/v), respectively, with the protection time up to 240 min. There was no bite within 120 min and 180 min, respectively, due to the action of Eucalyptus andA. indica seed oil, and thus 100% protection from the bite of Cx. quinquefasciatus mosquito was achieved. Conclusions: The present study clearly demonstrates the potential of Eucalyptus and A. indica seed oils as topical repellents against Cx. quinquefasciatus, the mosquito vector of filariasis.

  6. Evaluation of Andrographis paniculata Burm.f. (Family:Acanthaceae) extracts against Culex quinquefasciatus (Say.) and Aedes aegypti (Linn.) (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Marimuthu Govindarajan

    2011-01-01

    Objective:To investigate the larvicidal and ovicidal efficacy of different extracts of Andrographis paniculata (A. paniculata) against Culex quinquefasciatus (Cx. quinquefasciatus) Say and Aedes aegypti (Ae. aegypti ) L. (Diptera:Culicidae). Methods:Larvicidal efficacy of the crude leaf extracts of A. paniculata with five different solvents like benzene, hexane, ethyl acetate, methanol and chloroform was tested against the early third instar larvae of Cx. quinquefasciatus and Ae. aegypti. The ovicidal activity was determined against two mosquito species to various concentrations ranging from 50-300 ppm under the laboratory conditions. Results:The benzene, hexane, ethyl acetate, methanol and chloroform leaf extract of A. paniculata was found to be more effective against Cx. quinquefasciatus than Ae. aegypti. The LC50 values were 112.19, 137.48, 118.67, 102.05, 91.20 ppm and 119.58, 146.34, 124.24, 110.12, 99.54 ppm respectively. Among five tested solvent, methanol and ethyl acetate crude extract was found to be most effective for ovicidal activity against two mosquito species. The extract of methanol and ethyl acetate exerted 100%mortality at 200 ppm against Cx. quinquefasciatus and at 250 ppm against Ae. aegypti. Conclusions:From the results it can be concluded the crude extract of A. paniculata was a potential for controlling Cx. quinquefasciatus and Ae. aegypti mosquitoes.

  7. Efficacy of leaves extract of Calotropis procera Ait. (Asclepiadaceae) in controlling Anopheles arabiensis and Culex quinquefasciatus mosquitoes.

    Science.gov (United States)

    Elimam, Abdalla M; Elmalik, Khitma H; Ali, Faysal S

    2009-10-01

    The present study aimed to investigate, the larvicidal, adult emergence inhibition and oviposition deterrent activity of aqueous leaves extract of Calotropis procera against Anopheles arabiensis and Culex quinquefasciatus as natural mosquito larvicide. The larvicidal activity was monitored against 2nd, 3rd and 4th instar larvae of each mosquito species 24 h post-treatment. Adult emergence inhibition activity was tested by exposing 3rd instar larvae of each mosquito species to different concentrations of extracts (200, 400, 600, 800 and 1000 ppm for An. arabiensis and 100, 200, 300, 400, 500 and 600 ppm for Cx. quinquefasciatus). Probit analysis was used to analyze data from bioassay experiments. The oviposition deterrent activity was tested by using three different concentrations of extracts (1000, 500 and 200 for An. arabiensis, and 1000, 500 and 100 for Cx. quinquefasciatus) that caused high, moderate and low larval mortality in the larvicidal experiment against 3rd instar larvae. It was found that, LC50-LC90 values calculated were 273.53-783.43, 366.44-1018.59 and 454.99-1224.62 ppm for 2nd, 3rd and 4th larval instars, respectively, of An. arabiensis and 187.93-433.51, 218.27-538.27 and 264.85-769.13 ppm for 2nd, 3rd and 4th larval instars, respectively, of Cx. quinquefasciatus. Fifty percent of adult emergence inhibition (EI50) was shown at 277.90 and 183.65 ppm for An. arabiensis and Cx. quinquefasciatus, respectively. The pupal stage was not affected till a concentration of 5000 ppm. The extract showed oviposition deterrence and effective repellence against both mosquito species at different concentrations, with the observation on that maximal eggs were laid in low concentration of extract. These results suggest that the leaves extract of C. procera possess remarkable larvicidal, adult emergence inhibitor, repellent and oviposition deterrent effect against both An. arabiensis and Cx. quinquefasciatus, and might be used as natural biocides for mosquito

  8. Clinal patterns in genetic variation for northern leopard frog (Rana pipiens): Conservation status and population histories

    Science.gov (United States)

    Stockwell, Craig A.; Fisher, Justin D.L.; McLean, Kyle I.

    2016-01-01

    The security of the northern leopard frog (Rana pipiens) varies spatially with populations east and west of North Dakota considered as secure and at risk, respectively. We used genetic markers to characterize the conservation status of northern leopard frog populations across North Dakota. We used multiple regression analyses and model selection to evaluate correlations of expected heterozygosity (HE) with the direct and additive effects of: i) geographic location,ii) wetland density and iii) average annual precipitation. There was lower genetic diversity in the western portion of the state due to lower levels of diversity for populations southwest of the Missouri River. This may reflect a refugial/colonization signature for the only non-glaciated area of North Dakota. Genetic diversity was also positively associated with wetland densities which is consistent with the reliance of this species on a mosaic of wetlands. Our findings suggest that populations in the southwestern part of North Dakota are of higher conservation concern, a finding consistent with the higher risk noted for northern leopard frog populations in most states west of North Dakota. Our findings also pose the hypothesis that climate change induced changes in wetland densities will reduce genetic diversity of northern leopard frog populations.

  9. Solid-state NMR reveals differential carbohydrate utilization in diapausing Culex pipiens

    Science.gov (United States)

    Chang, James; Singh, Jugeshwar; Kim, Sungshil; Hockaday, William C.; Sim, Cheolho; Kim, Sung Joon

    2016-11-01

    Culex pipiens is the mosquito that vectors West Nile Virus and other human-pathogenic flavivruses in North America. In response to shortened day length and lower temperatures, female Cx. pipiense prepares for the diapause by actively feeding on carbohydrates to increase the biosynthesis of glycogen and lipid to store energy for overwintering. The effect of feeding different carbohydrates on glycogen and lipid biosynthesis in diapausing mosquitoes was investigated in vivo using 13C solid-state NMR. Diapause-destined adult females and nondiapausing counterparts after adult eclosion were fed with three different carbohydrate sources for 7 days: 1) 10% sucrose, 2) 10% D-[13C6]glucose, and 3) 1% D-[13C6]glucose co-provisioned with 10% sucrose. NMR measurements show that sucrose and glucose are metabolized differently in diapausing mosquitoes. Mosquitoes fed on sucrose primarily accumulate glycogen with increased branching structures, but less of lipids. In contrast, mosquitoes fed exclusively on glucose show accumulation of both glycogen and lipid with increased aliphatic chain length. Glucose is exclusively metabolized for the biosynthesis of triacylglyceride when mosquitoes were co-fed with sucrose. Our findings provide novel insights into the insect carbohydrate metabolism that governs glycogen and lipid biosynthesis during diapause, which is fundamental for the insect survival during inimical environments.

  10. Effect of chlorfenapyr on cypermethrin-resistant Culex pipiens pallens Coq mosquitoes.

    Science.gov (United States)

    Yuan, J Z; Li, Q F; Huang, J B; Gao, J F

    2015-03-01

    Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action that does not confer cross-resistance to neurotoxic insecticides. The effect of chlorfenapyr on pyrethorid-resistant Culex pipiens pallens Coq (Diptera: Culicidae) has not been fully investigated under laboratory conditions. In this study, cypermethrin-resistant C. p. pallens exhibited 376.79-fold and 395.40-fold increase in resistance to cypermethrin compared with susceptible strains after exposure for 24 and 48h, respectively. Larvae and adults were tested for susceptibility using dipping, topical, and impregnated paper methods as recommended by the WHO. No cross-resistance to chlorfenapyr was found. Increased mortality was apparent between 48 and 72h, indicating a slow rate of toxic activity. Synergism experiments with piperonyl butoxide (PBO) showed an antagonistic effect on chlorfenapyr toxicity. Mixtures of chlorfenapyr and cypermethrin could therefore provide additional benefits over either insecticide used alone. Mixtures of 5ng/ml chlorfenapyr and 500ng/ml cypermethrin exhibited a slight synergistic effect on cypermethrin-resistant mosquitoes (3.33, 6.84 and 2.34% after 24, 48 and 72h exposure, respectively. This activity was lost when the chlorfenapyr concentration was increased to 10 or 20ng/ml. Chlorfenapyr showed quite good results for pyrethroid-resistant C. p. pallens, and could improve public health by reducing the occurrence of mosquito bites and subsequently protecting against transmission of lymphatic filariasis and Japanese encephalitis. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Insulin signaling and FOXO regulate the overwintering diapause of the mosquito Culex pipiens.

    Science.gov (United States)

    Sim, Cheolho; Denlinger, David L

    2008-05-06

    The short day lengths of late summer program the mosquito Culex pipiens to enter a reproductive diapause characterized by an arrest in ovarian development and the sequestration of huge fat reserves. We suggest that insulin signaling and FOXO (forkhead transcription factor), a downstream molecule in the insulin signaling pathway, mediate the diapause response. When we used RNAi to knock down expression of the insulin receptor in nondiapausing mosquitoes (those reared under long day lengths) the primary follicles were arrested in a stage comparable to diapause. The mosquitoes could be rescued from this developmental arrest with an application of juvenile hormone, an endocrine trigger known to terminate diapause in this species. When dsRNA directed against FOXO was injected into mosquitoes programmed for diapause (reared under short day lengths) fat storage was dramatically reduced and the mosquito's lifespan was shortened, results suggesting that a shutdown of insulin signaling prompts activation of the downstream gene FOXO, leading to the diapause phenotype. Thus, the results are consistent with a role for insulin signaling in the short-day response that ultimately leads to a cessation of juvenile hormone production. The similarity of this response to that observed in the diapause of Drosophila melanogaster and in dauer formation of Caenorhabditis elegans suggests a conserved mechanism regulating dormancy in insects and nematodes.

  12. Artificial Selection for Different Host Preferences in Culex pipiens pallens (Diptera: Culicidae) Mosquitoes.

    Science.gov (United States)

    Yu, Jing; Li, Chun-Xiao; Dong, Yan-De; Xue, Rui-De; Zhao, Tong-Yan

    2015-09-01

    Most mosquito species display host preferences that are a crucial determinant of the transmission rate of mosquito-borne pathogens. Although a transgenic approach, based on driving genes for zoophily into vector populations, has been advocated as a malaria control strategy by the World Health Organization since 1982, the genes involved in mosquito host choice remain poorly understood. Culex pipiens pallens Coquillet mosquitoes were artificially selected for two different host preferences in a specially designed experimental enclosure. Of 3,035 mosquitoes obtained from larvae and pupae collected from the wild (the F0 generation), 27% preferentially fed on pigeons and 16% fed on mice. Following artificial selection for these host preferences over successive generations, the percentage of mosquitoes that preferred to feed on pigeons or mice gradually increased, eventually stabilizing at ∼55 and 34%, respectively, after the sixth generation. Intergenerational differences in host preferences were significant (P mosquitoes selected to prefer pigeons and those selected to prefer mice were both significant and consistent over almost six generations.

  13. The Morphological Variations of Culex pipiens Larvae (Diptera: Culicidae in Yazd Province, Central Iran

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    H Dehghan

    2010-12-01

    Methods: This study was carried out in two randomly selected rural villages in Yazd County, eastern Iran using dip­ping technique from April to October 2009. The data were analyzed using SPSS software version 16. Results: Average of siphon index in fourth-instrar larvae was 3.86±0.03, the minimum and maximum were calculated 2.43 and 5.14, respectively. Siphon/Saddle index was measured as average, minimum and maximum 3.2±0.2, 2.78, and 4.42 respectively. In our study, only 4 specimens had single seta 1 on segments III and VI (2.5% and the remaining beard double seta (97.5%. The maximum 3-6 branches seta 1a-S and 1b-S (95% were observed on siphon. Conclusion: More populations of Culex pipiens from different areas of Iran need to be studied to gain complete informa­tion about the taxonomy and ecology of the species in the country.

  14. Larvicidal activity of extracts of Ginkgo biloba exocarp for three different strains of Culex pipiens pallens.

    Science.gov (United States)

    Sun, Lixin; Dong, Huiqin; Guo, Chongxia; Qian, Jin; Sun, Jing; Ma, Lei; Zhu, Changliang

    2006-03-01

    Ethanolic extracts from the Ginkgo biloba L. exocarp from the Chinese ginkgo were assayed against larvae of three strains of Culex pipiens pallens Coquillett. The chemical compositions were detected using a Hewlett-Packard 6890/5973 mass spectrometric detector. The larvicidal bioassay was carried out according to the recommendations of the World Health Organization. The analysis of the essential oil of ginkgo exocarp showed that its major components are ginkgo acid (85.3%) and ginkgo phenolic (5.69%). The larvicidal bioassay showed that extracts of ginkgo exocarp have LC50 of 18.6, 12.7, and 25.0 mg/liter for deltamethrin-susceptible, deltamethrin-resistant, and field strains, respectively. The acute toxicity concentrations of the ginkgo extracts that killed 50% (LD50) of Wistar rats within 2 wk and young carp within 96 h were 4947.2 mg/kg and 557.9 mg/liter, respectively. These results are promising in creating new, effective, and affordable approaches to mosquito control.

  15. A laboratory study of cyromazine on Aedes aegypti and Culex quinquefasciatus and its activity on selected predators of mosquito larvae.

    Science.gov (United States)

    Nelson, F R; Holloway, D; Mohamed, A K

    1986-09-01

    In a laboratory study, the insect growth regulator, cyromazine, exerted a high level of biological activity on Aedes aegypti and Culex quinquefasciatus treated in the 4th larval instar. At 1.5 and 1.0 ppm this IGR produced 97 and 99% inhibition of emergence in adult Ae. aegypti, respectively. In Cx. quinquefasciatus, there was 99% inhibition at 1 ppm and complete inhibition at 1.5 ppm. The overall pupal mortality was higher than larval or adult stages of both species. This material induced different types of morphogenetic abnormalities in pupae and adults of the 2 species similar to those induced by other IGRs. However, most abnormalities were observed in the pupal stage. Adverse effects were not detected on the 4 mosquito predator species during the acute or posttreatment tests.

  16. Efficacy ofLimonia acidissima L. (Rutaceae) leaf extract on larval immatures of Culex quinquefasciatus Say 1823

    Institute of Scientific and Technical Information of China (English)

    Siddharthasankar Banerjee; Someshwar Singha; Subrata Laskar; Goutam Chandra

    2011-01-01

    Objective:To investigate the role of leaf extract ofLimonia acidissimaL. (Rutaceae) as a biocontrol agent against the larval form ofCulex quinquefasciatus, and characterization of bioactive component responsible for larvicidal activity.Methods:Larval mortality of mosquito species was observed after24, 48and72 hours of exposure to different concentrations of aqueous extract, solvent extract and subsequently bioactive compound. The bioactive compound was subjected toIR andGC-MS analysis.Results:Mortality rate at 3% concentration of crude extract were highest(90%) amongst all concentrations tested and subsequently highest(95%) mortality was achieved in chloroform: methanol extract at100 ppm concentrations. IRandGC-MS analysis of bioactive compound revealed the presence of steroid compound which may act as larvicide. Conclusions:The chloroform: methanol extract of mature leaves of Limonia acidissima was found to exhibit considerable mosquito larvicidal activity against Culex quinquefasciatus.

  17. Synthesis and insecticidal activity of acridone derivatives to Aedes aegypti and Culex quinquefasciatus larvae and non-target aquatic species

    Science.gov (United States)

    Roopan, Selvaraj Mohana; Bharathi, Annadurai; Al-Dhabi, Naif Abdullah; Arasu, Mariadhas Valan; Madhumitha, G.

    2017-01-01

    A serious Mosquito borne yellow fever is one of the grave diseases which affect the major population. Since there is no specific treatment for yellow fever, there is a necessity to develop an effective agent. The series of acridinone analogues 3 to 5 were synthesized with help of non-conventional microwave heating and confirmed by respective spectral characterization. 5c and 3b showed highest activity to kill 90% of larvae against A. aegypti and C. quinquefasciatus, respectively. Also the active products were treated to check the mortality of non-target aquatic species. Through the reports of the larvicidal bioassay, compounds 3b against C. quinquefasciatus whereas 5c against A. aegypti were found to be more active. By keeping this as a platform, further extension of the work can be done to find out a valuable drug for controlling disease vectors.

  18. Efficacy of herbal essential oils as insecticide against Aedes aegypti (Linn.), Culex quinquefasciatus (Say) and Anopheles dirus (Peyton and Harrison).

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2011-09-01

    The essential oils of Cananga odorata (ylang ylang), Citrus sinensis (orange), Cymbopogon citratus (lemongrass), Cymbopogon nardus (citronella grass), Eucalyptus citriodora (eucalyptus), Ocimum basilicum (sweet basil) and Syzygium aromaticum (clove), were tested for their insecticide activity against Aedes aegypti, Culex quinquefasciatus and Anopheles dirus using the WHO standard susceptibility test. These were applied in soybean oil at dose of 1%, 5% and 10% (w/v). C. citratus had the KT, values against the three mosquito species tested but the knockdown rates (at 10, 30 and 60 minutes) were lower than some essential oils. C. citratus oil had high insecticidal activity against Ae. aegypti, Cx. quinquefasciatus and An. dirus, with LC50 values of < 0.1, 2.22 and < 0.1%, respectively. Ten percent C. citratus gave the highest mortality rates (100%) 24 hours after application. This study demonstrates the potential for the essential oil of C. citratus to be used as an insecticide against 3 species of mosquitoes.

  19. [The effect of insecticide resistance on the demographic parameters of 3 strains of Culex quinquefasciatus (Diptera: Culicidae) under laboratory conditions].

    Science.gov (United States)

    Suárez, S; Montada, D; Fuentes, O; Castex, M; Leyva, M

    1998-01-01

    The life tables of 3 strains of Culex quinquefasciatus were studied under laboratory conditions: Slab, susceptible to reference; Old Havana, treated with cypermethrin until its fourth generation; and Cotorro, from the field. It was found that the different levels of resistance to organophosphate insecticides and pyrethroids present in the Cotorro and Old Havana strains did not influence either on the duration of the period of development of the immature stages or in the sexual proportion of the emerged adults, but they had a favorable and directly proportional effect on the survival and longevity of the adults. However, they exerted a negative and inversely proportional influence on the reproduction and population growth of these strains. Useful data for the use and management of insecticides within the strategies of control of Culex quinquefasciatus, an important vector of lymphatic filariasis, are provided.

  20. Evaluation of some aromatic plant extracts for mosquito larvicidal potential against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    Science.gov (United States)

    Jayaraman, M; Senthilkumar, A; Venkatesalu, V

    2015-04-01

    In the present investigation, larvicidal potential of hexane, choloroform, ethyl acetate, acetone, and methanol extracts of seven aromatic plants, viz., Blumea mollis, Chloroxylon swietenia, Clausena anisata, Feronia limnonia, Lantana camera, Plectranthus amboinicus, and Tagetes erecta were screened against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that all the extracts showed varied levels of larvicidal activity against the mosquito species tested. However, the ethyl acetate extract of Chloroxylon swietenia showed the remarkable larvicidal activity against C. quinquefasciatus, Ae. aegypti, and An. stephensi. After 12 h of exposure period, the larvicidal activity was LC50 = 194.22 and LC90 = 458.83 ppm (C. quinquefasciatus), LC50 = 173.04 and LC90 = 442.73 ppm (Ae. aegypti), and LC50 = 167.28 and LC90 = 433.07 ppm (An. stephensi), and the larvicidal activity after 24-h exposure period was LC50 = 94.12 and LC90 = 249.83 ppm (C. quinquefasciatus), LC50 = 80.58 and LC90 = 200.96 ppm (Ae. aegypti), and LC50 = 76.24 and LC90 = 194.51 ppm (An. stephensi). The larvicidal potential of other plant extracts were in order of ethyl acetate extract of Clausena anisata > methanol extract of P. amboinicus > acetone extract of F. limonia > methanol extract of T. erecta > methanol extract of B. mollis > and methanol extract of L. camera. The results of the present study offer a possible way for further investigations to find out the active molecule responsible for the activity.

  1. Ovicidal and Oviposition Deterrent Activities of Medicinal Plant Extracts Against Aedes aegypti L. and Culex quinquefasciatus Say Mosquitoes (Diptera: Culicidae)

    OpenAIRE

    Reegan, Appadurai Daniel; Gandhi, Munusamy Rajiv; Paulraj, Micheal Gabriel; Ignacimuthu,Savarimuthu

    2014-01-01

    Objectives To evaluate the ovicidal and oviposition deterrent activities of five medicinal plant extracts namely Aegle marmelos (Linn.), Limonia acidissima (Linn.), Sphaeranthus indicus (Linn.), Sphaeranthus amaranthoides (burm.f), and Chromolaena odorata (Linn.) against Culex quinquefasciatus and Aedes aegypti mosquitoes. Three solvents, namely hexane, ethyl acetate, and methanol, were used for the preparation of extracts from each plant. Methods Four different concentrations—62.5 parts per ...

  2. Evaluation of water and ethanol extracts of Schinus molle Linn. against immature Culex quinquefasciatus Say (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Kidanemariam Girmay

    2014-06-01

    Full Text Available Objective: To evaluate larvicidal and pupicidal activities of aqueous and ethanol extract of different parts of Schinus molle against filarial vector, Culex quinquefasciatus (Cx. quinquefasciatus in the laboratory. Methods: The mortality rate of third, fourth instar larvae and pupal stages were tested at 20, 40, 60, 80 and 100 mg/L of plant extract using WHO standard protocol with modifications. The mortality rate was recorded continuously for 24, 48 and 72 h post exposure period and percentage mortality was calculated. Results: Maximum percentage mortality of third instar was 83.3% in ethanol extract of mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period, 93.3% percentage mortality was recorded in ethanol extract of immature fruit at 100 mg/L. After 72 h exposure period, 100% mortality was recorded in water extract of leaf at 100 mg/L. In fourth instar larvae, maximum percentage mortality of 63.3% was recorded in water extract of mature fruit and ethanol extract of immature and mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period 86.6% mortality was recorded in ethanol extract of mature fruit at 100 mg/L. After 72 h exposure period, 93.3% mortality was recorded in ethanol extract of mature fruit at 100 mg/L. In general immature Cx. quinquefasciatus, percentage mortality was increased with increase in exposure time and concentration of the plant extracts tested. Conclusions: From this laboratory study, Schinus molle plant parts were proved to have larvicidal and pupicidal activity against immature Cx. quinquefasciatus.

  3. Evaluation of water and ethanol extracts of Schinus molle Linn. against immature Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Kidanemariam Girmay; Bemnet Fikre; Atsede Asmelash; Biskut Getachew; Emebet Tekle; Nagappan Raja

    2014-01-01

    Objective: To evaluate larvicidal and pupicidal activities of aqueous and ethanol extract of different parts of Schinus molle against filarial vector, Culex quinquefasciatus (Cx. quinquefasciatus) in the laboratory. Methods:The mortality rate of third, fourth instar larvae and pupal stages were tested at 20, 40, 60, 80 and 100 mg/L of plant extract using WHO standard protocol with modifications. The mortality rate was recorded continuously for 24, 48 and 72 h post exposure period and percentage mortality was calculated. Results: Maximum percentage mortality of third instar was 83.3%in ethanol extract of mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period, 93.3%percentage mortality was recorded in ethanol extract of immature fruit at 100 mg/L. After 72 h exposure period, 100%mortality was recorded in water extract of leaf at 100 mg/L. In fourth instar larvae, maximum percentage mortality of 63.3%was recorded in water extract of mature fruit and ethanol extract of immature and mature fruit at 100 mg/L after 24 h exposure period. After 48 h exposure period 86.6%mortality was recorded in ethanol extract of mature fruit at 100 mg/L. After 72 h exposure period, 93.3%mortality was recorded in ethanol extract of mature fruit at 100 mg/L. In general immature Cx. quinquefasciatus, percentage mortality was increased with increase in exposure time and concentration of the plant extracts tested. Conclusions: From this laboratory study, Schinus molle plant parts were proved to have larvicidal and pupicidal activity against immature Cx. quinquefasciatus.

  4. Smoke repellency and mosquito larvicidal potentiality of Mesua ferra L. leaf extract against filarial vector Culex quinquefasciatus Say

    Institute of Scientific and Technical Information of China (English)

    Someshwar Singha; Utpal Adhikari; Goutam Chandra

    2011-01-01

    Objective: Present study was made to evaluate the smoke repellent potentiality and mosquito larvicidal activity of Mesua ferra (M. ferra) leaves against filarial vector Culex quinquefasciatus (Cx.quinquefasciatus ). Methods: Crude, petroleum-ether, chloroform: methanol (1:1 v/v) and ethyl acetate extracts of mature plant leaves were investigated to establish its biocontrol potentiality under laboratory condition against larvae of Cx. quinquefasciatus at different concentrations i.e. 25 ppm, 50 ppm and 75 ppm. Mosquito coil prepared from M. ferra leaves powder were tested for smoke toxicity effect against Cx. quinquefasciatus adult mosquitoes. Results: The mortality rates of crude extract at 0.5% concentration were higher than all other concentrations tested against the first, second, third and fourth instars larvae at 24 h, 48 h and 72 h of exposure. Larval mortality rate in chloroform: methanol (1:1 v/v) extract was significantly higher (P<0.05) than other extracts. LC50 value of petroleum ether, chloroform: methanol (1:1 v/v) and ethyl acetate extracts were 195.33 ppm, 27.28 ppm and 74.19 ppm respectively, after 48 h of exposure. Smoke exposed gravid females oviposited fewer eggs when compared to non exposed female mosquitoes. Conclusions:In conclusion M. ferra crude and chloroform: methanol (1:1) extract can be used effectively against mosquito control programmes. Smoke from M. ferra can play an important role in the interruption of transmission of those diseases where mosquitoes act as vector at the individual level.

  5. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus

    OpenAIRE

    Bracco José Eduardo; Dalbon Moacyr; Marinotti Osvaldo; Barata José Maria Soares

    1997-01-01

    Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente), mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.

  6. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Bracco José Eduardo

    1997-01-01

    Full Text Available Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente, mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.

  7. Culex pipiens, an experimental efficient vector of West Nile and Rift Valley fever viruses in the Maghreb region.

    Directory of Open Access Journals (Sweden)

    Fadila Amraoui

    Full Text Available West Nile fever (WNF and Rift Valley fever (RVF are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 10(7.8 and 10(8.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14-21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology.

  8. Behavioral responses of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus against various synthetic and natural repellent compounds.

    Science.gov (United States)

    Sathantriphop, Sunaiyana; White, Sabrina A; Achee, Nicole L; Sanguanpong, Unchalee; Chareonviriyaphap, Theeraphap

    2014-12-01

    The behavioral responses of colony populations of Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles minimus to four essential oils (citronella, hairy basil, catnip, and vetiver), two standard repellents (DEET and picaridin), and two synthetic pyrethroids (deltamethrin and permethrin) were conducted in the laboratory using an excito-repellency test system. Results revealed that Cx. quinquefasciatus and An. minimus exhibited much stronger behavioral responses to all test compounds (65-98% escape for contact, 21.4-94.4% escape for non-contact) compared to Ae. aegypti (3.7-72.2% escape (contact), 0-31.7% (non-contact)) and Ae. albopictus (3.5-94.4% escape (contact), 11.2-63.7% (non-contact)). In brief, essential oil from vetiver elicited the greatest irritant responses in Cx. quinquefasciatus (96.6%) and An. minimus (96.5%) compared to the other compounds tested. The synthetic pyrethroids caused a stronger contact irritant response (65-97.8% escape) than non-contact repellents (0-50.8% escape for non-contact) across all four mosquito species. Picaridin had the least effect on all mosquito species. Findings from the current study continue to support the screening of essential oils from various plant sources for protective properties against field mosquitoes. © 2014 The Society for Vector Ecology.

  9. Experimental hut evaluation of the pyrrole insecticide chlorfenapyr on bed nets for the control of Anopheles arabiensis and Culex quinquefasciatus.

    Science.gov (United States)

    Mosha, F W; Lyimo, I N; Oxborough, R M; Malima, R; Tenu, F; Matowo, J; Feston, E; Mndeme, R; Magesa, S M; Rowland, M

    2008-05-01

    To determine the efficacy of chlorfenapyr against Anopheles arabiensis and Culex quinquefasciatus in East Africa and to identify effective dosages for net treatment in comparison with the commonly used pyrethroid deltamethrin. Chlorfenapyr was evaluated on bed nets in experimental huts against A. arabiensis and C. quinquefasciatus in Northern Tanzania, at application rates of 100-500 mg/m(2). In experimental huts, mortality rates in A. arabiensis were high (46.0-63.9%) for all dosages of chlorfenapyr and were similar to that of deltamethrin-treated nets. Mortality rates in C. quinquefasciatus were higher for chlorfenapyr than for deltamethrin. Despite a reputation for being slow acting, >90% of insecticide-induced mortality in laboratory tunnel tests and experimental huts occurred within 24 h, and the speed of killing was no slower than for deltamethrin-treated nets. Chlorfenapyr induced low irritability and knockdown, which explains the relatively small reduction in blood-feeding rate. Combining chlorfenapyr with a more excito-repellent pyrethroid on bed nets for improved personal protection, control of pyrethroid-resistant mosquitoes and pyrethroid resistance management would be advantageous.

  10. Insecticidal and repellent activity of Clausena dentata (Rutaceae) plant extracts against Aedes aegypti and Culex quinquefasciatus mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Ramkumar, Govindaraju; Karthi, Sengodan; Muthusamy, Ranganathan; Natarajan, Devarajan; Shivakumar, Muthugounder Subramanian

    2015-03-01

    Mosquito control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol agents. The present study is to evaluate adulticidal activity of Clausena dentata plant extract against Aedes aegypti and Culex quinquefasciatus mosquitoes. The adult mortality was observed after 24 h of exposure. The highest mortality was found in acetone extracts against Ae. aegypti and Cx. quinquefasciatus with the LC50 and LC90 4.1783 mg/ml (3.8201-7.1026), 9.3884 mg/ml (7. 8258-13.1820) and 4.2451 mg/ml (3.8547-8.0254), 12.3214 mg/ml (10.9287-16.2220), respectively. Smoke toxicity was observed at 10-min interval for 40 min, and the mortality data were recorded. Result shows that Ae. aegypti and Cx. quinquefasciatus are 85 ± 2 and 89 ± 1.5, respectively. A mortality of 100 % was recorded in the commercial mosquito control. These results suggest that the leaf extracts of C. dentata have a potential to be used as an ideal eco-friendly approach for the control of mosquitoes.

  11. Selection, Realized Heritability, and Fitness Cost Associated With Dimethoate Resistance in a Field Population of Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Alam, Mehboob; Waqas Sumra, Muhammad; Ahmad, Daniyal; Shah, Rizwan Mustafa; Binyameen, Muhammad; Ali Shad, Sarfraz

    2017-06-01

    Mosquitoes are known to be vectors of numerous diseases leading to human morbidity and mortality at large scale in the world. Insecticide resistance has become a serious concern in controlling the insect vectors of public health importance. Dimethoate is an organophosphate insecticide used to control different insect pests including mosquitoes. Biological parameters of susceptible, unselected, and dimethoate-selected strains of Culex quinquefasciatus Say were studied in the laboratory to recognize resistance development potential and associated fitness cost. The dimethoate-selected strain showed 66.48-fold resistance to dimethoate compared with the susceptible strain after three continuous selections of generations. Realized heritability estimates of dimethoate resistance in Cx. quinquefasciatus yielded a value of 0.19. In dimethoate-selected strain, the biological traits including larval weight, survival from first instar to pupae, fecundity, number of next-generation larvae, relative fitness, net reproductive rate, intrinsic rate of natural increase, and biotic potential were significantly reduced as compared with the unselected strain. However, adult longevity, mean relative growth rate, weight of egg raft, female ratio, pupal duration, and emergence rate of the dimethoate-selected strain did not differ significantly compared with that of the unselected strain. This study provides useful information to devise retrospective management strategy for dimethoate resistance in Cx. quinquefasciatus. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Evaluation of target specific larvicidal activity of the leaf extract of Typhonium trilobatum against Culex quinquefasciatus Say

    Institute of Scientific and Technical Information of China (English)

    Koyel Mallick Haldar; Papiya Ghosh; Goutam Chandra

    2011-01-01

    Objective: To investigate the target specific larvicidal potential of an edible herb Typhonium trilobatum (T. trilobatum) (L.) Schott against mosquito Culex quinquefasciatus (Cx. quinquefasciatus) Say. Methods: Different concentrations of crude and methanol extract of T. trilobatum mature leaves were treated against Cx. quinquefasciatus larvae. LC50 concentration of crude extract on mosquito 3rd instar larvae was tested on Chironomus circumdatus and Diplonychus annulatum larvae. Preliminary phytochemical analysis was performed in search of plant’s secondary metabolites. Results:100%mortality of 1st instar mosquito larvae was recorded at 0.4%concentration after 72 h of exposure of crude extract. At 72 h 0.5%concentration produced 100%, 89.99%and 79.99%mortality of 2nd, 3rd and 4th instar larvae respectively. 50 ppm methanol extract showed 73.67%mortality of 3rd instar mosquito larvae at 72 h. 400 ppm concentration was responsible for 100%mortality in 24 h. Application of LC50 concentration (of 3rd instar mosquito larva) against non target organisms like C. circumdatus and D. annulatum larvae produced no significant mortality among them. Secondary metabolites like terpenoids and free glycoside bound anthraquinones were found. Conclusions:This experimental study was a pioneer attempt to establish T. trilobatum as a valuable resource of effective target specific mosquito larvicide.

  13. Larvicidal and pupicidal activity of extracts and fractionates of Eichhornia crassipes (Mart.) Solms against the filarial vector Culex quinquefasciatus Say.

    Science.gov (United States)

    Jayanthi, P; Lalitha, P; Aarthi, N

    2012-11-01

    Petroleum ether, acetone, ethyl acetate, aqueous extract, methanol and ethanol fractionate of Eichhornia crassipes (Mart.) Solms was tested for their larvicidal efficacy against the different instars (I, II, III and IV) and pupae of Culex quinquefasciatus Say. The larval mortality was observed after 24 h of the treatment. The extracts showed a dose-dependent toxicity to larvae. The toxicity of the extracts decreased with increase in larval stage. Ethanol fractionate of E. crassipes showed the highest larvicidal and pupicidal activity against C. quinquefasciatus compared to other solvent extracts and fractionates with LC(50) 71.43, 94.68,120.42, 152.15 and 173.35 ppm for I, II, III, IV and pupae, respectively. Presence of metabolites like flavonoids, alkaloids, anthroquinones and anthocyanins in the tested extracts might be the reason for the larvicidal and pupicidal activity of the plant extracts and fractionates of waterhyacinth. Mosquito-repellent activity was not exhibited by these extracts at the tested concentrations. The results demonstrated the potential of the aquatic plant E. crassipes in the successful control of the filarial vector C. quinquefasciatus.

  14. Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J

    2015-06-16

    Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs

  15. Synthesis and Larvicidal Activity against Culex pipiens pallens of New Triazole Derivatives of Phrymarolin from Phryma leptostachya L.

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    Ji-Wen Zhang

    2013-12-01

    Full Text Available Twelve new triazole derivatives of Phrymarolin were prepared from Phrymarolin I and the structures of all the derivatives were fully characterized by 1H-NMR, 13C-NMR and MS spectral data analyses. Larvicidal activities against 4rd instar larvae of Culex pipiens pallens of these Phrymarolin analogues were assayed. Although the triazole derivatives of Phrymarolin showed certain larvicidal activity, they showed lower activity than Phrymarolin I. The typical non-natural groups triazole substituents reduced the larvicidal activity of Phrymarolin derivatives.

  16. Evaluación de la actividad insecticida de un producto granulado a base de Bacillus sphaericus sobre larvas de Anopheles albimanus y Culex quinquefasciatus en condiciones experimentales

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    Estrella Cárdenas

    2009-01-01

    Full Text Available Culex quinquefasciatus causa alergias por las picaduras y ha sido asociado con la encefalitis equina, mientras que Anopheles albimanus es vector de malaria. El objetivo fue evaluar la toxicidad de un producto granulado a base de Bacillus sphaericus sobre larvas de Culex quinquefasciatus y Anopheles albimanus. El estudio fue realizado sobre larvas de C. quinquefasciatus (Sibaté y Villavicencio y An albimanus (Cartagena y Barranquilla. Las concentraciones ensayadas de B. sphaericus fueron: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 y 500 ppm para larvas de An. albimanus y para larvas de C. quinquefasciatus fueron: 2, 4, 6, 8, 10, 12, 14 y 16 ppm. Se utilizaron 20 larvas en tres repeticiones por cada concentración del producto y el tiempo de exposición fue de 48 horas. El producto de B. sphaericus mostró alta mortalidad (entre 80 y 100% a bajas concentraciones (8 y 12 ppm para larvas de C. quinquefasciatus; mientras que para larvas de An. albimanus a concentraciones más altas (entre 40 y 200 ppm la mortalidad no superó el 50%. La CL50 Logit fue 176 ppm y la Probit fue 192 ppm de B. sphaericus para larvas de An. albimanus; mientras que para larvas de C. quinquefasciatus la CL50 Logit fue 1, 9 ppm y la Probit fue 2, 2 ppm. Se concluye que las larvas de C. quinquefasciatus fueron más susceptibles a bajas concentraciones (2 a 12 ppm de B. sphaericus, mientras que las larvas de An. albimanus mostraron alta toxicidad a concentraciones de 500 ppm.

