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Sample records for budworm helicoverpa assulta

  1. Comparative study on the responses of maxillary sensilla styloconica of cotton bollworm Helicoverpa armigera and Oriental tobacco budworm H. assulta larvae to phytochemicals

    Institute of Scientific and Technical Information of China (English)

    汤德良; 王琛柱; 罗林儿; 钦俊德

    2000-01-01

    Using the electro-physiological technique, the sensory mechanisms of maxillary sensilla styloconica to stimulants and deterrents were explored on two closely related species, the generalist Helicoverpa armigera and the specialist H. assulta. The results showed that: (i) in both species, cells sensitive to sucrose and azadirachtin were mainly in the lateral sensillum styloconicum, and those to inositol were in the medial sensillum styloconicum; (ii) sensitivity of medial sensillum styloconicum in H. assulta to inositol was higher than that in H. armigera; (iii) among 6 tested deterrents, only azadirachtin evoked high impulse discharge from the lateral sensillum styloconicum in both insects; (iv) the deterrents could disturb stimulants evoking impulse discharge from maxillary sensilla styloconica of both species in different degrees: To sucrose evoking impulses on lateral sensillum styloconicum, for H. armigera capsaicin had a strong inhibition and gossypol had a weak inhibition, while for H. assulta tann

  2. Biology and life table studies of the oriental tobacco budworm, Helicoverpa assulta (Lepidoptera: Noctuidae),influenced by different larval diets

    Institute of Scientific and Technical Information of China (English)

    Kai-Yun Wang; Yong Zhang; Hong-Yan Wang; Xiao-Ming Xia; Tong-Xian Liu

    2008-01-01

    Development, survivorship, pupal weight, oviposition, and life table parameters laboratory on an artificial diet, pepper (Capsicumfrutescens L.), and tobacco (Nicotiana tobacum L.). We found that the average developmental time of immature stages was longest on tobacco (36.2 d), intermediate on pepper (34.4 d), and shortest on artificial diet (33.5 d).Immature survival from egg to pupa varied from 31% on tobacco, 43% on pepper, and 74% on artificial diet. Pupal weight ranged from 197.4 mg/pupa on tobacco, 233.1 mg/pupa on pepper and 253.4 mg/pupa on artificial diet. The average numbers of eggs laid by adults reared as larvae on the artificial diet, pepper, or tobacco were 614, 421 and 334 eggs/female,respectively. Numbers of remaining eggs in ovaries of the adult females reared as larvae on the artificial diet, pepper, or tobacco were 16, 26, and 42 eggs/female, respectively. The longevity of adult females developed from larvae reared on the three diets was not significantly different, whereas the longevity of male adults from the larvae reared on artificial diet was longer (16.8 d) than that for males reared on tobacco (13.8 d) and pepper (13.3 d). The intrinsic, finite, gross, and net rates of increase were highest for females reared as larvae on artificial diet, lowest for females emerging from larvae reared on tobacco, and intermediate for females emerging from larvae reared on pepper. Generation times and doubling time of H. assulta were shortest for larvae fed artificial diet, intermediate from larvae reared on pepper, and longest from larvae reared on tobacco. We concluded that the artificial diet was the most suitable larval diet ofH. assulta followed by pepper, and tobacco.

  3. Comparative study on the responses of maxillary sensilla styloconica of cotton bollworm Helicoverpa armigera and Oriental tobacco budworm H. assulta larvae to phytochemicals

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using the electro-physiological technique, the sensory mechanisms of maxillary sensilla styloconica to stimulants and deterrents were explored on two closely related species, the generalist Helicoverpa armigera and the specialist H. assulta. The results showed that: (i) in both species, cells sensitive to sucrose and azadirachtin were mainly in the lateral sensillum styloconicum, and those to inositol were in the medial sensillum styloconicum; (ii) sensitivity of medial sensillum styloconicum in H. assulta to inositol was higher than that in H. armigera; (iii) among 6 tested deterrents, only azadirachtin evoked high impulse discharge from the lateral sensillum styloconicum in both insects; (iv) the deterrents could disturb stimulants evoking impulse discharge from maxillary sensilla styloconica of both species in different degrees: To sucrose evoking impulses on lateral sensillum styloconicum, for H. armigera capsaicin had a strong inhibition and gossypol had a weak inhibition, while for H. assulta tannic acid, gossypol, and tomatine all had strong inhibition except nicotine and capsaicin; to inositol evoking impulses on medial sensilum styloconicum, for H. armigera inhibition of tomatine was strong but that of gossypol was weak; and for H. assulta inhibition of gossypol was strong but that of nicotine was weak.

  4. Hybridization between Helicoverpa armigera and Helicoverpa assulta (Lepidoptera: Noctuidae): development and morphological characterization of F1 hybrids

    NARCIS (Netherlands)

    Zhao, X.C.; Dong, J.F.; Tang, Q.B.; Yan, Q.B.; Celbic, I.; Loon, van J.J.A.; Wang, C.Z.

    2005-01-01

    Reciprocal hybridizations between Helicoverpa armigera (Hubner) and Helicoverpa assulta (Guenee) were studied. The cross between females of H. armigera and males of H. assulta yielded only fertile males and sterile individuals lacking an aedeagus, valva or ostium bursae. A total of 492 larvae of the

  5. Attractiveness of tobacco volatiles induced by Helicoverpa armigera and Helicoverpa assulta to Campoletis chlorideae

    Institute of Scientific and Technical Information of China (English)

    YAN Zengguang; YAN Yunhua; WANG Chenzhu

    2005-01-01

    The attraction of Helicoverpa armigera- and Helicoverpa assulta-induced and mechanical damage-induced tobacco volatiles to Campoletis chlorideae was investigated, and the induced volatiles were analyzed. In windtunnel, C. Chlorideae was strongly attracted by herbivoreinduced tobacco volatiles. Mechanically damaged tobacco leaves, whether treated with caterpillar regurgitant or water, were more attractive to the parasitoid than undamaged tobacco leaves. GC-MS analysis revealed that only 4 compounds were released from undamaged tobacco leaves, whereas 13 compounds were commonly emitted from herbivore-infested and mechanically damaged tobacco leaves. Compound β-pinene was specifically induced by the infestation of H. Armigera, and (Z)-3-hexenal was only induced by the infestation of H. Armigera and H. Assulta, whereas hexyl acetate was only induced by mechanical damage. Tobacco leaves infested by H. Armigera and H. Assulta released larger amounts of volatiles than undamaged tobacco leaves did. Tobacco leaves treated with artificial damage plus caterpil- lars regurgitant or water emitted the same levels of volatiles, which were higher than that emitted by undamaged tobacco leaves. The emission amounts of single compounds were also different between differently treated plants. The differences were large between herbivore-induced and mechanical damage-induced compounds, and small between H. Armigera- and H. Assulta-induced compounds, and among compounds emitted from mechanically damaged plants treated with water or caterpillar regurgitant.

  6. Characterization of the Helicoverpa assulta nucleopolyhedrovirus genome and sequence analysis of the polyhedrin gene region

    Indian Academy of Sciences (India)

    Soo-Dong Woo; Jae Young Choi; Yeon Ho Je; Byung Rae Jin

    2006-09-01

    A local strain of Helicoverpa assulta nucleopolyhedrovirus (HasNPV) was isolated from infected H. assulta larvae in Korea. Restriction endonuclease fragment analysis, using 4 restriction enzymes, estimated that the total genome size of HasNPV is about 138 kb. A degenerate polymerase chain reaction (PCR) primer set for the polyhedrin gene successfully amplified the partial polyhedrin gene of HasNPV. The sequencing results showed that the about 430 bp PCR product was a fragment of the corresponding polyhedrin gene. Using HasNPV partial predicted polyhedrin to probe the Southern blots, we identified the location of the polyhedrin gene within the 6 kb EcoRI, 15 kb NcoI, 20 kb XhoI, 17 kb BglII and 3 kb ClaI fragments, respectively. The 3 kb ClaI fragment was cloned and the nucleotide sequences of the polyhedrin coding region and its flaking regions were determined. Nucleotide sequence analysis indicated the presence of an open reading frame of 735 nucleotides which could encode 245 amino acids with a predicted molecular mass of 29 kDa. The nucleotide sequences within the coding region of HasNPV polyhedrin shared 73.7% identity with the polyhedrin gene from Autographa californica NPV but were most closely related to Helicoverpa and Heliothis species NPVs with over 99% sequence identity.

  7. Testes and chromosomes in interspecific hybrids between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée)

    Institute of Scientific and Technical Information of China (English)

    TANG Qingbo; YAN Yunhua; ZHAO Xincheng; WANG Chenzhu

    2005-01-01

    The interspecific hybridization between Helicoverpa armigera females and Helicoverpa assulta males yielded F1 hybrids (RS), fertile males and sterile individuals with abnormal genitals. The reverse hybridization between H. assulta females and H. armigera males yielded F1 hybrids (SR)――fertile males and fertile females. The morphology of testes and the karyotype of chromosomes of larvae in the hybrids were investigated. Among the 2d old fifth-instar SR larvae, individuals without testes were fertile females and those with testes were fertile males. The length and breadth of testes between SR and parental species were not significantly different (p>0.05). Among the 2d old fifth-instar RS larvae, the testes were observed in all the individuals, but it could be classified into two types. The length and the breadth of testes in Type 1 larvae were not significantly different from those of their parental species (p>0.05), while those in Type 2 were significantly less than those of their parental species (p<0.01). Mitotic metaphase I of brain cells showed the diploid chromosomes number of both reciprocal hybrids was 2n=62, as many as their parents. The haploid number of 31 was confirmed by counts from spermatocytes at meiotic metaphase from SR male larvae and Type 1 larvae of RS. Meiosis was not observed in spermatocytes of Type 2 larvae of RS. Considering the characteristics of adult hybrids of RS, it was concluded that Type 1 individuals in RS were fertile and those of Type 2 were sterile. The sterility of Type 2 individuals in RS is attributed to the abnormity in development of testes and the failing meiosis of spermatocytes. As a result, the normal spermatozoon could not been produced.

  8. [Geostatistical analysis on distribution pattern of the tobacco budworm larva in Enshi, Hubei, China].

    Science.gov (United States)

    Xia, Peng-Liang; Wang, Rui; Tan, Jun

    2014-03-01

    Tobacco budworm (Helicoverpa assulta) larvae feed on tobacco leaves (Nicotiana sp.), resulting in significant loss in tobacco production. Geostatistical method was used to analyze H. assulta spatial patterns and dynamics in this paper. The results showed that, H. assulta larvae appeared 40 days after the tobacco plants transplanting, and reached its peak at the early-mature period. The nested spherical and exponential model was the major model for tobacco budworm larva in the field, suggesting its aggregated distribution. The spatial variability C/(C0 + C) was larger than 0.75, which indicated H. assulta larva had wider structural variation and narrower random variation. There was a massive migration of tobacco budworm larva in the fast-growing stage of tobacco. Its quantity became stable after that, especially at the mature stage of tobacco.

  9. 烟夜蛾血淋巴凝集素活性的研究%Hemagglutination activity of lectins in the hemolymph of Helicoverpa assulta

    Institute of Scientific and Technical Information of China (English)

    张利芬; 白素芬; 李欣

    2013-01-01

    利用血凝法检测烟夜蛾Helicoverpa assulta血淋巴对红细胞的凝集活性和不同发育期凝集素水平,同时选取13种糖进行凝集素糖抑制反应,以明确该凝集素与烟夜蛾发育的关系和糖结合特性.研究结果表明,在烟夜蛾的不同发育期均检测有凝集素,但各龄幼虫及不同日龄蛹的凝集活性存在明显差异,雌蛹凝集素水平高于同日龄的雄蛹,表明凝集素与发育期、虫龄及蜕皮过程有关,且与性别相关.烟夜蛾蛹血淋巴凝集素活性与近缘种棉铃虫H.armigera的相类似,均被D-半乳糖、L-鼠李糖、麦芽糖、乳糖明显抑制;D-葡萄糖、D-果糖、L-岩藻糖和蔗糖等也有抑制作用,但抑制程度不同;L-阿拉伯糖与棉铃虫凝集素的专一性结合更强;N-乙酰葡萄糖胺和L-山梨糖只对棉铃虫凝集素有抑制作用,而对烟夜蛾凝集素无抑制作用,说明这2个近缘种的凝集素不完全相同.%To understand the relationship between lectins and development in H.assulta,and the sugar-binding specificity of H.assulta lectin,Hemagglutination assays were used to determine the hemagglutinating activity (HA) of haemolymph extracted from Helicoverpa assulta to the erythrocytes,and the changes of HA titer during different developmental stages of H.assulta.Meanuhile,thirteen sugars were tested to determine their inhibitory effect on H.assulta lectin.The results showed that lectins were detected during all developmental stages of H.assulta.Hemagglutination activity (HA) titer fluctuated between and within the various developmental stages,particularly in different larval instars and pupal ages,female pupal H.assulta had higher HA titer than their male cohorts.These results indicated that HA of lectins may be related to developmental stage,larval instar and molting process,and was dependent on sex.The carbohydrate binding specificity of the lectins in pupal hemolymph from H.assulta and H.armigera was determined by

  10. The Inheritance of the Pheromone Sensory System in Two Helicoverpa Species: Dominance of H. armigera and Possible Introgression from H. assulta

    Science.gov (United States)

    Xu, Meng; Dong, Jun-Feng; Wu, Han; Zhao, Xin-Cheng; Huang, Ling-Qiao; Wang, Chen-Zhu

    2017-01-01

    Hybridization of sympatric closely related species may sometimes lead to introgression and speciation. The sister species Helicoverpa armigera and Helicoverpa assulta both use (Z)-11-hexadecenal and (Z)-9-hexadecenal as sex pheromone components but in reversed ratios. Female H. armigera and male H. assulta could hybridize and produce fertile male hybrids, which can then backcross with females of the two parent species to get backcross lines in the laboratory. In this study, we compared the olfactory responses to pheromone compounds in the periphery and in the antennal lobes (ALs) of males of the two species, as well as of their hybrids and backcrosses. Single-sensillum recordings were carried out to explore characteristics of male-specific sensilla on the antennae, and in vivo calcium imaging combined with digital 3D-reconstruction was used to describe what happens in the macroglomerular complex (MGC) of the AL. The results show that the population ratio of the two male-specific types of olfactory sensory neurons responding to two sex pheromone components are controlled by a major gene, and that the allele of H. armigera is dominant. Consistently, the study of the representative areas activated by sex pheromone components in the ALs further support the dominance of H. armigera. However, the topological structure of the MGC in the hybrid was similar but not identical to that in H. armigera. All subtypes of male-specific sensilla identified in the two species were found in the male hybrids and backcrosses. Moreover, two new subtypes with broader response spectra (the expanded A subtype and the expanded C subtype) emerged in the hybrids. Based on the inheritance pattern of the pheromone sensory system, we predict that when hybridization of female H. armigera and male H. assulta occurs in the field, male hybrids would readily backcross with female H. armigera, and introgression might occur from H. assulta into H. armigera through repeated backcrossing. PMID:28119570

  11. Molecular Cloning of Diapause Hormone Analog in Helicoverpa assulta%烟实夜蛾类滞育激素基因的分子克隆

    Institute of Scientific and Technical Information of China (English)