  17. Oxidative stress induced in PCB 126-exposed northern leopard frogs, Rana pipiens

    Science.gov (United States)

    Huang, Y.-W.; Hoffman, D.J.; Karasov, W.H.

    2007-01-01

    Northern leopard frogs Rana pipiens exposed to PCB 126 (3,3',4,4',5-pentachlorobiphenyl) were examined for hepatic oxidative stress. In a dose-response study, northern leopard frogs were injected intraperitoneally with either PCB 126 in corn oil (0.2, 0.7, 2.3, or 7.8 mg/kg body weight) or corn oil alone. In a time-course study, frogs received 7.8 mg/kg or corn oil alone, and were examined at 1, 2, 3, and 4 wk after dosing. Hepatic concentrations of reduced glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and total sulfhydryls (total SH), as well as activities of glutathione peroxidase (GSH-P), GSSG reductase (GSSG-R), glucose-6-phosphate dehydrogenase (G-6-PDH), and glutathione S-transferase (GSH-S-T) were measured. In the dose-response experiment, few effects were apparent 1 wk after dosing. In the time-course experiment, significant changes were observed in the 7.8-mg/kg group at 2 wk or more posttreatment. Hepatic concentrations of GSH and TBARS were higher than in corresponding controls at wk 3 and 4; the activities of GSSG-R and GSH-S-T were higher than in controls at wk 2 and 4; and the activity of G-6-PDH was increased at wk 2 and 4. These data collectively indicate that altered glutathione metabolism and oxidative stress occurred and were indicative of both toxicity and induction of protective mechanisms in frogs exposed to PCB. A similar delay in response was reported in fish and may relate to lower metabolic rate and physiological reactions in ectothermic vertebrates

  18. Effects of wetland vs. landscape variables on parasite communities of Rana pipiens: links to anthropogenic factors

    Science.gov (United States)

    Schotthoefer, Anna M.; Rohr, Jason R.; Cole, Rebecca A.; Koehler, Anson V.; Johnson, Catherine M.; Johnson, Lucinda B.; Beasley, Val R.

    2011-01-01

    The emergence of several diseases affecting amphibian populations worldwide has prompted investigations into determinants of the occurrence and abundance of parasites in frogs. To understand the spatial scales and identify specific environmental factors that determine risks of parasitism in frogs, helminth communities in metamorphic frogs of the northern leopard frog (Rana pipiens) were examined in relation to wetland and landscape factors at local (1 km) and regional (10 km) spatial extents in an agricultural region of Minnesota (USA) using regression analyses, ordination, and variance partitioning techniques. Greater amounts of forested and woody wetland habitats, shorter distances between woody wetlands, and smaller-sized open water patches in surrounding landscapes were the most consistently positive correlates with the abundances, richness, and diversity of helminths found in the frogs. Wetland and local landscape variables were suggested as most important for larval trematode abundances, whereas local and regional landscape variables appeared most important for adult helminths. As previously reported, the sum concentration of atrazine and its metabolite desethylatrazine, was the strongest predictor of larval trematode communities. In this report, we highlight the additional influences of landscape factors. In particular, our data suggest that anthropogenic activities that have resulted in the loss of the availability and connectivity of suitable habitats in the surrounding landscapes of wetlands are associated with declines in helminth richness and abundance, but that alteration of wetland water quality through eutrophication or pesticide contamination may facilitate the transmission of certain parasite taxa when they are present at wetlands. Although additional research is needed to quantify the negative effects of parasitism on frog populations, efforts to reduce inputs of agrochemicals into wetlands to limit larval trematode infections may be warranted

  19. Effects of chemical management for invasive plants on the performance of Lithobates pipiens tadpoles.

    Science.gov (United States)

    Curtis, Amanda N; Bidart, M Gabriela

    2017-05-12

    Invasive plants impact amphibians by altering habitat, altering species interactions, and releasing potentially toxic secondary chemicals. Despite being costly and having the potential to affect nontarget wildlife, chemical management is commonly used to control invasive plants. Prior research has indicated that individual effects of invasive plants or herbicides can be harmful to aquatic organisms; however, information is lacking on the combined effect of these factors on amphibians. A laboratory experiment was performed to assess the impact of leachates of the invasive plants Eurasian watermilfoil (Myriophyllum spicatum) and European buckthorn (Rhamnus cathartica), the herbicide Renovate(®) 3 (triclopyr [3, 5, 6-trichloro-2-pyridinyloxyacetic acid]), and the combined effects of each plant leachate and the herbicide on the growth, morphology, and survival of northern leopard frog (Lithobates pipiens) tadpoles. No effects of treatment on survival were observed. Tadpole exposure to M. spicatum reduced body mass by 17%, exposure to R. cathartica increased body mass by 36%, and exposure to R. cathartica + low herbicide increased body mass by 38% (although only early in the experiment). Exposure to Renovate 3 induced a 16% and 29% decrease in tadpole size in lower (0.22 mg triclopyr active ingredient [a.i.]/L) and higher (0.92 mg triclopyr a.i./L) concentration treatments, respectively. Results from the present study highlight the importance of considering both individual and combined effects of invasive plants and herbicides because they may have different outcomes for tadpole growth and development. Environ Toxicol Chem 2017;9999:1-7. © 2017 SETAC. © 2017 SETAC.

  20. Bioefficacy of acyclic monoterpenes and their saturated derivatives against the West Nile vector Culex pipiens.

    Science.gov (United States)

    Michaelakis, Antonios; Vidali, Veroniki P; Papachristos, Dimitrios P; Pitsinos, Emmanuel N; Koliopoulos, George; Couladouros, Elias A; Polissiou, Moschos G; Kimbaris, Athanasios C

    2014-02-01

    Twenty acyclic monoterpenes with different functional groups (acetoxy, hydroxyl, carbonyl and carboxyl) bearing a variable number of carbon double bonds were assayed as repellent and larvicidal agents against the West Nile vector Culex pipiens. Seven of them were derivatives that were synthesized through either hydrogenation or oxidation procedures. All repellent compounds were tested at the dose of 1mgcm(-2) and only neral and geranial were also tested at a 4-fold lower dose (0.25mgcm(-2)). Repellency results revealed that geranial, neral, nerol, citronellol, geranyl acetate and three more derivatives dihydrolinalool (3), dihydrocitronellol (5) and dihydrocitronellyl acetate (6) resulted in no landings. Based on the LC50 values the derivative dihydrocitronellyl acetate (6) was the most active of all, resulting in an LC50 value of 17.9mgL(-1). Linalyl acetate, citronellyl acetate, neryl acetate, geranyl acetate, dihydrocitronellol (5), dihydrocitronellal (7), citronellol, dihydrolinalyl acetate (2), citronellic acid and tetrahydrolinalyl acetate (1) were also toxic with LC50 values ranging from 23 to 45mgL(-1). Factors modulating toxicity have been identified, thus providing information on structural requirements for the selected acyclic monoterpenes. The acetoxy group enhanced toxicity, without being significantly affected by the unsaturation degree. Within esters, reduction of the vinyl group appears to decrease potency. Presence of a hydroxyl or carbonyl group resulted in increased activity but only in correlation to saturation degree. Branched alcohols proved ineffective compared to the corresponding linear isomers. Finally, as it concerns acids, data do not allow generalizations or correlations to be made.

  1. "Singing in the Tube"--audiovisual assay of plant oil repellent activity against mosquitoes (Culex pipiens).

    Science.gov (United States)

    Adams, Temitope F; Wongchai, Chatchawal; Chaidee, Anchalee; Pfeiffer, Wolfgang

    2016-01-01

    Plant essential oils have been suggested as a promising alternative to the established mosquito repellent DEET (N,N-diethyl-meta-toluamide). Searching for an assay with generally available equipment, we designed a new audiovisual assay of repellent activity against mosquitoes "Singing in the Tube," testing single mosquitoes in Drosophila cultivation tubes. Statistics with regression analysis should compensate for limitations of simple hardware. The assay was established with female Culex pipiens mosquitoes in 60 experiments, 120-h audio recording, and 2580 estimations of the distance between mosquito sitting position and the chemical. Correlations between parameters of sitting position, flight activity pattern, and flight tone spectrum were analyzed. Regression analysis of psycho-acoustic data of audio files (dB[A]) used a squared and modified sinus function determining wing beat frequency WBF ± SD (357 ± 47 Hz). Application of logistic regression defined the repelling velocity constant. The repelling velocity constant showed a decreasing order of efficiency of plant essential oils: rosemary (Rosmarinus officinalis), eucalyptus (Eucalyptus globulus), lavender (Lavandula angustifolia), citronella (Cymbopogon nardus), tea tree (Melaleuca alternifolia), clove (Syzygium aromaticum), lemon (Citrus limon), patchouli (Pogostemon cablin), DEET, cedar wood (Cedrus atlantica). In conclusion, we suggest (1) disease vector control (e.g., impregnation of bed nets) by eight plant essential oils with repelling velocity superior to DEET, (2) simple mosquito repellency testing in Drosophila cultivation tubes, (3) automated approaches and room surveillance by generally available audio equipment (dB[A]: ISO standard 226), and (4) quantification of repellent activity by parameters of the audiovisual assay defined by correlation and regression analyses.

  2. Behavioral Responses of Northern Leopard Frogs (Rana pipiens to Roads and Traffic: Implications for Population Persistence

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    Julie Bouchard

    2009-12-01

    Full Text Available A key goal in road ecology is to determine which species are most vulnerable to the negative effects of roads on population persistence. Theory suggests that species that avoid roads are less likely to be negatively affected by roads than those that do not avoid roads. The goal of this study was to take a step toward testing this prediction by evaluating the behavioral response to roads and traffic of a species whose populations are known to be negatively affected by roads and traffic, the northern leopard frog (Rana pipiens. We studied the movement patterns of northern leopard frogs during their spring migration from overwintering sites in a river to various breeding ponds that were disconnected from the river by roads. We performed short-distance translocations of migrating frogs, followed them visually, and documented their movement coordinates following each hop, both near the roads and in non-roaded areas. We found that frogs took longer to move near roads with more traffic and that their movement was quickest in areas without roads nearby. Frogs tended to deviate more from a straight-line course when they were released near roads than compared with control areas, but this response was independent of traffic volume. All frogs released near roads attempted to cross the road. On very low traffic roads (10.86 mean vehicles per hour, 94% of frogs crossed the road successfully, whereas at higher traffic roads (58.29 mean vehicles per hour 72% were successful. Our results suggest that frog's inability to avoid going onto roads and their slow movement combine to make them particularly vulnerable to road mortality, which likely explains the strong negative effects of roads on frog population abundance. Conservation efforts should focus on preventing frogs from accessing the road surface through the use of drift fencing and culverts.

  3. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus(Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality,deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus.Methods: Serial dilutions(0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules(WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design.Data on larval mortality, growth inhibition, deformities and adult’s emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyriproxyfen 1.0 WDG at 0.1 g/m3 was also tested in the field by collecting treated water samples monthly for 1–6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water.Results: Results revealed variations in fatality of different insect growth regulators(IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyriproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m3 of pyriproxyfen 1.0 WDG.Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.

  4. Evaluation of different formulations of IGRs against Aedes albopictus and Culex quinquefasciatus (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Gul Zamin Khan; Inamullah Khan; Imtiaz Ali Khan; Alamzeb; Muhammad Salman; Kalim Ullah

    2016-01-01

    Objective: To test the relative efficacy of pyriproxyfen and methoprene on mortality, deformity, inhibition and emergence to adult stages of Culex quinquefasciatus and Aedes albopictus. Methods: Serial dilutions (0.01–0.05 mg/L) of methoprene, pyriproxyfen 0.5 water dispersible granules (WDG) and pyriproxyfen 1.0 WDG were used to assess mortality and inhibition of 3rd instar larvae of Aedes albopictus and Culex quinquefasciatus. Each concentration and control was replicated four times in completely randomized design. Data on larval mortality, growth inhibition, deformities and adult's emergence was recorded weekly. On the basis of best comparative performance, the efficacy of pyr-iproxyfen 1.0 WDG at 0.1 g/m3 was also tested in the field by collecting treated water samples monthly for 1–6 months after field application. Twenty five 3rd instar larvae of Aedes and Culex spp. of the same cohorts were used for bioassays and compared with larvae in control cups containing 1 L of untreated tap water. Results: Results revealed variations in fatality of different insect growth regulators (IGRs) to the 3rd instar larvae of Culex and Aedes mosquitoes. Among the IGRs, pyr-iproxyfen 1.0 WDG was found best that exhibited significantly high emergence inhibition against Culex and Aedes spp. Based on the results, the IGRs were classified in terms of the tested parameters in order of pyriproxyfen 1.0 WDG > pyriproxyfen 0.5 WDG > methoprene. In case of field studies, pyriproxyfen 1.0 WDG, pool data of the entire target treated sites showed minimum adult emergence from water sampled of habitats treated with 0.1 g/m3 of pyriproxyfen 1.0 WDG. Conclusions: It is thus concluded that IGRs can be utilized as environment friendly control measures for Culex and Aedes spp. of mosquitoes on small and large scale. This will reduce the use of conventional insecticides by the public health authorities and help in reducing selection pressure of insecticides.

  5. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

    Science.gov (United States)

    Rahimi, Sara; Vatandoost, Hassan; Abai, Mohammad Reza; Raeisi, Ahmad; Hanafi-Bojd, Ahmad Ali; Rafi, Fatemeh

    2016-01-01

    Background: The irritant effect of some insecticides can cause a proportion of mosquitoes to leave the sprayed rooms before acquiring a lethal dose, so the repeated contact al sub-lethal dose may lead to extent the resistance. Methods: Larvae and pupae of Culex pipiens complex were collected in mass from open canals of waste water in capital city Tehran and reared to obtain the first generation at laboratory. Sugar-fed 2–3 days female mosquitoes were used for the experiments and compared with laboratory strain. The irritability tests of insecticides impregnated papers were measured in plastic conical exposure chambers placed which implemented at controlled conditions according to the method described by WHO. Number of take-offs were counted during 15 minutes of exposure time. Results: DDT had the most irritancy effect against field population of Cx. pipiens. DDT, permethrin and deltamethrin was moderately irritable against laboratory strain, whereas, addition to three previous insecticides, malathion, cyfluthrin and propoxur should be also considered as moderately irritable insecticides for field population of. Irritability level of etofenprox, fenithrothion, bendiocarb, and lambdacyhalothrin did not differ from control group. Conclusion: The irritability response of mosquitoes may have a negative impact on control measures. Periodical execution of irritability tests with insecticides that routinely used in vector control program is highly recommended. PMID:27308276

  6. Preparation of Ecofriendly Formulations Containing Biologically Active Monoterpenes with Their Fumigant and Residual Toxicities against Adults of Culex pipiens

    Directory of Open Access Journals (Sweden)

    Mohamed E. I. Badawy

    2016-01-01

    Full Text Available Different mixtures of monoterpenes (ketone, alcohol, and alkene were loaded on paper discs and wax and their knockdown activities were evaluated against Culex pipiens adults. Some individual monoterpenes were also evaluated by residual toxicity technique. Citronella oil as a reference was also loaded separately or in combination with monoterpenes on paper discs and wax. The ketone monoterpenes mixture (camphor, menthone, carvone, and fenchone on paper discs was the most active (KT50 = 17.20 min followed by ketone monoterpenes with citronella oil (KT50 = 20.79 min and citronella oil alone (KT50 = 28.72 min. Wax formulations proved that the ketone and alcohol (geraniol, thymol, and menthol monoterpenes gave the most activity as knockdown (KT50 = 31.79 and 43.39 min, resp.. Alcohol monoterpenes formulation recorded KT50 = 43.39 min. Residual activity of tested individual monoterpenes reported that the menthol was more toxic than camphor and camphene. Generally, this study suggests that the monoterpenes have the properties, which make them used as eco-friendly compounds in the control programs of Cx. pipiens adult. The use of paper discs is more applicable than wax in the adulticidal formulations.

  7. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major and mosquitoes (Culex pipiens.

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    Olivier Glaizot

    Full Text Available Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  8. High prevalence and lineage diversity of avian malaria in wild populations of great tits (Parus major) and mosquitoes (Culex pipiens).

    Science.gov (United States)

    Glaizot, Olivier; Fumagalli, Luca; Iritano, Katia; Lalubin, Fabrice; Van Rooyen, Juan; Christe, Philippe

    2012-01-01

    Avian malaria studies have taken a prominent place in different aspects of evolutionary ecology. Despite a recent interest in the role of vectors within the complex interaction system of the malaria parasite, they have largely been ignored in most epidemiological studies. Epidemiology of the disease is however strongly related to the vector's ecology and behaviour, and there is a need for basic investigations to obtain a better picture of the natural associations between Plasmodium lineages, vector species and bird hosts. The aim of the present study was to identify the mosquito species involved in the transmission of the haemosporidian parasites Plasmodium spp. in two wild populations of breeding great tits (Parus major) in western Switzerland. Additionally, we compared Plasmodium lineages, based on mitochondrial DNA cytochrome b sequences, between the vertebrate and dipteran hosts, and evaluated the prevalence of the parasite in the mosquito populations. Plasmodium spp. were detected in Culex pipiens only, with an overall 6.6% prevalence. Among the six cytochrome b lineages of Plasmodium identified in the mosquitoes, three were also present in great tits. The results provide evidence for the first time that C. pipiens can act as a natural vector of avian malaria in Europe and yield baseline data for future research on the epidemiology of avian malaria in European countries.

  9. Toxicity of Amorphigenin from the Seeds of Amorpha fruticosa against the Larvae of Culex pipiens pallens (Diptera: Culicidae

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    Yaping Liang

    2015-02-01

    Full Text Available The larvicidal activity of the crude petroleum ether, ethyl acetate, acetone, chloroform and ethanol extracts of Amorpha fruticosa seeds was individually assayed for toxicity against the early fourth-instar larva of the mosquito, Culex pipiens pallens after 24 h exposure. Of the tested extracts, the ethanol one exhibited the highest larvicidal activity (LC50 = 22.69 mg/L. Amorphigenin (8'-hydroxyrotenone, a rotenoid compound which exhibits a strong larvicidal activity with LC50 and LC90 values of 4.29 and 11.27 mg/L, respectively, was isolated from the ethanol extract by column chromatograpy. Its structure was elucidated by 1H-NMR, UV and IR spectral data. Furthermore, investigation of amorphigenin’s effects on mitochondrial complex I activity and protein synthesis in C. pipiens pallens larvae reveals that amorphigenin decreases mitochondrial complex I activities to 65.73% at 10.45 μmol/L, compared to the control, when NADH were used as the substrate. Meanwhile, amorphigenin at 10.45 μmol/L also caused a 1.98-fold decrease in protein content, compared to the control larvae treated with acetone only.

  10. Irritability Levels of Field and Laboratory Population of Culex pipiens Complex in Tehran to Different Groups of Insecticides

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    Sara Rahimi

    2016-01-01

    Full Text Available Background: The irritant effect of some insecticides can cause a proportion of mosquitoes to leave the sprayed rooms before acquiring a lethal dose, so the repeated contact al sub-lethal dose may lead to extent the resistance.Methods: Larvae and pupae of Culex pipiens complex were collected in mass from open canals of waste water in capital city Tehran and reared to obtain the first generation at laboratory. Sugar-fed 2–3 days female mosquitoes were used for the experiments and compared with laboratory strain. The irritability tests of insecticides impregnated pa­pers were measured in plastic conical exposure chambers placed which implemented at controlled conditions ac­cording  to  the  method  described  by WHO .Number of take-offs were counted during 15  minutes of exposure  time.Results: DDT had the most irritancy effect against field population of Cx. pipiens. DDT, permethrin and deltamethrin was moderately irritable against laboratory strain, whereas, addition to three previous insecticides, malathion, cyfluthrin and propoxur should be also considered as moderately irritable insecticides for field population of. Irritability level of etofenprox, fenithrothion, bendiocarb, and lambdacyhalothrin did not differ from control group.Conclusion: The irritability response of mosquitoes may have a negative impact on control measures. Periodical execution of irritability tests with insecticides that routinely used in vector control program is highly recommended.

  11. Multiple insecticide resistance/susceptibility status of Culex quinquefasciatus, principal vector of bancroftian filariasis from filaria endemic areas of northern India

    Institute of Scientific and Technical Information of China (English)

    Kaushal Kumar; Abhay K Sharma; Sarita Kumar; Sunita Patel; Manas Sarkar; Chauhan LS

    2011-01-01

    Objective:To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera:Culicidae) (Cx. Quinquefasciatus) to deltamethrin, cyfluthrin, permethrin, lambdacyhalothrin, DDT and malathion in filarial endemic areas of Uttar Pradesh, India. Methods:Insecticide susceptibility assays were performed on wild-caught adult female Cx. quinquefasciatus mosquitoes to deltamethrin (0.05%), cyfluthrin (0.15%), permethrin (0.75%), lambdacyhalothrin (0.05%), malathion (5.0%) and DDT (4.0%), the discriminating doses recommended by the World Health Organisation (WHO). Results: The data showed that Cx. quinquefasciatus is highly resistant to DDT and malathion;the mortality was 28.33%and 27.5%, respectively and incipient resistance to synthetic pyrethroids (deltamethrin, cyfluthrin, permethrin, and lambdacyhalothrin), where mortality ranged from 95.83%in permethrin to 98.33%in cyfluthrin and lambdacyhalothrin. Knockdown times (KDT50) in response to synthetic pyrethroids varied significantly between different insecticides (P<0.01) from 31.480 min for permethrin to 21.650 for cyfluthrin. Conclusions:The results presents here provide the status report of the insecticide resistance/susceptibility of Cx. quinquefasciatus in major filaria endemic areas of northern India.

  12. Possibility of culturing Pacific goliath grouper Epinephelus quinquefasciatus in water with different salinities

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    Lury García N.

    2015-01-01

    Full Text Available Objective. To assess the survival and growth of juvenile Pacific goliath grouper (Epinephelus quinquefasciatus in captivity at low salinities. Materials and methods. We randomly selected twelve juvenile goliath groupers with an average standard length of 44.2 ± 6.1 cm and 1492 ± 476 g in body weight, and raised them for three months in the laboratory in waters of 32-26, 20, 10 and 5 parts per thousand of salinity. Results. All juvenile Pacific goliath groupers tolerated the initial gradual transfer from full strength seawater to salinities of 32-26, 20, 10, and 5 parts per thousand, which was done over a period of four days. All of them survived and grew in body weight and length during the course of the three-month experiment, in all the treatments of high and low salinity water. The body condition factor (K for each fish was between 1.5 and 2.4. Conclusions. This is a first time trial that documents a randomized, controlled experiment demonstrating the ability of Pacific juvenile goliath grouper to gradually transfer from full strength seawater to water of lower salinity, and survive and grow well in these brackish waters.

  13. Actividad de picadura de Culex quinquefasciatus (SAY, 1863 en Bogotá, Colombia

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    Marco Andrés Rojas-Mogollón

    2013-09-01

    Full Text Available Resumen Antecedentes. La presencia de mosquitos en el sur de Bogotá se constituye en una molestia sanitaria debido a sus altas densidades. Objetivo. Caracterizar la abundancia mensual y la actividad de picadura de los mosquitos. Materiales y métodos. Se recolectaron mosquitos utilizando trampas Shannon, durante una noche por mes y por un periodo de seis meses, en dos sitios aledaños a fosos de excavación minera, inundadas por el río Tunjuelito. Resultados. Se recolectaron un total de 18891 mosquitos. 99,93% se determinaron como culex quinquefasciatus. Los meses de mayor abundancia de mosquitos fueron marzo y abril, los cuales presentan mayor precipitación. Se encontraron dos patrones de actividad nocturna, uno con un solo pico hacia la media noche en el sitio más cercano a las minas de excavación y otro con dos picos definidos en el sitio más cercano a las viviendas. La tasa de paridad fue de 64,4%. Conclusión. Este comportamiento diferente posiblemente esté asociado a las condiciones microambientales, como luz y actividad minera de la zona durante las 24 horas del día, pero no se encontró que estuviera relacionado con la presencia o ausencia de lluvia.

  14. SR450 And Superhawk XP Applications Of Bacillus thuringiensis israelensis Against Culex quinquefasciatus.

    Science.gov (United States)

    Dunford, James C; Stoops, Craig A; Estep, Alden S; Britch, Seth C; Richardson, Alec G; Walker, Todd W; Farooq, Muhammad; Hoel, David F; Platt, Raymond R; Smith, Vincent L; Wirtz, Robert A; Kerce, Jerry D

    2014-09-01

    Sprayer comparisons and larval morality assays were conducted following SR450 backpack mist blower and Superhawk XP thermal fogger applications of Vectobac® WDG Bacillus thuringiensis israelensis (Bti) against Culex quinquefasciatus. Bacillus thuringiensis israelensis was applied at maximum label rate in a 232.26-m(2) field plot located in north-central Florida with containers placed at 2 heights (ground level and 1.52 m above ground) on stakes positioned 3.04, 6.09, 9.14, 12.19, and 15.24 m from the spray line. Results indicated that there was no significant (P > 0.05) difference in 24- and 48-h larval mortality between the 2 sprayers or between the 2 heights. There was significant difference (P 70% larval mortality 3.04-9.14 m from the spray line, and <60% mortality at 12.19 and 15.24 m. The data suggest that the SR450 and Superhawk XP may be comparable sprayers for use with Bti to control mosquito larvae.

  15. Larvicidal activities of three plants against filarial vector Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Rawani, Anjali; Haldar, Koyel Mallick; Ghosh, Anupam; Chandra, Goutam

    2009-10-01

    The present study was carried out to establish the larvicidal properties of crude extracts of three plants, viz. Carica papaya, Murraya paniculata and Cleistanthus collinus against Culex quinquefasciatus as target species. The relative efficacy of the plant extracts in vector control was as follows: C. papaya seed extract > M. paniculata fruit extract > M. paniculata leaf extract > C. collinus leaf extract. Result of log-probit analysis (at 95% confidence level) revealed that LC(50) and LC(95) values gradually decreased with the exposure periods similar to the result in bioassay experiment for each of the plant extract. The results of preliminary qualitative phytochemical analysis of all the plants revealed the presence of many bioactive principles such as steroids, alkaloids, terpenes, saponins, etc. that may be responsible for their biocontrol potentiality. The appropriate lethal concentrations at 24 h for each of the extracts were also studied on non-target organisms such as Diplonychus annulatum and Chironomus circumdatus, and no change in the swimming behaviour and survivality was noticed, which indicates that all the extracts are safe for the aquatic ecosystem.

  16. Susceptibilidade larval de populações de Aedes aegypti e Culex quinquefasciatus a inseticidas químicos Larval susceptibility of Aedes aegypti and Culex quinquefasciatus populations to chemical insecticides

    Directory of Open Access Journals (Sweden)

    Jairo Campos

    2003-08-01

    Full Text Available OBJETIVO: Avaliar a susceptibilidade a inseticidas químicos de larvas de Culex quinquefasciatus e Aedes aegypti, provenientes de áreas sujeitas ou não a tratamentos de controle. MÉTODOS: Foram coletadas larvas de mosquitos em uma área não sujeita a tratamentos com inseticidas (Campinas, SP e em áreas sujeitas a esses tratamentos (Campo Grande, MS e Cuiabá, MT. Foram usados bioensaios com concentrações diagnóstico e concentrações múltipla de inseticidas organofosforados e piretróides, segundo padrão da Organização Mundial de Saúde, para avaliar a susceptibilidade dessas larvas. RESULTADOS: Ensaios com larvas de Culex quinquefasciatus de Campinas, SP, permitiram a suspeita de resistência à cipermetrina e evidenciaram resistência à ciflutrina. Larvas dessa espécie coletadas em Campo Grande, MS, e Campinas, SP, apresentaram resistência ao temephos. Para a colônia campineira desta espécie, foram estabelecidas as razões de resistência: RR50=6,36 e RR95=4,94, com base em linhagem susceptível padrão. Adicionalmente, os testes com Aedes aegypti mostraram susceptibilidade similar ao temephos em uma população de campo (Cuiabá, MT e uma de laboratório. CONCLUSÕES: Os resultados indicam resistência a organofosforado e piretróides em Culex quinquefasciatus, evidenciando a necessidade de avaliações e monitoramento da efetividade dos inseticidas a serem usados nos programas de controle de mosquitos.OBJECTIVE: To evaluate the susceptibility to chemical insecticides of Culex quinquefasciatus and Aedes aegypt larvae from areas subjected to control treatments or not. METHODS: Bioassays for diagnostic concentration and multiple concentration were performed for organophosphate and pyrethroid insecticides according to World Health Organization parameters. The susceptibility was assessed for mosquito larvae collected from an area not subjected to chemical control (Campinas, State of São Paulo, SP and from other areas (Campo

  17. Morphological changes in the skin of Rana pipiens in response to metabolic acidosis.

    Science.gov (United States)

    Page, R D; Frazier, L W

    1987-04-01

    The skin of Rana pipiens excretes H+ and this excretion is increased by metabolic acidosis. The mitochondria-rich (MR) cells of the skin have been found to mediate this H+ transport. The purpose of this study was to determine if there is a change in the MR cells of the skin during metabolic acidosis and if the isolated split epithelia of frog skin maintains its capacity to excrete H+. Metabolic acidosis was induced by injecting 120 mM NH4Cl (0.025 ml/g body wt) into the dorsal lymph sac three times a day for 2 days. The frogs were sacrificed and collagenase-split skins from the abdomen of normal and metabolic acidotic frogs were mounted between 2-ml chambers. H+ fluxes into both the mucosal and serosal media were measured and reported in units of (nmol) (cm2)-1 (min)-1. An increase in H+ flux was seen on both the mucosal and serosal sides of the acidotic split skins. The isolated epithelia were fixed, postosmicated, and dehydrated in the chamber. They were then embedded in Spurr's resin and 1-micron sections were cut and stained with Paragon multiple stain. Coded slides were used to count various cell types. Sections were randomly selected and approximately 40,000 cells were counted. Four basic cell types were noted and confirmed by TEM photomicrographs; basal (B) cells, granular (G) cells, keratinized cells, and MR cells. The ratio of G + B cells:MR cells in the normal skins was 1.0:0.021. The ratio in acidotic skins was 1.0:0.34. The average percentage of cell population of MR cells in the normal skins was 2.08 + 0.18 and in acidotic skins 3.20 + 0.36 (P less than 0.005). We conclude that the split skin maintains the capacity to acidify the mucosal fluid. Additionally, during metabolic acidosis there is an increased number of MR cells in the skin and this increase may be an adaptive mechanism of the skin to excrete excess H+ during acidosis.

  18. Genetic diversity based on 28S rDNA sequences among populations of Culex quinquefasciatus collected at different locations in Tamil Nadu, India.

    Science.gov (United States)

    Sakthivelkumar, S; Ramaraj, P; Veeramani, V; Janarthanan, S

    2015-09-01

    The basis of the present study was to distinguish the existence of any genetic variability among populations of Culex quinquefasciatus which would be a valuable tool in the management of mosquito control programmes. In the present study, population of Cx. quinquefasciatus collected at different locations in Tamil Nadu were analyzed for their genetic variation based on 28S rDNA D2 region nucleotide sequences. A high degree of genetic polymorphism was detected in the sequences of D2 region of 28S rDNA on the predicted secondary structures in spite of high nucleotide sequence similarity. The findings based on secondary structure using rDNA sequences suggested the existence of a complex genotypic diversity of Cx. quinquefasciatus population collected at different locations of Tamil Nadu, India. This complexity in genetic diversity in a single mosquito population collected at different locations is considered an important issue towards their influence and nature of vector potential of these mosquitoes.

  19. Mammalophilic feeding behaviour of Culex quinquefasciatus mosquitoes collected in the cities of Chetumal and Cancun, Yucatán Peninsula, Mexico.

    Science.gov (United States)

    Janssen, Nele; Fernandez-Salas, Ildefonso; Díaz González, Esteban Eduardo; Gaytan-Burns, Alejandro; Medina-de la Garza, Carlos E; Sanchez-Casas, Rosa María; Börstler, Jessica; Cadar, Daniel; Schmidt-Chanasit, Jonas; Jöst, Hanna

    2015-11-01

    The studie describes the blood-feeding behaviour of mosquitoes in Mexico, to understand host-vector relationships and dynamics of disease transmission. From September 2012 to November 2012 and in November 2013, 911 blood-fed Cx. quinquefasciatus mosquitoes were collected with aspirators inside houses in Chetumal and Cancun. Blood meals were analysed by PCR and subsequent Sanger sequencing of the cytochrome b gene. 93.3% of mosquitoes fed on mammals, 6.5% on birds and 0.2% on reptiles. The most frequent vertebrate hosts were humans (65.4%), dogs (23.2%), chicken (5.4%), cattle (2.2%) and cats (1.8%). Cx. quinquefasciatus most frequently fed on humans and dogs in both studied cities, which is in contrast to a previous study that demonstrated lower prevalence of mammalian blood in engorged Cx. quinquefasciatus. © 2015 John Wiley & Sons Ltd.

  20. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus

    Science.gov (United States)

    Yee, Donald A.; Kaufman, Michael G.; Ezeakacha, Nnaemeka F.

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  1. Larvicidal and Pupicidal Activities of Alizarin Isolated from Roots of Rubia cordifolia Against Culex quinquefasciatus Say and Aedes aegypti (L.) (Diptera: Culicidae).

    Science.gov (United States)

    Gandhi, M R; Reegan, A D; Ganesan, P; Sivasankaran, K; Paulraj, M G; Balakrishna, K; Ignacimuthu, S; Al-Dhabi, N A

    2016-08-01

    The mosquitocidal activities of different fractions and a compound alizarin from the methanol extract of Rubia cordifolia roots were evaluated on larvae and pupae of Culex quinquefasciatus Say and Aedes aegypti (L.) (Diptera: Culicidae). Larvae and pupae were exposed to concentrations of 2.5, 5.0, 7.5 and 10 ppm for fractions and 0.5, 1.0, 1.5 and 2.0 ppm for compound. After 24 h, the mortality was assessed and the LC50 and LC90 values were estimated for larvae and pupae. Among the 23 fractions screened, fraction 2 from the methanol extract of R. cordifolia showed good mosquitocidal activity against C. quinquefasciatus and A. aegypti. LC50 and LC90 values of fraction 2 were 3.53 and 7.26 ppm for C. quinquefasciatus and 3.86 and 8.28 ppm for A. aegypti larvae, and 3.76 and 7.50 ppm for C. quinquefasciatus and 3.92 and 8.05 ppm for A. aegypti pupae, respectively. Further, the isolated compound alizarin presented good larvicidal and pupicidal activities. LC50 and LC90 values of alizarin for larvae were 0.81 and 3.86 ppm against C. quinquefasciatus and 1.31 and 6.04 ppm for A. aegypti larvae, respectively. Similarly, the LC50 and LC90 values of alizarin for pupae were 1.97 and 4.79 ppm for C. quinquefasciatus and 2.05 and 5.59 ppm for A. aegypti pupae, respectively. The structure of the isolated compound was identified on the basis of spectroscopic analysis and compared with reported spectral data. The results indicated that alizarin could be used as a potential larvicide and pupicide.

  2. Environmental factors associated with the distribution of Anopheles arabiensis and Culex quinquefasciatus in a rice agro-ecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Mwangangi, Joseph; Shililu, Josephat; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-06-01

    Studies were conducted between May and June, 2006 to investigate the environmental factors affecting the distribution of An. arabiensis Patton and Culex quinquefasciatus Say in Mwea, Kenya. The sampling unit comprised all non-paddy aquatic habitats and ten randomly selected paddies and canals located within a 200 m radius from the periphery of the study site. Thirteen physico-chemical variables were recorded for each sampling site in each sampling occasion and a sample of mosquito larvae and other aquatic invertebrates collected. The non-paddy aquatic habitats identified included pools and marshes. Morphological identification of 1,974 mosquito larvae yielded four species dominated by Cx. quinquefasciatus (73.2%) and An. arabiensis (25.0%). Pools were associated with significantly higher Cx. quinquefasciatus larval abundance and less diversity of other aquatic invertebrates compared with other habitat types. In contrast, the abundance of An. arabiensis did not differ significantly among habitat types. Culex quinquefasciatus habitats had higher water conductivity and exhibited a higher abundance of other aquatic invertebrates than An. arabiensis habitats. Chi-square analysis indicated that the two species were more likely to coexist in the same habitats than would be expected by chance alone. Anopheles arabiensis larvae were positively associated with dissolved oxygen and adults of family Haliplidae and negatively associated with emergent vegetation and Heptageniidae larvae. Culex quinquefasciatus larvae were positively associated with dissolved oxygen, total dissolved solids, Chironomidae larvae, and Microvelidae adults and negatively associated with emergent vegetation. These findings suggest that both biotic and abiotic factors play a significant role in niche partitioning among Cx. quinquefasciatus and An. arabiensis, a factor that should be considered when designing an integrated vector control program.

  3. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Donald A Yee

    Full Text Available Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container

  4. How Diverse Detrital Environments Influence Nutrient Stoichiometry between Males and Females of the Co-Occurring Container Mosquitoes Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus.