    赵静雅; 张天翼; 徐卫华; 康乐

    2002-01-01

    根据烟实夜蛾(Helicoverpa assulta)的性信息素合成激活肽基因序列设计引物,以烟实夜蛾基因组DNA为模板进行PCR扩增,得到665 bp的特异性片段.该片段经过同源比较和活性测定,证实烟实夜蛾的基因组中存在类滞育激素基因.烟实夜蛾的类滞育激素是一个由24个氨基酸组成的神经肽,在第4和第5个氨基酸之间,插入了一个482 bp的内含子.进一步的分析表明,该神经肽在蛹期的食道下神经节中表达.%Diapause hormone (DH) is a neurohormone which is secreted from suboesophageal ganglion and responsi-ble for induction of enbryonic diapause in Bombyx mori. Here, using bioassay, we present evidence that Has-SGNP Ⅰ ,which clearly exhibited diapause egg inducing activity as does Bom-DH, is likely to be DH. We reported the molecularcharacterization of the Helicoverpa assulta diapause hormone analog by polymerase chain reaction. A 665 bp fragment con-taining the entire DH-like gene was isolated and characterized. DH-like gene comprised two exons interspersed by a singleintron, and the consensus sequence for splicing junction is identified at the exon/intron boundary. The result shows thatDH-like gene is localized in the genome of Helicoverpa assulta.

  12. Modified artificial diet for rearing of tobacco budworm, Helicoverpa armigera, using the Taguchi method and Derringer's desirability function.

    Science.gov (United States)

    Assemi, H; Rezapanah, M; Vafaei-Shoushtari, R; Mehrvar, A

    2012-01-01

    With the aim to improve the mass rearing feasibility of tobacco budworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), design of experimental methodology using Taguchi orthogonal array was applied. To do so, the effect of 16 ingredients of an artificial diet including bean, wheat germ powder, Nipagin, ascorbic acid, formaldehyde, oil, agar, distilled water, ascorbate, yeast, chloramphenicol, benomyl, penicillin, temperature, humidity, and container size on some biological characteristics of H. armigera was evaluated. The selected 16 factors were considered at two levels (32 experiments) in the experimental design. Among the selected factors, penicillin, container size, formaldehyde, chloramphenicol, wheat germ powder, and agar showed significant effect on the mass rearing performance. Derringer's desirability function was used for simultaneous optimization of mass rearing of tobacco budworm, H. armigera, on a modified artificial diet. Derived optimum operating conditions obtained by Derringer's desirability function and Taguchi methodology decreased larval period from 19 to 15.5 days (18.42 % improvement), decreased the pupal period from 12.29 to 11 days (10.49 % improvement), increased the longevity of adults from 14.51 to 21 days (44.72 % improvement), increased the number of eggs/female from 211.21 to 260, and increased egg hatchability from 54.2% to 72% (32.84 % improvement). The proposed method facilitated a systematic mathematical approach with a few well-defined experimental sets.

  13. 烟夜蛾幼虫中肠Bt Cry1Ac毒素受体蛋白cDNA片段的克隆和序列测定%Molecular Cloning and Sequencing of cDNA Fragment Encoding Bt Cry1Ac Toxin Binding Protein from the Midgut of Helicoverpa assulta Guenée Larva

    Institute of Scientific and Technical Information of China (English)

    安世恒; 郭线茹; 罗梅浩; 蒋金炜; 马继盛

    2005-01-01

    利用RT-PCR技术扩增烟夜蛾(Helicoverpa assulta Guenée)幼虫中肠Bt毒素Cry1Ac受体蛋白APN(N-氨基肽酶,aminopeptidase N,APN)基因片段,克隆和测序结果表明,测序得到的812 bp的片段编码270个氨基酸残基,且该片段在阅读框内.通过同源性分析发现,其核苷酸序列与棉铃虫(H. armigera)、澳洲棉铃虫(H. punctigera)、烟芽夜蛾(H. virescens)、舞毒蛾(Lymantria dispar)、小菜蛾(Plutella xylostella)、印度谷螟(Plodia interpunctella)RC688品系和HD198品系、烟草天蛾(Manduca sexta)和家蚕(Bombyx mori)的Cry1Ac受体蛋白基因的同源性分别为97.0%,90.0%,78.0%,63.5%,55.0%,60.3%,61.2%,55.0%和59.0%.推导的烟夜蛾Cry1Ac受体蛋白基因的氨基酸序列与棉铃虫、烟芽夜蛾、斑实夜蛾、舞毒蛾的氨基酸序列同源性分别为95.6%,81.0%,82.7%和55.7%.该片段编码的氨基酸属于氨肽酶家族,与烟夜蛾对Bt Cry1Ac毒素的抗性有关.

  14. Interpretation of the biological species concept from interspecific hybridization of two Helicoverpa species

    Institute of Scientific and Technical Information of China (English)

    WANG ChenZhu

    2007-01-01

    The biological species concept defines species in terms of interbreeding. Interbreeding between species is prevented by reproductive isolation mechanisms. Based on our results of interspecific hybridization between Helicoverpa armigera and Helicoverpa assulta, reproductive isolation mechanisms of the two species are analyzed. A combination of prezygotic factors (absent sex attraction and physical incompatibility of the genitalia) and postzygotic factors (female absence and partial sterility in F1 hybrids) causes reproductive isolation of the two species. In addition, the role of interspecific hybridization in speciation is discussed.

  15. Expression in antennae and reproductive organs suggests a dual role of an odorant-binding protein in two sibling Helicoverpa species.

    Directory of Open Access Journals (Sweden)

    Ya-Lan Sun

    Full Text Available Odorant-binding proteins (OBPs mediate both perception and release of semiochemicals in insects. These proteins are the ideal targets for understanding the olfactory code of insects as well as for interfering with their communication system in order to control pest species. The two sibling Lepidopteran species Helicoverpa armigera and H. assulta are two major agricultural pests. As part of our aim to characterize the OBP repertoire of these two species, here we focus our attention on a member of this family, OBP10, particularly interesting for its expression pattern. The protein is specifically expressed in the antennae of both sexes, being absent from other sensory organs. However, it is highly abundant in seminal fluid, is transferred to females during mating and is eventually found on the surface of fertilised eggs. Among the several different volatile compounds present in reproductive organs, OBP10 binds 1-dodecene, a compound reported as an insect repellent. These results have been verified in both H. armigera and H. assulta with no apparent differences between the two species. The recombinant OBP10 binds, besides 1-dodecene, some linear alcohols and several aromatic compounds. The structural similarity of OBP10 with OBP1 of the mosquito Culex quinquefasciatus, a protein reported to bind an oviposition pheromone, and its affinity with 1-dodecene suggest that OBP10 could be a carrier for oviposition deterrents, favouring spreading of the eggs in these species where cannibalism is active among larvae.

  16. Commercial production of transgenic Bt insect-resistant cotton varieties and the resistance management for bollworm (Helicoverpa armigera Hubner)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are currently three kinds of transgenic Bt insect-resistant cotton germplasm lines, Shanxi 94-24, Zhongxin 94 and R19, in China. They showed high resistance to the neonate larvae of bollworm (Helicoverpa armigera). Transgenic Bt insect-resistant cotton varieties or hybrids have been bred using the three kinds of germplasm lines as parents. Our researches reveal that there exist different expressions in resistant level at different developmental stages in the three categories of germplasm lines. When neonate larvae are fed with leaves of cotton plant at the seeding stage with less than 10 leaves on the main stem, the mortality of the neonate larvae is 100%, but the resistance level will decline at later season. When Bt gene has been transferred to the cotton genome, it can be steadily transferred to the progeny, the level of resistance to bollworm keeps fundamentally uniform. Such insects as tobacco budworm (Heliothis virencens) in laboratory directive selection are very apt to produce resistance to the Bt insecticidal crystal protein. From the present crop system of cotton region in the Yangtze and Yellow River Valleys, and the expression characteristic of transgenic Bt resistant cotton, we suggest that the resistance to toxin protein in bollworm is not apt to be produced if the transgenic Bt insect-resistant cotton varieties are released and grown in the regions except in the Xinjiang cotton region. The managing strategies to delay or retard the resistance are discussed.

  17. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    Science.gov (United States)

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position.

  18. Battle in the New World: Helicoverpa armigera versus Helicoverpa zea (Lepidoptera: Noctuidae)

    Science.gov (United States)

    2016-01-01

    The corn earworm Helicoverpa zea (Boddie) and the old world bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are allopatric species and occur in important agricultural crops. In maize, both species tend to infest the ear. The introduction of H. armigera in Brazil has created a new scenario, where these Helicoverpa species might cohabit and interact with one another, affecting the prevalence of each species in the agroecosystem, integrated pest management, and insect resistance management. In this study, larval occurrence and proportion of these species in maize was assessed in three regions of Brazil during three crop seasons. Interaction between the species was evaluated in interspecific and intraspecific scenarios under laboratory and field conditions. Helicoverpa zea was predominant in Rio Grande do Sul and the Planaltina, DF (central Brazil). In western Bahia, H. zea was predominant in the first collection, but approximately equal in number to H armigera in the second crop season. Both species exhibit high cannibalism/predation rates, and larval size was the primary factor for larval survival in the interaction studies. Larva of H. zea had higher survival when interacting with H. armigera, indicating that H. zea has an advantage in intraguild interactions with H. armigera in maize. Overall, the results from this study indicate that maize might play a role as a source of infestation or a sink of insecticide or Bt protein unselected H. armigera populations, depending on the H. zea:H. armigera intraguild competition and adult movement in the landscape. PMID:27907051

  19. Interactions between Bacillus thuringiensis and parasitoids of late-instar larvae of the spruce budworm (Lepidoptera: Tortricidae)

    NARCIS (Netherlands)

    Schoenmaker, A.; Cusson, M.; Frankenhuyzen, van K.

    2001-01-01

    We investigated interactions between Bacillus thuringiensis Berliner var. kurstaki and parasitoids that attack late instars of the eastern spruce budworm, Choristoneura fumiferana (Clemens). In a petri-dish arena, females of Tranosema rostrale rostrale (Brishke) (Hymenoptera: Ichneumonidae) were abl

  20. Monitoring Spruce Budworm with Light Traps: The Effect of Trap Position

    Directory of Open Access Journals (Sweden)

    Marc Rhainds

    2014-01-01

    Full Text Available Daily records of adult spruce budworms, Choristoneura fumiferana (Clemens (Lepidoptera: Tortricidae, captured at light traps at multiple locations in New Brunswick in the 1970s, are analyzed in relation to the physical position of light traps (tree canopies or forest clearings. Captures at light traps deployed in tree canopies were 4–400 times greater than those in forest clearings, especially for males. The phenology of captures (median date or duration of flight period did not differ in relation to trap location. Captures of both males and females in tree canopies were highly correlated with egg densities, whereas no significant relationship was observed for either sex in forest clearings. Monitoring programs for spruce budworm adults using light traps should be standardized by deploying traps in tree canopies.

  1. Bollgard cotton and resistance of tobacco budworm (Lepidoptera: Noctuidae) to conventional insecticides in southern Tamaulipas, Mexico.

    Science.gov (United States)

    Terán-Vargas, A P; Rodríguez, J C; Blanco, C A; Martínez-Carrillo, J L; Cibrián-Tovar, J; Sánchez-Arroyo, H; Rodríguez-del-Bosque, L A; Stanley, D

    2005-12-01

    Insecticide susceptibility in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), was determined for 8 yr (1991-2001) with larvae sampled from cotton in southern Tamaulipas, Mexico. Before 1996, when Bollgard cotton expressing the Cry1A(c) delta-endotoxin was introduced into the region, two important patterns were documented. The first was economically significant increases in resistance to certain insecticide groups. The second was occurrence of virtually complete control failures in the field during 1994 and 1995. The largest resistance changes were recorded for the type II pyrethroids cypermethrin and deltamethrin. These products are the most widely used products in the region. Resistance ratios for these products increased up to > 100-fold from 1991 to 1995. After 1996, the resistance levels declined. These findings did not occur with other products of scant use (e.g., permethrin, profenofos, and endosulfan) or low tobacco budworm efficacy coupled to a high use pattern (e.g., methyl parathion). This clear trend toward reversal of resistance to type II pyrethroids can be understood, in part, with respect to two factors: 1) the high adoption rate of transgenic cotton in the region, from 31.2% in the beginning (1996) to approximately 90% in 1998; this has considerably curbed the use of synthetic insecticides, with the attending loss of selection pressure on this pest; and 2) the potential immigration to the region of susceptible tobacco budworms from cultivated and wild suitable hosts as well as from transgenic cotton might have influenced the pest population as a whole. The influence of transgenic cotton on southern Tamaulipas can be more clearly seen by the drastic reduction of insecticide use to control this important pest. Now tobacco budworms in this region are susceptible to type II pyrethroids. Two effective and fundamentally different pest management tools are now available to cotton growers in southern Tamaulipas: transgenic cotton

  2. Survivorship of Helicoverpa zea and Heliothis virescens on cotton plant structures expressing a Bacillus thuringiensis vegetative insecticidal protein.

    Science.gov (United States)

    Bommireddy, P L; Leonard, B R

    2008-08-01

    A series of tests quantified bollworm, Helicoverpa zea (Boddie), and tobacco budworm, Heliothis virescens (F.), larval survival on plant structures of a nontransgenic cotton (Gossypium hirsutum L.), 'Coker 312', and two transgenic cottons expressing Vip3A protein or both Vip3A + CrylAb proteins (VipCot). Vegetative and reproductive structures including terminal leaves, flower bud (square) bracts, whole debracted squares, flower petals, flower anthers, and intact capsules (bolls) were harvested from plants in field plots. Each structure was infested with 2-d-old larvae from one of the two heliothine species. Larvae were allowed to feed for 96 h on fresh tissue. Survivorship at 96 h after infestation was significantly lower on all structures of Vip3A and VipCot cotton lines compared with similar structures of Coker 312. VipCot plant structures generally resulted in lower larval survivorship compared with similar structures of the Vip3A cotton line. H. zea survivorship ranged from 4 to 28% and from 1 to 18% on Vip3A and VipCot plant structures, respectively. H. virescens survivorship ranged from 10 to 43% and from 2 to 12% on Vip3A and VipCot plant structures, respectively. H. virescens survivorship was higher on VIP3A plant structures compared with that for H. zea on similar structures. These differences between species were not observed on plants from the cotton line expressing VipCot proteins. The results for these plant structures demonstrate that the combination of proteins expressed in VipCot cotton lines are more effective than Vip3A cotton lines against this heliothine complex.

  3. GENE CLONE AND SEQUENCE ANALYSIS OF 18S RIBOSOMAL DNA OF HELICOVERPA ASSULTA (GUEN(E)E)%烟夜蛾18S rDNA的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    李海超; 乔奇; 原国辉; 郭线茹; 罗梅浩; 吴少英

    2009-01-01

    利用PCR方法克降得到了烟夜蛾18S rDNA全基因序列,基因全长1904bp;构建了其全长、保守区和非保守区的系统发育树,比较了与其他已知蛾类昆虫18S rDNA全序列的同源性.结果表明,蛾类之间该基因的同源性达到92%以上,利用其多变区构建的发育树更能反映蛾类昆虫的亲缘关系;比较烟夜蛾与棉铃虫的18S rDNA序列发现,两个近缘种之间仅有lO个核苷酸的差异.