    Science.gov (United States)

    Yee, Donald A; Kaufman, Michael G; Ezeakacha, Nnaemeka F

    2015-01-01

    Allocation patterns of carbon and nitrogen in animals are influenced by food quality and quantity, as well as by inherent metabolic and physiological constraints within organisms. Whole body stoichiometry also may vary between the sexes who differ in development rates and reproductive allocation patterns. In aquatic containers, such as tree holes and tires, detrital inputs, which vary in amounts of carbon and nitrogen, form the basis of the mosquito-dominated food web. Differences in development times and mass between male and female mosquitoes may be the result of different reproductive constraints, which could also influence patterns of nutrient allocation. We examined development time, survival, and adult mass for males and females of three co-occurring species, Aedes albopictus, Ae. aegypti, and Culex quinquefasciatus, across environments with different ratios of animal and leaf detritus. We quantified the contribution of detritus to biomass using stable isotope analysis and measured tissue carbon and nitrogen concentrations among species and between the sexes. Development times were shorter and adults were heavier for Aedes in animal versus leaf-only environments, whereas Culex development times were invariant across detritus types. Aedes displayed similar survival across detritus types whereas C. quinquefasciatus showed decreased survival with increasing leaf detritus. All species had lower values of 15N and 13C in leaf-only detritus compared to animal, however, Aedes generally had lower tissue nitrogen compared to C. quinquefasciatus. There were no differences in the C:N ratio between male and female Aedes, however, Aedes were different than C. quinquefasciatus adults, with male C. quinquefasciatus significantly higher than females. Culex quinquefasciatus was homeostatic across detrital environments. These results allow us to hypothesize an underlying stoichiometric explanation for the variation in performance of different container species under similar

  5. Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico.

    Science.gov (United States)

    Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D

    2010-06-01

    Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain

  6. Larvicidal activity of essential oil of Peumus boldus Molina and its ascaridole-enriched fraction against Culex quinquefasciatus.

    Science.gov (United States)

    de Castro, Débora Silva Borges; da Silva, Denise Brentan; Tibúrcio, Jacqueline Domingues; Sobral, Marcos Eduardo Guerra; Ferraz, Vany; Taranto, Alex Gutterres; Serrão, José Eduardo; de Siqueira, João Máximo; Alves, Stênio Nunes

    2016-12-01

    Culex quinquefasciatus (Say, 1823), known as the domestic mosquito, is a common and abundant species throughout the world, and a cosmopolitan species. The adults of this mosquito are important in terms of public and animal health since they display adaptability to different hosts. In humans, they are responsible for the transmission of various diseases. One manner of control of this vector is the use of insecticidal or larvicidal products, which may have the drawback of toxicity to mammals and can be harmful to the environment. The present work evaluated the larvicidal potential of the essential oil (EO) and ascaridole-enriched fraction (EF4-5) obtained from the leaves of Peumus boldus Molina (boldo). The EO, obtained by steam distillation, was analyzed by GC/MS and fractionated on silica gel. EO and EF4-5, containing 31.4% and 89.5% ascaridole, respectively, were evaluated against C. quinquefasciatus at concentrations of 100, 50 and 25 μg/ml on the third and fourth instars. They showed lethal concentrations (LC50) of 82.14 and 41.85 μg/ml, respectively. Larvae treated with the EF4-5 showed morphological changes in the midgut, with cells possessing a cytoplasm that contained small vacuole-like structures, as well as a nucleus with decondensed chromatin and a cell apex with a short brush border. The cells of the fat body showed larger protein granules, which were acidophilic relative to the larvae of the control group. Moreover, the enriched fraction at a dose of 50 μg/ml showed a residual larvicidal effect according to exposure time on C. quinquefasciatus. This residual effect deserves consideration, since a long-term larvicidal product may be a useful tool for vector control. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Susceptibilidade larval de populações de Aedes aegypti e Culex quinquefasciatus a inseticidas químicos

    Directory of Open Access Journals (Sweden)

    Campos Jairo

    2003-01-01

    Full Text Available OBJETIVO: Avaliar a susceptibilidade a inseticidas químicos de larvas de Culex quinquefasciatus e Aedes aegypti, provenientes de áreas sujeitas ou não a tratamentos de controle. MÉTODOS: Foram coletadas larvas de mosquitos em uma área não sujeita a tratamentos com inseticidas (Campinas, SP e em áreas sujeitas a esses tratamentos (Campo Grande, MS e Cuiabá, MT. Foram usados bioensaios com concentrações diagnóstico e concentrações múltipla de inseticidas organofosforados e piretróides, segundo padrão da Organização Mundial de Saúde, para avaliar a susceptibilidade dessas larvas. RESULTADOS: Ensaios com larvas de Culex quinquefasciatus de Campinas, SP, permitiram a suspeita de resistência à cipermetrina e evidenciaram resistência à ciflutrina. Larvas dessa espécie coletadas em Campo Grande, MS, e Campinas, SP, apresentaram resistência ao temephos. Para a colônia campineira desta espécie, foram estabelecidas as razões de resistência: RR50=6,36 e RR95=4,94, com base em linhagem susceptível padrão. Adicionalmente, os testes com Aedes aegypti mostraram susceptibilidade similar ao temephos em uma população de campo (Cuiabá, MT e uma de laboratório. CONCLUSÕES: Os resultados indicam resistência a organofosforado e piretróides em Culex quinquefasciatus, evidenciando a necessidade de avaliações e monitoramento da efetividade dos inseticidas a serem usados nos programas de controle de mosquitos.

  8. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

  9. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    DEFF Research Database (Denmark)

    Derua, Yahya A.; Kisinza, William N.; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus...... to receive either ivermectin or placebo. Twenty four hours after treatment, one volunteer from each group was concurrently exposed to 50 laboratory reared An. gambiae on one arm and 50 laboratory reared Cx. quinquefasciatus on the other arm for 15-30 minutes. Engorged mosquitoes were maintained on 10...

  10. 竹提取物对淡色库蚊Culex pipiens pallens幼虫的活性评价%EVALUATION OF EXTRACTS FROM BAMBOO FOR BIOLOGICAL ACTIVITY AGAINST CULEX PIPIENS PALLENS

    Institute of Scientific and Technical Information of China (English)

    操海群; 岳永德; 彭镇华; 花日茂; 汤锋

    2004-01-01

    报道了竹提取物对淡色库蚊Culex pipiens pallens幼虫的毒杀作用.研究结果表明,巨县苦竹(Pleioblastusjuxianensis)、白纹短穗竹(Brachystachyum albostriatum)、灰水竹(Phyllostachysplatyglossa)和苦竹(Pleioblastus amarus)提取物对淡色库蚊幼虫的24h致死中浓度(LC50)分别为30.65 mg/L、53.94 mg/L、41.21 mg/L、54.49 mg/L.巨县苦竹索氏抽提物对淡色库蚊幼虫的毒杀作用明显强于间歇振荡提取物,前者对淡色库蚊幼虫的LC50为30.65 mg/L,95%置信限27.12~34.63 mg/L;后者的LC50为48.34 mg/L,95%置信限为40.37~59.62 mg/L.巨县苦竹乙醚浸提物对淡色库蚊幼虫的毒杀作用效果显著,125mg/L浓度时12h校正死亡率为56.67%,24h后达92.90%;石油醚浸提物及甲醇浸提物对淡色库蚊幼虫的毒杀作用则不明显,24h校正死亡率均不超过40%.研究结果将有助于综合利用竹类资源,开发新型环境友好农药.%The extracts from 7 species of bamboo were tested for larvicidal activity against Culex pipiens pallens. At the tested concentration, the extracts of selected bamboo had different degree of toxic effects on the fourth instar larvae of Culex pipiens pallens. Among them,the extracts of Pleioblastus juxianensis, Brachystachyum albostriatum, Phyllostachys platyglossa and Pleioblastus amarus were found to be effective with LC50values at 24h of 30.65 mg/L,53.94 mg/L, 41.21 mg/L and 54.49 mg/L respectively, against Culex pipiens pallens larvae. The extract of Pleioblastus juxianensis by Soxhlet method showed stronger activity than the extract obtained by interval-shaking, the LC50 of which were 30.65 mg/L and 48.34 mg/L, respectively.The diethyl ether extract of Pleioblastus juxianensis exhibited better larvicidal activity than the methanol extract and the petroleum ether extract. The results would help to provide the basis for the study of environment acceptable pesticide for mosquito control, and also help to comprehensively utilize the source of

  11. PERBANDINGAN PENGARUH BIOSIDA SANDOZ DENGAN BACTIMOS TERHADAP PENCEMAR BIOLOGIS, CULEX QUINQUEFASCIATUS DALAM SATU UJI COBA LAPANGAN DI JAKARTA, INDONESIA

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    I. G. Seregeg

    2012-09-01

    Full Text Available A field trial of Bacillus thuringiensis serotype H-14 has been done in Rawasari, Jakarta. Bacillus thuringiensis serotype H-14 under the trade-name of Sandoz 402 I in wde formulation and under the trade-name of Bactimos in wdp formulation is a specific agent against mosquito larvae (WHO mimeo. series, 1980. The result of the trial showed that both formulations have a short killing ef­fect, not more than one day against the larvae of Culex quinquefasciatus in Jakarta, Indonesia. Bactimos wdp has a better killing effect against early instar larvae as compared to Sandoz wdc.

  12. Pengaruh Pengasapan (Thermal Fogging Insektisida Piretroid (Malation 95% Terhadap Nyamuk Aedes aegypti dan Culex quinquefasciatus di Pemukiman

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    Hasan Boesri

    2009-12-01

    Full Text Available The evaluation of piretroid insecticide (active ingredient Malation 95% was con-ducted in Sub district Tengarang, Semarang Segency, Central Java Province. The insecti-cide was applied using thermal fogging method for dosages of 125, 250, 375, 500 and 625 ml/ha (diluted in diesel to 10 litters. The evaluation of the efficacy was conducted against two mosquito species, Aedes aegypti (the main dengue haemorrhagic fever and Culex quinquefasciatus (the urban lymphatic fil-ariasis vector. Result of the evaluation was revealed that dosages of 500 and 625 ml/ha were effective against both tested mosquito species indoor and outdoor.

  13. Blood-feeding patterns of Culex quinquefasciatus and other culicines and implications for disease transmission in Mwea rice scheme, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Muriu, Simon; Shililu, Josephat; Mwangangi, Joseph M; Jacob, Benjamin G; Mbogo, Charles; Githure, John; Novak, Robert J

    2008-05-01

    Studies were conducted in Mwea Rice Scheme, Kenya during the period April 2005 and January 2007 to determine the host-feeding pattern of culicine mosquitoes. Mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an Enzyme-Linked Immunosorbent Assay. A total of 1,714 blood-engorged samples comprising Culex quinquefasciatus Say (96.1%), Culex annulioris Theobald (1.8%), Culex poicilipes Theobald (0.9%), Aedes cuminsi Theobald (1.0%), Aedes taylori Edwards (0.1%), and Mansonia africana Theobald (0.1%) were tested. Except for A. taylori, in which the single blood meal tested was of bovine origin, the other species fed mostly on both bovine (range 73.3-100%) and goats (range 50-100%). Donkeys were also common hosts for all species (range 19.4-23.5%) except A. taylori and M. africana. C. quinquefasciatus was the only species containing human blood meals (0.04), and indoor collected populations of this species had significantly higher frequency of human blood meals (9.8%) compared with outdoor-collected populations (3.0%). Mixed blood feeding was dominant among culicine species comprising 50.0%, 73.3%, 73.5%, 80.6%, and 94.1% of the samples for M. africana, C. poicilipes, C. quinquefasciatus, C. annulioris, and A. cuminsi, respectively. Ten mixed blood meal combinations including a mixture of all the four hosts were observed in C. quinquefasciatus, compared to one blood meal combination for M. Africana, and two combinations for C. poicilipes, C. annulioris, and A. cuminsi. Mixed bovine and goat blood meal was the most common combination among the five culicine species followed by a mixture of donkey, bovine, and goat blood meals. We conclude that culicine species in Mwea are least likely to be vectors of lymphatic filariasis due to their high "preference" for livestock over human hosts, but they present an increased risk for arbovirus transmission particularly Rift Valley Fever virus, in which domestic animals serve

  14. Flight muscle-specific expression of act88F: GFP in transgenic Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Allen, Margaret L; Christensen, Bruce M

    2004-12-01

    A strategy to engineer a strain of Culex mosquitoes refractory to filarial transmission is described. A requirement for success of the strategy is identification of a flight muscle-specific promoter that functions in the mosquito. A GFP marker gene under the control of the promoter region of the Drosophila melanogaster act88F gene was inserted into the genome of Culex quinquefasciatus. Transformation was confirmed by Mendelian genetics. Hybridization of a genomic Southern blot to a radiolabeled probe verified that the entire donor plasmid integrated into the mosquito genome. GFP expression in the transgenic mosquitoes was restricted to the flight muscles.

  15. Studies on mid gut microbiota of wild caught Culex (Culex quinquefasciatus mosquitoes from Barasat (North 24 Parganas of West Bengal.

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    Abhishek Pal

    2014-06-01

    Full Text Available Mosquitoes are haematophagous insects that serve as obligate intermediate host for numerous diseases like Filaria, Malaria, Dengue, etc. Mosquitoes can be considered as a holobiont units in which host (mosquitoes and its gut microbiota are involved in a complex reciprocal interaction. The naturally acquired microbiota can modulate mosquitos’ vectorial capacity by inhibiting the development of pathogens. But, enough care has not been taken in West Bengal to investigate on the midgut microbiota of Culex mosquitoes. Therefore, a preliminary attempt has been undertaken to study the morphology, growth pattern and antibiotic susceptibility of midgut microbiota of Culex (Culex quinquefasciatus mosquitoes collected from Barasat areas (North 24 Parganas of West Bengal..

  16. Aqueous neem extract versus neem powder on Culex quinquefasciatus: implications for control in anthropogenic habitats.

    Science.gov (United States)

    Kudom, Andreas A; Mensah, Ben A; Botchey, Mary A

    2011-01-01

    Control programs using conventional insecticides to target anthropogenic mosquito habitats are very expensive because these habitats are widespread, particularly in cities of most African countries. Additionally, there are serious environmental concerns regarding large-scale application of most conventional insecticides. Clearly there is a need for alternative methods that are more effective, less expensive, and environmentally friendly. One such method would be the application of preparations made from parts of the neem tree, Azadirachta indica A. Jussieu (Sapindales: Meliaceae). In this study, aqueous crude extracts and crude powder were prepared from different parts of neem, and the efficacies of the preparations on juvenile stages of Culex quinquefasciatus Say (Diptera: Culicidae) were evaluated in the laboratory. When larvae were exposed to a concentration of 0.1 g/mL extract for 24 hours, percent mean mortality (± SE) was 72.7 plusmn; 1.8 for the bark, 68.7 ± 1.6 for fruits and 60 ± 1.6 for leaves. These means were not significantly different (χ(2) = 4.12; df = 2; p = 0.127). At a concentration of 0.01 g/mL, > 95% of the larvae died within 24 hours of exposure to powdered neem leaf, but it took 120 hours to reach the same level of larval mortality in aqueous leaf extract. The crude extract slowly inhibited the growth and development of mosquitoes while the crude powder acted more as a barrier; the mosquitoes probably died from suffocation. However, both types of preparations can be made and used by local people to control mosquito breeding in anthropogenic habitats, especially in urbanized areas.

  17. Olfactory responses of the antennal trichoid sensilla to chemical repellents in the mosquito, Culex quinquefasciatus.

    Science.gov (United States)

    Liu, Feng; Chen, Li; Appel, Arthur G; Liu, Nannan

    2013-11-01

    Insect repellents are widely used to protect against insect bites and thus prevent allergic reaction and the spread of disease. To gain insight into the mosquito's response to chemicals repellents, we investigated the interaction between the olfactory system of the mosquito Culex quinquefasciatus Say and chemical repellents using single sensillum recording. The interactions of 50 repellent chemicals with olfactory receptor neurons were measured in six different types of mosquito sensilla: long sharp trichoid (LST), short sharp trichoid (SST), short blunt trichoid I (SBT-I), short blunt trichoid II (SBT-II), short blunt trichoid-curved (SBT-C), and grooved peg (GP). A single olfactory neuron reacted to the chemical repellents in each of the sensilla except for SBT-I and SBT-II, where two neurons were involved. Other than LST and GP, which showed no or very weak responses to the repellents tested, all the sensilla showed significant excitatory responses to certain types of repellents. Terpene-derived chemicals such as eucalyptol, α-pinene, and camphor, stimulated olfactory receptor neurons in a dose-dependent manner and mosquitoes responded more strongly to terpene-derived chemical repellents than to non-terpene-derived chemicals such as dimethyl phthalate. Mosquitoes also exhibited a similar response to stereoisomers of chemicals such as (-)-β-pinene versus (+)-β-pinene, and (-)-menthone versus (+)-menthone. This study not only demonstrates the effects of chemical repellents on the mosquito olfactory system but also provides important information that will assist those screening new mosquito repellents and designing new mosquito control agents.

  18. Residential characteristics aggravating infestation by Culex quinquefasciatus in a region of Northeastern Brazil Características agravantes por infestación residencial de Culex quinquefasciatus, en una región del Noreste de Brasil Características agravantes por infestação residencial de Culex quinquefasciatus, em Olinda, PE

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    Juliana Cavalcanti Correia

    2012-12-01

    Full Text Available OBJECTIVE: Analyse how basic sanitation conditions, water supply and housing conditions affect the concentration of Culex quinquefasciatus METHODS: Populations of C. quinquefasciatus in 61 houses in the municipality of Olinda, PE, were monitored between October 2009 and October 2010. Observations were carried out in homes without the presence of preferred breeding sites in order to identify characteristics that may be aggravating factors for the development of the mosquito. Five aggravating factors were analysed: vegetation cover surrounding the home, number of residents/home, water storage, sewage drainage and water drainage. These characteristics were analysed in terms of presence or absence and as indicators of the degree of infestation, which was estimated through monitoring the concentration of eggs (oviposition traps - BR-OVT and adults (CDC light traps. RESULTS: Sewage drainage to a rudimentary septic tank or to the open air was the most frequent aggravating factor in the homes (91.8%, although the presence of vegetation was the only characteristic that significantly influenced the increase in the number of egg rafts (p = 0.02. The BR-OVT achieved positive results in 95.1% of the evaluations, with the presence of at least one egg raft per month. A total of 2,366 adults were caught, with a mosquito/room/night ratio of 32.9. No significant difference was found in the number of mosquitoes caught in the homes. CONCLUSIONS: Although the sanitation and water supply influence the population density of C. quinquefasciatus, residence features that are not usually considered in control measures can be aggravating factors in sustaining the mosquito population.OBJETIVO: Analizar como las condiciones de saneamiento básico, abastecimiento de agua y habitaciones afectan la densidad de Culex quinquefasciatus MÉTODOS: se monitoreó la población de C. quinquefasciatus en 61 residencias del municipio de Olinda, PE, Brasil, de octubre de 2009 a octubre de

  19. Larvicidal Activities of Indigenous Bacillus thuringiensis Isolates and Nematode Symbiotic Bacterial Toxins against the Mosquito Vector, Culex pipiens (Diptera: Culicidae

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    Ashraf M Ahmed

    2017-06-01

    Full Text Available Background: The incidence of mosquito-borne diseases and the resistance of mosquitoes to conventional pesticides have recently caused a panic to the authorities in the endemic countries. This study was conducted to identify native larvicidal biopesticides against Culex pipiens for utilization in the battle against mosquito-borne diseases.Methods: Larvicidal activities of new indigenous Bacillus thuringiensis isolates and crude toxin complexes (TCs of two nematode bacterial-symbionts, Photorhabdus luminescens akhurstii (HRM1 and Ph. luminescens akhurstii (HS1 that tested against Cx. pipiens. B. thuringiensis isolates were recovered from different environmental samples in Saudi Arabia, and the entomopathogenic nematodes, Heterorhabditis indica (HRM1 and He. sp (HS1 were iso­lated from Egypt. Larvicidal activities (LC50 and LC95 of the potentially active B. thuringiensis strains or TCs were then evaluated at 24 and 48h post-treatment.Results: Three B. thuringiensis isolates were almost as active as the reference B. thuringiensis israelensis (Bti-H14, and seven isolates were 1.6–5.4 times more toxic than Bti-H14. On the other hand, the TCs of the bacterial sym­bionts, HRM1 and HS1, showed promising larvicidal activities. HS1 showed LC50 of 2.54 folds that of HRM1 at 24h post-treatment. Moreover, histopathological examinations of the HS1-treated larvae showed deformations in midgut epithelial cells at 24h post-treatment.Conclusion: Synergistic activity and molecular characterization of these potentially active biocontrol agents are currently being investigated. These results may lead to the identification of eco-friend mosquito larvicidal product(s that could contribute to the battle against mosquito-borne diseases.

  20. Larvicidal activity of selected plant hydrodistillate extracts against the house mosquito, Culex pipiens, a West Nile virus vector.

    Science.gov (United States)

    Cetin, Huseyin; Yanikoglu, Atila; Cilek, James E

    2011-04-01

    The larvicidal activity of hydrodistillate extracts from Chrysanthemum coronarium L., Hypericum scabrum L., Pistacia terebinthus L. subsp. palaestina (Boiss.) Engler, and Vitex agnus castus L. was investigated against the West Nile vector, Culex pipiens L. (Diptera: Culicidae). Yield and identification of the major essential oils from each distillation was determined by GC-MS analyses. The major essential oil component for each plant species was as follows: α-pinene for P. terebinthus palaestina, and H. scabrum (45.3% and 42.3%, respectively), trans-β-caryophyllene for V. agnus castus (22.1%), and borneol for C. coronarium (20.9%). A series of distillate concentrations from these plants (that ranged from 1 ppm to 500 ppm, depending on plant species) were assessed against late third to early fourth C. pipiens larvae at 1, 6, and 24 h posttreatment. In general, larval mortality to water treated with a distillate increased as concentration and exposure time increased. H. scabrum and P. terebinthus palaestina were most effective against the mosquito larvae and both produced 100% mortality at 250 ppm at 24-h continuous exposure compared with the other plant species. Larval toxicity of the distillates at 24 h (LC(50) from most toxic to less toxic) was as follows: P. terebinthus palaestina (59.2 ppm) > H. scabrum (82.2 ppm) > V. agnus castus (83.3 ppm) > C. coronarium (311.2 ppm). But when LC(90) values were compared, relative toxicity ranking changed as follows: H. scabrum (185.9 ppm) > V. agnus castus (220.7 ppm) > P. terebinthus palaestina (260.7 ppm) > C. coronarium (496.3 ppm). Extracts of native Turkish plants continue to provide a wealth of potential sources for biologically active agents that may be applied against arthropod pests of man and animals.

  1. The effect of shade on the container index and pupal productivity of the mosquitoes Aedes aegypti and Culex pipiens breeding in artificial containers.

    Science.gov (United States)

    Vezzani, D; Albicócco, A P

    2009-03-01

    The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae

  2. Laboratory evaluation of selected larvicides and insect growth regulators against field-collected Culex quinquefasciatus larvae from urban Dhaka, Bangladesh.

    Science.gov (United States)

    Ali, A; Chowdhury, M A; Hossain, M I; Mahmud-Ul-Ameen; Habiba, D B; Aslam, A F

    1999-03-01

    Five organophosphates (OPs) (chlorpyrifos, chlorpyrifos methyl, fenthion, malathion, and temephos), 3 pyrethroids (bifenthrin, cypermethrin, and permethrin), 1 phenyl pyrazole (fipronil), 2 microbial pesticides (Bacillus thuringiensis serovar. israelensis [B.t.i.] and Bacillus sphaericus), and 3 insect growth regulators (IGRs) (diflubenzuron, methoprene, and pyriproxyfen) were evaluated against field-collected Culex quinquefasciatus larvae from urban Dhaka, Bangladesh. The LC90 values of all OPs, except for temephos (LC90 = 0.0096 ppm), were high, ranging from 0.13 ppm (fenthion) to 2.882 ppm (chlorpyrifos methyl). Pyrethroid LC90 values were 0.021 ppm (bifenthrin), 0.00061 (cypermethrin), and 0.017 ppm (permethrin). Fipronil exhibited a superior activity with LC90 value of 0.000896 ppm. Technical powders of B.t.i. and B. sphaericus (VectoBac TP and VectoLex TP) were considered highly effective against the Cx. quinquefasciatus larvae. The IGRs also were effective with pyriproxyfen (LC90 = 0.0011 ppm), being 3 times and 47 times more active than diflubenzuron (LC90 = 0.0034 ppm) and methoprene (LC90 = 0.052 ppm), respectively. In general, toxicity ranking of chemicals and microbials tested was phenyl pyrazole > IGRs > pyrethroids > microbials > OPs.

  3. Bioefficacy of plant-mediated gold nanoparticles and Anthocepholus cadamba on filarial vector, Culex quinquefasciatus (Insecta: Diptera: Culicidae).

    Science.gov (United States)

    Kumar, A Naresh; Jeyalalitha, T; Murugan, K; Madhiyazhagan, P

    2013-03-01

    Mosquito-borne diseases in India, e.g., malaria, dengue, chikungunya, filariasis, and Japanese encephalitis cause thousands of deaths per year. Mosquito control is to enhance the health and quality of life of county residents and visitors through the reduction of mosquito populations. Mosquito control is of serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Noble metal nanoparticles have been used because of their unique optical properties; especially gold and silver have a broad absorption band in the visible region of electromagnetic spectrum. Synthesis of gold nanoparticles using Cymbopogan citratus is an ecofriendly approach for safer environment. C. citratus leaf broth was a good reducing agent that converted chloroauric acid (HAuCl(4)) to metal gold and further heating converted it into nanoparticles. Characterization using UV spectrophotometer, X-ray diffraction, Fourier transform infrared spectroscopy, particle size analyzer, and transmission electron microscopy confirmed that the particles are gold nanoparticles ranging between 10 and 110 nm with an average particles size of 20 nm. Further biosynthesized gold nanoparticles and Anthocephalus cadamba were experimented for the larvicidal effect on the filarial vector, Culex quinquefasciatus. Results showed that the gold nanoparticles are much toxic than the plant extract. Observed lethal concentrations (LC(50) and LC(90)) were 1.08 and 2.76 ppm for gold nanoparticles and 21.82 and 79.52 ppm for the third instar of C. quinquefasciatus.

  4. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus.

    Science.gov (United States)

    Anjali, Rawani; Atanu, Banerjee; Goutam, Chandra

    2012-06-01

    Mosquito control by phytochemicals is an alternative method to synthetic insecticides, as it is biodegradable and non resistant to vector mosquito. Polianthes tuberosa is a perennial plant distributed in many parts of India. The present study was undertaken to scientifically evaluate the larvicide and biting deterrency activity of bud of Polianthes tuberosa against Culex quinquefasciatus and Anopheles stephensi. Crude and solvent extract [ethyl acetate, chloroform: methanol (1:1, v/v), acetone] of fresh, mature, bud of P. tuberosa was tested against (ex. quinquefasciatus and An. stephensi. The repellent activity tested by chloroform: methanol (1:1, v/v) solvent extract against both mosquito species. The appropriate lethal concentrations at 24h for chloroform: methanol (1:1, v/v) extract was also studied on non target organisms such as Toxorhynchites larvae, Diplonychus annulatum and Chironomus circumdatus. In a 72 hour bioassay experiment, 0.5% crude extract showed the highest mortality and chloroform: methanol (1:1, v/v) solvent extract showed the highest mortality, the maximum (p larvicide agent. There is no changes in the activity non-target organism so, it is safe to use.

  5. Oviposition responses of gravid female Culex quinquefasciatus to egg rafts and low doses of oviposition pheromone under semifield conditions.

    Science.gov (United States)

    Braks, Marieta A; Leal, Walter S; Cardé, Ring T

    2007-03-01

    Semifield experiments were conducted to study the oviposition of gravid Culex quinquefasciatus females in response to one or 10 egg rafts, or 3.0 microg of synthetic oviposition pheromone, (-)-(5R, 6S)-6-acetoxy-5-hexadecanolide, a dose equivalent to 10 egg rafts. These treatments were added to the small bowls filled with either hay infusion or water in a small (0.3-m spacing) or a large-square design (3.4-m spacing). Oviposition choice was more pronounced in the "small square" assays. Mean number of egg rafts laid in response to a single egg raft in an oviposition jar filled with hay infusion was significantly greater than with all other treatments. When the oviposition pheromone dose was increased from one to 10 rafts or when 3.0 microg synthetic oviposition pheromone were dispensed on a floating receptacle, synergistic effects were observed between the oviposition pheromone and the hay infusion at both distances. This study is the first demonstration that the amount in a single raft induces oviposition of gravid Cx. quinquefasciatus females under semi-natural conditions.

  6. Relative toxicity of neem fruit, bitter gourd, and castor seed extracts against the larvae of filaria vector, Culex quinquefasciatus (Say).

    Science.gov (United States)

    Batabyal, Lata; Sharma, Preeti; Mohan, Lalit; Maurya, Prejwltta; Srivastava, C N

    2009-10-01

    In search of a natural larvicide, petroleum ether, carbon tetrachloride, and methanol extracts of Azadirachta indica fruits and seed extracts of bitter gourd (Momordica charantia) and castor (Ricinus communis) were tested for larvicidal activity against Culex quinquefasciatus. Among the extracts tested, the methanol extract of Az. indica was observed the most potent with LC(50) at 74.04 and 58.52 ppm and LC(-90) at 201.83 and 171.70 ppm as compared to methanol extract of M. charantia with LC(50) at 101.18 and 93.58 ppm and LC(90) at 322.81 and 302.62 ppm carbon tetrachloride extract of R. communis with LC(50) at 144.11 and 92.44 ppm and LC(90) at 432.42 and 352.89 ppm after 24 and 48 h, respectively. The methanol extract of Az. indica exhibited potential results and can be exploited as a preferred natural larvicide for the control of filarial vector, Cx. quinquefasciatus.

  7. Assessment of residual bio-efficacy and persistence of Ipomoea cairica plant extract against Culex quinquefasciatus Say mosquito.

    Science.gov (United States)

    Thiagaletchumi, Maniam; Zuharah, Wan Fatma; Ahbi Rami, Rattanam; Fadzly, Nik; Dieng, Hamady; Ahmad, Abu Hassan; AbuBakar, Sazaly

    2014-09-01

    Specification on residual action of a possible alternative insecticide derived from plant materials is important to determine minimum interval time between applications and the environmental persistence of the biopesticides. The objective of this study is to evaluate crude acethonilic extract of Ipomoea cairica leaves for its residual and persistence effects against Culex quinquefasciatus larvae. Wild strain of Cx. quinquefasciatus larvae were used for the purpose of the study. Two test designs, replenishment of water and without replenishment of water were carried out. For the first design, a total of 10 ml of test solution containing Ip. cairica extracts was replenished daily and replaced with 10 ml of distilled water. For the second design, treatment water was maintained at 1500 ml and only evaporated water was refilled. Larval mortality was recorded at 24 hours post-treatment after each introduction period and trials were terminated when mortality rate falls below 50%. Adult emergences from survived larvae were observed and number of survivals was recorded. For the non-replenishment design, mortality rate significantly reduced to below 50% after 28 days, meanwhile for replenishment of water declined significantly after 21 days (P water design. The short period of residual effectiveness of crude acethonilic extract of Ip. cairica leaves with high percentage of larval mortality on the first few days, endorses fewer concerns of having excess residues in the environment which may carry the risk of insecticide resistance and environmental pollution.

  8. Mtx toxins synergize Bacillus sphaericus and Cry11Aa against susceptible and insecticide-resistant Culex quinquefasciatus larvae.

    Science.gov (United States)

    Wirth, Margaret C; Yang, Yangkun; Walton, William E; Federici, Brian A; Berry, Colin

    2007-10-01

    Two mosquitocidal toxins (Mtx) of Bacillus sphaericus, which are produced during vegetative growth, were investigated for their potential to increase toxicity and reduce the expression of insecticide resistance through their interactions with other mosquitocidal proteins. Mtx-1 and Mtx-2 were fused with glutathione S-transferase and produced in Escherichia coli, after which lyophilized powders of these fusions were assayed against Culex quinquefasciatus larvae. Both Mtx proteins showed a high level of activity against susceptible C. quinquefasciatus mosquitoes, with 50% lethal concentrations (LC(50)) of Mtx-1 and Mtx-2 of 0.246 and 4.13 microg/ml, respectively. The LC(50)s were 0.406 to 0.430 microg/ml when Mtx-1 or Mtx-2 was mixed with B. sphaericus, and synergy improved activity and reduced resistance levels. When the proteins were combined with a recombinant Bacillus thuringiensis strain that produces Cry11Aa, the mixtures were highly active against Cry11A-resistant larvae and resistance was also reduced. The mixture of two Mtx toxins and B. sphaericus was 10 times more active against susceptible mosquitoes than B. sphaericus alone, demonstrating the influence of relatively low concentrations of these toxins. These results show that, similar to Cyt toxins from B. thuringiensis subsp. israelensis, Mtx toxins can increase the toxicity of other mosquitocidal proteins and may be useful for both increasing the activity of commercial bacterial larvicides and managing potential resistance to these substances among mosquito populations.

  9. Evaluation of Bacillus sphaericus bioinsecticide produced with white soybean meal as culture medium for the control of Culex (Culex) quinquefasciatus.

    Science.gov (United States)

    Melo, André L A; Soccol, Carlos R; Thomaz-Soccol, Vanete; Nogueira, Miodeli

    2009-03-01

    Bioinsecticides are shown to be useful in control programs to prevent several diseases, based on their specificity and efficiency against insect vectors. In the current study a bioinsecticide based on Bacillus sphaericus was produced using a white soybean culture medium and applied to larvae of Culex quinquefasciatus, the susceptible species, and Aedes aegypti, the refractory species used as the negative control. Efficacy was compared with that of the product fermented with the Luria Bertani (LB) reference medium. The experiments showed that C. quinquefasciatus was highly susceptible to the product prepared with white soybean meal, reaching 100% larval mortality even at 10mg/L, while A. aegypti failed to reach 70% mortality at a concentration of 1g/L. By comparison with the reference medium, the proposed culture medium showed high larvicidal power, reaching a LD90 of 2.26 mg/L, while 4.37 mg/L was needed for the LB medium to achieve the same mortality rate. Cost comparison between the formulations favored the use of the bioinsecticide produced with white soybean meal. After factoring in the LD90 value, the cost ratio favored the new raw material by nearly 1:220.

  10. Larvicidal and pupicidal properties of Acalypha alnifolia Klein ex Willd. (Euphorbiaceae) leaf extract and the microbial insecticide Metarhizium anisopliae (Metsch.) against lymphatic filarial vector, Culex quinquefasciatus..

    Science.gov (United States)

    This study was made to determine the mosquitocidal properties of Acalypha alnifolia leaf extract combined with the use of Metarizhium anisopliae spores for control of the lymphatic filariasis vector Culex quinquefasciatus. The methanolic leaf extract showed larvicidal and pupicidal effects after 24...

  11. Larvicidal and pupicidal properties of Acalypha alnifolia Klein ex willd.(Euphorbiaceae) leaf extract and the microbial insecticide Metarhizium anisopliae (Metsch.) against lymphatic filarial vector, Culex quinquefasciatus Sa

    Science.gov (United States)

    This study was made to determine the mosquitocidal properties of Acalypha alnifolia leaf extract combined with the use of Metarizhium anisopliae spores for control of the lymphatic filariasis vector Culex quinquefasciatus. The methanolic leaf extract showed larvicidal and pupicidal effects after 24...

  12. The effects of herbal essential oils on the oviposition-deterrent and ovicidal activities of Aedes aegypti (Linn.), Anopheles dirus (Peyton and Harrison) and Culex quinquefasciatus (Say).

    Science.gov (United States)

    Siriporn, P; Mayura, S

    2012-03-01

    The effect of oviposition-deterrent and ovicidal of seven essential oils were evaluated towards three mosquito vectors, Aedes aegypti, Anopheles dirus and Culex quinquefasciatus. The oviposition activity index (OAI) values of six essential oils namely Cananga odorata, Cymbopogon citratus, Cymbopogon nardus, Eucalyptus citriodora, Ocimum basilicum and Syzygium aromaticum indicated that there were more deterrent than the control whereas Citrus sinensis oil acted as oviposition attractant. At higher concentration (10%) of Ca. odorata (ylang ylang flowers) showed high percent effective repellency (ER) against oviposition at 99.4% to Ae. aegypti, 97.1% to An. dirus and 100% to Cx. quinquefasciatus, respectively. The results showed that mean numbers of eggs were lower in treated than in untreated water. In addition, there was an inverse relationship between essential oil concentrations and ovicidal activity. As the concentration of essential oil increased from 1%, 5% and up to 10% conc., the hatching rate decreased. The essential oil of Ca. odorata at 10% conc. gave minimum egg hatch of 10.4% (for Ae. aegypti), 0.8% (for An. dirus) and 1.1% (for Cx. quinquefasciatus) respectively. These results clearly revealed that the essential oil of Ca. odorata served as a potential oviposition-deterrent and ovicidal activity against Ae. aegypti, An. dirus and Cx. quinquefasciatus.

  13. Green synthesis of silver nanoparticles using Cadaba indica lam leaf extract and its larvicidal and pupicidal activity against Anopheles stephensi and Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    K. Kalimuthu

    2013-09-01

    Full Text Available Green nanoparticle synthesis was achieved using environmentally acceptable plant extracts and eco-friendly reducing and capping agents. In the present study, activity of silver nanoparticles (AgNPs synthesized using Cadaba indica lam plant against Anopheles stephensi and Culex quinquefasciatus was determined. A range of concentrations of synthesized AgNPs (3.125, 6.25, 12.5, 25, 50 ppm and crude extract (50, 100, 150, 200, 250 ppm were tested against A. stephensi and C. quinquefasciatus. The synthesized AgNPs from C. indica lam were much more toxic than crude extract in both mosquito species. The cured extract high mortality values were 50% lethal concentration (LC50=88.22, 90.84 ppm; 90% lethal concentration (LC90=172.94, 178.55 ppm, and the AgNPs high mortality values were LC50=3.90, 4.39 ppm; LC90=19.04, 17.35 ppm against A. stephensi and C. quinquefasciatus, respectively. The results recorded from ultraviolet-visible spectrophotometer, scanning electron microscopy, energy dispersive X-ray and Fourier transformed infrared support the biosynthesis and characterization of silver nanoparticles. These results suggest that the leaf cured extracts of C. indica lam and green synthesis of silver nanoparticles have the potential to be used as an ideal eco-friendly approach for the control of A. stephensi and C. quinquefasciatus.