  4. Genomics and genetic engineering of Helicoverpa armigera nucleopolyhedroviruses

    NARCIS (Netherlands)

    Chen, X.

    2001-01-01

    The single nucleocapsid nucleopolyhedrovirus (SNPV) of the bollworm Helicoverpa armigera has been extensively used to control this insect around the world, especially in China. However, in order to compete with chemical insecticides - mainly for speed of action -novel approaches are sought to improv

  5. Rapid identification of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) using ribosomal RNA internal transcribed spacer 1

    Science.gov (United States)

    Rapid identification of invasive species is crucial for deploying management strategies to prevent establishment. Recent Helicoverpa armigera (Hübner) invasions and subsequent establishment in some countries of South America has increased the risk of this species invading North America. Differentiat...

  6. Reconstruction of HaSNPV with helicoverpa hormone receptor 3

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to develop a more efficient virus for controlling the cotton bollworm Helicoverpa armigera,Helicoverpa hormone receptor 3 (HHR3), which is involved in the ecdysteroid regulatory pathway, was used to genetically modify wild HaSNPV. HaSNPV-HHR3 budded virus and occlusion body virus were constructed in three steps: preparation of pFastBacHaPhpP10-HHR3 donor plasmid, transposition of HHR3 into the HaBacHZ8 bacmid, and transfection of HzAM1 cells to get HaSNPV-HHR3 virus. HHR3was proved to be expressed in the HaSNPV-HHR3 virus infected HzAM1 cells by immunoblotting. Results of bioassay indicated that the body weight of the HaSNPV-HHR3 infected larvae was lower than the larvae infected with wild virus and uninfected normal larvae, which suggests that HaSNPV-HHR3 delayed larval growth.

  7. Study on the Ultrastructures of Antennal Sensilla in Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    WANG Gui-rong; GUO Yu-yuan; WU Kong-ming

    2002-01-01

    The morphology and structures of antennal sensilla of Helicoverpa armigera are observed under scanning and transmission electron microscopes. Antennae of Helicoverpa armigera are made up of scapus,pedicel and flagellum that the latter consists of 70 - 82 segments. The inner side surface of antenna is cataphracted and most of the antennal sensilla lie on its outer, upper and lower surfaces. Both the antennae of male and female contain five kinds of antennal sensilla, namely, sensillum trichodeum, sensillum basiconicum, sensillum chaeticum, ear-shaped sensillum and sensillum coeloconicum, and the kinds, number and distribution of antennal sensilla of both sexes are similar. There are a large number of serrate cuticular processes on antennal surface, especially on the middle and basic parts of antenna. Sensillum trichodeum and sensillum basiconicum, the main chemical odor receptors on antennae of Helicoverpa armigera, consist of cuticularwall, sheath cells, lymph and dendrites. There are significant differences between the internal structures of the two kinds of sensilla. In sensillum trichodeum, the cuticular-wall is thicker, less lipophilic pore channels and has one or a few dendrites, while in sensillum basiconicum, the cuticular-wall is thinner, abundant lipophilic pore channels and has much more dendrites.

  8. Automated detection and mapping of crown discolouration caused by jack pine budworm with 2.5 m resolution multispectral imagery

    Science.gov (United States)

    Leckie, Donald G.; Cloney, Ed; Joyce, Steve P.

    2005-05-01

    Jack pine budworm ( Choristoneura pinus pinus (Free.)) is a native insect defoliator of mainly jack pine ( Pinus banksiana Lamb.) in North America east of the Rocky Mountains. Periodic outbreaks of this insect, which generally last two to three years, can cause growth loss and mortality and have an important impact ecologically and economically in terms of timber production and harvest. The jack pine budworm prefers to feed on current year needles. Their characteristic feeding habits cause discolouration or reddening of the canopy. This red colouration is used to map the distribution and intensity of defoliation that has taken place that year (current defoliation). An accurate and consistent map of the distribution and intensity of budworm defoliation (as represented by the red discolouration) at the stand and within stand level is desirable. Automated classification of multispectral imagery, such as is available from airborne and new high resolution satellite systems, was explored as a viable tool for objectively classifying current discolouration. Airborne multispectral imagery was acquired at a 2.5 m resolution with the Multispectral Electro-optical Imaging Sensor (MEIS). It recorded imagery in six nadir looking spectral bands specifically designed to detect discolouration caused by budworm and a near-infrared band viewing forward at 35° was also used. A 2200 nm middle infrared image was acquired with a Daedalus scanner. Training and test areas of different levels of discolouration were created based on field observations and a maximum likelihood supervized classification was used to estimate four classes of discolouration (nil-trace, light, moderate and severe). Good discrimination was achieved with an overall accuracy of 84% for the four discolouration levels. The moderate discolouration class was the poorest at 73%, because of confusion with both the severe and light classes. Accuracy on a stand basis was also good, and regional and within stand

  9. The biochemical basis for l-canavanine tolerance by the tobacco budworm Heliothis virescens (Noctuidae)

    Science.gov (United States)

    Melangeli, Coromoto; Rosenthal, Gerald A.; Dalman, Douglas L.

    1997-01-01

    The tobacco budworm, Heliothis virescens (Noctuidae), a destructive insect pest, is remarkably resistant to l-canavanine, l-2-amino-4-(guanidinooxy)butyric acid, an arginine antimetabolite that is a potent insecticide for nonadapted species. H. virescens employs a constitutive enzyme of the larval gut, known trivially as canavanine hydrolase (CH), to catalyze an irreversible hydrolysis of l-canavanine to l-homoserine and hydroxyguanidine. As such, it represents a new type of hydrolase, one acting on oxygen–nitrogen bonds (EC 3.13.1.1). This enzyme has been isolated from the excised gut of H. virescens and purified to homogeneity; it exhibits an apparent Km value for l-canavanine of 1.1 mM and a turnover number of 21.1 μmol·min−1·μmol−1. This enzyme has a mass of 285 kDa and is composed of two subunits with a mass of 50 kDa or 47.5 kDa. CH has a high degree of specificity for l-canavanine as it cannot function effectively with either l-2-amino-5-(guanidinooxy)pentanoate or l-2-amino-3-(guanidinooxy)propionate, the higher or lower homolog of l-canavanine, respectively. l-Canavanine derivatives such as methyl-l-canavanine, or l-canaline and O-ureido-l-homoserine, are not metabolized significantly by CH. PMID:9122181

  10. Data of in vitro synthesized dsRNAs on growth and development of Helicoverpa armigera

    OpenAIRE

    Yojana R. Chikate; Vishal V. Dawkar; Barbole, Ranjit S.; Tilak, Priyadarshini V.; Gupta, Vidya S.; Ashok P. Giri

    2016-01-01

    The data presented in this article is related to the research article “RNAi of selected candidate genes interrupts growth and development of Helicoverpa armigera” (Chikate et al., 2016) [1]. RNA interference (RNAi) is emerging as a potent insect pest control strategy over current methods and their resistance by pest. In this study we tested 15 different in vitro synthesized dsRNAs for gene silencing in Helicoverpa armigera. These dsRNAs were specific against H. armigera enzymes/proteins such ...

  11. Efficacy of Venom from Tentacle of Jellyfish Stomolophus meleagris (Nemopilema nomurai against the Cotton Bollworm Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Huahua Yu

    2014-01-01

    Full Text Available Efficacy of venom from tentacle of jellyfish Stomolophus meleagris against the cotton bollworm Helicoverpa armigera was determined. Venom from tentacle of jellyfish Stomolophus meleagris could inhibit the growth of Helicoverpa armigera and the weight inhibiting rate of sample NFr-2 was 60.53%. Of the six samples, only NFr-2 had high insecticidal activity against Helicoverpa armigera and the corrected mortality recorded at 7 d was 74.23%.