  14. Culex pipiens s.l. and Culex torrentium (Culicidae) in Wrocław area (Poland): occurrence and breeding site preferences of mosquito vectors.

    Science.gov (United States)

    Weitzel, Thomas; Jawień, Piotr; Rydzanicz, Katarzyna; Lonc, Elzbieta; Becker, Norbert

    2015-01-01

    Both ornithophilic mosquito species, Culex pipiens s.l. (L.) and Culex torrentium (Martini, 1925), occur sympatric in temperate Europe. They are presumed to be primary vectors of West Nile and Sindbis viruses. Differentiation of these morphologically similar Culex species is essential for evaluation of different vector roles, for mosquito surveillance and integrated control strategies. Cx. torrentium has been neglected or erroneously determined as Cx. pipiens s.l. in some previous studies, because only males of both species can be diagnosed reliably by morphology. Thus, knowledge about species abundance, geographical distribution, breeding site preferences and the zoonotic risk assessment is incomplete also in Poland. In Wrocław area (Silesian Lowland), besides typical urban breeding sites, huge sewage irrigation fields provide suitable breeding conditions for Culex species. They are also inhabited by 180 resident and migratory bird species serving as potential virus reservoirs. In this study, morphology of larvae and males as well as species diagnostic enzyme markers, namely adenylate kinase (AK) and 2-hydroxybutyrate dehydrogenase (HBDH), were used to discriminate Cx. pipiens s.l. and Cx. torrentium. In a total of 650 Culex larvae from 24 natural and artificial breeding sites, Cx. pipiens s.l. had a proportion of 94.0% and Cx. torrentium only 6.0%. It could be shown that both species are well adapted to various breeding site types like ditches, catch basins, flower pots and buckets with diverse water quality. Cx. torrentium preferred more artificial water containers in urban surrounding (12% species proportion), whereas in semi-natural breeding sites, Cx. torrentium was rare (3%). In 12 of 24 breeding sites, larvae of both species have been found associated.

  15. Identification of chemical constituents and larvicidal activity of essential oil from Murraya exotica L. (Rutaceae) against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Krishnamoorthy, Shanmugam; Chandrasekaran, Manivachagam; Raj, Gnanaprakasam Adaikala; Jayaraman, Mahalingam; Venkatesalu, Venugopalan

    2015-05-01

    This study was conducted to evaluate the phytochemical composition and larvicidal effect of leaf essential oil from Murraya exotica against early fourth-instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. Gas chromatography (GC) and gas chromatography mass spectrometry (GC-MS) analyses revealed that the essential oil contained 27 components. The major chemical components identified were β-humulene (40.62%), benzyl benzoate (23.96%), β-caryophyllene (7.05%) and α-terpinene (5.66%). The larval mortality was observed after 12 and 24 h of exposure period. The results revealed that essential oil showed varied levels of larvicidal activity against A. aegypti, A. stephensi and C. quinquefasciatus. After 12 h of exposure period, the larvicidal activities were LC₅₀ = 74.7 and LC₉₀ = 152.7 ppm (A. aegypti), LC₅₀ = 56.3 and LC₉₀ = 107.8 ppm (A. stephensi ), and LC₅₀ = 74.4 and LC₉₀ = 136.9 ppm (C. quinquefasciatus) and the larvicidal activities after 24 h of exposure period were LC₅₀ = 35.8 and LC₉₀ = 85.4 ppm (A. aegypti), LC₅₀ = 31.3 and LC₉₀ = 75.1 ppm (A. stephensi), and LC₅₀ = 43.2 and LC₉₀ = 103.2 ppm (C. quinquefasciatus). These results suggest that leaf essential oil from M. exotica is a promising and eco-friendly source of natural larvicidal agent against A. aegypti, A. stephensi and C. quinquefasciatus.

  16. Efficacy of larvicidal and pupicidal activity of Catharanthus roseus aqueous and solvent extracts against Anopheles stephensi Liston and Culex quinquefasciatus Say (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Selladurai Subarani; Selvi Sabhanayakam; Chinnaperumal Kamaraj; Gandhi Elango; Mohamed Abdul Kadir

    2013-01-01

    Objective:To investigate the larvicidal and pupicidal activities of aqueous, ethyl acetate and methanol extracts of Catharanthus roseus (C. roseus) against malaria and filariasis vectors. Methods:The larvicidal and pupicidal activities of C. roseus leaf extracts were tested against the fourth instar larvae and pupae of Anopheles stephensi (An. stephensi) and Culex quinquefasciatus (Cx. quinquefasciatus). The mortality was observed after 24 and 48 h post the treatment. The data were subjected to probit analysis to determine the lethal concentrations (LC50 and LC90) at which 50%and 90%of the treated larvae or pupae of the tested species were killed. Results:The larval and pupal mortality were observed after 24 and 48 h of exposure of aqueous, ethyl acetate and methanol extracts of C. roseus; no mortality was observed in the control group. The LC50 values against the fourth-instar larvae of An. stephensi were 68.62 and 72.04 mg/mL for the aqueous extract, 82.47 mg/mL for the ethyl acetate extract, and 78.80 and 86.64 mg/mL for the methanol extract, while the aqueous, ethyl acetate and methanol extracts had LC50 values of 85.21, 76.84 and 94.20 mg/mL against the fourth-instar larvae of Cx. quinquefasciatus. The aqueous, ethyl acetate and methanol extracts had LC50 values of 118.08, 182.47 and 143.80 mg/mL against the pupae of An. stephensi and 146.20, 226.84 and 156.62 mg/mL against the pupae of Cx. quinquefasciatus, respectively. Conclusions: The aqueous and methanol extracts of C. roseus leaves had an excellent potential to control the malarial vector An. stephensi and filariasis vector Cx. quinquefasciatus.

  17. A shut-down in expression of an insulin-like peptide, ILP-1, halts ovarian maturation during the overwintering diapause of the mosquito Culex pipiens.

    Science.gov (United States)

    Sim, C; Denlinger, D L

    2009-06-01

    Short day-length is used to programme adult diapause in the mosquito, Culex pipiens. The downstream endocrine event that halts ovarian maturation is a shut-down in juvenile hormone (JH) production, and recent evidence suggests that the insulin signalling pathway may be a key upstream player in executing this developmental arrest. Genes encoding insulin-like peptides-1, -2 and -5 were identified in C. pipiens, and we report that transcript levels of insulin-like peptides-1 and -5 were significantly lower in diapausing females than in their nondiapausing counterparts. Genes encoding both insulin-like peptides-1 and -5 were suppressed using RNA interference in mosquitoes programmed for nondiapause, and ovarian maturation was monitored. Knocking down insulin-like peptide-1 with RNAi in nondiapausing mosquitoes resulted in a cessation of ovarian development akin to diapause, and this arrest in development could be reversed with an application of JH. Knocking down insulin-like peptide-5 did not alter ovarian development. These results are consistent with a role for insulin-like peptide-1 in the signalling pathway leading from the perception of short day-lengths to the shut-down in JH production that characterizes adult diapause in C. pipiens.

  18. Experimental transmission of Hepatozoon gracilis (Wenyon, 1909) com. nov., in its natural host the bean skink lizard (Mabuya quinquetaeniata quinquetaeniata) and vector Culex (C.) pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Adham, Fatma K; Gabre, Refaat M; Ayaad, Tahany A; Galal, Fatma H

    2007-12-01

    The bean skink lizard Mabuya quinquetaeniata quinquetaeniata (Family: Scincidae) collected from Abu-Rawash, Giza was infected with the protozoon Hepatozoon gracilis. The mean percent of infection rate all over the year was 12.57% with the highest peak was in October (33%), meanwhile the lowest infection rate was detected in June (2.1%) and no infection was detected in February. Microscopical examination of experimentally infected Culex (C.) pipiens L smears revealed the presence of gamogony and sporogony stages of H. gracilis in their haemoceal. Cx. pipiens was capable to transmit H. gracilis to non-infected M. q. quinquetaeniata under laboratory conditions (21 +/- 1 & 60-70% R.H) after a prepatent period of 32 +/- 1 days from the infective bite. Various developmental schizogony stages were detected both in the lung endothelial cells and liver parenchymal cells. Developmental stages of H. gracilis in both vector or vertebrate host were described. Cx. pipiens was unable to transmit H. gracilis to snake, Psammophis schokari present in the same area of the bean skink lizard.

  19. Cloning and expression of cry2Aa from native Bacillus thuringiensis strain SY49-1 and its insecticidal activity against Culex pipiens (Diptera: Culicidae).

    Science.gov (United States)

    Yilmaz, Semih; Azizoglu, Ugur; Ayvaz, Abdurrahman; Temizgul, Ridvan; Atciyurt, Zehra Büşra; Karabörklü, Salih

    2017-04-01

    Bacillus thuringiensis (Berliner) (Bt) is well known for having toxicity against pest insects because of their ability to form endospores and broad-range activity of their parasporal inclusions. In this study, a new member of cry2A gene from previously characterized native B. thuringiensis SY49-1 strain was cloned, expressed and used for its activity against Culex pipiens (Diptera: Culicidae) larvae. The sequence analysis of the cloned cry2A gene revealed that it encodes a polypeptide of 633 aa residues with 99% identity to Cry2Aa protein with expected molecular weight of 70.7 kDa. Bacillus thuringiensis delta-endotoxin nomenclature committee designed our sequence as Cry2Aa18 being a new member of Bt toxins. Bioassays against last instar larvae of C. pipiens indicated that Cry2Aa18 has considerable toxicity with LC50 of 630 μg ml(-1). In order to prevent the spread of infectious diseases mediated by C. pipiens, this newly characterized cry2Aa18 gene could constitute as an important biological control tool for controlling mosquito larvae living in freshwater systems and can be used as a good alternative for minimizing the use of chemicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Adulticidal and repellent properties of Cassia tora Linn. (Family: Caesalpinaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi.

    Science.gov (United States)

    Amerasan, Duraisamy; Murugan, Kadarkarai; Kovendan, Kalimuthu; Mahesh Kumar, Palanisamy; Panneerselvam, Chellasamy; Subramaniam, Jayapal; John William, Samuel; Hwang, Jiang-Shiou

    2012-11-01

    Mosquitoes have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The adulticidal and repellent activities of crude hexane, chloroform, benzene, acetone, and methanol extracts of the leaf of Cassia tora were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The adult mortality was observed after 24 h of exposure. All extracts showed moderate adulticidal effects; however, the highest adult mortality observed was found in methanol extract. The LC(50) and LC(90) values of C. tora leaf extracts against adulticidal activity of (hexane, chloroform benzene, acetone, and methanol) C. quinquefasciatus, A. aegypti, and A. stephensi were the following: C. quinquefasciatus LC(50) values were 338.81, 315.73, 296.13, 279.23, and 261.03 ppm and LC(90) values were 575.77, 539.31, 513.99, 497.06, and 476.03 ppm; A. aegypti LC(50) values were 329.82, 307.31, 287.15, 269.57, and 252.03 ppm and LC(90) values were 563.24, 528.33, 496.92, 477.61, and 448.05 ppm; and A. stephensi LC(50) values were 317.28, 300.30, 277.51, 263.35, and 251.43 ppm and LC(90) values were 538.22, 512.90, 483.78, 461.08, and 430.70 ppm, respectively. The results of the repellent activity of hexane, chloroform, benzene, acetone, and methanol extracts of C. tora plant at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of forearm in man and exposed against adult female mosquitoes. In this observation, this plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the repellent activity is dependent on the strength of the plant extracts. These results suggest that the leaf solvent plant extracts have the potential to be used as an ideal eco-friendly approach for the control of

  1. ITN mixtures of chlorfenapyr (Pyrrole) and alphacypermethrin (Pyrethroid) for control of pyrethroid resistant Anopheles arabiensis and Culex quinquefasciatus.

    Science.gov (United States)

    Oxborough, Richard M; Kitau, Jovin; Matowo, Johnson; Feston, Emmanuel; Mndeme, Rajab; Mosha, Franklin W; Rowland, Mark W

    2013-01-01

    Pyrethroid resistant Anopheles gambiae malaria vectors are widespread throughout sub-Saharan Africa and continued efficacy of pyrethroid ITNs is under threat. Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action conferring no cross-resistance to existing public health insecticides. Mixtures of chlorfenapyr (CFP) and alphacypermethrin (alpha) may provide additional benefits over chlorfenapyr or alphacypermethrin used alone. An ITN mixture of CFP 100 mg/m(2)+alpha 25 mg/m(2) was compared with CFP 100 mg/m(2) and alpha 25 mg/m(2) in a small-scale experimental hut trial in an area of wild An. arabiensis. The same treatments were evaluated in tunnel tests against insectary-reared pyrethroid susceptible and resistant Culex quinquefasciatus. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Tunnel tests showed that mixtures of CFP 100+ alpha 25 were 1.2 and 1.5 times more effective at killing susceptible Cx. quinquefasciatus than either Alpha 25 (P = 0.001) or CFP 100 (P = 0.001) ITNs. Mixtures of CFP100+ alpha 25 were 2.2 and 1.2 times more effective against resistant Cx. quinquefasciatus than either alpha 25 (P = 0.001) or CFP100 (P = 0.003) ITNs. CFP 100+ alpha 25 produced higher levels of blood-feeding inhibition than CFP alone for susceptible (94 vs 46%, P = 0.001) and resistant (84 vs 53%, P = 0.001) strains. In experimental huts the mixture of CFP 100+ Alpha 25 killed 58% of An. arabiensis, compared with 50% for alpha and 49% for CFP, though the differences were not significant. Blood-feeding inhibition was highest in the mixture with a 76% reduction compared to the untreated net (P = 0.001). ITN mixtures of chlorfenapyr and alphacypermethrin should restore effective control of resistant populations of An. gambiae malaria vectors, provide protection from blood-feeding, and may have benefits for resistance management, particularly in areas with low or moderate

  2. ITN mixtures of chlorfenapyr (Pyrrole and alphacypermethrin (Pyrethroid for control of pyrethroid resistant Anopheles arabiensis and Culex quinquefasciatus.

    Directory of Open Access Journals (Sweden)

    Richard M Oxborough

    Full Text Available Pyrethroid resistant Anopheles gambiae malaria vectors are widespread throughout sub-Saharan Africa and continued efficacy of pyrethroid ITNs is under threat. Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action conferring no cross-resistance to existing public health insecticides. Mixtures of chlorfenapyr (CFP and alphacypermethrin (alpha may provide additional benefits over chlorfenapyr or alphacypermethrin used alone. An ITN mixture of CFP 100 mg/m(2+alpha 25 mg/m(2 was compared with CFP 100 mg/m(2 and alpha 25 mg/m(2 in a small-scale experimental hut trial in an area of wild An. arabiensis. The same treatments were evaluated in tunnel tests against insectary-reared pyrethroid susceptible and resistant Culex quinquefasciatus. Performance was measured in terms of insecticide-induced mortality, and blood-feeding inhibition. Tunnel tests showed that mixtures of CFP 100+ alpha 25 were 1.2 and 1.5 times more effective at killing susceptible Cx. quinquefasciatus than either Alpha 25 (P = 0.001 or CFP 100 (P = 0.001 ITNs. Mixtures of CFP100+ alpha 25 were 2.2 and 1.2 times more effective against resistant Cx. quinquefasciatus than either alpha 25 (P = 0.001 or CFP100 (P = 0.003 ITNs. CFP 100+ alpha 25 produced higher levels of blood-feeding inhibition than CFP alone for susceptible (94 vs 46%, P = 0.001 and resistant (84 vs 53%, P = 0.001 strains. In experimental huts the mixture of CFP 100+ Alpha 25 killed 58% of An. arabiensis, compared with 50% for alpha and 49% for CFP, though the differences were not significant. Blood-feeding inhibition was highest in the mixture with a 76% reduction compared to the untreated net (P = 0.001. ITN mixtures of chlorfenapyr and alphacypermethrin should restore effective control of resistant populations of An. gambiae malaria vectors, provide protection from blood-feeding, and may have benefits for resistance management, particularly in areas with low or

  3. Mosquito larvicidal, ovicidal, and repellent properties of botanical extracts against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, M; Mathivanan, T; Elumalai, K; Krishnappa, K; Anandan, A

    2011-08-01

    Mosquito-borne diseases have an economic impact, including loss in commercial and labor outputs, particularly in countries with tropical and subtropical climates; however, no part of the world is free from vector-borne diseases. In mosquito control programs, botanical origin may have the potential to be used successfully as eggs, larvae, and adult. The larvicidal, ovicidal, and repellent activities of crude benzene and ethyl acetate extracts of leaf of Ervatamia coronaria and Caesalpinia pulcherrima were assayed for their toxicity against three important vector mosquitoes, viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in benzene extract of E. coronaria against the larvae of Anopheles Stephensi, Aedes aegypti, and Culex quinquefasciatus with the LC(50) and LC(90) values were 79.08, 89.59, and 96.15 ppm and 150.47, 166.04, and 174.10 ppm, respectively. Mean percent hatchability of the ovicidal activity was observed 48 h posttreatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. The leaf extract of E. coronaria was found to be most effective than Caesalpinia pulcherrima against eggs/egg rafts of three vector mosquitoes. For E. coronaria, the benzene extract exerted 300, 250, and 200 ppm against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus, respectively. The results of the repellent activity of benzene and ethyl acetate extract of E. coronaria and Caesalpinia pulcherrima plants at three different concentrations of 1.0, 2.5, and 5.0 mg/cm(2) were applied on skin of fore arm in man and exposed against adult female mosquitoes. In this observation, these two plant crude extracts gave protection against mosquito bites without any allergic reaction to the test person, and also, the

  4. Larvicidal activity of Morinda citrifolia L. (Noni) (Family: Rubiaceae) leaf extract against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    Science.gov (United States)

    Kovendan, Kalimuthu; Murugan, Kadarkarai; Shanthakumar, Shanmugam Perumal; Vincent, Savariar; Hwang, Jiang-Shiou

    2012-10-01

    Morinda citrifolia leaf extract was tested for larvicidal activity against three medically important mosquito vectors such as malarial vector Anopheles stephensi, dengue vector Aedes aegypti, and filarial vector Culex quinquefasciatus. The plant material was shade dried at room temperature and powdered coarsely. From the leaf, 1-kg powder was macerated with 3.0 L of hexane, chloroform, acetone, methanol, and water sequentially for a period of 72 h each and filtered. The yield of extracts was hexane (13.56 g), chloroform (15.21 g), acetone (12.85 g), methanol (14.76 g), and water (12.92 g), respectively. The extracts were concentrated at reduced temperature on a rotary vacuum evaporator and stored at a temperature of 4°C. The M. citrifolia leaf extract at 200, 300, 400, 500, and 600 ppm caused a significant mortality of three mosquito species. Hexane, chloroform, acetone, and water caused moderate considerable mortality; however, the highest larval mortality was methanolic extract, observed in three mosquito vectors. The larval mortality was observed after 24-h exposure. No mortality was observed in the control. The third larvae of Anopheles stephensi had values of LC(50) = 345.10, 324.26, 299.97, 261.96, and 284.59 ppm and LC(90) = 653.00, 626.58, 571.89, 505.06, and 549.51 ppm, respectively. The Aedes aegypti had values of LC(50) = 361.75, 343.22, 315.40, 277.92, and 306.98 ppm and LC(90) = 687.39, 659.02, 611.35, 568.18, and 613.25 ppm, respectively. The Culex quinquefasciatus had values of LC(50) = 382.96, 369.85, 344.34, 330.42, and 324.64 ppm and LC(90) = 726.18, 706.57, 669.28, 619.63, and 644.47 ppm, respectively. The results of the leaf extract of M. citrifolia are promising as good larvicidal activity against the mosquito vector Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. This is a new eco-friendly approach for the control of vector control programs. Therefore, this study provides first report on the larvicidal activities against three

  5. Modeling the distribution of the West Nile and Rift Valley Fever vector Culex pipiens in arid and semi-arid regions of the Middle East and North Africa.

    Science.gov (United States)

    Conley, Amy K; Fuller, Douglas O; Haddad, Nabil; Hassan, Ali N; Gad, Adel M; Beier, John C

    2014-06-24

    The Middle East North Africa (MENA) region is under continuous threat of the re-emergence of West Nile virus (WNV) and Rift Valley Fever virus (RVF), two pathogens transmitted by the vector species Culex pipiens. Predicting areas at high risk for disease transmission requires an accurate model of vector distribution, however, most Cx. pipiens distribution modeling has been confined to temperate, forested habitats. Modeling species distributions across a heterogeneous landscape structure requires a flexible modeling method to capture variation in mosquito response to predictors as well as occurrence data points taken from a sufficient range of habitat types. We used presence-only data from Egypt and Lebanon to model the population distribution of Cx. pipiens across a portion of the MENA that also encompasses Jordan, Syria, and Israel. Models were created with a set of environmental predictors including bioclimatic data, human population density, hydrological data, and vegetation indices, and built using maximum entropy (Maxent) and boosted regression tree (BRT) methods. Models were created with and without the inclusion of human population density. Predictions of Maxent and BRT models were strongly correlated in habitats with high probability of occurrence (Pearson's r=0.774, r=0.734), and more moderately correlated when predicting into regions that exceeded the range of the training data (r=0.666,r=0.558). All models agreed in predicting high probability of occupancy around major urban areas, along the banks of the Nile, the valleys of Israel, Lebanon, and Jordan, and southwestern Saudi Arabia. The most powerful predictors of Cx. pipiens habitat were human population density (60.6% Maxent models, 34.9% BRT models) and the seasonality of the enhanced vegetation index (EVI) (44.7% Maxent, 16.3% BRT). Maxent models tended to be dominated by a single predictor. Areas of high probability corresponded with sites of independent surveys or previous disease outbreaks. Cx

  6. Chemical composition and larvicidal evaluation of Mentha, Salvia, and Melissa essential oils against the West Nile virus mosquito Culex pipiens.

    Science.gov (United States)

    Koliopoulos, George; Pitarokili, Danae; Kioulos, Elias; Michaelakis, Antonios; Tzakou, Olga

    2010-07-01

    The volatile metabolites of wild-growing Mentha spicata, M. longifolia, M. suaveolens, Melissa officinalis, Salvia fruticosa, S. pomifera subsp. calycina, and S. pomifera subsp. pomifera from Greece were determined by gas chromatography and gas chromatography-mass spectrometry. The insecticidal properties of the analyzed essential oils were screened on Culex pipiens larvae. Additionally two of the main components of the essential oils, piperitenone oxide and 1,8-cineole were assayed against C. pipiens in order to define the affiliation between them and the larvicidal properties of the oils. The most effective oils were M. suaveolens (major constituent piperitenone oxide, 62.4%), M. spicata (piperitenone oxide, 35.7% and 1,8-cineole, 14.5%) and M. longifolia--Central Greece (piperitenone oxide, 33.4%; 1,8-cineole, 24.5% and trans-piperitone epoxide, 17.4%), which exhibited LC(50) values ranging from 47.88 to 59.33 mg l(-1). Medium activity revealed the oils of M. officinalis (terpin-4-ol, 15.8%; caryophyllene oxide, 13.2%; sabinene, 12.9%; beta-pinene, 12.1%; and trans-caryophyllene, 10.2%), M. longifolia--Southern Greece (carvone, 54.7% and limonene 20.0%), S. pomifera subsp. pomifera (trans-caryophyllene, 22.5% and trans-thujone, 21.0%), S. pomifera subsp. calycina--West Southern Greece (trans-thujone, 56.1% and 1,8-cineole, 10.4%), and S. fruticosa--population 2 (camphor, 23.1%; alpha-pinene, 12.7%; and borneol, 12.6%), with LC(50) values ranging from 78.28 to 91.45 mg l(-1). S. pomifera subsp. calycina (Central Greece) essential oil (trans-thujone, 26.5% and cis-thujone, 12.0%) presented rather low activity (LC(50) values 140.42 mg l(-1)), while S. fruticosa--population 1 (1,8-cineole, 31.4% and camphor, 22.6%) was the only inactive oil. Additionally, the constituent piperitenone oxide was found to be highly active (LC(50) values 9.95 mg l(-1)), whereas 1,8-cineole revealed no toxicity.

  7. Alteration of the hypothalamic-pituitary-gonadal axis in estrogen- and androgen-treated adult male leopard frog, Rana pipiens

    Directory of Open Access Journals (Sweden)

    Jones Jeremy T

    2005-01-01

    Full Text Available Abstract Background Gonadal steroids, in particular 5 alpha-dihydrotestosterone (DHT and 17 beta-estradiol (E2, have been shown to feed back on the hypothalamic-pituitary-gonadal (HPG axis of the ranid frog. However, questions still remain on how DHT and E2 impact two of the less-studied components of the ranid HPG axis, the hypothalamus and the gonad, and if the feedback effects are consistently negative. Thus, the goal of the study was to examine the effects of DHT and E2 upon the HPG axis of the gonadally-intact, sexually mature male leopard frogs, Rana pipiens. Methods R. pipiens were implanted with silastic capsules containing either cholesterol (Ch, a control, DHT, or E2 for 10 or 30 days. At each time point, steroid-induced changes in hypothalamic GnRH and pituitary LH concentrations, circulating luteinizing hormone (LH, and testicular histology were examined. Results Frogs implanted with DHT or E2 for 10 days did not show significant alterations in the HPG axis. In contrast, frogs implanted with hormones for 30 days had significantly lower circulating LH (for both DHT and E2, decreased pituitary LH concentration (for E2 only, and disrupted spermatogenesis (for both DHT and E2. The disruption of spermatogenesis was qualitatively similar between DHT and E2, although the effects of E2 were consistently more potent. In both DHT and E2-treated animals, a marked loss of all pre-meiotic germ cells was observed, although the loss of secondary spermatogonia appeared to be the primary cause of disrupted spermatogenesis. Unexpectedly, the presence of post-meiotic germ cells was either unaffected or enhanced by DHT or E2 treatment. Conclusions Overall, these results showed that both DHT and E2 inhibited circulating LH and disrupted spermatogenesis progressively in a time-dependent manner, with the longer duration of treatment producing the more pronounced effects. Further, the feedback effects exerted by both steroid hormones upon the HPG axis were

  8. Mtx toxins from Lysinibacillus sphaericus enhance mosquitocidal cry-toxin activity and suppress cry-resistance in Culex quinquefasciatus.

    Science.gov (United States)

    Wirth, Margaret C; Berry, Colin; Walton, William E; Federici, Brian A

    2014-01-01

    The interaction of Mtx toxins from Lysinibacillus sphaericus (formerly Bacillus sphaericus) with Bacillus thuringiensis subsp. israelensis Cry toxins and the influence of such interactions on Cry-resistance were evaluated in susceptible and Cry-resistant Culex quinquefasciatus larvae. Mtx-1 and Mtx-2 were observed to be active against both susceptible and resistant mosquitoes; however varying levels of cross-resistance toward Mtx toxins were observed in the resistant mosquitoes. A 1:1 mixture of either Mtx-1 or Mtx-2 with different Cry toxins generally showed moderate synergism, but some combinations were highly toxic to resistant larvae and suppressed resistance. Toxin synergy has been demonstrated to be a powerful tool for enhancing activity and managing Cry-resistance in mosquitoes, thus Mtx toxins may be useful as components of engineered bacterial larvicides. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    Flávia P Morais de Medeiros

    2005-07-01

    Full Text Available This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae; and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

  10. Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus.

    Science.gov (United States)

    Medeiros, Flávia P Morais de; Santos, Maria Alice Varjal de Melo; Regis, Leda; Rios, Eugênia M Maranhão; Rolim Neto, Pedro J

    2005-07-01

    This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae); and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

  11. Efficacy of indigenous larvivorous fishes against Culex quinquefasciatus in the presence of alternative prey: implications for biological control.

    Science.gov (United States)

    Aditya, Gautam; Pal, Santanu; Saha, Nabaneeta; Saha, Goutam

    2012-12-01

    Indigenous larvivorous fishes bear potential for regulating vector mosquitoes through trophic interactions. The mosquito prey preference of five indigenous larvivorous fishes in the presence of alternative food items was assessed to highlight their use in mosquito vector management. Laboratory experiments were carried out using the larvivorous fishes Ambassis (=Chanda) nama, Parambassis (=Chanda) ranga, Colisa fasciatus, Esomus danricus and Aplocheilus panchax, as predators and IV instar Culex quinquefasciatus larvae as target prey. Mosquito prey preference of these fishes in the presence of chironomid larvae, tubificid worms and artificial fish foods, in varied proportions, were assessed using preference index. The fishes consumed considerable amount of mosquito larvae both in absence and presence of alternative food items. However, the positive selectivity for mosquito larvae at all densities were significantly (p control by these fishes.

  12. Rotational application of bioinsecticide with deltamethrin-An antilarval measure for the control of filarial vector, Culex quinquefasciatus (Culicidae: Diptera).

    Science.gov (United States)

    Gayathri, V; Jeyalakshmi, T; Shanmugasundaram, R; Murthy, P Balakrishna

    2004-10-01

    A laboratory investigation was undertaken to study the cyclic usage of field recommended doses of Bacillus thuringiensis israelensis (Bti), Bacillus sphaericus (Bsp) and combination of Bti and Bsp (half the recommended dose of each) with deltamethrin 2.8 EC to attain better control of mosquito larvae. To understand the susceptibility status of the Culex quinquefasciatus larvae in the field, early fourth instar field collected larvae were exposed to the above treatments of biopesticides and were monitored for their persistency till 50% mortality was obtained. The larvae those survived in each treatment were transferred to the concentration of deltamethrin that gave 50% mortality. Observations on larval mortality after the treatment with deltamethrin were recorded after 24 h. The results revealed that Bti excels Bsp, as it recorded 54% mortality only on 17th day after application. The other salient finding of this study is LC50 of deltamethrin is sufficient to follow the biopesticides application for an effective control of Culex larvae.

  13. LINKAGE OF KNOCKDOWN RESISTANCE AND THE SODIUM CHANNEL GENE MUTATION IN CULEX PIPIENS PALLENS *%淡色库蚊(Culex pipiens Pallens)与击倒抗性(kdr)相关的钠通道基因突变

    Institute of Scientific and Technical Information of China (English)

    宋锋林; 赵彤言; 董言德; 曹晓梅; 张晓龙

    2005-01-01

    本研究采用RT-PCR技术,使用简并引物分别从淡色库蚊(Culex pipiens pallens)敏感品系和抗溴氰菊酯品系中扩增出钠通道ⅡS4~ⅡS6区域的基因片段,长度为359bp.该基因片段所编码的氨基酸与黑尾果蝇(Drosophila melanogaster)、家蝇(Musca domestica)、埃及伊蚊(Aedes aegypti)、冈比亚按蚊(Anopheles gambiae)及德国小蠊(Blattella germanica)等昆虫相应区域的氨基酸序列具有较高的同源性,其同源性分别为95.8%,95.0%,100.0%,98.3%和95.0%.经序列比对,确认抗溴氰菊酯品系淡色库蚊钠通道基因在1014位点发生了突变:该位点的碱基"A"突变为"T",其对应氨基酸由亮氨酸(L)变为苯丙氨酸(F),该突变(L1014F型)在多种昆虫中较为常见.

  14. Mukia maderaspatana (Cucurbitaceae) extract-mediated synthesis of silver nanoparticles to control Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Chitra, Govindaraj; Balasubramani, Govindasamy; Ramkumar, Rajendiran; Sowmiya, Rajamani; Perumal, Pachiappan

    2015-04-01

    Mosquitoes and mosquito-borne diseases are prone to raise health and economic impacts. Synthetic insecticide-based interventions are indeed in situations of epidemic outbreak and sudden increases of adult mosquitoes. Nanoparticles are being used in many commercial applications and were found that aqueous silver ions can be reduced by an aqueous extract of plant parts to generate extremely stable silver nanoparticles in water. Based on this, silver nanoparticles (SNPs) were synthesized using leaf aqueous extract (LAE) of Mukia maderaspatana. Further, the synthesized SNPs were characterized by UV-visible spectrum, which indicated a strong plasmon resonance at 427 nm. X-ray diffraction (XRD) analysis revealed the average crystalline size of the synthesized SNPs was approximately 64 nm by Debye-Scherrer formulae. Fourier transform infrared (FTIR) spectroscopy analysis revealed the presence of different functional groups like amines, halides, alkanes, alkynes, amides, and esters with respective stretches, which are responsible for the bio-reduction of silver ions. Field emission scanning electron microscopy (FESEM) depicted the spherical morphology of SNPs with size range of 13-34 nm. The larvicidal activity of LAE and SNPs exhibited an effective mortality to Aedes aegypti and Culex quinquefasciatus. The lethal concentration (LC50; LC90) of LAE and SNPs were found to be 0.506; 1.082, 0.392; 0.870 ppm and 0.211; 0.703, 0.094; 0.482 ppm, respectively on A. aegypti and C. quinquefasciatus. Thus, the synthesized SNPs have shown preponderant larvicidal activity, but further studies are needed to formulate the potential larvicidal agents.

  15. Chemical constituents and larvicidal potential of Feronia limonia leaf essential oil against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus.

    Science.gov (United States)

    Senthilkumar, A; Jayaraman, M; Venkatesalu, V

    2013-03-01

    In the present investigation, the leaf essential oil of Feronia limonia was evaluated for chemical constituents and mosquito larvicidal activity against the larvae of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. GC and GC-MS analyses revealed that the essential oil contain 51 compounds. Estragole (34.69 %) and β-pinene(23.59 %) were identified as the major constituents followed by methyl (Z)-caryophyllene (11.05 %), eugenol (6.50 %), linalool (3.97 %), phytol (3.27 %), sabinene (2.41 %) and limonene (2.27 %). Larval mortality was observed after 12 and 24 h of exposure period. The oil showed remarkable larvicidal activity against A. stephensi (LC(50) = 38.93 and LC(90) = 108.64 ppm (after 12 h); LC(50) = 15.03 and LC(90) = 36.69 ppm (after 24 h)), A. aegypti (LC(50) = 37.60 and LC(90) = 104.69 ppm (after 12 h); LC(50) = 11.59 and LC(90) = 42.95 ppm (after 24 h)) and C. quinquefasciatus (LC(50) = 52.08 and LC(90) = 124.33 ppm (after 12 h); LC(50) = 22.49 and LC(90) = 60.90 ppm (after 24 h)). Based on the results, the essential oil of F. limonia can be considered as a new source of larvicide for the control of vector mosquitoes.

  16. Effect of temperature on life history traits during immature development of Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) from Córdoba city, Argentina.

    Science.gov (United States)

    Grech, Marta G; Sartor, Paolo D; Almirón, Walter R; Ludueña-Almeida, Francisco F

    2015-06-01

    We investigated how ambient temperature under fluctuating conditions affects the larval-pupal immature traits of Aedes aegypti and Culex quinquefasciatus mosquitoes from Córdoba city, Argentina, and established each species development threshold and physiological time. Based on life tables, three cohorts of each mosquito species were reared in the laboratory under small fluctuating temperatures conditions of 15.2±1.7°C, 17.9±1.6°C, 21.6±0.7°C and 25.3±0.4°C for Ae. aegypti, and 16.6±1.7°C, 18.7±1.7°C and 25.2±0.3°C for Cx. quinquefasciatus. Immature development time and survival values, and also thermal development threshold and physiological time were estimated. Development times of all larval and pupal stages of Ae. aegypti and Cx. quinquefasciatus were significantly affected by the rearing temperatures, decreasing when temperature increased. Mean Ae. aegypti total (larva+pupa) development time ranged from 21.9 to 8.6 days, at 15.2 and 25.3°C, whereas, for Cx. quinquefasciatus varied between 23.5 to 9.2 days at 16.6 and 25.2°C, respectively. Larval and pupal survival of both species was affected by different rearing temperatures, increasing in general as temperature increased. For Ae. aegypti the total immature survival ranged from 26% at 15.2°C to 92% at 21.6°C; however, temperature did not have significant effect on this variable. The total immature survival of Cx. quinquefasciatus was significantly and positively affected by temperatures, ranging from 32 to 88%, at 16.6 and 25.2°C. The temperature development threshold and the physiological time estimated for Ae. aegypti and Cx. quinquefasciatus were 11.11°C and 93.74 degree-days, and 10.96°C and 136.87 degree-days, respectively. The results of the present study showed that temperature significantly affects the larval-pupal immature traits of these mosquito species of sanitary importance, from the central region of Argentina. All the parameters recorded are useful for the development of

  17. Mosquito larvicidal properties of silver nanoparticles synthesized using Heliotropium indicum (Boraginaceae) against Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan

    2014-06-01

    Mosquitoes transmit dreadful diseases to human beings wherein biological control of these vectors using plant-derived molecules would be an alternative to reduce mosquito population. In the present study activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using Helitropium indicum plant leaves against late third instar larvae of Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (30, 60, 90, 120, and 150 μg/mL) were tested against the larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. The synthesized AgNPs from H. indicum were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy analysis, transmission electron microscopy, and histogram. The synthesized AgNPs showed larvicidal effects after 24 h of exposure. Considerable mortality was evident after the treatment of H. indicum for all three important vector mosquitoes. The LC50 and LC90 values of H. indicum aqueous leaf extract appeared to be effective against A. stephensi (LC50, 68.73 μg/mL; LC90, 121.07 μg/mL) followed by A. aegypti (LC50, 72.72 μg/mL; LC90, 126.86 μg/mL) and C. quinquefasciatus (LC50, 78.74 μg/mL; LC90, 134.39 μg/mL). Synthesized AgNPs against the vector mosquitoes of A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 18.40 and 32.45 μg/mL, A. aegypti had LC50 and LC90 values of 20.10 and 35.97 μg/mL, and C. quinquefasciatus had LC50 and LC90 values of 21.84 and 38.10 μg/mL. No mortality was observed in the control. These results suggest that the leaf aqueous extracts of H. indicum and green synthesis of silver nanoparticles have the

  18. The diapause program impacts renal excretion and molecular expression of aquaporins in the northern house mosquito, Culex pipiens.

    Science.gov (United States)

    Yang, Liu; Denlinger, David L; Piermarini, Peter M

    2016-12-27

    Adult females of the mosquito Culex pipiens entering diapause increase sugar water ingestion and reduce evaporative water loss, but how these attributes of the diapause program impact activity of the renal excretory system remains unknown. Here we compared the renal excretory capacity of diapausing and non-diapausing females, as well as the molecular expression of aquaporin (AQP) genes that encode channels involved in transporting water and/or small metabolites. Baseline urine excretion rates in diapausing mosquitoes were higher than in those of their non-diapausing counterparts, possibly a consequence of the intense sugar feeding associated with diapause. But, diapausing mosquitoes exhibited a much lower capacity for diuresis than non-diapausing mosquitoes. The suppressed diuretic capacity likely reflects reduced investment in the energetically-expensive post-prandial diuresis, an event not observed in diapausing mosquitoes. The mRNA expression levels of two genes encoding AQPs, Eglp1 and Aqp12L, in diapausing mosquitoes were down-regulated (on day 14) and up-regulated (on both days 3 and 14), respectively, in whole body samples. These changes were not evident in the excretory system (i.e., Malpighian tubules and hindgut), which showed no differential expression of AQPs as a function of diapause. Several AQP mRNAs were, however, differentially expressed in the midgut, ovaries, and abdominal body wall of diapausing mosquitoes, suggesting that AQPs in these tissues may be playing important non-excretory roles that are unique to diapause physiology.

  19. Enhanced toxicity of binary mixtures of larvicidal constituents from Asarum heterotropoides root to Culex pipiens pallens (Diptera: Culicidae).

    Science.gov (United States)

    Perumalsamy, Haribalan; Kim, Jun-Ran; Kim, Soon-Il; Kwon, Hyung Wook; Ahn, Young-Joon

    2012-01-01

    The toxicity of pellitorine alone or in combination with (-)-asarinin, alpha-asarone, methyleugenol, or pentadecane (1:1, 1:2, 1:3, 2:1, and 3:1 ratios) to third instars from an insecticide-susceptible KS-CP strain and -resistant DJ-CP colony of Culex pipiens pallens Coquillett was evaluated using a direct-contact mortality bioassay. The binary mixture of pellitorine and (-)-asarinin (3:1 ratio) was significantly more toxic against KS-CP larvae (0.95 mg/liter) and DJ-CP larvae (1.07 mg/liter) than either pellitorine (2.08 mg/liter for KS-CP and 2.33 mg/liter for DJ-CP) or (-)-asarinin (11.45 and 12.61 mg/liter) alone. The toxicity of the other binary mixtures (1:1, 1:2, 1:3, and 2:1 ratios) and pellitorine did not differ significantly from each other. Based on the co-toxicity coefficient (CC) and synergistic factor (SF), the three binary mixtures (1:3, 2:1, and 3:1) operated synergistically (CC, 250-390 and SF, 1.4-2.2 for KS-CP; CC, 257-279 and SF, 1.1-2.1 for DJ-CP). The binary mixtures of pellitorine and (-)-asarinin merit further study as potential larvicides for the control of insecticide-resistant mosquito populations.

  20. REPELLENT EFFECT OF OCIMUM BASILICUM AND GLYCYRRHIZA GLABRA EXTRACTS AGAINST THE MOSQUITO VECTOR, CULEX PIPIENS (DIPTERA: CULICIDAE).

    Science.gov (United States)

    Hassan, Mostafa I; Hammad, Kotb M; Saeed, Saeed M

    2015-08-01

    Essential or volatile oils of plants have been variously reported to have many medicinal applications. Methanol, acetone and petroleum ether extracts of Ocimum basilicum and Glycyrrhiza glabra were screened for their repellency effect against Culex pipiens mosquito. The repellent action of the present plants extracts were varied depending on the solvent used and dose of extract. Methanol extract of O. basilicum exhibited the lowest repellent activity as it recorded 77.4% at 6.7mg/cm2. The petroleum ether and acetone extract of 0. basilicum showed repellency of 98.1 & 84.6% respectively, at dose of 6.7mg/cm2, while methanolic extract of G. glabra recorded 73.8 & 50.3% at dose of 6.7 &1.7mg/cm2 respectively, the petroleum ether and acetone extract of G. glabra showed repellency of 76.3 & 81.6%, respectively at dose of 6.7mg/cm2, compared with the commercial formulation, N.N. diethyl toulamide (DEET) which exhibited 100% repellent action at dose of 1.8mg/cm2, respectively. The results may contribute to design an alternative way to control mosquitoes currently based on applications of synthetic insecticides. These extracts could be developed commercially as an effective personal protection meaure against mosquito bites and thus to control diseases caused by mosquito-borne pathogens.

  1. Effect of environmental temperature on the ability of Culex pipiens (Diptera: Culicidae) to transmit West Nile virus.

    Science.gov (United States)

    Dohm, David J; O'Guinn, Monica L; Turell, Michael J

    2002-01-01

    Environmental temperature can affect the ability of mosquitoes to transmit an arbovirus. However, results of various studies indicate that these effects are not consistent among viruses or mosquito species, and there is no information available on the effect of environmental temperature on the ability of North American mosquito species to transmit West Nile (WN) virus. We evaluated the effect of incubation temperature (18, 20, 26, or 30 degrees C) on the ability of Culex pipiens L. derived from specimens collected during the outbreak in New York in 1999 to transmit a strain of WN virus obtained from a crow that died during this outbreak. Although mosquitoes fed on the same viremic chickens, infection rates were directly related to subsequent incubation temperatures. In mosquitoes held at 30 degrees C, virus was recovered from nearly all mosquitoes tested, disseminated infections were detected as early as 4 d after the infectious blood meal, and >90% of all mosquitoes had a disseminated infection 12 or more days after the infectious blood meal. In contrast, for mosquitoes held at 18 degrees C, disseminated infections were not detected until 25 d after the infectious blood meal, and even after 28 d, <30% contained a disseminated infection. Results for mosquitoes held at 20 and 26 degrees C were intermediate for both infection and dissemination rates. The effect of environmental temperature should to be considered when evaluating the vector competence of these mosquitoes and modeling risk of WN virus transmission in nature.

  2. The role of miR-2∼13∼71 cluster in resistance to deltamethrin in Culex pipiens pallens.

    Science.gov (United States)

    Guo, Qin; Huang, Yun; Zou, Feifei; Liu, Bingqian; Tian, Mengmeng; Ye, Wenyun; Guo, Juxin; Sun, Xueli; Zhou, Dan; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Changliang

    2017-05-01

    Excessive and continuous application of deltamethrin has resulted in the development of deltamethrin resistance among mosquitoes, which becomes a major obstacle for mosquito control. In a previous study, differentially expressed miRNAs between deltamethrin-susceptible (DS) strain and deltamethrin-resistant (DR) strain using illumina sequencing in Culex pipiens pallens were identified. In this study, we applied RNAi and the Centers for Disease Control and Prevention (CDC) bottle bioassay to investigate the relationship between miR-2∼13∼71 cluster (miR-2, miR-13 and miR-71) and deltamethrin resistance. We used quantitative real-time PCR (qRT-PCR) to measure expression levels of miR-2∼13∼71 clusters. MiR-2∼13∼71 cluster was down regulated in adult female mosquitoes from the DR strain and played important roles in deltamethrin resistance through regulating target genes, CYP9J35 and CYP325BG3. Knocking down CYP9J35 and CYP325BG3 resulted in decreased mortality of DR mosquitoes. This study provides the first evidence that miRNA clusters are associated with deltamethrin resistance in mosquitoes. Moreover, we investigated the regulatory networks formed between miR-2∼13∼71 cluster and its target genes, which provide a better understanding of the mechanism involved in deltamethrin resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Evaluation of temephos and chlorpyrifos-methyl against Culex pipiens (Diptera: Culicidae) larvae in septic tanks in Antalya, Turkey.

    Science.gov (United States)

    Cetin, H; Yanikoglu, A; Kocak, O; Cilek, J E

    2006-11-01

    The larvicidal activity of chlorpyrifos-methyl and temephos was evaluated against Culex pipiens L. (Diptera: Culicidae) in septic tanks in Antalya, Turkey. Chlorpyrifos-methyl (Pyrifos MT 25 emulsifiable concentrate [EC] ) was evaluated at application rates of 0.04, 0.08, and 0.12 mg active ingredient (AI)/liter, and temephos (Temeguard 50 EC) was evaluated at 0.02, 0.04, and 0.06 mg (AI)/liter during a 21-d study. Generally, overall larval reduction in septic tanks from single- and multifamily dwellings treated with either larvicide was significantly greater than pretreatment levels and control tanks for the duration of the study. At 14 d posttreatment, duration of control was greatest in multifamily tanks treated with chlorpyrifos-methyl at the highest application rate with similar levels of control through 21 d for single-family dwellings (range 97-100%). Septic tanks from both types of family dwellings treated at the highest application rate of temephos resulted in >90% reduction through day 21 (range 91-100%). Laboratory bioassays of septic tank water treated at field application rates, without daily dilution, revealed that complete larval mortality was achieved for 21 d at each application rate and formulation. It is thought that daily addition of water and organic matter to the septic tanks in the single and multifamily dwellings influenced the duration of effectiveness of the larvicides.

  4. Vector competence of Culex quinquefasciatus Say, 1823 exposed to different densities of microfilariae of Dirofilaria immitis (Leidy, 1856 Competência vetorial de Culex quinquefasciatus Say, 1823 exposto a diferentes densidades de microfilárias de Dirofilaria immitis (Leidy, 1856

    Directory of Open Access Journals (Sweden)

    Gílcia Aparecida de Carvalho

    2008-01-01

    Full Text Available The metropolitan region of Recife, Brazil is endemic for Dirofilaria immitis and has an environment favorable to the development of Culex quinquefasciatus. The goal of this study was to evaluate the vector competence of the Cx. quinquefasciatus RECIFE population for D. immitis transmission. A total of 2,104 females of Cx. quinquefasciatus RECIFE population were exposed to different densities of D. immitis microfilariae blood meals, ranging from 1,820 to 2,900 mf/ml of blood, in a natural membrane apparatus. The results showed a variation between 92.3% and 98.8% of females fed. The exposure of the Cx. quinquefasciatus RECIFE population to different densities of microfilariae did not influence the mortality of the mosquitoes. Infective larvae from D. immitis were observed in the Malpighian tubules beginning on the 12th day, whereas larvae were observed in the head and proboscis beginning on the 13th day following infection. The vector efficiency index (VEI presented by the mosquitoes ranged from 7.8 to 56.5. The data demonstrates that the Cx. quinquefasciatus RECIFE population has great potential for the transmission of D. immitis, as it allowed the development of the filarid until the infectious stage at the different densities of microfilariae to which it was exposed.A Região Metropolitana do Recife é endêmica para Dirofilaria immitis e possui ambiente favorável para o desenvolvimento de Culex quinquefasciatus. Neste estudo avaliou-se a competência vetorial de Cx. quinquefasciatus população RECIFE para a transmissão de D. immitis. Para tanto, 2.104 fêmeas de Cx. quinquefasciatus população RECIFE foram expostas a diferentes densidades de microfilárias de D. immitis, variando de 1.820 a 2.900 mf/ml de sangue por meio de membrana natural. Os resultados obtidos demonstraram variação de 92,3% a 98,8% de fêmeas ingurgitadas após a alimentação. A exposição de Cx. quinquefasciatus população RECIFE a diferentes densidades de

  5. Isolation and Biochemical Characterizations of Mid Gut Microbiota of Culex (Culex quinquefasciatus Mosquitoes in Some Urban Sub Urban & Rural Areas of West Bengal.

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    Rahul Kumar

    2013-06-01

    Full Text Available Mosquitoes, in general are medically important vectors of many diseases like Malaria, Dengue and Filariasis, which are a great challenge for public health in many countries. All animals and plants establish symbiotic relationship with microbes. Mosquitoes can be considered as an holobiont units in which the host (mosquito and its microbiota are involved in complex reciprocal multipartite interaction such as host reproduction and survival, protection against natural enemies. This naturally acquired microbial flora can modulate the mosquitos’ vectorial capacity by inhibiting the development of pathogen. But enough care has not been under taken regarding the biochemical characterization of Culex mosquitoes (Culex quinquefasciatus in West Bengal. Therefore a preliminary investigation have been undertaken for the determination of biochemical characterization such as gram staining, pattern of growth, detection of economically important enzyme as well as antibiotic susceptibility assay of midgut bacterial isolates of Culex (Culex quinquefasciatus in some urban, sub-urban and rural areas of West Bengal.

  6. Efficacy of three formulations of diflubenzuron, an insect growth regulator, against Culex quinquefasciatus Say, the vector of Bancroftian filariasis in India

    OpenAIRE

    C Sadanandane; Doss, P. S. Boopathi; Jambulingam, P.

    2012-01-01

    Background & objectives: Insect growth regulators (IGRs) offer alternatives to conventional chemical larvicides that pose problem of resistance and environmental safety. However, only a limited number of IGRs have been approved for use in mosquito control. In the present study, two new formulations of the IGR diflubenzuron, 2 per cent granular (GR) and 2 per cent tablet (DT) were tested for its efficacy against Culex quinquefasciatus, in comparison to its 25 per cent wettable powder (WP) form...

  7. Larval habitat for the avian malaria vector culex quinquefasciatus (Diptera: Culicidae) in altered mid-elevation mesic-dry forests in Hawai'i

    Science.gov (United States)

    Reiter, M.E.; Lapointe, D.A.

    2009-01-01

    Effective management of avian malaria (Plasmodium relictum) in Hawai'i's endemic honeycreepers (Drepanidinae) requires the identification and subsequent reduction or treatment of larval habitat for the mosquito vector, Culex quinquefasciatus (Diptera: Culicidae). We conducted ground surveys, treehole surveys, and helicopter aerial surveys from 20012003 to identify all potential larval mosquito habitat within two 100+ ha mesic-dry forest study sites in Hawai'i Volcanoes National Park, Hawai'i; 'Ainahou Ranch and Mauna Loa Strip Road. At 'Ainahou Ranch, anthropogenic sites (43%) were more likely to contain mosquitoes than naturally occurring (8%) sites. Larvae of Cx. quinquefasciatus were predominately found in anthropogenic sites while Aedes albopictus larvae occurred less frequently in both anthropogenic sites and naturally-occurring sites. Additionally, moderate-size (???20-22,000 liters) anthropogenic potential larval habitat had >50% probability of mosquito presence compared to larger- and smaller-volume habitat (<50%). Less than 20% of trees surveyed at ' Ainahou Ranch had treeholes and few mosquito larvae were detected. Aerial surveys at 'Ainahou Ranch detected 56% (95% CI: 42-68%) of the potential larval habitat identified in ground surveys. At Mauna Loa Strip Road, Cx. quinquefasciatus larvae were only found in the rock holes of small intermittent stream drainages that made up 20% (5 of 25) of the total potential larval habitat. The volume of the potential larval habitat did not influence the probability of mosquito occurrence at Mauna Loa Strip Road. Our results suggest that Cx. quinquefasciatus abundance, and subsequently avian malaria, may be controlled by larval habitat reduction in the mesic-dry landscapes of Hawai'i where anthropogenic sources predominate.

  8. Larvicidal, Ovicidal, and Repellent Activities of Marine Sponge Cliona celata (Grant) Extracts against Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae)

    OpenAIRE

    Reegan, Appadurai Daniel; Kinsalin, Arokia Valan; Paulraj, Michael Gabriel; Ignacimuthu,Savarimuthu

    2013-01-01

    Solvent extracts of marine sponge Cliona celata (Grant) were screened for larvicidal, ovicidal, and repellent properties against the filarial vector Culex quinquefasciatus Say and dengue vector Aedes aegypti L. Larvicidal and ovicidal activities of hexane, ethyl acetate, and methanol extracts were tested in four different concentrations ranging as 62.5, 125, 250, and 500 ppm. Among the three solvent extracts of C. celata, methanol extract showed the highest larvicidal activity at 500 ppm agai...

  9. Differential effect of human ivermectin treatment on blood feeding Anopheles gambiae and Culex quinquefasciatus

    OpenAIRE

    Derua, Yahya A; Kisinza, William N; Simonsen, Paul Erik

    2015-01-01

    BACKGROUND: Widespread and large scale use of ivermectin in humans and domestic animals can have unexpected effects on non-target organisms. As a search for a possible explanation for an observed longitudinal decline in density of anopheline vector mosquitoes, but not in Culex quinquefasciatus, in an area of north-eastern Tanzania which has been exposed to ivermectin mass drug administration, this study assessed and compared the effect of human ivermectin treatment on blood feeding Anopheles ...

  10. Larvicidal activity of green synthesized silver nanoparticles using bark aqueous extract of Ficus racemosa against Culex quinquefasciatus andCulex gelidus

    Institute of Scientific and Technical Information of China (English)

    Kanayairam Velayutham; Chinnadurai Siva; Abdul Abdul Rahuman; Govindasamy Rajakumar; Selvaraj Mohana Roopan; Gandhi Elango; Chinnaperumal Kamaraj; Sampath Marimuthu; Thirunavukkarasu Santhoshkumar; Moorthy Iyappan

    2013-01-01

    Objective:To investigate the larvicidal activity of synthesized silver nanoparticles (AgNPs) utilizing aqueous bark extract ofFicus racemosa (F. racemosa) was tested against fourth instar larvae of filariasis vector,Culex quinquefasciatus (Cx. quinquefasciatus) and japanese encephalitis vectors,Culex gelidus (Cx. gelidus).Methods:The synthesizedAgNPs was characterized byUV-vis spectrum,X-ray diffraction (XRD),Scanning electron microscopy (SEM) andFourier transform infrared (FTIR).The larvicidal activities were assessed for24 h against the larvae ofCx. quinquefasciatus andCx. gelidus with varying concentrations of aqueous bark extract ofF. racemosa and synthesizedAgNPs.LC50 andr2 values were calculated.Results:The maximum efficacy was observed in crude aqueous extract ofF. racemosa against the larvae of Cx. quinquefasciatus andCx. gelidus (LC50=67.72 and63.70 mg/L;r2=0.995 and0.985) and the synthesizedAgNPs (LC50=12.00 and11.21 mg/L;r2=0.997 and0.990), respectively.SynthesizedAg NPs showed theXRD peaks at2θ values of27.61,29.60,35.48,43.48 and79.68were identified as (210), (121), (220), (200) and (311) reflections, respectively.TheFTIR spectra ofAgNPs exhibited prominent peaks at3425,2878,1627 and1382 in the region500-3000 cm-1.The peaks correspond to the presence of a stretching vibration of (NH)C=O group.SEM analysis showed shape in cylindrical, uniform and rod with the average size of250.60 nm.Conclusions:The biosynthesis of silver nanoparticles using bark aqueous extract ofF. racemosa and its larvicidal activity against the larvae of disease spreading vectors.The maximum larvicidal efficacy was observed in the synthesizedAgNPs.

  11. Mosquito larvicidal properties ofOrthosiphon thymiflorus(Roth) Sleesen. (Family:Labiatae) against mosquito vectors,Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    K Kovendan; K Murugan; S Vincent; Donald R Barnard

    2012-01-01

    ABSTRACT Objective:To determine the mosquito larvicidal activities of hexane, chloroform, ethyl acetate, acetone and methanol leaf extract ofOrthosiphon thymiflorus (O. thymiflorus) againstAnopheles stephensi (An. stephensi), Culex quinquefasciatus (Cx. quinquefasciatus) andAedes aegypti (Ae. aegypti).Methods: The larvicidal activity was assayed against three mosquito species at various concentrations ranging from (50-450 ppm) under the laboratory conditions. TheLC50and LC90value of theO. thymiflorus leaf extract was determined by Probit analysis.Results: The LC50values of hexane, chloroform, ethyl acetate, acetone and methanol extract ofO. thymiflorus third instar larvae ofAn. stephensiwereLC50= 201.39, 178.76, 158.06, 139.22 and118.74 ppm;Cx. quinquefasciatus were LC50=228.13, 209.72, 183.35, 163.55 and149.96 ppm andAe. aegyptiwere LC50=215.65, 197.91, 175.05, 154.80 and137.26 ppm, respectively. Maximum larvicidal activity was observed in the methanolic extract followed by acetone, ethyl acetate chloroform and hexane extract. The larval mortality was observed after24h exposure. No mortality was observed in control.Conclusions:The present results suggest that the effective plant crude extracts have potential to be used as an ideal eco-friendly approach for the control of mosquito vectors. This study provides the first report on the larvicidal activity of this plant crude solvent extract of againstAn. stephensi, Cx. quinquefasciatus andAe. aegyptimosquitoes.

  12. Mosquito control in Dar es Salaam. II. Impact of expanded polystyrene beads and pyriproxyfen treatment of breeding sites on Culex quinquefasciatus densities.

    Science.gov (United States)

    Chavasse, D C; Lines, J D; Ichimori, K; Majala, A R; Minjas, J N; Marijani, J

    1995-04-01

    In two contrasting areas of Dar es Salaam (Ilala and Mikocheni) all enclosed breeding sites of Culex quinquefasciatus, such as latrines and septic tanks, were treated with a floating layer of expanded polystyrene beads. 7 months later checks in both study areas revealed only one site (from which the polystyrene had been removed during emptying) containing immature stages of Cx quinquefasciatus. Open breeding sites such as areas of flooded land and blocked drains were treated with pyriproxyfen (an insect growth regulator) at a concentration of 0.1 ppm. Emergence of Cx quinquefasciatus adults from these sites was inhibited for 4 weeks during the rainy season and for up to 11 weeks during the dry season. The problem of mosquito breeding sites caused by bathroom sullage water was addressed through a combination of health education and indirect pressure from the Urban Malaria Control Project (UMCP) via local community leaders. Households responsible for these sites were encouraged to eliminate them by diverting the water into an enclosed drainage structure, usually a pit latrine. After two weekly visits 64.7% of households had complied and 93.4% had complied after five visits. 5 months later, only 15.7% had reverted to allowing sullage water to collect into puddles. Densities of Cx quinquefasciatus adults dropped by 76.7% in Mikocheni and by 46.2% in Ilala following intervention, but increased by 84.9% and 25.6% in two untreated comparison areas. The reasons for differential success of the combined interventions in the two treated areas are discussed.

  13. Mosquito larvicidal properties of Orthosiphon thymiflorus (Roth) Sleesen. (Family: Labiatae) against mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Kovendan, K; Murugan, K; Vincent, S; Barnard, Donald R

    2012-04-01

    To determine the mosquito larvicidal activities of hexane, chloroform, ethyl acetate, acetone and methanol leaf extract of Orthosiphon thymiflorus (O. thymiflorus) against Anopheles stephensi (An. stephensi), Culex quinquefasciatus (Cx. quinquefasciatus) and Aedes aegypti (Ae. aegypti). The larvicidal activity was assayed against three mosquito species at various concentrations ranging from (50-450 ppm) under the laboratory conditions. The LC(50) and LC(90) value of the O. thymiflorus leaf extract was determined by Probit analysis. The LC(50) values of hexane, chloroform, ethyl acetate, acetone and methanol extract of O. thymiflorus third instar larvae of An. stephensi were LC(50)= 201.39, 178.76, 158.06, 139.22 and 118.74 ppm; Cx. quinquefasciatus were LC(50)=228.13, 209.72, 183.35, 163.55 and 149.96 ppm and Ae. aegypti were LC(50)=215.65, 197.91, 175.05, 154.80 and 137.26 ppm, respectively. Maximum larvicidal activity was observed in the methanolic extract followed by acetone, ethyl acetate chloroform and hexane extract. The larval mortality was observed after 24 h exposure. No mortality was observed in control. The present results suggest that the effective plant crude extracts have potential to be used as an ideal eco-friendly approach for the control of mosquito vectors. This study provides the first report on the larvicidal activity of this plant crude solvent extract of against An. stephensi, Cx. quinquefasciatus and Ae. aegypti mosquitoes. Copyright © 2012 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

  14. Larvicidal, adult emergence inhibition and oviposition deterrent effects of foliage extract from Ricinus communis L. against Anopheles arabiensis and Culex quinquefasciatus in Sudan.

    Science.gov (United States)

    Elimam, Abdalla M; Elmalik, Khitma H; Ali, Faysal S

    2009-08-01

    Malaria and filariases are prevalent in Sudan and their control depends largely on preventive measures against mosquito vectors. The present work aimed to investigate the larvicidal, adults emergence inhibition and oviposition deterrent effects of aqueous extracts from leaves of Ricinus communis L. against the mosquitoes, Anopheles arabiensis and Culex quinquefasciatus as a biological control means. The larval mortality was observed after 24 hours. The LC50 values calculated were 403.65, 445.66 and 498.88 ppm against 2nd, 3rd and 4th instar larvae of An. arabiensis and 1091.44, 1364.58 and 1445.44 ppm against 2nd, 3rd and 4th larval instars of Cx. quinquefasciatus. 50% of adult emergence inhibition (EI50) were 374.97 and 1180.32 ppm against 3rd instar larvae of An. arabiensis and Cx. quinquefasciatus. The extract showed oviposition deterrent effect against both species. Results reveal that the crude extract of R. communis possesses remarkable larvicidal, adult emergence inhibition and oviposition deterrent properties against both the tested species and can be used as biological control means.

  15. Larvicidal potentiality, longevity and fecundity inhibitory activities of Bacillus sphaericus (Bs G3-IV on vector mosquitoes, Aedes aegypti and Culex quinquefasciatus

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    Arjunan Nareshkumar

    2012-12-01

    Full Text Available Intervention measures to control the transmission of vector-borne diseases include control of the vector population. In mosquito control, synthetic insecticides used against both the larvae (larvicides and adults (adulticides create numerous problems, such as environmental pollution, insecticide resistance and toxic hazards to humans. In the present study, a bacterial pesticide, Bacillus sphaericus (Bs G3-IV, was used to control the dengue and filarial vectors, Aedes aegypti and Culex quinquefasciatus. Bacillus sphaericus (Bs G3-IV was very effective against Aedes aegypti and Culex quinquefasciatus, showing significant larval mortality. Evaluated lethal concentrations (LC50 and LC90 were age-dependent, with early instars requiring a lower concentration compared with later stages of mosquitoes. Culex quinquefasciatus was more susceptible to Bacillus sphaericus (Bs G3-IV than was Aedes aegypti. Fecundity rate was highly reduced after treatment with different concentrations of Bacillus sphaericus (Bs G3-IV. Larval and pupal longevity both decreased after treatment with Bacillus sphaericus (Bs G3-IV, total number of days was lower in the B. sphaericus treatments compared with the control. Our results show the bacterial pesticide Bacillus sphaericus (Bs G3-IV to be an effective mosquito control agent that can be used for more integrated pest management programs.

  16. Pathogenicity of the Fungus, Aspergillus clavatus, isolated from the locust, Oedaleus senegalensis, against larvae of the mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus.

    Science.gov (United States)

    Seye, Fawrou; Faye, Oumar; Ndiaye, Mady; Njie, Ebrima; Marie Afoutou, José

    2009-01-01

    The use of insect pathogenic fungi is a promising alternative to chemical control against mosquitoes. Among the Hyphomycetes isolated from insects for mosquito control, the genus Aspergillus remains the least studied. In September 2005, four fungi were isolated from the Senegalese locust, Oedaleus senegalensis Kraus (Orthoptera: Acrididae), collected in Dakar, Senegal. One of these fungi, identified as Aspergillus clavatus, Desmazières (Eurotiales: Trichocomaceae) was highly pathogenic against larvae of the mosquitoes Aedes aegypti L., Anopheles gambiae s.l. Giles and Culex quinquefasciatus Say (Diptera: Culicidae). An application of 1.2 mg/ml dry conidia yielded 100% mortality after 24 hours against both Ae. aegypti and Cx. quinquefasciatus while with An. gambiae it was 95%. With unidentified species in the genus Aspergillus, mortality after 24 h was studies revealed that A. clavatus penetrated the cuticle, invaded the gut and disintegrated its cells. Some Cx. quinquefasciatus larvae, treated with A. clavatus reached the pupal stage and produced infected adults. However, the infection was mainly located on the extremity of their abdomen. These results suggest that A. clavatus could be an effective tool to manage mosquito proliferation.

  17. Insect repellent activity of medicinal plant oils against Aedes aegypti (Linn.), Anopheles minimus (Theobald) and Culex quinquefasciatus Say based on protection time and biting rate.

    Science.gov (United States)

    Phasomkusolsil, Siriporn; Soonwera, Mayura

    2010-07-01

    This study investigated insect bite protection and length of the protection with 30 repellents which were divided into 3 categories: plant oil, essential oil and essential oil with ethyl alcohol, tested against three mosquito species, Aedes aegypti, Anopheles minimus and Culex quinquefasciatus, under laboratory conditions. The plant oil group was comprised of Phlai (Zingiber cassumunar) and Sweet basil (Ocimum basilicum). Both substances were effective as repellents and feeding deterrents against An. minimus (205 minutes protection time and a biting rate of 0.9%), Cx. quinquefasciatus (165 minutes protection time and 0.9% biting rate) and Ae. aegypti (90 minutes protection time and 0.8% biting rate). Essential oil from citronella grass (Cymbopogon nardus) exhibited protection against biting from all 3 mosquito species: for An. minimus, Cx. quinquefasciatus and Ae. aegypti, the results were 130 minutes and 0.9%, 140 minutes and 0.8%, and 115 minutes and 0.8%, respectively. The period of protection time against Ae. aegypti for all repellent candidates tested was lower than the Thai Industrial Standards Institute (TISI) determined time of greater than 2 hours.

  18. Insecticidal potential of Ocimum canum plant extracts against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus larval and adult mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Murugan, Jimmantiyur Madhappan; Ramkumar, Govindaraju; Shivakumar, Muthugoundar Subramanian

    2016-01-01

    Mosquitoes have developed resistance to various synthetic insecticides, making their control increasingly difficult. Insecticides of botanical origin may serve as suitable natural control. This study evaluates the toxic potential of Ocimum canum (Sims) leaf extract and powder against Anopheles stephensi (Liston), Aedes aegypti (Lin) and Culex quinquefasciatus (Say) larval and adult mosquitoes. Larval mortality was observed after 24 h recovery period and adult smoke toxicity observed for 40 min duration at 10 min interval. Methanol extract of O. canum showed highest larval mortality against the larvae of C. quinquefasciatus LC50 = 28.3225, LC90 = 44.1150; Ae. aegypti LC50 = 43.327, LC90 = 61.249; and An. stephensi LC50 = 30.2001, LC90 = 48.2866 ppm. The smoke toxicities were 93% mortality in C. quinquefasciatus, 74% in Ae. aegypti and 79% in An. stephensi adults, respectively, whereas 100% mortality was recorded in the commercial mosquito control. Our results suggest that O. canum leaf extract and powder are natural insecticide, and ideal eco friendly approach for mosquito control.

  19. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis

    Science.gov (United States)

    Elaagip, Arwa H.; Kenawy, Mohamed A.; Ayres, Constância F. J.; Peterson, A. Townsend; Soliman, Doaa E.

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades. PMID:27695107

  20. Climate Change Influences on the Global Potential Distribution of the Mosquito Culex quinquefasciatus, Vector of West Nile Virus and Lymphatic Filariasis.

    Science.gov (United States)

    Samy, Abdallah M; Elaagip, Arwa H; Kenawy, Mohamed A; Ayres, Constância F J; Peterson, A Townsend; Soliman, Doaa E

    2016-01-01

    Rapid emergence of most vector-borne diseases (VBDs) may be associated with range expansion of vector populations. Culex quinquefasciatus Say 1823 is a potential vector of West Nile virus, Saint Louis encephalitis virus, and lymphatic filariasis. We estimated the potential distribution of Cx. quinquefasciatus under both current and future climate conditions. The present potential distribution of Cx. quinquefasciatus showed high suitability across low-latitude parts of the world, reflecting the current distribution of the species. Suitable conditions were identified also in narrow zones of North Africa and Western Europe. Model transfers to future conditions showed a potential distribution similar to that under present-day conditions, although with higher suitability in southern Australia. Highest stability with changing climate was between 30°S and 30°N. The areas present high agreement among diverse climate models as regards distributional potential in the future, but differed in anticipating potential for distribution in North and Central Africa, southern Asia, central USA, and southeastern Europe. Highest disparity in model predictions across representative concentration pathways (RCPs) was in Saudi Arabia and Europe. The model predictions allow anticipation of changing distributional potential of the species in coming decades.

  1. Characterisation of Culex quinquefasciatus (Diptera: Culicidae larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Marta Grech

    2013-09-01

    Full Text Available The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase.

  2. Evaluation of halofenozide against prey mosquito larvae Culex pipiens and the predator fish Gambusia affinis: impact on growth and enzymatic activities.

    Science.gov (United States)

    Soltani, N; Chouahda, S; Smagghe, G

    2008-01-01

    Culex pipiens (Diptera: Culicidae) is the most widely distributed mosquito species in Algeria and many other countries in the world. Mosquitoes are generally controlled by conventional insecticides but these may pose strong secondary effects on the environment. In this context, the insect growth regulators (IGRs) have shown promise in controlling pest insects. Halofenozide (23% EC) is a novel IGRs belonging to the class of non-steroidal ecdysone agonists, and it was found toxic for larvae of C. pipiens. In addition biological methods constitute an alternative to chemical control. Several fish species have been tested against mosquitoes, and Gambusia affinis was found very efficient. In the present study we evaluated the impact of this new potent insecticide (halofenozide) on growth and metric indexes in the larvivorous fish G. affinis under laboratory conditions. In addition, the effects were evaluated on the enzymatic activities of acetyl cholinesterase (AChE) and glutathione S-transferase (GST). The insecticide was added in water at two concentrations (12.6 and 28.6 microg/L) corresponding to the LC50 and LC90 obtained against fourth instar larvae of C. pipiens, and adult females of G. affinis were exposed to halofenozide for 30 days. At different exposure times we measured the length and weight of fishes, the index of condition (K), the gonado-somatic ratio (GSR) and the hepato-somatic ratio (HSR). The results showed that halofenozide had no significant (p>0.05) effects on growth, metric indexes and AChE activities. However, treatment caused a significant induction (p<0.05) in GST activities at days 15 and 30 with the highest dose. Our results indicate that this ecdysteroid agonist presented only minor secondary effects on the non-target fish species, and so it has potential for controlling of mosquitoes in an integrated manner.

  3. Cloning and Overexpression of CYP6F1, a Cytochrome P450 Gene,from Deltamethrin-resistant Culex pipiens pallens

    Institute of Scientific and Technical Information of China (English)

    Mao-Qing GONG; Chang-Liang ZHU; Yan GU; Xiao-Bang HU; Yan SUN; Lei MA; Xiu-Lan LI; Li-Xin SUN; Jing SUN; Jin QIAN

    2005-01-01

    CYP6F1 (GenBank/EMBL accession No. AY662654), a novel gene with a complete encoding sequence in the cytochrome P450 family 6, was cloned and sequenced from deltamethrin-resistant 4th instar larvae of Culex pipiens pallens. The cDNA sequence of CYP6F1 has an open reading frame of 1527bp, which encodes a putative protein of 508 amino acid residues. The deduced amino acid sequence of CYP6F1 indicated that the encoded P450 has conserved domains of a putative membrane-anchoring signal,putative reductase-binding sites, a typical heme-binding site, an ETLR motif and substrate recognition sites.Semi-quantitative RT-PCR analysis indicated that the CYP6F1 gene was expressed to a greater extent in the deltamethrin-resistant strain than in the susceptible strain of Cx. pipiens pallens. The expression levels of the CYP6F1 gene in the deltamethrin-resistant 1 st, 2nd, 3rd, 4th instar larvae and adult female mosquitoes differed, with highest expression levels in the 4th instar larvae. In addition, the CYP6F1 gene was stably expressed in mosquito C6/36 cells, and the expected 61.2 kDa band was identified by Western blotting. The cells transfected with CYP6F1 had an increased resistance to deltamethrin as compared with control cells.These results indicate that CYP6F1 is expressed at higher levels in the deltamethrin-resistant strain, and may confer some insecticide resistance in Cx. pipiens pallens.

  4. Controlling Aedes albopictus and Culex pipiens pallens using silver nanoparticles synthesized from aqueous extract of Cassia fistula fruit pulp and its mode of action.

    Science.gov (United States)

    Fouad, Hatem; Hongjie, Li; Hosni, Dawood; Wei, Jiqian; Abbas, Ghulam; Ga'al, Hassan; Jianchu, Mo

    2017-05-25

    Mosquitoes act as key vector for transmission of devastating parasites and pathogens which affect millions of people globally. In this research, the green synthesis of silver nanoparticles of Cassia fistula fruit pulp as an innovative and operative tool against vector mosquitoes is presented. Silver nanoparticles were characterized by a series of techniques including Fourier transform infrared spectroscopy, Transmission Electron Microscope and confirmed by Scanning Electron Microscope, UV-Vis spectrophotometry and X-ray diffraction. Silver nanoparticles were highly effective against the larvae (I-IV instar) and pupae of Aedes albopictus and Culex pipiens pallens after 24, 48 and 72 h of treatment. Ae. albopictus had LC50 values ranging from 8.3 mg/L (I instar) to 17.3 mg/L (pupae) and LC50 ranging from 1.1 mg/L (I instar) to 19.0 mg/L (pupae) against Cx. pipiens pallens. The systemic effect of AgNPs was further assessed in the fourth instar larvae of Ae. albopictus and Cx. pipiens pallens by measuring the levels of total proteins and activity of two important marker enzymes: Acetylcholinesterase and α- and β-carboxylesterase. Overall, the findings of the study suggest that the use of Cassia fistula-fruit pulp extract mediated synthesis of silver nanoparticles can be used for controlling vector mosquitoes. This is the first report on the mosquito larvicidal and pupicidal activity of AgNPs synthesized by Cassia fistula fruit pulp and its possible mechanism of action.