  12. Tarsi of male heliothine moths contain aldehydes and butyrate esters as potential pheromone components

    Science.gov (United States)

    The Noctuidae is one of the most specious moth families and contains the genera Helicoverpa and Heliothis. Their major sex pheromone component is (Z)-11-hexadecenal except for Helicoverpa assulta and Helicoverpa gelotopoeon both of which utilize (Z)-9-hexadecenal. The minor components of heliothine ...

  13. Combining Tpi and CO1 genetic markers to discriminate invasive Helicoverpa armigera from local Helicoverpa zea (Lepidoptera:Noctuidae) populations in the southeastern United States

    Science.gov (United States)

    The recent establishment of the Old World pest Helicoverpa armigera into South America has had significant economic consequences and places the rest of the hemisphere at risk, emphasizing the need for improved methods of monitoring. A major complication is that a sibling species endemic to the New W...

  14. Combining Tpi and CO1 Genetic Markers to Discriminate Invasive Helicoverpa armigera From Local Helicoverpa zea (Lepidoptera: Noctuidae) Populations in the Southeastern United States.

    Science.gov (United States)

    Nagoshi, Rodney N; Gilligan, Todd M; Brambila, Julieta

    2016-10-01

    The recent establishment of the Old World pest Helicoverpa armigera (Hübner) into South America has had significant economic consequences and places the rest of the hemisphere at risk, emphasizing the need for improved methods of monitoring. A major complication is that a sibling species endemic to the New World, Helicoverpa zea (Boddie), is morphologically very similar, with the two species capable of producing fertile hybrids in the laboratory. The consequences of such hybridization in the field are uncertain, but could result in significant and unpredictable changes in the timing, range, and pesticide susceptibilities of Helicoverpa infestations. The objective here is to provide new genetic resources applicable to Helicoverpa populations in northern Florida and neighboring states (a region at risk for H. armigera) that can distinguish the two species and possible hybrids. The genetic variability in segments of the mitochondrial cytochrome oxidase 1 (CO1) and the Z-linked triosephosphate isomerase (Tpi) genes were determined for H. zea from the southeastern United States. These were compared to DNA sequences from H. armigera specimens from Morocco, Australia, and Europe. Phylogenetic network analysis showed a clear demarcation between the two species for all gene segments. These results extend earlier studies establishing CO1 as marker for discriminating the Helicoverpa species complex and introduce a new sex-linked genomic marker. The CO1 and Tpi markers in combination provide a more accurate and sensitive method than existing techniques for identifying hybridization between H. zea and H. armigera and could potentially be used to extrapolate the likely source of invasive H. armigera populations.

  15. Evaluation of an aerial spray strategy against the spruce budworm (choristoneura fumiferana clem.) using fenitrothion and B.t., (bacillus thuringiensis): Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kettela, E.G.

    1993-12-31

    This report presents results from a series of trials to evaluate replicate test sites, two treated with fenitrothion followed by an application of Bacillus thuringiensis (B.t.) and two treated with two applications of B.t. A team of Cessna 188 aircraft equipped with Micronair AU4000 rotary atomizers applied all spray treatments; there were also unsprayed control plots for comparison. The investigators conducted biological evaluations of 60 selected balsam fir trees at each treatment site to record such information as number of buds and shoots, defoliation category for each bud/shoot, number of spruce budworms, and state of development of each bud/shoot. They also determined spray deposition. The report concludes with an assessment of the comparative efficacy of the treatments studied on spruce budworm mortality.

  16. Case history of population change in a `bacillus thuringiensis`-treated versus an untreated outbreak of the western spruce budworm. Forest Service research note

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R.R.; Paul, H.G.

    1996-09-01

    Larval densities of the western spruce budworm (Choristoneura occidentalis Freeman) were monitored for 12 years (1984-95) on permanent sample plots in northeastern Oregon. The time series spanned a period of general budworm infestations when populations increased rapidly from low densities, plateaued for a time at high-outbreak densities, and then declind suddenly. Midway through the period (1988), an area with half of the sample plots was sprayed with the microbial insecticide Bacillus thuringiensis (B.t.) in an operational suppression project. The other sample plots were part of an untreated area. In the treated area, B.t. spray reduced numbers of larvae by more than 90 percent; however, populations returned to an outbreak density within 3 years. In the untreated area, populations remained at outbreak densities and continued to fluctuate due to natural feedback processes. Natural decline of the population (1992-95) in the monitored area was largely unexplained and coincided with an overall collapse of the budworm outbreak in the Blue Mountains.

  17. Identification and characterization of digestive serine proteases from inhibitor-resistant Helicoverpa zea larval midgut

    NARCIS (Netherlands)

    Volpicella, M.; Cordewener, J.H.G.; Jongsma, M.A.; Gallerani, R.; Ceci, L.R.; Beekwilder, M.J.

    2006-01-01

    Protease inhibitors mediate a natural form of plant defence against insects, by interfering with the digestive system of the insect. In this paper, affinity chromatography was used to isolate trypsins and chymotrypsins from Helicoverpa zea larvae, which had been raised on inhibitor-containing diet.

  18. Functional analysis of two inhibitor of apoptosis (iap) orthologs from Helicoverpa armigera nucleopolyhedrovirus

    NARCIS (Netherlands)

    Liang, Ch.Y.; Lange, de J.; Chen, X.W.; Oers, van M.M.; Vlak, J.M.; Westenberg, M.

    2012-01-01

    Baculoviruses induce apoptotic responses in cultured insect cells, which can severely limit viral replication. To overcome this host response baculoviruses carry anti-apoptotic genes, including members of the p35 and inhibitor of apoptosis (iap) gene families. The baculovirus Helicoverpa armigera nu

  19. Horizontal and vertical transmission of wild-type and recombinant Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus

    NARCIS (Netherlands)

    Zhou, M.; Sun, X.; Sun, X.C.; Vlak, J.M.; Hu, Z.H.; Werf, van der W.

    2005-01-01

    Transmission plays a central role in the ecology of baculoviruses and the population dynamics of their hosts. Here, we report on the horizontal and vertical transmission dynamics of wild-type Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV-WT) and a genetically modified variant

  20. Bollworm responses to release of genetically modified Helicoverpa armigera nucleopolyhedroviruses in cotton

    NARCIS (Netherlands)

    Sun, X.; Chen, X.; Zhang, Z.; Wang, H.; Bianchi, F.J.J.A.; Peng, H.; Vlak, J.M.; Hu, Z.

    2002-01-01

    Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) has been developed as a commercial biopesticide to control the cotton bollworm, H. armigera, in China. The major limitation to a broader application of this virus has been the relative long time to incapacitate the target insect.

  1. Infection of Helicoverpa armigera by endophytic Beauveria bassiana colonizing tomato plants

    Science.gov (United States)

    A novel endophytic strain of Beauveria bassiana was isolated from leaf tissue of a wild tomato plant. This strain and two B. bassiana strains previously isolated from soil were evaluated for their ability to endophytically colonize tomatoes and subsequent in planta efficacy against Helicoverpa armig...

  2. Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

    Science.gov (United States)

    The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested ...

  3. Natural control of Helicoverpa armigera in smallholder crops in East Africa.

    NARCIS (Netherlands)

    Berg, van de H.