  5. Effects of gamma radiation on the activity of the mosquito culex pipiens L. II. Effects on the sexual vitality of the mosquito

    OpenAIRE

    El Banby, M. A. [محمد البنبي; Wakid, A. M.; Shoman, A. A.

    1988-01-01

    The effects of 3 gamma doses on the sex vitality of the mosquito Culex pipiens L. were studied after irradiation of the larvae, pupae or newly emerged adults. No significant effect on the sex attraction was obseived when irradiation was done at the larval or adult stages with 40 Gray. However, there was a clear effect of radiation at all doses tested on the attraction of males to females when they were irradiated in the pupal stage. At 80 and 120 Gray, there was a significant decrease, whe...

  6. Molecular cloning and preliminary function study of iron responsive element binding protein 1 gene from cypermethrin-resistant Culex pipiens pallens

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    Tan Wenbin

    2011-11-01

    Full Text Available Abstract Background Insecticide resistance jeopardizes the control of mosquito populations and mosquito-borne disease control, which creates a major public health concern. Two-dimensional electrophoresis identified one protein segment with high sequence homology to part of Aedes aegypti iron-responsive element binding protein (IRE-BP. Method RT-PCR and RACE (rapid amplification of cDNA end were used to clone a cDNA encoding full length IRE-BP 1. Real-time quantitative RT-PCR was used to evaluate the transcriptional level changes in the Cr-IRE strain Aedes aegypti compared to the susceptible strain of Cx. pipiens pallens. The expression profile of the gene was established in the mosquito life cycle. Methyl tritiated thymidine (3H-TdR was used to observe the cypermethrin resistance changes in C6/36 cells containing the stably transfected IRE-BP 1 gene of Cx. pipiens pallens. Results The complete sequence of iron responsive element binding protein 1 (IRE-BP 1 has been cloned from the cypermethrin-resistant strain of Culex pipiens pallens (Cr-IRE strain. Quantitative RT-PCR analysis indicated that the IRE-BP 1 transcription level was 6.7 times higher in the Cr-IRE strain than in the susceptible strain of 4th instar larvae. The IRE-BP 1 expression was also found to be consistently higher throughout the life cycle of the Cr-IRE strain. A protein of predicted size 109.4 kDa has been detected by Western blotting in IRE-BP 1-transfected mosquito C6/36 cells. These IRE-BP 1-transfected cells also showed enhanced cypermethrin resistance compared to null-transfected or plasmid vector-transfected cells as determined by 3H-TdR incorporation. Conclusion IRE-BP 1 is expressed at higher levels in the Cr-IRE strain, and may confer some insecticide resistance in Cx. pipiens pallens.

  7. Insecticidal potency of Aspergillus terreus against larvae and pupae of three mosquito species Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti.

    Science.gov (United States)

    Ragavendran, Chinnasamy; Natarajan, Devarajan

    2015-11-01

    Microbial control agents offer alternatives to chemical pest control, as they can be more selective than chemical insecticides. The present study evaluates the mosquito larvicidal and pupicidal potential of fungus mycelia using ethyl acetate and methanol solvent extracts produced by Aspergillus terreus against Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. The A. terreus mycelia were extracted after 15 days from Sabouraud dextrose broth medium. The ethyl acetate extracts showed lethal concentration that kills 50% of the exposed larvae (LC50) and lethal concentration that kills 90% of the exposed larvae (LC90) values of the first, second, third, and fourth instar larvae of An. stephensi (LC50 = 97.410, 102.551, 29.802, and 8.907; LC90 = 767.957, 552.546, 535.474, and 195.677 μg/ml), Cx. quinquefasciatus (LC50 = 89.584, 74.689, 68.265, and 67.40; LC90 = 449.091, 337.355, 518.793, and 237.347 μg/ml), and Ae. aegypti (LC50 = 83.541, 84.418, 80.407, and 95.926; LC90 = 515.464, 443.167, 387.910, and 473.998 μg/ml). Pupicidal activity of mycelium extracts was tested against An. stephensi (LC50 = 25.228, LC90 = 140.487), Cx. quinquefasciatus (LC50 = 54.525, LC90 = 145.366), and Ae. aegypti (LC50 = 10.536, LC90 = 63.762 μg/ml). At higher concentration (500 μg/ml), mortality starts within the first 6 h of exposure. One hundred percent mortality occurs at 24-h exposure. The overall result observed that effective activity against selected mosquito larvae and pupae after 24 h was a dose and time-dependent activity. These ensure that the resultant mosquito population reduction is substantial even where the larvicidal and pupicidal potential is minimal. The FTIR spectra of ethyl acetate extract reflect prominent peaks (3448.32, 3000.36, 2914.59, 2118.73, 1668.21, 1436.87, 1409.02, 954.33, 901.13, and 704.67 cm(-1)). The spectra showed a sharp absorption band at 1314.66 cm(-1) assigned to wagging vibration of

  8. Cryptic invasion of Northern Leopard Frogs (Rana pipiens) across phylogeographic boundaries and a dilemma for conservation of a declining amphibian

    Science.gov (United States)

    O'Donnell, Ryan P.; Drost, Charles A.; Mock, Karen E.

    2017-01-01

    Anthropogenic introduction of species is a major contributor to loss of biodiversity. Translocations within the range of a species are less frequently recognized, but have the potential for negative effects as well. Genetic mixing may lead to loss of local adaptations or further decline through outbreeding depression. These cryptic invasions may be quite difficult to recognize, but genetic tools can be used to recognize and monitor such intraspecific introductions. Conversely, translocations within species can be an important conservation tool to reduce inbreeding depression and replace lost genetic diversity. Thus, cryptic invasions can be either an aid or a hindrance to conservation efforts. We tested for the presence of non-native genotypes and assessed the extent and nature of introgression in populations of Northern Leopard Frog (Rana pipiens) in the southwestern US, where populations have declined to a few remnant populations. The most abundant and diverse complex of populations in the region contained a mitochondrial haplotype that was not native to the western US, probably resulting from the introduction of released pets, laboratory animals, or release during fish stocking. These non-native haplotypes were well integrated into a large complex of ponds and lakes, contributing to high genetic diversity in this area. Logistically, the geographic extent of non-native genetic influence within this population precludes eliminating or controlling the non-native component of this population. We recommend assessing the progress and fate of the introgression over time—along with population fitness parameters—to determine whether this introduction is beneficial or detrimental to population persistence. Meanwhile, translocations from nearby locations with similar environmental conditions have the best prospects for avoiding problems with outbreeding depression in other declining populations and will also most effectively preserve regional genetic diversity.

  9. Low-cost and eco-friendly green synthesis of silver nanoparticles using Feronia elephantum (Rutaceae) against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).

    Science.gov (United States)

    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Muthukumaran, Udaiyan

    2014-05-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. The use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Feronia elephantum plant leaf extract against late third-instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus was determined. The range of concentrations of synthesized AgNPs (5, 10, 15, 20, and 25 μg mL(-1)) and aqueous leaf extract (25, 50, 75, 100, and 125 μg mL(-1)) were tested against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of F. elephantum for all three important vector mosquitoes. The synthesized AgNPs from F. elephantum were highly toxic than crude leaf aqueous extract to three important vector mosquito species. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy analysis (EDX). Synthesized AgNPs against the vector mosquitoes A. stephensi, A. aegypti, and C. quinquefasciatus had the following LC50 and LC90 values: A. stephensi had LC50 and LC90 values of 11.56 and 20.56 μg mL(-1); A. aegypti had LC50 and LC90 values of 13.13 and 23.12 μg mL(-1); and C. quinquefasciatus had LC50 and LC90 values of 14.19 and 24.30 μg mL(-1). No mortality was observed in the control. These results suggest that the green synthesis of silver nanoparticles using F. elephantum has the potential to be used as an ideal eco-friendly approach for the control of A. stephensi, A. aegypti, and C

  10. Larvicidal, ovicidal, and adulticidal efficacy of Erythrina indica (Lam.) (Family: Fabaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-02-01

    Mosquitoes are the major vector for the transmission of malaria, dengue fever, yellow fever, filariasis, schistosomiasis, and Japanese encephalitis. Mosquito control is facing a threat because of the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. In view of the recently increased interest in developing plant origin insecticides as an alternative to chemical insecticide, this study was undertaken to assess the larvicidal, ovicidal, and adulticidal potential of the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts from the medicinal plant Erythrina indica against the medically important mosquito vectors, Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae). The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of leaf of E. indica against the larvae of A. stephensi, A. aegypti, and C. quinquefasciatus with the LC50 and LC90 values of 69.43, 75.13, and 91.41 ppm and 125.49, 134.31, and 167.14 ppm, respectively. The mean percent hatchability of the eggs was observed after 48 h post treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of E. indica against A. stephensi, A. aegypti, and C. quinquefasciatus exerted 100 % mortality (zero hatchability) at 150, 200, and 250 ppm, respectively. Control eggs showed above 99.3-100 % hatchability. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and

  11. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera:Culicidae) through bioactive fraction of Cayratia trifolia leaf

    Institute of Scientific and Technical Information of China (English)

    Sumanta Chakraborty; Someshwar Singha; Kuntal Bhattacharya; Goutam Chandra

    2013-01-01

    Objective:To investigate the mosquito larvicidal activity of Cayratia trifolia (L.) Domin (Vitaceae:Vitales) (C. trifolia) which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides. Methods:Young and mature leaves of C. trifolia were investigated for larvicidal activity against 3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year. The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleum-ether, benzene, chloroform:methanol (1:1 v/v), acetone, absolute alcohol and distilled water. Dose dependent mortality was recorded against each solvent extract. Determination of LD50 and LD90 were executed through log-probit analysis using the most bioactive fraction. The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables. Justification of larvicidal activity was established through student’s t-test. Costing effects were evaluated on the non-target water fauna under laboratory conditions. Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods. Results:Significant variations in mortality rate were noted with respect to the type of leaves (mature and senescence), concentration of leaf extract and between seasons. The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD50 and LD90 value of 10.70 mg/L and 27.64 mg/L respectively. No significant mortality was recorded in non-target water population. Chromatographic analyses of the water extract revealed the presence of steroids, triterpene glycosides, essential oil, phenolics and diterpenes as

  12. Control of human filarial vector, Culex quinquefasciatus Say 1823 (Diptera: Culicidae) through bioactive fraction of Cayratia trifolia leaf

    Science.gov (United States)

    Chakraborty, Sumanta; Singha, Someshwar; Bhattacharya, Kuntal; Chandra, Goutam

    2013-01-01

    Objective To investigate the mosquito larvicidal activity of Cayratia trifolia (L.) Domin (Vitaceae: Vitales) (C. trifolia) which is distributed in many parts of India with medicinal properties as vector control is facing threat due to the emergence of resistance to synthetic insecticides. Methods Young and mature leaves of C. trifolia were investigated for larvicidal activity against 3rd instars larvae of Culex quinquefasciatus in different seasons throughout the year. The active fractions were extracted using six different solvents in a non-polar to polar fashion viz petroleum-ether, benzene, chloroform: methanol (1:1 v/v), acetone, absolute alcohol and distilled water. Dose dependent mortality was recorded against each solvent extract. Determination of LD50 and LD90 were executed through log-probit analysis using the most bioactive fraction. The fluctuations in mortality were statistically co-related through ANOVA analyses concerning different seasons and types of leaves as random variables. Justification of larvicidal activity was established through student's t-test. Costing effects were evaluated on the non-target water fauna under laboratory conditions. Thin layer chromatographic techniques were performed for phytochemical analysis and categorization of chemical personality of the active fractions using the most effective solvent extract following standard methods. Results Significant variations in mortality rate were noted with respect to the type of leaves (mature and senescence), concentration of leaf extract and between seasons. The water extract among all the solvent extracts was found to induce cent percent mortality at 50 mg/L in test mosquito species within 24 h with a LD50 and LD90 value of 10.70 mg/L and 27.64 mg/L respectively. No significant mortality was recorded in non-target water population. Chromatographic analyses of the water extract revealed the presence of steroids, triterpene glycosides, essential oil, phenolics and diterpenes as

  13. Ciclo de vida de Culex quinquefasciatus Say, 1826 (Diptera: Culicidae bajo condiciones no controladas en Bogotá.

    Directory of Open Access Journals (Sweden)

    Myriam Janeth Salazar

    2004-12-01

    Full Text Available El objetivo de este trabajo fue estudiar varios aspectos del crecimiento y el desarrollo de los estadios inmaduros de Culex quinquefasciatus Say, 1826 (Diptera: Culicidae, especie antropofílica frecuentemente encontrada en Bogotá. Con este fin, se realizaron dos experimentos en diferentes épocas del año 2001 (enero-febrero y septiembre-octubre, bajo condiciones no controladas (luz, temperatura y humedad relativa. Se colocaron recipientes plásticos transparentes con agua de charca a la que se le adicionó concentrado para perro; se tomaron cuatro balsas al azar para estudiar el ciclo de vida utilizando los parámetros de la tabla de vida: mortalidad y supervivencia. Las hembras ovipositaron entre cinco y ocho días después de la ingestión de sangre. El número de huevos por balsa varió entre 152 y 203. La eclosión de larvas L1 fue de 50% en el primer experimento y de 75% en el segundo. Se destacó la naturaleza no sincrónica de la eclosión de las L1, la menor duración proporcional del estadio de pupa (11% del tiempo del desarrollo total y la eficiencia del cambio pupa-adulto (98,61%. Se reporta una menor duración del ciclo de lo informado previamente. Además, los altos porcentajes de eclosión (83,58%, pupación (86,63% y emergencia (98,61% con las condiciones presentes para estos experimentos (temperatura media 14,8°C y 15,1°C y humedad relativa del 72,5% y 74,1%, respectivamente indican el alto grado de adaptación de C. quinquefasciatus al ambiente bogotano. Estas características, más la capacidad vectorial y la resistencia a los insecticidas, hacen de esta especie un problema de salud pública.

  14. Whole transcriptome responses among females of the filariasis and arbovirus vector mosquito Culex pipiens implicate TGF-β signaling and chromatin modification as key drivers of diapause induction.

    Science.gov (United States)

    Hickner, Paul V; Mori, Akio; Zeng, Erliang; Tan, John C; Severson, David W

    2015-07-01

    Culex pipiens mosquitoes are important disease vectors inhabiting temperate zones, worldwide. The seasonal reduction in temperature and photoperiod accompanying late summer and early fall prompts female mosquitoes to enter diapause, a stage of developmental arrest and physiological conditioning that enhances survival during the winter months. To investigate the molecular mechanisms underlying diapause induction, we used custom whole transcriptome microarrays to identify differences in gene expression following exposure to nondiapause (long days, 25 °C) and diapause-inducing (short days, 18 °C) environmental conditions. Using a two-way ANOVA, we identified 1130 genes that were differentially expressed. We used the expression of these genes across three time points to construct a gene co-expression network comprising five modules. Genes in modules 1, 2, and 3 were largely up-regulated, while genes in modules 4 and 5 were down-regulated when compared to nondiapause conditions. Pathway enrichment analysis of the network modules revealed some potential regulatory mechanisms driving diapause induction. Module 1 was enriched for genes in the TGF-ß and Wnt signaling pathways; module 2 was enriched for genes involved in insect hormone biosynthesis, specifically, ecdysone synthesis; module 3 was enriched for genes involved in chromatin modification; and module 5 was enriched for genes in the circadian rhythm pathway. Our results suggest that TGF-β signaling and chromatin modification are key drivers for the integration of environmental signals into the diapause induction phase in C. pipiens mosquitoes.

  15. Evaluación de palaemonetes argentinus (Decapoda, Natantia en el control biológico de larvas de Culex pipiens (Diptera, Culicidae en condiciones de laboratorio

    Directory of Open Access Journals (Sweden)

    Giri Federico

    2003-01-01

    Full Text Available The predator-prey relationship of Palaemonetes argentinus Nobili, 1901 and Culex pipiens s.l. larvae was studied under laboratory conditions. The prawns were separated in two groups, isolated and grouped ones. Mosquitoe larvae were offered to prawns in two forms, limited and unlimited offer to both groups. In the first analysis, values of predation did not differ significantly between males and females of P. argentinus. Predation in 24 h was 14,9 ± 4,2 larvae/prawn. A reduction of predation was observed with unlimited offer for the same hour, during all the experiment. Predation with unlimited offer was higher on the first day than on the second, but returned to high values on the third day, for both groups. In the grouped experiment, predation with limited offer was total on the first days, decreasing to the last day. As a result, P. argentinus was considered an efficient predator of C. pipiens s.l. larvae under laboratory conditions.

  16. Influence of Ribeiroia ondatrae (Trematoda: Digenea) infection on limb development and survival of northern leopard frogs (Rana pipiens): effects of host stage and parasite-exposure level

    Science.gov (United States)

    Schotthoefer, Anna M.; Koehler, Anson V.; Meteyer, Carol U.; Cole, Rebecca A.

    2003-01-01

    Recent evidence suggests that infection by larvae of the trematode Ribeiroia ondatrae accounts for a significant proportion of limb malformations currently observed in amphibian populations of North America. However, the effects of R. ondatrae infection on northern leopard frogs (Rana pipiens), one of the species most frequently reported with malformations, have not been adequately explored. Moreover, the risk factors associated with R. ondatrae-induced malformations have not been clearly identified. We examined the effects of timing of infection on tadpole survival and limb development. Rana pipiens tadpoles were individually exposed to R. ondatrae cercariae at the pre-limb-bud (Gosner stages 24 and 25), limb-bud (Gosner stages 27 and 28), or paddle (Gosner stages 31–33) stages of development and monitored through metamorphosis. The effects of infection were stage-specific. Infections acquired at the pre-limb-bud stage resulted in a high mortality rate (47.5–97.5%), whereas tadpoles infected at the limb-bud stage displayed a high malformation rate (16% overall), and the magnitude of effects increased with the level of exposure to cercariae. In contrast, infections acquired at the paddle stage had no effect on limb development or tadpole survival, which suggests that the timing of R. ondatrae infection in relation to the stage structure of tadpole populations in the wild is an important determinant of the degree to which populations are affected by R. ondatrae.

  17. Predicting distribution of Aedes aegypti and Culex pipiens complex, potential vectors of Rift Valley fever virus in relation to disease epidemics in East Africa

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    Clement Nyamunura Mweya

    2013-10-01

    Full Text Available Background: The East African region has experienced several Rift Valley fever (RVF outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. Methods: Diverse ecological niche modelling techniques have been developed for this purpose: we present a maximum entropy (Maxent approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Results: Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Conclusion: Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods.

  18. Essential oils of indigenous in Greece six Juniperus taxa: chemical composition and larvicidal activity against the West Nile virus vector Culex pipiens.

    Science.gov (United States)

    Vourlioti-Arapi, F; Michaelakis, A; Evergetis, E; Koliopoulos, G; Haroutounian, S A

    2012-05-01

    The chemical composition of 14 essential oils (EOs), obtained from various parts (leaves, fruits, wood) of the six indigenous in Greece Juniperus family taxa, was determined by GC and GC/MS analysis. The insecticidal properties of these EOs were evaluated against Culex pipiens L. larvae of 3rd and early 4th instars, in order to delineate the relationship between the phytochemical content of the EOs and their larvicidal activities. The analytical data indicated that the EOs mainly consisted of monoterpenes, mostly cyclic and only occasionally aliphatic, and to a lesser percent, of diterpenes. The larvicidal bioassays against C. pipiens larvae revealed that the most active EO was derived from the wood of Juniperus drupacea and contains mainly non-oxygenated monoterpenes and a significant amount of diterpenes, displaying the highest chemodiversity. Its initial LC(50) value was 26.47 mg L(-1). On the contrary, the EO isolated from J. phoenicea berries, which consisted of monoterpenes (non-oxygenated, cyclic), was the less active displaying an LC(50) value of 96.69 mg L(-1). In respect to the contained phytochemicals, myrcene was assayed as the most toxic, displaying an LC(50) value of 33.83 mg L(-1), while the four isomers of pinene abundant in all EOs were less active exhibiting LC(50) values ranging from 70.40 to 94.88 mg L(-1). Results herein reveal that the EOs isolated from the studied Juniperus family taxa represent an inexpensive source of natural mosquito control mixtures.

  19. TOXICITY OF EUPATORIUM CANNABINUM L. AGAINST SECOND AND FOURTH INSTAR LARVAE OF CULEX QUINQUEFASCIATUS AND AEDES AEGYPTI

    Directory of Open Access Journals (Sweden)

    Arshed Iqbal Dar

    2013-02-01

    Full Text Available The aim of the study was to demonstrate the toxicity of Eupatorium cannabinum L. against 2nd and 4th instar larvae of Culex quinquefasciatus and Aedes aegypti. For growth inhibitory activities early 2nd instar and 4th instar of Culex were taken in 500 ml capacitor glass beakers each beaker containing 25 larvae of 2nd and 4th instar separately. The beaker contains 240 ml water and 1 ml of test concentration of Eupatorium extract. Four different concentration regions from 20 to 50 ppm concentration were used. Each concentration has three replicates with one control and one untreated group. The following observations were recorded and growth inhibitory activities were photographed. Toxicity of acetone extract of Eupatorium cannabinum L. was observed against 2nd and 4th instar larvae of Aedes aegypti when four different concentrations were taken along with a control and uncontrolled group in three replicates, it was noticed that larval motility was dose dependent; as the dose concentration increases the mortality also increases. With the view to discourage further aggravation of environmental pollution through the use of synthetic insecticides, it is imperative to explore the abundant natural plant resources and replace the intrinsically hazardous chemicals through natural plant products not only to combat malaria but also precious human life from the ill effects of the synthetic chemicals.

  20. Synergistic Activity Between S-Layer Protein and Spore-Crystal Preparations from Lysinibacillus sphaericus Against Culex quinquefasciatus Larvae.

    Science.gov (United States)

    Lozano, Lucía C; Dussán, Jenny

    2017-03-01

    Lysinibacillus sphaericus is used for the biological control of mosquitoes. The main toxicity mechanism of pathogenic strains is a binary toxin produced during sporulation. S-layer is a proteinaceous structure on the surface of bacteria; its functions have been involved in the interaction between bacterial cells and the environment, for example, as protective coats, surface recognition, and biological control. In L. sphaericus, S-layer protein (SlpC) is expressed in vegetative cells, and is also found in spore-crystal preparations; it has larvicidal activity in Culex spp. In this study, partial and completed sporulated culture toxicities were compared; also, S-layer protein and spore-crystal proteins were tested against Culex quinquefasciatus larvae for possible interactions. Larvicidal activity obtained with a combination of SlpC and spore-crystal proteins from strain III(3)7 showed no significant interaction, whereas, combinations of both preparations from strain 2362 showed synergistic effect. The highest synergistic activity observed was between spore protein complex from strain 2362 and SlpC from III(3)7. S-layer protein could be considered a good alternative in formulation improvement, for biological control of mosquitoes.

  1. Influence of light and habitat on predation of Culex quinquefasciatus (Diptera: Culicidae) larvae by the waterbugs(Hemiptera: Heteroptera)

    Institute of Scientific and Technical Information of China (English)

    Nabaneeta Saha; Gautam Aditya; Animesh Bal; Goutam K. Saha

    2008-01-01

    The influence of light and habitat structure on the predation of Culex quinquefasciatus larvae by the common heteropteran water bug, Diplonychus (= Sphaerodema)annulatus, D. rusticus and Anisops bouvieri was assessed in the laboratory. It was revealed that water bugs predate more in presence of light than in dark conditions. While A. bouvieri consumed more prey in structured conditions, D. annulatus and D. rusticus consumed more prey in open conditions. The selection of prey size as well as the respective numbers varied between predators and treatments significantly. Prey vulnerability (PV), an indicator of predatory efficiency, was highest for D. annulatus, moderate for D. rusticus and low forA.bouvieri. Prey consumption and PV values under different treatment conditions indicate that for belostomatid water bugs D. annulatus and D. rusticus, the order of prey consumption under different habitat and light/dark combinations is light open > dark open > light vegetated > dark vegetated. In the case of the backswimmer, A. bouvieri, the order of prey consumption appeared to be light structured > dark structured > light open > dark open. These findings were consistent with resource-partitioning by water bug species sharing the same guild. If the observed results are extended to natural settings the efficiency of these predators in controlling mosquito populations will vary with the structural complexity of habitats and the intensity of light.

  2. Some observations on overwintering sites of adult Culex quinquefasciatus (Diptera: Culicidae) and strategies followed under natural and seminatural conditions.

    Science.gov (United States)

    Thareja, V; Singh, Rangoli; Singha Naorem, Anjana

    2016-01-01

    Field population of adult Culex quinquefasciatus Say, landed in December, congregated and overwintered in indoor artificial sites in Delhi. Repeated sampling strategy by individually collecting the adults was adopted to study their overwintering strategies for 4 years (December to April). They remained vagile and readily repopulated the resting sites after the removal of samples. A large percentage of females was fertile, unfed and nulliparous indicating that reproduction ceased in them. Adult survival was significantly prolonged to a maximum of 3 months under natural conditions. Gonotrophic cycle also got prolonged. Close to quitting, they became gravid and left in April without oviposition. No adults were observed on the sites for the rest of the year. Oviposition was induced in the blood-engorged females when provided with food, water and outdoor conditions. Oviposition might have been induced directly by water and food provided them energy under seminatural conditions. Eggs were laid singly or in the form of rafts, and the number in both the cases was low. Singly laid eggs did not hatch, and in rafts, hatching was ~80 %. Winter conditions seemed to strongly impact fertility, blood feeding, fecundity, oviposition behaviour, egg hatchability and longevity. Use of the overwintering sites as biological tool, as a part of environmental control in IPM, is suggested for organising antivector measures during winter. There is a need of exploring and creating more sites of this kind.

  3. A FIELD CONTROL TRIAL OF CULEX QUINQUEFASCIATUS LARVAE BY POLYMER FORMULATIONS OF OMS-786 AND OMS-971 IN JAKARTA

    Directory of Open Access Journals (Sweden)

    IG. Seregeg

    2012-09-01

    Full Text Available Suatu uji coba lapangan penggunaan larvisida OMS-971a (chlorpyrifos dan OMS-786b (temephos dalam formulasi lepas terkendali (controlled release formulation = CRF terhadap larva Culex quinquefasciatus telah dilakukan dalam selokan-selokan di Kampung Sunter, Jakarta Utara. Tidak ada penurunan yang nyata baik kerapatan larva maupun kerapatan pupa, segera setelah penebaran larvisida tersebut dalam dosis 1 ppm. Akan tetapi penurunan kerapatan larva baru terlihat selama satu sampai dua bulan sesudah penebaran. Pada penelitian ini chlorpyrifos terlihat sedikit lebih berpengaruh (effective dibandingkan dengan temephos. Pengaruh dari temephos" sa'nd granules" sebagai formulasi pem­banding hanya berlangsung paling lama satu minggu, pada penggunaan dosis sebesar lppm. Keadaan dasar selokan dengan endapan lumpur yang tebal diperkirakan telah melumpuhkan daya kerja temephos SG, yang langsung tenggelam ke dasar selokan setelah penebaran. Hal ini berbeda dengan formulasi chlorpyrifos dan temephos yang bersifat lepas terkendali (CRF, berada dalam suatu keadaan yang tetap mengapung di atas permukaan air. Chlorpyrifos dapat memberikan daya kendali terhadap larva sebesar 70 - 94% pada minggu ke 5-8 dan terhadap pupa sebesar 87% pada minggu ke 6 dan 92% pada minggu ke 7. Temephos CRF memberikan daya kendali terhadap larva sebesar 90-96 % pada minggu ke 4-8 dan menurun menjadi 75-96% pada minggu ke 8-9.

  4. Report on the surveillance of insecticidal resistance of Culex pipiens pallens in Hanzhuang%微山湖区韩庄镇淡色库蚊抗药性现状监测报告

    Institute of Scientific and Technical Information of China (English)

    赵方明; 杨秋兰

    2011-01-01

    Culex pipiens pallens was collected from the Weishan Lake district and its insecticidal resistance was measured using a standard WHO bioassay. Cx. Pipiens pallens of Hanzhuang was resistant to five insecticides to some degree. The LC50 of Cx. Pipiens pallens to propoxur, DDVP, acetofenate, deltamethrin, and cypermethrin was 0. 474 1, 1. 401 2, 0. 242 0, 0. 003 4, and 0. 004 1 mg · L-1 , respectively. Cx. Pipiens pallens was most resistant to synthetic py-rethroid pesticides.%采用WHO生物测试法,测定了微山湖区韩庄镇淡色库蚊幼虫对常用杀虫剂的抗性水平.结果 显示韩庄镇淡色库蚊幼虫对残杀威、DDVP、三氯杀虫酯、溴氰菊酯、氯氰菊酯等5种常用杀虫剂的LC5.分别为0.474 1、1.401 2、0.242 0、0.003 4和0.004 1 mg· L-1,以菊酯类杀虫剂抗性最高.

  5. 淡色库蚊对3种化学杀虫剂交互抗性的实验研究%Experimental study on cross-resistance of Culex pipiens pallens to 3 kinds of chemical pesticides

    Institute of Scientific and Technical Information of China (English)

    蒋滨; 李士根; 全芯; 薛庆节; 谭文彬; 刘永春; 王新国; 王怀位

    2014-01-01

    目的:了解淡色库蚊对常用化学杀虫剂的交互抗性,为合理使用化学杀虫剂提供依据。方法采用WHO生物测定方法,检测淡色库蚊敏感品系和抗敌敌畏、抗残杀威、抗氯氰菊酯3种抗性品系IV龄幼虫分别对敌敌畏、残杀威和氯氰菊酯3种化学杀虫剂的抗性。结果淡色库蚊抗敌敌畏品系对敌敌畏、残杀威和氯氰菊酯3种化学杀虫剂的抗性系数分别为14.47、8.96和207.27,抗残杀威品系对上述3种杀虫剂的抗性系数分别为3.27、6.93和8.65,抗氯氰菊酯品系对3种杀虫剂的抗性系数分别为2.93、1.61和501.11。结论长期使用一种化学杀虫剂易产生抗性,并对其他化学杀虫剂产生不同程度的交互抗性。使用杀虫剂时应注意选择药物品种和剂量,以避免和延缓蚊虫抗药性的产生。%Objective To understand the cross-resistance of Culex pipiens pallens to common pesticides,so as to provide the evidence for improving the application of chemical pesticides. Methods The IV instar larvae of DDVP-resistant,propoxur-resistant and cypermethrin-resistant strains as well as the sensitive strain of Culex pipiens pallens were collected to detect the re-sistance to DDVP,propoxur and cypermethrin based on the WHO bioassay method. Results The resistance coefficients of DDVP-resistant strain to DDVP,propoxur and cypermethrin were 14.47,8.96 and 207.27 respectively. The resistance coeffi-cients of propoxur-resistant strain to DDVP,propoxur and cypermethrin were 3.27,6.93 and 8.65 respectively. The resistance coefficients of cypermethrin-resistant strain to DDVP,propoxur and cypermethrin were 2.93,1.61 and 501.11 respectively. Con-clusion The resistance and cross-resistance could be generated during the long-term application of a single kind of chemical pesticide,and we should pay more attention to the varieties and dosages of them.

  6. Mosquito larvicidal potential of silver nanoparticles synthesized using Chomelia asiatica (Rubiaceae) against Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-03-01

    Mosquitoes transmit serious human diseases, causing millions of deaths every year. Mosquito control is to enhance the health and quality of life of county residents and visitors through the reduction of mosquito populations. Mosquito control is a serious concern in developing countries like India due to the lack of general awareness, development of resistance, and socioeconomic reasons. Today, nanotechnology is a promising research domain which has a wide ranging application in vector control programs. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, larvicidal activity of aqueous leaf extract and silver nanoparticles (AgNPs) synthesized using C. asiatica plant leaves against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Cx. quinquefasciatus. The range of varying concentrations of synthesized AgNPs (8, 16, 24, 32, and 40 μg/mL) and aqueous leaf extract (40, 80, 120, 160, and 200 μg/mL) were tested against the larvae of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus. The synthesized AgNPs from C. asiatica were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis (EDX). Considerable mortality was evident after the treatment of C. asiatica for all three important vector mosquitoes. The LC50 and LC90 values of C. asiatica aqueous leaf extract appeared to be effective against An. stephensi (LC50, 90.17 μg/mL; LC90, 165.18 μg/mL) followed by Ae. aegypti (LC50, 96.59 μg/mL; LC90, 173.83 μg/mL) and Cx. quinquefasciatus (LC50, 103.08 μg/mL; LC90, 183.16 μg/mL). Synthesized AgNPs against the vector mosquitoes of An. stephensi, Ae. aegypti, and Cx. quinquefasciatus had the following LC50 and LC90

  7. Evaluation of indoor residual spraying with the pyrrole insecticide chlorfenapyr against pyrethroid-susceptible Anopheles arabiensis and pyrethroid-resistant Culex quinquefasciatus mosquitoes.

    Science.gov (United States)

    Oxborough, R M; Kitau, J; Matowo, J; Mndeme, R; Feston, E; Boko, P; Odjo, A; Metonnou, C G; Irish, S; N'guessan, R; Mosha, F W; Rowland, M W

    2010-10-01

    Chlorfenapyr is a pyrrole insecticide with a unique non-neurological mode of action. Laboratory bioassays of chlorfenapyr comparing the mortality of pyrethroid-susceptible and -resistant Anopheles gambiae s.s. and Culex quinquefasciatus mosquitoes indicated that operational cross-resistance is unlikely to occur (resistance ratio ranged between 0 and 2.1). Three trials of chlorfenapyr indoor residual spraying were undertaken in experimental huts in an area of rice irrigation in northern Tanzania that supports breeding of A. arabiensis. Daily mosquito collections were undertaken to assess product performance primarily in terms of mortality. In the second trial, 250mg/m(2) and 500mg/m(2) chlorfenapyr were tested for residual efficacy over 6 months. Both dosages killed 54% of C. quinquefasciatus, whilst for A. arabiensis 250mg/m(2) killed 48% compared with 41% for 500mg/m(2); mortality was as high at the end of the trial as at the beginning. In the third trial, 250mg/m(2) chlorfenapyr was compared with the pyrethroid alpha-cypermethrin dosed at 30mg/m(2). Chlorfenapyr performance was equivalent to the pyrethroid against A. arabiensis, with both insecticides killing 50% of mosquitoes. Chlorfenapyr killed a significantly higher proportion of pyrethroid-resistant C. quinquefasciatus (56%) compared with alpha-cypermethrin (17%). Chlorfenapyr has the potential to be an important addition to the limited arsenal of public health insecticides for indoor residual control of A. arabiensis and pyrethroid-resistant species of mosquito. Copyright © 2010 Royal Society of Tropical Medicine and Hygiene.

  8. Synthesis of silver and gold nanoparticles using Jasminum nervosum leaf extract and its larvicidal activity against filarial and arboviral vector Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Lallawmawma, H; Sathishkumar, Gnanasekar; Sarathbabu, Subburayan; Ghatak, Souvik; Sivaramakrishnan, Sivaperumal; Gurusubramanian, Guruswami; Kumar, Nachimuthu Senthil

    2015-11-01

    Silver and gold nanoparticles of Jasminum nervosum L. had unique optical properties such as broad absorbance band in the visible region of the electromagnetic spectrum. Characterization of the nanoparticles using UV spectrophotometer, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the particles were silver (AgNPs) and gold (AuNPs) ranging between 4-22 and 2-20 nm with an average particles size of 9.4 and 10 nm, respectively. AgNPs and AuNPs of J. nervosum had high larvicidal activity on the filarial and arboviral vector, Culex quinquefasciatus, than the leaf aqueous extract. Observed lethal concentrations (LC50 and LC95) against the third instar larvae were 57.40 and 144.36 μg/ml for AgNPs and 82.62 and 254.68 μg/ml for AuNPs after 24 h treatment, respectively. The lethal time to kill 50% of C. quinquefasciatus larvae were 2.24 and 4.51 h at 150 μg/ml of AgNPs and AuNPs, respectively, while in the case of aqueous leaf extract of J. nervosum it was 9.44 h at 500 μg/ml (F 2,14 = 397.51, P < 0.0001). The principal component analysis plot presented differential clustering of the aqueous leaf extract, AgNP and AuNPs in relation to lethal dose and lethal time. It is concluded from the present findings that the biosynthesised AgNPs and AuNPs using leaf aqueous extract of J. nervosum could be an environmentally safer nanobiopesticide, and provided potential larvicidal effect on C. quinquefasciatus larvae which could be used for prevention of several dreadful diseases.

  9. Toxicological effects of Sphaeranthus indicus Linn. (Asteraceae) leaf essential oil against human disease vectors, Culex quinquefasciatus Say and Aedes aegypti Linn., and impacts on a beneficial mosquito predator.