    1993-01-01

    The African bollworm, Helicoverpa (=Heliothis) armigera , is one of the worst agricultural pests in Africa, attacking a variety of food and cash crops. For development of sustainable pest management, it is essential to study the ecology and natural mortality factors of the pest, and recently, the ne

  4. Carbon dioxide receptor genes in cotton bollworm Helicoverpa armigera

    Science.gov (United States)

    Xu, Wei; Anderson, Alisha

    2015-04-01

    Carbon dioxide (CO2) is important in insect ecology, eliciting a range of behaviours across different species. Interestingly, the numbers of CO2 gustatory receptors (GRs) vary among insect species. In the model organism Drosophila melanogaster, two GRs (DmelGR21a and DmelGR63a) have been shown to detect CO2. In the butterfly, moth, beetle and mosquito species studied so far, three CO2 GR genes have been identified, while in tsetse flies, four CO2 GR genes have been identified. In other species including honeybees, pea aphids, ants, locusts and wasps, no CO2 GR genes have been identified from the genome. These genomic differences may suggest different mechanisms for CO2 detection exist in different insects but, with the exception of Drosophila and mosquitoes, limited attention has been paid to the CO2 GRs in insects. Here, we cloned three putative CO2 GR genes from the cotton bollworm Helicoverpa armigera and performed phylogenetic and expression analysis. All three H. armigera CO2 GRs (HarmGR1, HarmGR2 and HarmGR3) are specifically expressed in labial palps, the CO2-sensing tissue of this moth. HarmGR3 is significantly activated by NaHCO3 when expressed in insect Sf9 cells but HarmGR1 and HarmGR2 are not. This is the first report characterizing the function of lepidopteran CO2 receptors, which contributes to our general understanding of the molecular mechanisms of insect CO2 gustatory receptors.

  5. Demographics and genetic variability of the new world bollworm (Helicoverpa zea) and the old world bollworm (Helicoverpa armigera) in Brazil.

    Science.gov (United States)

    Leite, Natália A; Alves-Pereira, Alessandro; Corrêa, Alberto S; Zucchi, Maria I; Omoto, Celso

    2014-01-01

    Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1) assess the occurrence of both species on different hosts; (2) infer the demographic parameters and genetic structure; (3) determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4) infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI) gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  6. Demographics and genetic variability of the new world bollworm (Helicoverpa zea and the old world bollworm (Helicoverpa armigera in Brazil.

    Directory of Open Access Journals (Sweden)

    Natália A Leite

    Full Text Available Helicoverpa armigera is one of the primary agricultural pests in the Old World, whereas H. zea is predominant in the New World. However, H. armigera was first documented in Brazil in 2013. Therefore, the geographical distribution, range of hosts, invasion source, and dispersal routes for H. armigera are poorly understood or unknown in Brazil. In this study, we used a phylogeographic analysis of natural H. armigera and H. zea populations to (1 assess the occurrence of both species on different hosts; (2 infer the demographic parameters and genetic structure; (3 determine the potential invasion and dispersal routes for H. armigera within the Brazilian territory; and (4 infer the geographical origin of H. armigera. We analyzed partial sequence data from the cytochrome c oxidase subunit I (COI gene. We determined that H. armigera individuals were most prevalent on dicotyledonous hosts and that H. zea were most prevalent on maize crops, based on the samples collected between May 2012 and April 2013. The populations of both species showed signs of demographic expansion, and no genetic structure. The high genetic diversity and wide distribution of H. armigera in mid-2012 are consistent with an invasion period prior to the first reports of this species in the literature and/or multiple invasion events within the Brazilian territory. It was not possible to infer the invasion and dispersal routes of H. armigera with this dataset. However, joint analyses using sequences from the Old World indicated the presence of Chinese, Indian, and European lineages within the Brazilian populations of H. armigera. These results suggest that sustainable management plans for the control of H. armigera will be challenging considering the high genetic diversity, polyphagous feeding habits, and great potential mobility of this pest on numerous hosts, which favor the adaptation of this insect to diverse environments and control strategies.

  7. Cloning, expression and localization of a trypsin-like serine protease in the spruce budworm, Choristoneura fumiferana

    Institute of Scientific and Technical Information of China (English)

    Wen-Ying He; Yi-Ping Zheng; Lin Tang; Si-Chun Zheng; Catherine Béliveau; Daniel Doucet; Michel Cusson; Qi-Li Feng

    2009-01-01

    A trypsin-like molting-related serine protease cDNA (CfMRSP) was cloned from the spruce budworm, Choristoneura fumiferana. The full-length CfMRSP comple-mentary DNA (cDNA) encoded a 43 kDa protein that contained a trypsin-like serine protease catalytic domain, but no clip domain. The C-terminal extension contained five cystein residues, which may allow the protein to form a homodimer through interchain disulfide bonds and regulate the activity of CfMRSP. Phylogenetic tree analysis showed that CfMRSP clusters with lepidopteran homologues such as serine protease 1 of Lonomia obliqua, hemolymph proteinase 20 (HP20), pattern recognition serine proteinase precursor (ProHP14) and a trypsin-like protein of Manduca sexta. Northern blot analysis of devel-opmental expression of CfMRSP indicated that its transcripts were found primarily in the epidermis and were produced during all of the tested stadia, from 4th instar larvae to pupae, but increased levels of C/MRSP transcripts were always found after each molt. A high level of the protein was found in the epidermis by immunohistochemistry analysis. Altogether these data suggest that CfMRSP plays a role in the epidermis during molting and metamorphosis.

  8. Immune responses of Helicoverpa armigera to different kinds of pathogens

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-Fan

    2010-03-01

    Full Text Available Abstract Background Insects react against pathogens through innate immunity. The cotton bollworm Helicoverpa armigera (H. armigera is an important defoliator and an extremely destructive pest insect of many crops. The elucidation of the mechanism of the immune response of H. armigera to various pathogens can provide a theoretical basis for new approaches to biologically control this pest. Results Four kinds of pathogens Bacillus thuringiensis, Klebsiella pneumoniae, Candida albicans, and Autographa californica multiple nucleocapsid nucleopolyhedrovirus harbored green fluorescence protein and polyhedron (AcMNPV-GFP were used to challenge the insect. The cellular and humoral immune responses to the pathogens were analyzed in the challenged H. armigera. The results show that in the five kinds of haemocytes, only granulocytes phagocytized the Gram-negative and Gram-positive bacteria and fungi. All haemocytes can be infected by AcMNPV. Fourteen immune-related genes including pattern recognition receptors (PRRs such as peptidoglycan recognition proteins (HaPGRP and HaPGRP C and Gram-Negative Bacteria-Binding Protein (HaGNBP, and antimicrobial peptides (AMPs such as cecropin-1, 2 and 3 (HaCec-1, 2 and 3, lysozyme (HaLys, attacin (HaAtt, gallerimycin-like (HaGall, gloverin-like (HaGlo, moricin-like (HaMor, cobatoxin-like (HaCob, galiomicin-like (HaGali, and immune inducible protein (HaIip appeared in different expression profiles to different pathogen infections. The transcripts of 13 immune related genes (except HaPGRPC are obviously up-regulated by Gram-positive bacteria. HaCec-1 and 3, HaMor, HaAtt, HaLys, HaIip, HaPGRP and HaGNBP are greatly up-regulated after fungal infection. HaGNBP, HaCec-2, HaGall, HaGlo, HaMor, HaCob, HaGali obviously increased in Gram-negative bacterial infection. Only five genes, HaGNBP, HaCec-1, HaGali, HaGlo, and HaLys, are weakly up-regulated after viral infection. The AMP transcripts had higher expression levels than the

  9. Ultramorphology of sensilla on the proboscis in three noctuid moths ( Lepidoptera: Noctuidae)%三种夜蛾成虫口器感器的超微形态

    Institute of Scientific and Technical Information of China (English)