    Science.gov (United States)

    Chellappandian, Muthiah; Thanigaivel, Annamalai; Vasantha-Srinivasan, Prabhakaran; Edwin, Edward-Sam; Ponsankar, Athirstam; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Senthil-Nathan, Sengottayan; Benelli, Giovanni

    2017-04-28

    Use of environmentally friendly, decomposable natural products for effective vector control has gained considerable momentum in modern society. In this study, essential oil of Sphaeranthus indicus (Si-EO) was extracted and further phytochemical screening revealed fourteen compounds with prominent peak area percentage of 24.9 and 22.54% in 3,5-di-tert-butyl-4-hydroxybenzaldehyde and benzene,2-(1,1-dimethylethyl)-1,4-dimethoxy, respectively. The Si-EO was further evaluated for their larvicidal response against Culex quinquefasciatus and Aedes aegypti at different dosages (62.5, 125, 250 and 500 ppm). The Si-EO displayed prominent larvicidal activity at higher concentration (500 ppm) against both species of mosquitoes. The LC50 and LC90 values of oils were observed at 130 and 350 ppm against C. quinquefasciatus larvae and at 140 and 350 ppm against A. aegypti larvae, respectively. Repellent bioassay established higher protection rate at 200 ppm up to 120 min against both the mosquitoes. However, adulticidal response displayed higher mortality rate only at 700 and 800 ppm against C. quinquefasciatus and A. aegypti, respectively. Toxicological screening against mosquito predator Toxorhynchites splendens revealed that the Si-EO was harmless even at the concentration of 1500 ppm. Overall, these results suggest that the Si-EO plays a significant role as a new bio-rational product against ecological burden mosquito vectors which provides an eco-friendly alternative to synthetic pesticides.

  10. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms.

    Science.gov (United States)

    Murugan, Kadarkarai; Nataraj, Devaraj; Madhiyazhagan, Pari; Sujitha, Vasu; Chandramohan, Balamurugan; Panneerselvam, Chellasamy; Dinesh, Devakumar; Chandirasekar, Ramachandran; Kovendan, Kalimuthu; Suresh, Udaiyan; Subramaniam, Jayapal; Paulpandi, Manickam; Vadivalagan, Chithravel; Rajaganesh, Rajapandian; Wei, Hui; Syuhei, Ban; Aziz, Al Thabiani; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Canale, Angelo; Benelli, Giovanni

    2016-03-01

    Mosquito-borne diseases represent a deadly threat for millions of people worldwide. The Culex genus, with special reference to Culex quinquefasciatus, comprises the most common vectors of filariasis across urban and semi-urban areas of Asia. In recent years, important efforts have been conducted to propose green-synthesized nanoparticles as a valuable alternative to synthetic insecticides. However, the mosquitocidal potential of carbon nanoparticles has been scarcely investigated. In this study, the larvicidal and pupicidal activity of carbon nanoparticle (CNP) and silver nanoparticle (AgNP) was tested against Cx. quinquefasciatus. UV-Vis spectrophotometry, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, and Raman analysis confirmed the rapid and cheap synthesis of carbon and silver nanoparticles. In laboratory assays, LC50 (lethal concentration that kills 50 % of the exposed organisms) values ranged from 8.752 ppm (first-instar larvae) to 18.676 ppm (pupae) for silver nanoparticles and from 6.373 ppm (first-instar larvae) to 14.849 ppm (pupae) for carbon nanoparticles. The predation efficiency of the water bug Lethocerus indicus after a single treatment with low doses of silver and carbon nanoparticles was not reduced. Moderate evidence of genotoxic effects induced by exposure to carbon nanoparticles was found on non-target goldfish, Carassius auratus. Lastly, the plant extract used for silver nanosynthesis was tested for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. Overall, our results pointed out that AgNP and CNP can be a candidate for effective tools to reduce larval and pupal populations of filariasis vectors, with reduced genotoxicity and impact on behavioral traits of other aquatic organisms sharing the same ecological

  11. Ovicidal and adulticidal potential of leaf and seed extract of Albizia lebbeck (L.) Benth. (Family: Fabaceae) against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Rajeswary, Mohan

    2015-05-01

    Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus, and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. In the present study, hexane, benzene, chloroform, ethyl acetate, and methanol extracts of leaf and seed of Albizia lebbeck were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. One hundred percent mortality was observed at 250, 200, and 150 ppm for leaf methanol extract and 375, 300, and 225 ppm for seed methanol extract of A. lebbeck against C. quinquefasciatus, Ae. aegypti, and An. stephensi, respectively. The adulticidal activity of plant leaf and seed extracts showed moderate toxic effect on the adult mosquitoes after 24 h of exposure period. However, the highest adulticidal activity was observed in the leaf methanol extract of A. lebbeck against An. stephensi where the LC₅₀ and LC₉₀ values were 65.12 and 117.70 ppm, respectively. Compared to leaf extracts, seeds have low potency against three mosquito species. No mortality was recorded in the control. Our data suggest that the crude hexane, benzene, chloroform, ethyl acetate, and methanol solvent extracts of A. lebbeck have the potential to be used as an eco-friendly approach for the control of the An. stephensi, Ae. aegypti, and C. quinquefasciatus. These results suggest that the leaf and seed extracts have the potential to be used as an ideal

  12. Olyset Duo® (a pyriproxyfen and permethrin mixture net: an experimental hut trial against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus in Southern Benin.

    Directory of Open Access Journals (Sweden)

    Corine Ngufor

    Full Text Available BACKGROUND: Alternative compounds which can complement pyrethroids on long-lasting insecticidal nets (LN in the control of pyrethroid resistant malaria vectors are urgently needed. Pyriproxyfen (PPF, an insect growth regulator, reduces the fecundity and fertility of adult female mosquitoes. LNs containing a mixture of pyriproxyfen and pyrethroid could provide personal protection through the pyrethroid component and reduce vector abundance in the next generation through the sterilizing effect of pyriproxyfen. METHOD: The efficacy of Olyset Duo, a newly developed mixture LN containing pyriproxyfen and permethrin, was evaluated in experimental huts in southern Benin against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus. Comparison was made with Olyset Net® (permethrin alone and a LN with pyriproxyfen alone (PPF LN. Laboratory tunnel tests were performed to substantiate the findings in the experimental huts. RESULTS: Overall mortality of wild pyrethroid resistant An. gambiae s.s. was significantly higher with Olyset Duo than with Olyset Net (50% vs. 27%, P = 0.01. Olyset DUO was more protective than Olyset Net (71% vs. 3%, P<0.001. The oviposition rate of surviving blood-fed An. gambiae from the control hut was 37% whereas none of those from Olyset Duo and PPF LN huts laid eggs. The tunnel test results were consistent with the experimental hut results. Olyset Duo was more protective than Olyset Net in the huts against wild pyrethroid resistant Cx. quinquefasciatus although mortality rates of this species did not differ significantly between Olyset Net and Olyset Duo. There was no sterilizing effect on surviving blood-fed Cx. quinquefasciatus with the PPF-treated nets. CONCLUSION: Olyset Duo was superior to Olyset Net in terms of personal protection and killing of pyrethroid resistant An. gambiae, and sterilized surviving blood-fed mosquitoes. Mixing pyrethroid and pyriproxyfen on a LN shows potential for malaria control and

  13. Potential of biologically active plant oils to control mosquito larvae (Culex pipiens, Diptera: Culicidae from an egyptian locality Potencial de óleos de plantas biologicamente ativos para o controle da larva do mosquito Culex pipiens (Diptera: Culicidae de localidade egípcia

    Directory of Open Access Journals (Sweden)

    Hanem Fathy Khater

    2008-04-01

    Full Text Available The insecticidal effect of six commercially available plant oils was tested against 4th larval instars of Culex pipiens. Larvae were originally collected from Meit El-Attar, Qalyubia Governorate, Egypt, and then reared in the laboratory until F1 generation. The LC50 values were 32.42, 47.17, 71.37, 83.36, 86.06, and 152.94 ppm for fenugreek (Trigonella foenum-grecum, earth almond (Cyperus esculentus, mustard (Brassica compestris, olibanum (Boswellia serrata, rocket (Eruca sativa, and parsley (Carum ptroselinum, respectively. The tested oils altered some biological aspects of C. pipiens, for instance, developmental periods, pupation rates, and adult emergences. The lowest concentrations of olibanum and fenugreek oils caused remarkable prolongation of larval and pupal durations. Data also showed that the increase of concentrations was directly proportional to reduction in pupation rates and adult emergences. Remarkable decrease in pupation rate was achieved by mustard oil at 1000 ppm. Adult emergence was suppressed by earth almond and fenugreek oils at 25 ppm. In addition, the tested plant oils exhibited various morphological abnormalities on larvae, pupae, and adult stages. Consequently, fenugreek was the most potent oil and the major cause of malformation of both larval and pupal stages. Potency of the applied plant oils provided an excellent potential for controlling C. pipiens.O efeito inseticida de seis óleos de plantas comercialmente disponíveis foi testado contra larvas de 4ºinstar de Culex pipiens. Larvas foram coletadas originalmente de Meit El-Attar, Qalyubia Governorate, Egito e então cultivadas no laboratório até a geração F1. Os valores LC50 foram 32,42, 47,17, 71,37, 83,36, 86,06 e 152,94 ppm para o feno grego (Trigonella foenum-grecum, amêndoa da terra (Cyperus esculentus, mostarda (Brassica compestris, olíbano (Boswellia serrata, rocket (Eruca sativa e salsa (Carum ptroselium, respectivamente. Os óleos testados alteraram

  14. Evaluación del triflumurón y la mezcla de Bacillus thuringiensis más Bacillus sphaericus para el control de las formas immaduras de Aedes aegypti y culex quinquefasciatus en sumideros en Cali, Colombia

    OpenAIRE

    Pérez Flórez, Mauricio; Giraldo Calderón, Gloria I.; Morales, Carlos A.; Ocampo, Clara Beatriz

    2008-01-01

    Introducción. En Cali los sumideros son uno de los principales criaderos de Aedes aegypti y Culex quinquefasciatus que son controlados por la Secretaría de Salud Municipal utilizando el insecticida triflumurón desde 1999. Se sospecha falla al tratamiento. Objetivos. Evaluar la eficacia del Starycide® (triflumurón) y VectoMax® (mezcla bacteriana de Bacillus thuringiensis var. israelensis y Bacillus sphaericus) en el control de A. aegypti y C. quinquefasciatus en los sumideros y ...

  15. Toxicity of seaweed-synthesized silver nanoparticles against the filariasis vector Culex quinquefasciatus and its impact on predation efficiency of the cyclopoid crustacean Mesocyclops longisetus.

    Science.gov (United States)

    Murugan, Kadarkarai; Benelli, Giovanni; Ayyappan, Suganya; Dinesh, Devakumar; Panneerselvam, Chellasamy; Nicoletti, Marcello; Hwang, Jiang-Shiou; Kumar, Palanisamy Mahesh; Subramaniam, Jayapal; Suresh, Udaiyan

    2015-06-01

    Nearly 1.4 billion people in 73 countries worldwide are threatened by lymphatic filariasis, a parasitic infection that leads to a disease commonly known as elephantiasis. Filariasis is vectored by mosquitoes, with special reference to the genus Culex. The main control tool against mosquito larvae is represented by treatments with organophosphates and insect growth regulators, with negative effects on human health and the environment. Recently, green-synthesized nanoparticles have been proposed as highly effective larvicidals against mosquito vectors. In this research, we attempted a reply to the following question: do green-synthesized nanoparticles affect predation rates of copepods against mosquito larvae? We proposed a novel method of seaweed-mediated synthesis of silver nanoparticles using the frond extract of Caulerpa scalpelliformis. The toxicity of the seaweed extract and silver nanoparticles was assessed against the filarial vector Culex quinquefasciatus. Then, we evaluated the predatory efficiency of the cyclopoid crustacean Mesocyclops longisetus against larval instars of C. quinquefasciatus in a nanoparticle-contaminated water environment. Green-synthesized silver nanoparticles were characterized by UV-vis spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In mosquitocidal assays, the LC₅₀ values of the C. scalpelliformis extract against C. quinquefasciatus were 31.38 ppm (I), 46.49 ppm (II), 75.79 ppm (III), 102.26 ppm (IV), and 138.89 ppm (pupa), while LC₅₀ of silver nanoparticles were 3.08 ppm, (I), 3.49 ppm (II), 4.64 ppm (III), 5.86 ppm (IV), and 7.33 ppm (pupa). The predatory efficiency of the copepod M. longisetus in the control treatment was 78 and 59% against I and II instar larvae of C. quinquefasciatus. In a nanoparticle-contaminated environment, predation efficiency was 84 and 63%, respectively. Predation was higher against first instar larvae over other instars

  16. Ovicidal, larvicidal and adulticidal properties of Asparagus racemosus (Willd.) (Family: Asparagaceae) root extracts against filariasis (Culex quinquefasciatus), dengue (Aedes aegypti) and malaria (Anopheles stephensi) vector mosquitoes (Diptera: Culicidae).

    Science.gov (United States)

    Govindarajan, Marimuthu; Sivakumar, Rajamohan

    2014-04-01

    Several diseases are associated to the mosquito-human interaction. Mosquitoes are the carriers of severe and well-known illnesses such as malaria, arboviral encephalitis, dengue fever, chikungunya fever, West Nile virus and yellow fever. These diseases produce significant morbidity and mortality in humans and livestock around the world. The present investigation was undertaken to study the ovicidal, larvicidal and adulticidal activities of crude hexane, ethyl acetate, benzene, chloroform and methanol extracts of root of Asparagus racemosus were assayed for their toxicity against three important vector mosquitoes, viz., Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi (Diptera: Culicidae). The mean percent hatchability of the eggs was observed after 48 h post-treatment. The percent hatchability was inversely proportional to the concentration of extract and directly proportional to the eggs. All the five solvent extracts showed moderate ovicidal activity; however, the methanol extract showed the highest ovicidal activity. The methanol extract of Asparagus racemosus against Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi exerted 100% mortality (zero hatchability) at 375, 300 and 225 ppm, respectively. Control eggs showed 99-100% hatchability. The larval mortality was observed after 24 h of exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in methanol extract of root of Asparagus racemosus against the larvae of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi with the LC50 and LC90 values were 115.13, 97.71 and 90.97 ppm and 210.96, 179.92, and 168.82 ppm, respectively. The adult mortality was observed after 24 h recovery period. The plant crude extracts showed dose-dependent mortality. At higher concentrations, the adult showed restless movement for some times with abnormal wagging and then died. Among the extracts tested, the highest adulticidal activity was observed in

  17. Larvicidal activity of Ipomoea cairica (L.) Sweet and Ageratina adenophora (Spreng.) King & H. Rob. plant extracts against arboviral and filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae).

    Science.gov (United States)

    Samuel, Lallianrawna; Lalrotluanga; Muthukumaran, Rajendra Bose; Gurusubramanian, Guruswami; Senthilkumar, Nachimuthu

    2014-06-01

    Culex quinquefasciatus Say, an arboviral and filarial vector, is one of the most widespread mosquitoes in the world, and insecticide-resistant populations have been reported worldwide. Due to the emergence of resistance in C. quinquefasciatus plant based products or plant extracts may be alternative sources in integrated vector management program. The present study was carried out to establish the larvicidal activities of crude solvent extracts prepared from flowers and leaves of Ipomoea cairica and Ageratina adenophora against third instar larvae of C. quinquefasciatus as target species. The plant extracts were prepared with petroleum ether, chloroform and methanol solvents using sequential extraction method to determine the best extractant for subsequent isolation and characterization of active ingredient. The total yield of plant extract in the Soxhlet extraction ranged between 0.79% and 19.35%. The qualitative phytochemical study of the plant extracts from different solvents showed the presence of alkaloids, flavonoids, phenols, terpenes, saponins and tannins in different combinations. I. cairica and A. adenophora plant extracts were found to be effective against third instar larvae of C. quinquefasciatus causing 77-100% mortality at 48h. Highest mortality was observed at 500ppm and the order of larvicidal action was observed to be of methanol extract of I. cairica flower>petroleum ether extract of A. adenophora leaf>chloroform extract of I. cairica leaf. High mortality (100%) with low LC50 and LT50 were observed in methanolic flower extract (LC50 - 8.43ppm; LT50 - 2.51h at 48h) of I. cairica, and petroleum ether (LC50 - 133.56ppm; LT50 - 9.45h at 48h) leaf extract of A. adenophora. Lethal concentration (LC50 and LC90) values gradually decreased with the exposure periods, lethal time (LT50 and LT90) decreased with the concentration in bioassay experiment with the crude plant extracts. There was a significant correlation (three-way factorial ANOVA) was noticed

  18. Efficacy studies of Vectobac 12as and Teknar HP-D larvicides against 3rd-instar Ochlerotatus taeniorhynchus and Culex quinquefasciatus in small plot field studies.

    Science.gov (United States)

    Floore, T G; Petersen, J L; Shaffer, K R

    2004-12-01

    Efficacy studies were conducted with VectoBac 12AS and Teknar HP-D larvicides against 3rd-instar Ochlerotatus taeniorhynchus and Culex quinquefasciatus in small field test plots. The products were obtained off the shelf from distributors and had different lot numbers. They were evaluated over a 2-year period in spring 2002 and 2003. Application rates were 0.29, 0.58, and 1.10 liter/ha and evaluations were made 24 and 48 h after treatment. Both products performed well in these studies, with VectoBac 12AS being more effective at the 0.29 liter/ha rate.

  19. Controle de Aedes (Stegomyia aegypti (Linnaeus, 1762 e Culex (Culex quinquefasciatus Say, 1823 através de formulados contendo Bacillus thuringiensis israelensis em temperaturas controladas

    Directory of Open Access Journals (Sweden)

    João Zequi

    2011-11-01

    Abstract. Aedes (Stegomyia aegypti (Linnaeus and Culex (Culex quinquefasciatus Say are important pathogen vectors in urban environments. This study was designed to evaluate commercial formulations containing Bacillus thuringiensis israelensis de Barjac for the control of Ae. aegypti and Cx. quinquefasciatus and to assess their efficiency as compared to manufacturers´ claims. The tested products were the liquid formulation of Aquabac® XT 1200 ITU/mg, Teknar® 3000AAU/mg, and Vectobac® AS 1200 ITU/mg, and the solid products Vectobac® WDG 3000 ITU/mg, Vectobac® Tablet 2200 ITU/mg, and the trial formulation of Biouel 500 ITU/mg. All products were tested at 25±2°C temperature and the liquid formulations were also tested at 15±2°C, 35±2°C, and at room temperature (25.37 to 28.73ºC. The experiments were conducted with 25 larvae at the early 4th stage, in 150 mL of distilled water; the dead larvae were counted 24 hours after product application. Results were analyzed using Probit to calculate CL50. The 25±2°C temperature, Vectobac WDG, and Vectobac Tablet were the most efficient in controlling Ae. aegypti, with CL50 of 0.10 (0.08 – 0.11 mg/L and 0.10 (0.09 – 0.11 mg/L, respectively. The most efficient products for Cx. quinquefasciatus were Vectobac WDG, Vectobac AS, Biouel, and Vectobac T. When the potency claimed by manufacturers was compared to our laboratory results, Biouel had the best performance for both species. Vectobac AS was the most efficient for both species of Culicidae tested at 15±2°C, 35±2°C and at room temperature (25.37 to 28.37°C. Lower product concentrations were required at 35±2°C room temperature to control Cx. quinquefasciatus than for Ae. aegypti.

  20. Evaluation of Pioneer eco-backpack sprayer and Twister XL backpack sprayer using Aqualuer against caged adult Aedes albopictus and Culex quinquefasciatus.

    Science.gov (United States)

    Xue, Rui-De; Qualls, Whitney A; Smith, Mike L; Zhao, Tong-Yan; Brown, James R

    2012-12-01

    A Pioneer Eco-Backpack electric cold ultra-low volume (ULV) sprayer and a gas-powered Twister XL 3950 series 2 motorized knapsack ULV sprayer with Aqualuer (20.6% permethrin AI) were evaluated against caged adult Aedes albopictus and Culex quinquefasciatus in St. Augustine, FL. The Pioneer Eco-Backpack sprayer provided 100% knockdown of both species of mosquitoes at 15 min; the Twister XL backpack sprayer resulted in 17-23% knockdown at 15 min. Both backpack sprayers with Aqualuer resulted in 100% mortality of both species at 24 h. The new Pioneer Eco-Backpack sprayer powered by electricity could be a potential tool for mosquito control.

  1. Contribution of different aquatic habitats to adult Anopheles arabiensis and Culex quinquefasciatus (Diptera: Culicidae) production in a rice agroecosystem in Mwea, Kenya.

    Science.gov (United States)

    Mwangangi, Joseph M; Muturi, Ephantus J; Shililu, Josephat; Muriu, Simon M; Jacob, Benjamin; Kabiru, Ephantus W; Mbogo, Charles M; Githure, John; Novak, Robert

    2008-06-01

    Studies were conducted to determine the contribution of diverse larval habitats to adult Anopheles arabiensis Patton and Culex quinquefasciatus Say production in a rice land agro-ecosystem in Mwea, Kenya. Two sizes of cages were placed in different habitat types to investigate the influence of non-mosquito invertebrates on larval mortalities and the contribution of each habitat type to mosquito productivities, respectively. These emergence traps had fine netting material covers to prevent adult mosquitoes from ovipositing in the area covered by the trap and immature mosquitoes from entering the cages. The emergence of Anopheles arabiensis in seeps, tire tracks, temporary pools, and paddies was 10.53%, 17.31%, 12.50%, and 2.14%, respectively, while the corresponding values for Cx. quinquefasciatus were 16.85% in tire tracks, 8.39% in temporary pools, and 5.65% in the paddies from 0.125 m3 cages during the study. Cages measuring 1 m3 were placed in different habitat types which included paddy, swamp, marsh, ditch, pool, and seep to determine larval habitat productivity. An. arabiensis was the predominant anopheline species (98.0%, n = 232), although a few Anopheles coustani Laveran (2.0%, n = 5) emerged from the habitats. The productivity for An. arabiensis larvae was 6.0 mosquitoes per m2 for the temporary pools, 5.5 for paddy, 5.4 for marsh, 2.7 for ditch, and 0.6 for seep. The Cx. quinquefasciatus larval habitat productivity was 47.8 mosquitoes per m2 for paddies, 35.7 for ditches, 11.1 for marshes, 4.2 for seeps, 2.4 for swamps, and 1.0 for temporary pools. Pools, paddy, and marsh habitat types were the most productive larval habitats for An. arabiensis while paddy, ditch, and marsh were the most productive larval habitats for Cx. quinquefasciatus. The most common non-mosquito invertebrate composition in the cages included Dytiscidae, Notonectidae, Belostomatidae, and Ephemerellidae, and their presence negatively affected the number of emergent mosquitoes from

  2. Early warning of West Nile virus mosquito vector: climate and land use models successfully explain phenology and abundance of Culex pipiens mosquitoes in north-western Italy.

    Science.gov (United States)

    Rosà, Roberto; Marini, Giovanni; Bolzoni, Luca; Neteler, Markus; Metz, Markus; Delucchi, Luca; Chadwick, Elizabeth A; Balbo, Luca; Mosca, Andrea; Giacobini, Mario; Bertolotti, Luigi; Rizzoli, Annapaola

    2014-06-12

    West Nile Virus (WNV) is an emerging global health threat. Transmission risk is strongly related to the abundance of mosquito vectors, typically Culex pipiens in Europe. Early-warning predictors of mosquito population dynamics would therefore help guide entomological surveillance and thereby facilitate early warnings of transmission risk. We analysed an 11-year time series (2001 to 2011) of Cx. pipiens mosquito captures from the Piedmont region of north-western Italy to determine the principal drivers of mosquito population dynamics. Linear mixed models were implemented to examine the relationship between Cx. pipiens population dynamics and environmental predictors including temperature, precipitation, Normalized Difference Water Index (NDWI) and the proximity of mosquito traps to urban areas and rice fields. Warm temperatures early in the year were associated with an earlier start to the mosquito season and increased season length, and later in the year, with decreased abundance. Early precipitation delayed the start and shortened the length of the mosquito season, but increased total abundance. Conversely, precipitation later in the year was associated with a longer season. Finally, higher NDWI early in the year was associated with an earlier start to the season and increased season length, but was not associated with abundance. Proximity to rice fields predicted higher total abundance when included in some models, but was not a significant predictor of phenology. Proximity to urban areas was not a significant predictor in any of our models. Predicted variations in start of the season and season length ranged from one to three weeks, across the measured range of variables. Predicted mosquito abundance was highly variable, with numbers in excess of 1000 per trap per year when late season temperatures were low (average 21°C) to only 150 when late season temperatures were high (average 30°C). Climate data collected early in the year, in conjunction with local land

  3. Larvicidal efficacy of various formulations of Bacillus sphaericus against the resistant strain of Culex quinquefasciatus (Diptera: Culicidae) from southern India.

    Science.gov (United States)

    Subbiah, P; Ramesh, N; Sundaravadivelu, K; Samuel, P; Tyagi, B K

    2009-04-01

    Use of Bacillus sphaericus Neide (Bs) as potential biolarvicide in developing countries is limited due to development of resistance by target mosquitoes. Efforts are taken to look for appropriate formulations or combination of Bs to prevent or delay resistance problem. Here, we report the efficacy of a formulated Bs product to kill Bs resistant Culex quinquefasciatus Say larvae. The laboratory reared resistance colony was maintained by subjecting selection pressure with Bs (2362) toxin. Bioassays were conducted with lyophilized, standard formulated and Bs formulated by us (all belong to strain 2362, serotype H5a5b) against Bs resistant and susceptible colonies. The Bs resistant larvae showed a high level of resistance against lyophilized toxin with resistance ratio (RR) of 8375.2, 1055.6 and 11422.3 folds at LC(50), LC(90) and LC(95) levels, respectively, when compared with Bs susceptible larvae. With formulation of standard powder, the RR between Bs resistant and susceptible larvae were 1.01, 1.13 and 1.19 folds only at LC(50), LC(90) and LC(95) levels, respectively. This observation was comparable with our formulation prepared by a ground mixture of lyophilized Bs and a placebo (plaster of Paris). It is evident from our study, that the placebo present in our Bs 2362 formulation was responsible for increasing the efficacy of Bs lyophilized toxin against resistant larvae. The putative mechanism behind this toxicity phenomenon remains to be investigated to evolve new mosquito control strategies. A cross resistance to indigenous strain of Bs B42 (H5a5b) against Bs resistant larvae was also reported in this study.

  4. Mosquito larvicidal activity of some common spices and vegetable waste onCulex quinquefasciatus andAnopheles stephensi

    Institute of Scientific and Technical Information of China (English)

    Someshwar Singha; Goutam Chandra

    2011-01-01

    Objective:To investigate the larvicidal activities of crude and chloroform: methanol (1:1 v/v) extracts of some common spices (Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa) and vegetable waste (Solanum tuberosum germinated tuber) againstAnopheles stephensiandCulex quinquefasciatus mosquito larvae.Methods:Larval mortality of above mosquito species were observed after 24, 48 and72 h of exposure to five concentrations of aqueous extract (0.1%, 0.2%, 0.3%, 0.4% and0.5%) and four concentrations (25, 50, 75 ppm) of chloroform: methanol (1:1 v/v) extract. The lethal concentration of individual spices or vegetable waste was determined by log-probit analysis (at95%confidence level) and effect of crude and chloroform: methanol (1:1 v/v) extracts were recorded on non target organisms.Results:Relative mortality rate of both larval mosquito species were recorded in the following sequences:Cuminum cyminum>Allium sativum>Zingiber offinale, Curcuma longa > Solanum tuberosum germinated tuber for crude extract, and efficacy of chloroform: methanol (1:1 v/v) extract were as follows:Curcuma longa > Zingiber offinale > Solanum tuberosum germinated tuber >Cuminum cyminum>Allium sativum.Conclusions: Crude and chloroform: methanol (1:1 v/v) extract of Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa andSolanum tuberosum germinated tuber can be recommended effectively in mosquito control programmes at very low concentrations. No mortality and other abnormalities were noticed on non target organisms and further studies are needed to investigate the chemical structure of active principal which are responsible for larvicidal activity.

  5. Infection of malaria (Anopheles gambiae s.s.) and filariasis (Culex quinquefasciatus) vectors with the entomopathogenic fungus Metarhizium anisopliae.

    Science.gov (United States)

    Scholte, Ernst-Jan; Njiru, Basilio N; Smallegange, Renate C; Takken, Willem; Knols, Bart G J

    2003-09-15

    Current intra-domiciliary vector control depends on the application of residual insecticides and/or repellents. Although biological control agents have been developed against aquatic mosquito stages, none are available for adults. Following successful use of an entomopathogenic fungus against tsetse flies (Diptera: Glossinidae) we investigated the potency of this fungus as a biological control agent for adult malaria and filariasis vector mosquitoes. In the laboratory, both sexes of Anopheles gambiae sensu stricto and Culex quinquefasciatus were passively contaminated with dry conidia of Metarhizium anisopliae. Pathogenicity of this fungus for An. gambiae was further tested for varying exposure times and different doses of oil-formulated conidia. Comparison of Gompertz survival curves and LT50 values for treated and untreated specimens showed that, for both species, infected mosquitoes died significantly earlier (p control groups. No differences in LT50 values were found for different exposure times (24, 48 hrs or continuous exposure) of An. gambiae to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 x 10(7) to 1.6 x 10(10) conidia/m2) gave LT50 values of 9.69 +/- 1.24 (lowest dose) to 5.89 +/- 0.35 days (highest dose), with infection percentages ranging from 4.4-83.7%. Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult Anopheles and Culex mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.

  6. Infection of malaria (Anopheles gambiae s.s. and filariasis (Culex quinquefasciatus vectors with the entomopathogenic fungus Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Smallegange Renate C

    2003-09-01

    Full Text Available Abstract Background Current intra-domiciliary vector control depends on the application of residual insecticides and/or repellents. Although biological control agents have been developed against aquatic mosquito stages, none are available for adults. Following successful use of an entomopathogenic fungus against tsetse flies (Diptera: Glossinidae we investigated the potency of this fungus as a biological control agent for adult malaria and filariasis vector mosquitoes. Methods In the laboratory, both sexes of Anopheles gambiae sensu stricto and Culex quinquefasciatus were passively contaminated with dry conidia of Metarhizium anisopliae. Pathogenicity of this fungus for An. gambiae was further tested for varying exposure times and different doses of oil-formulated conidia. Results Comparison of Gompertz survival curves and LT50 values for treated and untreated specimens showed that, for both species, infected mosquitoes died significantly earlier (p 50 values were found for different exposure times (24, 48 hrs or continuous exposure of An. gambiae to dry conidia. Exposure to oil-formulated conidia (doses ranging from 1.6 × 107 to 1.6 × 1010 conidia/m2 gave LT50 values of 9.69 ± 1.24 (lowest dose to 5.89 ± 0.35 days (highest dose, with infection percentages ranging from 4.4–83.7%. Conclusion Our study marks the first to use an entomopathogenic fungus against adult Afrotropical disease vectors. Given its high pathogenicity for both adult Anopheles and Culex mosquitoes we recommend development of novel targeted indoor application methods for the control of endophagic host-seeking females.

  7. Histopathological effects of Aspergillus clavatus (Ascomycota: Trichocomaceae) on larvae of the southern house mosquito, Culex quinquefasciatus (Diptera: Culicidae).

    Science.gov (United States)

    Bawin, Thomas; Seye, Fawrou; Boukraa, Slimane; Zimmer, Jean-Yves; Raharimalala, Fara Nantenaina; Ndiaye, Mady; Compere, Philippe; Delvigne, Frank; Francis, Frédéric

    2016-04-01

    Aspergillus clavatus (Ascomycota: Trichocomaceae) was previously found to be an opportunistic pathogen of mosquitoes (Diptera: Culicidae). In the present study, the mechanism leading to its insecticidal activity was investigated regarding histological damages on Culex quinquefasciatus larvae exposed to A. clavatus spores. Multiple concentration assays using spore suspensions (0.5-2.5 × 10(8) spores ml(-1)) revealed 17.0-74.3 % corrected mortalities after 48 h exposure. Heat-deactivated spores induced a lower mortality compared to nonheated spores suggesting that insecticidal effects are actively exerted. Spore-treated and untreated larvae were prepared for light microscopy as well as for scanning and transmission electron microscopy. Spores failed to adhere to the external body surface (except the mouth parts) of these aquatic immature stages but progressively filled the digestive tract where their metabolism seemed to activate. In parallel, the internal tissues of the larvae, i.e. the midgut wall, the skeletal muscles, and the cuticle-secreting epidermis, were progressively destroyed between 8 and 24 h of exposure. These observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to their necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. A. clavatus enzymes or toxins responsible for these pathogenic effects need to be identified in further studies before any use of this fungus in mosquito control. Copyright © 2016 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  8. Chemical composition and larvicidal activity of essential oil of Origanum majorana (Lamiaceae) cultivated in Morocco against Culex pipiens (Diptera:Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Fouad El-Akhal; Abdelhakim El Ouali Lalami; Yassine Ez Zoubi; Hassane Greche; Raja Guemmouh

    2014-01-01

    Objective:To evaluate the larvicidal activity of essential oil of Origanum majorana (Lamiaceae) cultivated in Morocco against Culex pipiens (Diptera:Culicidae). Methods: The analysis and the identification of the various constituents of essential oil were carried out by gas chromatography coupled with mass spectrometry. Biological test was performed according to a standard methodology inspired by the World Health Organization protocol with slight modification. Results:This oil mainly consisted of monoterpene and sesquiterpenes. The majority compounds are 4-terpinene (28.96%), γ-terpinene (18.57%), α-terpinene (12.72%) and sabinene (8.02%). The lethal concentrations (LC50 and LC90) measured for the essential oil Origanum majorana, were respectively of the order of 258.71 mg/L and 580.49 mg/L.

  9. Induction of cytochrome P450-associated monooxygenases in northern leopard frogs, Rana pipiens, by 3,3',4,4',5-pentachlorobiphenyl

    Science.gov (United States)

    Huang, Y.-W.; Melancon, M.J.; Jung, R.E.; Karasov, W.H.

    1998-01-01

    Northern leopard frogs (Rana pipiens) were injected intraperitoneally either with a solution of polychlorinated biphenyl (PCB) 126 in corn oil at a concentration of 0.2, 0.7, 2.3 and 7.8 mg/kg body weight or with corn oil alone. Appropriate assay conditions with hepatic microsomes were determined for four cytochrome P450-associated monooxygenases: ethoxyresorufin-O-dealkylase (EROD), methoxy-ROD (MROD), benzyloxy-ROD (BROD) and pentoxy-ROD (PROD). One week after PCB administration, the specific activities of EROD, MROD, BROD and PROD were not elevated at doses ? 0.7 mg/kg (p > 0.05), but were significantly increased at doses ? 2.3 mg/kg compared to the control groups (p frogs.

  10. Low levels of the herbicide atrazine alter sex ratios and reduce metamorphic success in Rana pipiens tadpoles raised in outdoor mesocosms.

    Science.gov (United States)

    Langlois, Valérie S; Carew, Amanda C; Pauli, Bruce D; Wade, Michael G; Cooke, Gerard M; Trudeau, Vance L

    2010-04-01

    There are conflicting reports regarding the effects of atrazine (ATZ) on amphibian development. Therefore, further studies are needed to examine the potential mechanisms of action of ATZ in amphibians. Our aim in this study was to determine whether low concentrations of ATZ affect gonadal development and metamorphosis in the Northern leopard frog, Rana pipiens. Tadpoles were exposed in outdoor mesocosms to nominal concentrations of 0.1 and 1.8 microg/L of formulated ATZ from Gosner stage 27 (G27) to metamorphic climax (G42). Exposure to 17alpha-ethinylestradiol (EE2; 1.5 microg/L) provided a positive control for induction of testicular oocytes in males. Endocrine-related gene expression and gonadal histopathology were examined at G42 and in a subset of premetamorphic G34 tadpoles that failed to metamorphose. Gonadal gross morphology revealed that the 1.8-microg/L ATZ treatment produced 20% more females compared with the control. Histologic analysis revealed that 22% of EE2-treated males had testicular oocytes, whereas none were observed in any animals from the control or either ATZ groups. ATZ increased brain estrogen receptor alpha mRNA to 2.5 times that of the control at premetamorphosis and altered liver levels of 5beta-reductase activity at metamorphosis. In contrast, brain aromatase mRNA level and activity did not change. ATZ treatments significantly reduced metamorphic success (number of animals reaching metamorphosis) without affecting body weight, snout-vent length, or age at metamorphosis. Gene expression analysis indicated that ATZ decreased the expression of deiodinase type 3 in the tail at premetamorphosis. Our study indicates that exposure to low concentrations of ATZ in experimental mesocosms alters gonadal differentiation and metamorphosis in developing R. pipiens.

  11. Larvicidal, Biological and Genotoxic Effects, and Temperature-Toxicity Relationship of Some Leaf Extracts of Nerium oleander (Apocynaceae on Culex pipiens (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Shaurub H El-Sayed

    2015-10-01

    Full Text Available  Background: The present study was undertaken to study the larvicidal activity of different extracts of Nerium ole­ander leaves, and post-treatment temperature- toxicity relationship of these extracts against Culex pipiens. Further, the most potent extract was used to evaluate its biological and genotoxic activities. Methods: Crude extracts of N. oleander leaves were prepared using water, chloroform, acetone and diethyl ether as solvents. Extraction was carried out using soxhlet apparatus. Bioassay test was carried out on the larvae, and the LC50 of each extract was determined. Thus, newly hatched first instar larvae were treated, and the mortality count was recorded daily till pupation (accumulated mortality. The LC50 of diethyl ether extract, as the most potent ex­tract, was used for the further biological and genotoxic studies. Results: The results obtained indicated that diethyl ether extract of N. oleander leaves was the most potent extract, with LC50 of 10500 mg/l. The toxicity of the four extracts, using the LC50, at 10 °C was higher than that at 35 °C. The LC50 of diethyl ether extract significantly decreased the larval duration, pupal duration, percentage of pupation, percentage of adult emergence, longevity of females, fecundity, and oviposition activity index, whereas the growth index and the percentage of development per day of larvae and pupae were significantly increased compared to non-treated insects. Moreover, treatment with this extract induced significant dominant lethality in both male and female adults.  Conclusion: It appears that diethyl ether extract of N. oleander leaves is potential control agent to Cx. pipiens

  12. The effect of predatory fish exudates on the ovipostional behaviour of three mosquito species: Culex quinquefasciatus, Aedes aegypti and Culex tarsalis.

    Science.gov (United States)

    Van Dam, A R; Walton, W E

    2008-12-01

    Three mosquito species, Culex tarsalis Coquillett, Culex quinquefasciatus Say and Aedes aegypti L. (Diptera: Culicidae), were examined in laboratory binary choice experiments to investigate whether fish exudates from the mosquitofish, Gambusia affinis (Baird & Girard) (Cyprinodontiformes: Poecilliidae), deter oviposition and whether the responses of these mosquito species to fish exudates in oviposition sites are consistent with the risk of predation from fish experienced by each species in their respective natural breeding habitats. Culex tarsalis was deterred significantly from egg laying by the presence of fish exudates in oviposition cups, consistent with high levels of predation by fish in natural breeding sites. Egg laying by Cx quinquefasciatus was slightly reduced in water with fish exudates, but was not consistently deterred by water conditioned by mosquitofish, consistent with the species' relatively low risk of fish predation in natural habitats. Oviposition by container-breeding Ae. aegypti was not deterred by the presence of fish exudates in oviposition cups, consistent with a low risk of predation by fish in natural habitats.

  13. Efficacy of seed extracts of Annona squamosa and Annona muricata (Annonaceae) for the control of Aedes albopictus and Culex quinquefasciatus (Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Fara Nantenaina Raharimalala; Beby Rasoahantaveloniaina; Pierre Herv Ravelonandro; Patrick Mavingui

    2014-01-01

    Objective: To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex quinquefasciatus under laboratory conditions. Methods:Aqueous and oil extracts of the two plants were prepared from dried seeds. Preliminary identifications of the chemical components of each seed extracts were performed using micro-reactional and GCP techniques. Larvae and adults of Aedes albopictus and Culex quinquefasciatus were collected from the breeding sites in coastal and highlands regions of Madagascar. WHO standardized tests of susceptibility for larvae and imaginal stage of mosquitoes were realized to determine mortality and LC50 of mosquitoes. Results: Chemical identifications showed that these extracts contain alkaloids and flavonoids compounds that probably confer their biological insecticidal proprieties. CPG analysis showed also the presence of various fatty acids. On adult mosquitoes, significant insecticidal effects were observed with both aqueous and oil extracts of the two plant seeds compared to mortality induced by deltamethrin, an insecticide used as reference. Extracts of Annona muricata induced high mortality rate to both species of mosquito compared to extracts of Annona squamosa at all concentrations tested. The LC50 of seed extracts ranged from 1% to 5% for adults and 0.5% to 1% for larvae. Conclusions: The seed extracts of these two plants may be used as mosquito controlling agents and offer a new approach to a less costly, practical and environmentally friendly control of vector borne diseases.

  14. UPAYA AWAL PENGEMBANGAN MANAJEMEN VEKTOR MELALUI KAJIAN PEMANFAATAN JENTIK NYAMUK PENGGANGGU PEMUKIMAN DATARAN RENDAH (Culex quinquefasciatus SEBAGAI MAKANAN lKAN

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    I. G. Seregeg

    2012-11-01

    Full Text Available A field trial to create an initial effort of vector management through investigating the benefit of "household disturbance mosquito" larvae (Culex quinquefasciatus as fish fodder was conducted during May, June, July, 2002 in Jakarta. Method of study involves the use of 2 aquariums, each 76 cm long, 41 cm wide and 41 cm height. They were placed in a partially opened room of which its east side was surrounded with ornamental plants providing fresh air and protecting them from heat of the sun. Each aquarium was also equipped with electrical circulating water pump and 2 cm plastic gauge filter. Ten golden fish babies (Cyprinus carpio were filled in each of the aqurium. Those fish babies (10 in each aquarium were grown through different fish fodder, one with conventional fodder and the other with mosquito larvae. Result showed that after 3 months the average weight of fish was significantly different, the ones fed with mosquito larvae were heavier than those of conventional feeder.   Keywords: Culex quinquefasciatus, vector management, larvae

  15. Anti-juvenile activity of Azadirachta indica extract on the development and morphometry of filaria vector, Culex quinquefasciatus (Diptera: Culicidae) Say.

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    Sharma, Preeti; Mohan, Lalit; Srivastava, Chand N

    2009-10-01

    Efficacy of extracts of Ageratum conyzoides, Argemone mexicana, and Azadirachta indica were tested against Culex quinquefasciatus larvae. Petroleum ether extracts of A. conyzoides and A. mexicana with LC(50) values 425.60 and 267.90 ppm and 140.15 and 137.70 ppm after a period of 24 and 48 h, respectively, were found effective. However, the methanol extract of A. indica with LC(50) values 21.95 and 11.30 ppm after 24 and 48 h of exposure, respectively, was the most competent larvicide. The methanol extract of A. indica, being the most potent extract was therefore studied for its impact on the developmental scenario of the mosquito. It had a significant effect on the life cycle of the vector, C. quinquefasciatus. Hatching was delayed and its rate was reduced compared to control. Larval and pupal development was arrested resulting in decreased pupal transformation and adult emergence. Larval and pupal periods were prolonged with appearance of larval-pupal and pupal-adult intermediates, with an overall increase in the developmental period. Disrupted egg shells, dechitinized body walls, and distorted intestines were observed, indicating clearly the anti-juvenile potential of the extract. The growth index was considerably reduced.

  16. Strong larvicidal activity of three species of Spilanthes (Akarkara) against malaria (Anopheles stephensi Liston, Anopheles culicifacies, species C) and filaria vector (Culex quinquefasciatus Say).

    Science.gov (United States)

    Pandey, Vibha; Agrawal, Veena; Raghavendra, K; Dash, A P

    2007-12-01

    A system for biocontrol of malaria and filarial mosquito vectors has been developed using herbal extracts of three Spilanthes species, S. acmella L.var oleraceae Clarke, S. calva L. and S. paniculata Wall ex DC. Cent percent mortalities was achieved against the late third/early fourth instar larvae of A. stephensi Liston, A. culicifacies species C and C. quinquefasciatus Say using crude hexane extract obtained from flower heads of Spilanthes spp. Of the three plant species, S. acmella extract proved to be the most effective in inducing complete lethality at minimum doses, the respective LC50 and LC90 values being 4.57 and 7.83 (A. stephensi), 0.87 and 1.92 (A. culicifacies) and 3.11 and 8.89 ppm (C. quinquefasciatus). This was followed by S. calva and S. paniculata extracts, respectively. This is the first report of achieving cent percent lethality against these mosquito larvae using minimal doses of plant extracts from this or any other plant species.

  17. Toxicity of pirimiphos methyl (Actellic 25EC) on Anopheles gambiae s.s., Culex quinquefasciatus (Diptera: Culicidae), and potential biocontrol agent, Poecilia reticulata (Pisces: Poeciliidae).

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    Anogwih, Joy A

    2014-08-01

    The toxicity of an emulsifiable formulation of pirimiphos methyl (Actellic 25EC) on Anopheles gambiae s.s. Giles, Culex quinquefasciatus Say (Diptera: Culicidae), and predator fish Poecilia reticulata Peters (Pisces: Poeciliidae) was investigated. Acute toxicity tests were carried out to determine the effect of the larvicide on mosquito larvae and fish species. To investigate the nontarget effects on P. reticulata, fish of similar size (3.5 +/- 0.2 cm) were randomly selected and exposed for 28 d, under static renewal bioassay, to sublethal concentrations of the larvicide capable of killing 30 and 70% of Cx. quinquefasciatus. The 24 h LC50 value of pirimiphos methyl on the test organisms ranged between 20.44 and 697.30 microg liter(-1). The ultrastructural changes observed in the intestinal cells of P. reticulata were characterized by degenerating cell membranes with gradual loss of gray area in pycnotic nucleus at lower concentration. Marked damage was found at higher concentration including distinct loss of gray areas in cytosol, absence of cristae, numerous ruptures, and several dead cells. Pirimiphos methyl was toxic to a predatory fish species, and for its relevance in vector control and crop protection, warrants cumulative assessment to establish its comprehensive ecological risk, and the dosage required for field larviciding.

  18. Bioefficacy of a long-lasting insecticide impregnated net on blood feeding inhibition of Anopheles maculatus Theobald and Culex quinquefasciatus Say.

    Science.gov (United States)

    Beng, Tan Swee; Vythilingam, Indra; Lim, Lee Han

    2014-05-01

    This study aimed to evaluate the bioefficacy and blood feeding inhibition of mosquitoes under laboratory conditions using the WHO tunnel test method on unwashed and washed long-lasting insecticide impregnated net with extrinsic heat treatment of 30 degrees C followed by 80 degrees C on the same net during washing. PermaNet exhibited fairy high durability to washing (5 washes) and had fairy long-lasting bioefficacy against Anopheles maculatus for blood feeding inhibition on both unwashed (39 months) and washed (26 months) nets. However, Perma-Net exhibited lower bioefficacy against Culex quinquefasciatus. This study also suggested that the application of extrinsic heat treatment of 30 degrees C followed by an increased heat at 80 degrees C on the same net exerted significant differences (p 0.05). An. maculatus exhibited significant differences in resting preference after a successful blood meal, as more blood-fed and live females preferred to rest and stay near the bait in the mouse cage, and more dead and unfed females were found in the outer cage of both the unwashed and washed nets (p < 0.05). Conversely, fully blood-fed and live Cx. quinquefasciatus females did not show any resting preference between the mouse cage and outer cage, but there were more dead and unfed females in the mouse cage of both the unwashed and washed nets (p < 0.05).

  19. Green synthesis of silver nanoparticles using Sida acuta (Malvaceae) leaf extract against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae).

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    Veerakumar, Kaliyan; Govindarajan, Marimuthu; Rajeswary, Mohan

    2013-12-01

    Mosquitoes act as a vector for most of the life-threatening diseases like malaria, yellow fever, dengue fever, chikungunya fever, filariasis, encephalitis, West Nile Virus infection, etc. Under the Integrated Mosquito Management, emphasis was given on the application of alternative strategies in mosquito control. The continuous application of synthetic insecticides causes development of resistance in vector species, biological magnification of toxic substances through the food chain, and adverse effects on environmental quality and nontarget organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. In the present study, the larvicidal activity of silver nanoparticles (AgNPs) synthesized using Sida acuta plant leaf extract against late third instar larvae of Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti was determined. Range of concentrations of synthesized AgNPs (10, 20, 30, 40, and 50 μg/mL) and aqueous leaf extract (50, 100, 150, 200, and 250 μg/mL) were tested against the larvae of C. quinquefasciatus, A. stephensi and A. aegypti. The synthesized AgNPs from S. acuta leaf were highly toxic than crude leaf aqueous extract in three important vector mosquito species. The results were recorded from UV-Vis spectrum, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis. Larvae were exposed to varying concentrations of aqueous crude extract and synthesized AgNPs for 24 h. Considerable mortality was evident after the treatment of S. acuta for all three important vector mosquitoes. The LC50 and LC90 values of S. acuta aqueous leaf extract appeared to be most effective

  20. Genome analysis of cytochrome P450s and their expression profiles in insecticide resistant mosquitoes, Culex quinquefasciatus.

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    Ting Yang

    Full Text Available Here we report a study of the 204 P450 genes in the whole genome sequence of larvae and adult Culex quinquefasciatus mosquitoes. The expression profiles of the P450 genes were compared for susceptible (S-Lab and resistant mosquito populations, two different field populations of mosquitoes (HAmCq and MAmCq, and field parental mosquitoes (HAmCq(G0 and MAmCq(G0 and their permethrin selected offspring (HAmCq(G8 and MAmCq(G6. While the majority of the P450 genes were expressed at a similar level between the field parental strains and their permethrin selected offspring, an up- or down-regulation feature in the P450 gene expression was observed following permethrin selection. Compared to their parental strains and the susceptible S-Lab strain, HAmCq(G8 and MAmCq(G6 were found to up-regulate 11 and 6% of total P450 genes in larvae and 7 and 4% in adults, respectively, while 5 and 11% were down-regulated in larvae and 4 and 2% in adults. Although the majority of these up- and down-regulated P450 genes appeared to be developmentally controlled, a few were either up- or down-regulated in both the larvae and adult stages. Interestingly, a different gene set was found to be up- or down-regulated in the HAmCq(G8 and MAmCq(G6 mosquito populations in response to insecticide selection. Several genes were identified as being up- or down-regulated in either the larvae or adults for both HAmCq(G8 and MAmCq(G6; of these, CYP6AA7 and CYP4C52v1 were up-regulated and CYP6BY3 was down-regulated across the life stages and populations of mosquitoes, suggesting a link with the permethrin selection in these mosquitoes. Taken together, the findings from this study indicate that not only are multiple P450 genes involved in insecticide resistance but up- or down-regulation of P450 genes may also be co-responsible for detoxification of insecticides, insecticide selection, and the homeostatic response of mosquitoes to changes in cellular environment.

  1. The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa

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    Howard Annabel FV

    2010-09-01

    Full Text Available Abstract Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new

  2. Spatially targeting Culex quinquefasciatus aquatic habitats on modified land cover for implementing an Integrated Vector Management (IVM program in three villages within the Mwea Rice Scheme, Kenya

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    Githure John

    2006-05-01

    Full Text Available Abstract Background Continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and Culex mosquitoes associated with arbovirus transmission and thus guide control intervention. The aim of this study was to determine whether remotely sensed data could be used to identify rice-related Culex quinquefasciatus breeding habitats in three rice-villages within the Mwea Rice Scheme, Kenya. We examined whether a land use land cover (LULC classification based on two scenes, IKONOS at 4 m and Landsat Thematic Mapper at 30 m could be used to map different land uses and rice planted at different times (cohorts, and to infer which LULC change were correlated to high density Cx. quinquefasciatus aquatic habitats. We performed a maximum likelihood unsupervised classification in Erdas Imagine V8.7® and generated three land cover classifications, rice field, fallow and built environment. Differentially corrected global positioning systems (DGPS ground coordinates of Cx. quinquefasciatus aquatic habitats were overlaid onto the LULC maps generated in ArcInfo 9.1®. Grid cells were stratified by levels of irrigation (well-irrigated and poorly-irrigated and varied according to size of the paddy. Results Total LULC change between 1988–2005 was 42.1 % in Kangichiri, 52.8 % in Kiuria and and 50.6 % Rurumi. The most frequent LULC changes was rice field to fallow and fallow to rice field. The proportion of aquatic habitats positive for Culex larvae in LULC change sites was 77.5% in Kangichiri, 72.9% in Kiuria and 73.7% in Rurumi. Poorly – irrigated grid cells displayed 63.3% of aquatic habitats among all LULC change sites. Conclusion We demonstrate that optical remote sensing can identify rice cultivation LULC sites associated with high Culex oviposition. We argue that the regions of higher Culex abundance based on oviposition surveillance sites reflect underlying differences in abundance of larval

  3. Acute larvicidal toxicity of five essential oils (Pinus nigra, Hyssopus officinalis, Satureja montana, Aloysia citrodora and Pelargonium graveolens) against the filariasis vector Culex quinquefasciatus: Synergistic and antagonistic effects.

    Science.gov (United States)

    Benelli, Giovanni; Pavela, Roman; Canale, Angelo; Cianfaglione, Kevin; Ciaschetti, Giampiero; Conti, Fabio; Nicoletti, Marcello; Senthil-Nathan, Sengottayan; Mehlhorn, Heinz; Maggi, Filippo

    2017-04-01

    Mosquito vector control is facing a number of important and timely challenges, mainly due to the rapid development of pesticide resistance and environmental concerns. In this scenario, screening of botanical resources for their mosquitocidal activity may offer effective and eco-friendly tools against Culicidae vectors. Culex quinquefasciatus Say (Diptera: Culicidae) is a vector of lymphatic filariasis and of dangerous arboviral diseases, such as West Nile and St. Louis encephalitis. In this study, the chemical composition of five essential oils obtained from different plants, namely Pinus nigra J.F. Arnold var. italica (Pinaceae), Hyssopus officinalis L. subsp. aristatus (Lamiaceae), Satureja montana L. subsp. montana (Lamiaceae), Aloysia citriodora Palau (Verbenaceae) and Pelargonium graveolens L'Hér (Geraniaceae), was investigated by GC-MS analysis. Furthermore, it was evaluated their acute toxicity on larvae of C. quinquefasciatus. Then, the most effective oils were selected, in order to focus on the potential synergistic and antagonistic effects, testing them in binary mixtures on C. quinquefasciatus larvae. Results showed that the higher effectiveness was obtained by S. montana subsp. montana essential oil (LC50=25.6μL·L(-1)), followed by P. nigra var. italica (LC50=49.8μL·L(-1)) and A. citriodora (LC50=65.6μL·L(-1)), while the other essential oils showed LC50 values higher than 90μL·L(-1). The larvicidal effectiveness can be enhanced by preparing simple binary mixtures of essential oils, such as S. montana+A. citriodora (ratio 1:1), which showed higher larvicidal toxicity (LC50=18.3μL·L(-1)). On the other hand, testing S. montana+P. nigra (1:1) an antagonistic effect was detected, leading to a LC50 (72.5μL·L(-1)) higher than the LC50 values calculated for the two oils tested separately. Overall, our results add useful knowledge to allow the employ of synergistic essential oil blends as effective, cheap and eco-friendly mosquito larvicides.

  4. Atividade predatória de Helobdella triserialis lineata (Hirudinea: Glossiphonidae sobre formas imaturas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae em laboratório Predatory activity of Helobdella triserialis lineata (Hirudinea: Glossiphonidae on immature forms of Aedes ftuviatilis and Culex quinquefasciatus (Diptera: Culicidae in the laboratory

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    Rotraut Anna Gertrud Bohlmann Cônsoli

    1984-10-01

    Full Text Available Foi avaliada a atividade predatória, em laboratório, de Helobdella triserialis lineata (Hirudinea: Glossiphonidae sobre ovos, larvas e pupas de Aedes fluviatilis e Culex quinquefasciatus (Diptera: Culicidae, bem como a influência da presença desses hirudíneos sobre o comportamento de oviposição das fêmeas das duas espécies de mosquitos. Experimentos adicionais foram feitos testando a influência da profundidade da água e da sua salinidade sobre a capacidade predatória dos hirudíneos. Nas condições do experimento, foi observada predação de larvas e pupas, porém não de ovos das duas espécies de dípteros. Número estatisticamente menor de desovas foi depositado por fêmeas de Cx. quinquefasciatus em recipientes que continham hirudíneos, não ocorrendo o mesmo com fêmeas de Ae. fluviatilis. As diferentes profundidades de água testadas não interferiram na atividade predatória de H. t. lineata e somente em concentrações acima de 3% de NaCl essa atividade mostrou-se bastante diminuída.Experiments were conducted to determine the predatory activity of Helobdella triserialis lineata (Hirudinea: Glossiphonidae on eggs, larvae and pupae of Aedes fluviatilis and Culex quinquefasciatus (Diptera: Culicidae in the laboratory, The influence of the leeches on selection, of ovipositing sites by the females of both species of mosquitoes, as well as the role of salinity and water depth in relation to predation were investigated. Larvae and pupae of both species of mosquitoes were efficiently predated, but eggs were not touched. A significantly lower number of eggmasses of Cx. quinquefasciatus were deposited on water containing leeches, but the same did not occur with Ae. fluviatilis. The different depths of water investigated did not interfere with predation and only at concentrations above 3% NaCl was predation considerably diminished.

  5. Development of Wuchereria bancrofti in Culex pipiens L. (Diptera: Culicidae) exposed in the larval instar to sublethal dosages of insecticides and one insect growth regulator and their influence on reproduction of filaria-infected mosquitoes.

    Science.gov (United States)

    Seif, A I; Husseiny, I M; Soliman, B A; Soliman, M A; el-Kady, M A

    1997-12-01

    The effects of exposure of Culex pipiens larvae to sublethel concentrations of larvicides on uptake, development of Wuchereria bancrofti, survival rate and reproduction of filaria-infected mosquitoes were investigated. Fourth instar larvae of Cx. pipiens were exposed to LC40 of the surfactant Triton X-100, the insect growth regulator DPX alone or combined with LC10 of the surfactant and permethrin alone or combined with LC10 of the surfactant. Adults that survived insecticide treatments and controls were infected by allowing them to feed on microfilaremic volunteers. Significant reduction in the uptake of microfilaria was observed in groups treated with Triton X-100 alone or combined either with permethrin or DPX when compared to control. The overall infection and infective rates were significantly reduced in mosquitoes treated with Triton X-100 either alone or combined with permethrin. Treatment with Triton X-100 and DPX prolonged the extrinsic incubation period (EIP) and retarded the development of filarial larvae, while permethrin either alone or combined with Triton X-100 and DPX combined with Triton X-100 shortened the EIP. All larvicides reduced the number of infective larvae (L3)/mosquito and induced deformities among he different parasite stages, especially in mosquitoes treated with combination of permethrin and Triton X-100 or mixture of DPX and Triton X-100 where 36% and 54.9% respectively of L3S were deformed. In treated mosquitoes, a low percentage of L3S was detected in the head and proboscis region while the majority was trapped in the thoracic region. The survival rates of mosquitoes were reduced in cases treated with permethrin, DPX and Triton X-100 while treatment with mixture of DPX and Triton X-100 induced higher rate of mortalities when compared to control. Egg production of filaria- infected Cx. pipiens was significantly reduced in mosquitoes treated with DPX and Triton X-100. It was observed that the addition of Triton X-100 to DPX or to

  6. Ipomoea batatas (Convolvulaceae)-mediated synthesis of silver nanoparticles for controlling mosquito vectors of Aedes albopictus, Anopheles stephensi, and Culex quinquefasciatus (Diptera:Culicidae).

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    Pavithra Bharathi, V; Ragavendran, C; Murugan, N; Natarajan, D

    2016-12-08

    We proposed an effective and eco-friendly control of dengue, malaria, and filariasis-causing vectors. We tested Ipomoea batatas leaves-mediated silver nanoparticles (AgNPs) against first to fourth instar larvae and adults of Aedes albopictus, Anopheles stephensi, and Culex quinquefasciatus at different concentrations. The synthesized AgNPs showed broad spectrum of larvicidal and adulticidal effects after 48 h of exposure. The characterization of synthesized AgNPs was done using various spectral and microscopy analyses. The maximum efficacy was observed in synthesized AgNPs against the adult of Ae. albopictus with the LC50 and LC90 values were 10.069 and 15.657 μg/mL, respectively, followed by others.

  7. A study of population changes in adult Culex quinquefasciatus Say (Diptera: Culicidae) during a mosquito control programme in Dubai, United Arab Emirates.

    Science.gov (United States)

    Holmes, P R

    1986-02-01

    The effectiveness of insecticidal control measures on adult Culex quinquefasciatus Say in Dubai, United Arab Emirates, was examined. Direct treatment of the study site with cypermethrin applied as a fog caused a temporary reduction both in total numbers (males and females) and in the proportion of older females. When cypermethrin was applied as an ultra low volume formulation at dusk and dawn numbers of males were greatly reduced, but numbers of females were not affected. It appears that the adulticiding operations had little overall effect on the total numbers or survival rate of females, or breeding success. The oviposition cycle duration was estimated to be two days, with the survival rate per oviposition cycle calculated as 30%. With these values it is thought unlikely that filariasis would be transmitted in Dubai.

  8. Molecular structure of the prothoracicotropic hormone gene in the northern house mosquito, Culex pipiens, and its expression analysis in association with diapause and blood feeding.

    Science.gov (United States)

    Zhang, Q; Denlinger, D L

    2011-04-01

    We cloned the gene that encodes prothoracicotropic hormone (PTTH) in the northern house mosquito, Culex pipiens, and investigated its expression profile in short-day (diapause-destined) and long-day (nondiapause-destined) individuals from the fourth-instar larval stage to 2 months of adulthood, as well as after a blood meal. The deduced C. pipiens PTTH (Cupip-PTTH) amino acid sequence contains seven cysteines with a specific spacing pattern. Sequence alignment suggests that Cupip-PTTH is 23% identical to Drosophila melanogaster PTTH, but is ≥59% identical to the PTTHs of other mosquitoes. Cupip-PTTH has structural characteristics similar to those of Bombyx mori PTTH and some vertebrate nerve growth factors with cysteine-knot motifs. PTTH transcripts exhibit a daily cycling profile during the final (fourth) larval instar, with peak abundance occurring late in the scotophase. The fourth-larval instar stage is one day longer in short-day larvae than in long-day larvae, resulting in larger larvae and adults. This additional day of larval development is associated with one extra PTTH cycle. No cycling was observed in pupae, but PTTH transcripts were slightly higher in short-day pupae than in long-day pupae throughout much of the pupal stage. PTTH expression persisted at a nearly constant level in diapausing adult females for the first month but then dropped by ∼50%, while expression decreased at the beginning of adulthood in nondiapausing females and then remained at a low level as long as the females were denied a blood meal. However, when nondiapausing females were offered a blood meal, PTTH transcripts rose approximately 7 fold in 2 h and remained elevated for 24 h. A few diapausing females (∼10%) will take a blood meal when placed in close proximity to a host, but much of the blood is ejected and such meals do not result in mature eggs. Yet, elevated PTTH mRNA expression was also observed in diapausing females that were force fed. Our results thus point to

  9. Mosquito nets treated with a mixture of chlorfenapyr and alphacypermethrin control pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes in West Africa.

    Science.gov (United States)

    N'Guessan, Raphael; Ngufor, Corine; Kudom, Andreas A; Boko, Pelagie; Odjo, Abibathou; Malone, David; Rowland, Mark

    2014-01-01

    The effectiveness of insecticide treated nets is under threat across Africa south of the Sahara from the selection of pyrethroid resistance in Anopheles gambiae mosquitoes. To maintain progress against malaria it is necessary to identify alternative residual insecticides for mosquito nets. Mixtures of pyrethroid and insecticides with novel mode of action provide scope for both improved control and management of resistance through concurrent exposure to unrelated insecticides. The pyrrole chlorfenapyr and the pyrethroid alphacypermethrin were tested individually and as a mixture on mosquito nets in an experimental hut trial in southern Benin against pyrethroid resistant An gambiae and Culex quinquefasciatus mosquitoes. The nets were deliberately holed to simulate the effect of wear and tear. The nets treated with the mixture of chlorfenapyr 200 mg/m² and alphacypermethrin 25 mg/m² killed a proportion of An gambiae (77%, 95%CI: 66-86%) significantly greater than nets treated with alphacypermethrin 25 mg/m(2) (30%, 95%CI: 21-41%) but not significantly different from nets treated with chlorfenapyr 200 mg/m² (69%, 95%CI: 57-78%). The nets treated with the mixtures procured personal protection against An gambiae biting(58-62%) by a greater margin than the alphacypermethrin treated net (39%), whereas the chlorfenapyr treated net was not protective. A similar trend in mortality and blood feeding inhibition between treatments was observed in Cx quinquefasciatus to that seen in An. gambiae, although the effects were lower. A mixture of alphacypermethrin with chlorfenapyr applied at 100 mg/m² had an effect similar to the mixture with chlorfenapyr at 200 mg/m². The effectiveness of ITNs against pyrethroid resistant mosquitoes was restored by the mixture: the alphacypermethrin component reduced human-vector contact while the chlorfenapyr controlled pyrethroid-resistant mosquitoes. The complementary action of these unrelated insecticides demonstrates that the combination on

  10. Mosquito larvicidal activity of silver nanoparticles synthesised using actinobacterium, Streptomyces sp. M25 against Anopheles subpictus, Culex quinquefasciatus and Aedes aegypti.

    Science.gov (United States)

    Shanmugasundaram, T; Balagurunathan, R

    2015-12-01

    The present work reports the larvicidal potential of microbially synthesised silver nanoparticles (AgNPs) by using an actinobacterium, Streptomyces sp. M25 isolated from Western Ghats, Tamil Nadu, India. The biomass of Streptomyces sp. was exposed to 1 mM silver nitrate (AgNO3) solution. The synthesis of AgNPs was confirmed by visual inspection followed by instrumental analysis such as UV-vis spectroscopy, fourier transform infrared spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy and transmission electron microscopy (TEM) with selected area electron diffraction. Based on the TEM and XRD analysis, the average size of the AgNPs was determined to be 10-35 nm. The biosynthesised AgNPs exhibited significant larvicidal activity against malarial vector, Anopheles subpictus (LC50 51.34 mg/L and χ (2) value of 8.228), filarial vector, Culex quinquefasciatus (LC50 48.98 mg/L and χ (2) value of 14.307) and dengue vector, Aedes aegypti (LC50 60.23 mg/L and χ (2) value of 4.042), respectively. Similarly, AgNO3 had larvicidal activity against malarial vector, A. subpictus (LC50 42.544 mg/L and χ (2) value of 2.561), filarial vector, C. quinquefasciatus (LC50 44.922 mg/L and χ (2) value of 1.693) and dengue vector, A. aegypti (LC50 39.664 mg/L and χ (2) value of 5.724), respectively. The current study is a rapid, cost effective, eco-friendly and single step approach. The Streptomyces sp. M25 is a newly added source for the synthesis of AgNPs with improved larvicidal activity.

  11. Efficacy of seed extracts of Annona squamosa and Annona muricata(Annonaceae) for the control of Aedes albopictus and Culex quinquefasciatus(Culicidae)

    Institute of Scientific and Technical Information of China (English)

    Lala; Harivelo; Raveloson; Ravaomanarivo; Herisolo; Andrianiaina; Razafindraleva; Fara; Nantenaina; Raharimalala; Beby; Rasoahantaveloniaina; Pierre; Herv; Ravelonandro; Patrick; Mavingui

    2014-01-01

    Objective:To evaluate the potential efficacy of seed extracts of Annona squamosa and Annona muricata used as natural insecticides to control adult and larvae of the vectors Aedes albopictus and Culex quinquefasciatus under laboratory conditions.Methods:Aqueous and oil extracts of the two plants were prepared from dried seeds.Preliminary identifications of the chemical components of each seed extracts were performed using microreactional and GCP techniques.Larvae and adults of Aedes albopictus and Culex quinquefasciatus were collected from the breeding sites in coastal and highlands regions of Madagascar.WHO standardized tests of susceptibility for larvae and imaginal stage of mosquitoes were realized to determine mortality and LC50 of mosquitoes.Results:Chemical identifications showed that these extracts contain alkaloids and flavonoids compounds that probably confer their biological insecticidal proprieties.CPG analysis showed also the presence of various fatty acids.On adult mosquitoes,significant insecticidal effects were observed with both aqueous and oil extracts of the two plant seeds compared to mortality induced by deltamethrin,an insecticide used as reference.Extracts of Annona muricata induced high mortality rate to both species of mosquito compared to extracts of Annona squamosa at all concentrations tested.The LC50 of seed extracts ranged from 1%to 5%for adults and 0.5%to 1%for larvae.Conclusions:The seed extracts of these two plants may be used as mosquito controlling agents and offer a new approach to a less costly,practical and environmentally friendly control of vector borne diseases.

  12. Evaluation of aqueous and ethanol extract of bioactive medicinal plant, Cassia didymobotrya (Fresenius) Irwin & Barneby against immature stages of filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

    Science.gov (United States)

    Nagappan, Raja

    2012-01-01

    Objective To evaluate aqueous and ethanol extract of Cassia didymobotrya leaves against immature stages of Culex quinquefasciatus. Methods The mortality rate of immature mosquitoes was tested in wide and narrow range concentration of the plant extract based on WHO standard protocol. The wide range concentration tested in the present study was 10 000, 1 000, 100, 10 and 1 mg/L and narrow range concentration was 50, 100, 150, 200 and 250 mg/L. Results 2nd instar larvae exposed to 100 mg/L and above concentration of ethanol extract showed 100% mortality. Remaining stages such as 3rd, 4th and pupa, 100% mortality was observed at 1 000 mg/L and above concentration after 24 h exposure period. In aqueous extract all the stages 100% mortality was recorded at 1 000 mg/L and above concentration. In narrow range concentration 2nd instar larvae 100% mortality was observed at 150 mg/L and above concentration of ethanol extract. The remaining stages 100% mortality was recorded at 250 mg/L. In aqueous extract all the tested immature stages 100% mortality was observed at 250 mg/L concentration after 24 h exposure period. The results clearly indicate that the rate of mortality was based dose of the plant extract and stage of the mosquitoes. Conclusions From this study it is confirmed and concluded that Cassia didymobotrya is having active principle which is responsible for controlling Culex quinquefasciatus. The isolation of bioactive molecules and development of simple formulation technique is important for large scale implementation. PMID:23569999

  13. Landscape factors influencing the spatial distribution and abundance of mosquito vector Culex quinquefasciatus (Diptera: Culicidae) in a mixed residential-agricultural community in Hawai'i

    Science.gov (United States)

    Reiter, M.E.; Lapointe, D.A.

    2007-01-01

    Mosquito-borne avian diseases, principally avian malaria (Plasmodium relictum Grassi and Feletti) and avian pox (Avipoxvirus sp.) have been implicated as the key limiting factor associated with recent declines of endemic avifauna in the Hawaiian Island archipelago. We present data on the relative abundance, infection status, and spatial distribution of the primary mosquito vector Culex quinquefasciatus Say (Diptera: Culicidae) across a mixed, residential-agricultural community adjacent to Hawai'i Volcanoes National Park on Hawai'i Island. We modeled the effect of agriculture and forest fragmentation in determining relative abundance of adult Cx. quinquefasciatus in Volcano Village, and we implement our statistical model in a geographic information system to generate a probability of mosquito capture prediction surface for the study area. Our model was based on biweekly captures of adult mosquitoes from 20 locations within Volcano Village from October 2001 to April 2003. We used mixed effects logistic regression to model the probability of capturing a mosquito, and we developed a set of 17 competing models a priori to specifically evaluate the effect of agriculture and fragmentation (i.e., residential landscapes) at two spatial scales. In total, 2,126 mosquitoes were captured in CO 2-baited traps with an average probability of 0.27 (SE = 0.10) of capturing one or more mosquitoes per trap night. Twelve percent of mosquitoes captured were infected with P. relictum. Our data indicate that agricultural lands and forest fragmentation significantly increase the probability of mosquito capture. The prediction surface identified areas along the Hawai'i Volcanoes National Park boundary that may have high relative abundance of the vector. Our data document the potential of avian malaria transmission in residential-agricultural landscapes and support the need for vector management that extends beyond reserve boundaries and considers a reserve's spatial position in a highly

  14. Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study

    Directory of Open Access Journals (Sweden)

    Irish SR

    2008-06-01

    Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.

  15. Aspectos da distribuição de Culex (Culex quinquefasciatus Say (Diptera, Culicidae na região do rio Pinheiros, na cidade de São Paulo, Estado de São Paulo, Brasil Aspects of the distribution of Culex (Culex quinquefasciatus Say (Diptera, Culicidae in the region of the Pinheiros River, in the city of São Paulo, State of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Sirlei Antunes de Morais

    2006-09-01

    Full Text Available A distribuição de Culex (Culex quinquefasciatus Say (1823 ao longo das margens do rio Pinheiros e os principais fatores que levam à proliferação da espécie foram estudados efetuando-se coletas semanais de mosquitos adultos, no período de um ano, em três pontos eqüidistantes às margens do rio. Para as coletas de mosquitos utilizou-se aspirador à bateria, por um período de cinco minutos. Os mosquitos foram identificados, diferenciados segundo o sexo e contados. Para verificação do estado fisiológico, as fêmeas foram separadas em vazias, com sangue e com ovos. Foram coletados 35.684 mosquitos, todos identificados como Cx. quinquefasciatus, sendo 39,4% fêmeas e 60,6% machos. As freqüências tomaram proporções diferentes entre os pontos de coletas e, em uma série temporal. O ambiente impactado do rio Pinheiros representa um excelente criadouro de Cx. quinquefasciatus, confirmado pela ocorrência de picos acentuados na freqüência de mosquitos, com desenvolvimento de forma explosiva e sobreposições entre as gerações, após as chuvas e em épocas de verão.The distribution of Culex (Culex quinquefasciatus Say (1823 along of the margins of the Pinheiros river and the main factors that lead to the proliferation of the species were studied doing weekly collections of adult mosquitoes, in the period of one year, in three equidistant points in the margins of the river. For the collections of mosquitoes battery vacuum cleaner was used, for a period of five minutes. The mosquitoes were identified, differentiated according to the sex and counted. For verification of the physiological state, the females were differentiated in empty, with blood or eggs. A total of 35.684 mosquitoes were captured, all of them were identified as Cx. quinquefasciatus, being 39.4% females and 60.6% males. The frequencies took different proportions between the points of collections and in a temporary series. The damaged environment of the Pinheiros river

  16. Tricaine (MS-222) is a safe anesthetic compound compared to benzocaine and pentobarbital to induce anesthesia in leopard frogs (Rana pipiens).

    Science.gov (United States)

    Cakir, Yavuz; Strauch, Stephen M

    2005-01-01

    Tricaine (MS-222) is used commonly for sedation, immobilization, and anesthesia of poikilothermic animals. The anesthetic efficacy of different concentrations of MS-222 was compared to benzocaine and pentobarbital on the physiological changes, heart rate and ECG (electrocardiogram) parameters in the leopard frog, Rana pipiens. Loss of righting reflex (RR), loss of pain response (NR = nociceptor response) and recovery time were measured. Heart rate and ECG parameters were also tested before and during anesthesia. The time to loss of RR and NR decreased while recovery time markedly increased with the increasing concentration of MS-222. Benzocaine at 200 mg/l induced a rapid anesthesia, but all frogs needed resuscitation. Pentobarbital at 300 mg/l induced a slow anesthesia, however, all of the frogs also needed resuscitation. All anesthetics at the mentioned concentrations decreased heart rate significantly as well as altered the ECG parameters. All anesthetics prolonged the Q-T interval, and MS-222 at 800 mg/l and benzocaine at 200 mg/l were the most effective anesthetic co