    王娜; 魏劲松; 党露; 王建波; 花保祯

    2012-01-01

    为确定不同种类夜蛾口器及其感器在超微结构上的差异,采用扫描电子显微镜对棉铃虫Helicoverpa armigera( Hübner)、烟夜蛾H.assulta( Guenée)和银纹夜蛾Argyrogramma agnata (Staudinger)3种鳞翅目(Lepidoptera)夜蛾科(Noctuidae)重要农业害虫雌、雄成虫口器感器的超微形态进行了观察和比较.结果表明:3种夜蛾雌、雄成虫口器感器类型均无明显差异.棉铃虫和烟夜蛾口器感器在类型和形状上十分类似,均具有毛形、锥形和栓锥形感器;喙管末端的栓锥感器粗、密,棱纹明显.银纹夜蛾 口器感器与两种铃夜蛾区别明显,除上述3类感器外,还具有腔锥形感器;其喙管末端的栓锥感器细、疏,棱纹不明显.结果显示口器感器可用于夜蛾的分类及亲缘关系研究.%The ultramorphology of sensilla on the proboscis in three pest noctuid moths of agricultural significance, the cotton boUworm Helicoverpa armigera ( H(u)bner) , the Oriental tobacco budworm moth H. assulta ( Guenee) , and the silver looper moth Argyrogramma agnata ( Staudinger) , were investigated using scanning electron microscopy and compared to reveal the ultramorphological differences of the proboscis sensilla among these noctuid moths. The results showed that sexual dimorphism is not found in types of the proboscis sensilla in these species. The proboscises in H. armigera and H. assulta are similar in sensillum types and morphology, sharing similar sensilla trichodea, sensilla basiconica, and sensilla styloconica. Sensilla styloconica bear prominent ridges and are densely borne on the distal part of the proboscis. The proboscis in A. agnata, however, bears sensilla coeloconica in addition to the three types of sensilla mentioned above; sensilla styloconica are slender, lack prominent ridges, and are sparsely distributed on the distal part of the proboscis. The results suggest that the proboscis sensilla can be used in the classification and phylogenetic

  10. Parasitism of Helicoverpa armigera pupae (Lepidoptera: Noctuidae) by Tetrastichus howardi and Trichospilus diatraeae (Hymenoptera: Eulophidae)

    OpenAIRE

    Harley Nonato de Oliveira; Juliana Simonato; Daniele Fabiana Glaeser; Fabrício Fagundes Pereira

    2016-01-01

    Helicoverpa armigera is a pest that was recently detected in Brazil, which causes significant losses in various crops in different regions of the country. Biological control has been reported to offer a promising alternative in the management of this pest. Thus, this study evaluated the ability of the parasitoids Tetrastichus howardi and Trichospilus diatraeae to parasitize pupae of H. armigera in the laboratory. H. armigera pupae were individually exposed to 15 female Trichospilus diatraeae ...

  11. Timeline and geographical distribution of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae: Heliothinae) in Brazil

    OpenAIRE

    Sosa-Gómez, Daniel R.; Alexandre Specht; Paula-Moraes, Silvana V.; Adilson Lopes-Lima; Silvia A.C. Yano; Adriana Micheli; Morais,Elisangela G.F.; Paulo Gallo; Pereira,Paulo R.V.S.; José R. Salvadori; Marcos Botton; Maurício M. Zenker; Azevedo-Filho,Wilson S.

    2016-01-01

    ABSTRACT This study presents registers of Helicoverpa armigera (Hübner) occurrence to assess its spatial and temporal distribution in Brazil. We used data from collections, especially from the Southern Region, systematic collections in Rio Grande do Sul, occasional collections of caterpillars and adults in different regions of Brazil, as well as literature registers. We conclude that the introduction of H. armigera in Brazil probably occurred before October 2008. We also register that in Augu...

  12. Evolution, ecology and management of resistance in Helicoverpa spp. to Bt cotton in Australia.

    Science.gov (United States)

    Downes, Sharon; Mahon, Rod

    2012-07-01

    Prior to the widespread adoption of two-gene Bt cotton (Bollgard II®) in Australia, the frequency of resistance alleles to one of the deployed proteins (Cry2Ab) was at least 0.001 in the pests targeted namely, Helicoverpa armigera and Helicoverpa punctigera. In the 7 years hence, there has been a statistically significant increase in the frequency of alleles conferring Cry2Ab resistance in field populations of H. punctigera. This paper reviews the history of deploying Bt cotton in Australia, the characteristics of the isolated Cry2Ab resistance that likely impact on resistance evolution, aspects of the efficacy of Bollgard IIχ, and the behavioural ecology of Helicoverpa spp. larvae as it pertains to resistance management. It also presents up-to-date frequencies of resistant alleles for H. punctigera and reviews the same information for H. armigera. This is followed by a discussion of current resistance management strategies. The consequences of the imminent release of a third generation product that utilizes the novel vegetative insecticidal protein Vip3A are then considered. The area planted to Bt-crops is anticipated to continue to rise worldwide and many biotechnical companies intend to add Vip3A to existing products; therefore the information reviewed herein for Australia is likely to be pertinent to other situations.

  13. Activity of spores and extracellular proteins from six Cry+ strains and a Cry- strain of Bacillus thuringiensis subsp. kurstaki against the western spruce budworm, Choristoneura occidentalis (Lepidoptera: Tortricidae).

    Science.gov (United States)

    Kalmykova, Galina; Burtseva, Ljudmila; Milne, Ross; van Frankenhuyzen, Kees

    2009-05-01

    We characterized insecticidal activity of previously untested strains of Bacillus thuringiensis kurstaki belonging to two crystal serovars (K-1 and K-73) against the western spruce budworm (Choristoneura occidentalis Freeman 1967). By testing various components, we demonstrated that spores play a critical role in the pathogenesis of each strain. Spore-free crystals caused low mortality and purified spores were generally not toxic. The addition of spores to purified protoxin increased toxicity several hundred-fold, regardless of the parental strain from which the spores or protoxins were derived. The crystal and spore components did not account for full insecticidal activity of whole sporulated cultures owing to the toxicity of soluble proteins that are secreted during cell growth. We observed a marked difference in toxicity of secreted proteins between the K-1 and K-73 type strains, with the K-1 preparations causing much higher mortality, mass reduction, and inhibition of pupation. There was a consistent correlation between relative toxicity of secreted protein preparations and the presence and quantity of the Vip3A protein, suggesting that this protein contributes to the virulence of B. thuringiensis subsp. kurstaki in western spruce budworm larvae. However, other virulence factors have to be invoked to explain the synergizing effect of spores from both K-1 and K-73 strains on Cry protein toxicity.

  14. Dual Cry2Ab and Vip3A resistant strains of Helicoverpa armigera and Helicoverpa punctigera (Lepidoptera: Noctuidae); testing linkage between loci and monitoring of allele frequencies.

    Science.gov (United States)

    Walsh, T K; Downes, S J; Gascoyne, J; James, W; Parker, T; Armstrong, J; Mahon, R J

    2014-08-01

    Considerable attention has been given to delaying the evolution of insect resistance to toxins produced by transgenic crops. The major pests of cotton in Australia are the Lepidoptera Helicoverpa armigera (Hubner, 1805) and Helicoverpa punctigera (Wallengren), and the toxins deployed in current and imminent transgenic cotton varieties are Cry1Ac, Cry2Ab and Vip3A from Bacillus thuringiensis. In this study, lines that carry alleles conferring resistance to Cry2Ab and Vip3A were isolated using F2 tests. Extensive work on the Cry2Ab resistant lines, and preliminary work on the Vip3A resistant lines, suggested a single common resistance to each toxin in both species thereby justifying the use of more efficient F1 tests as the primary means for monitoring changes over time. A potential further efficiency could be gained by developing a single resistant line that carries both types of Bt resistance. Herein we report on work with both H. armigera and H. punctigera that tests whether dual Cry2Ab-Vip3A resistant lines can be developed and, if so, whether they can be used to effectively monitor resistance frequencies. Furthermore, the creation of dual resistant lines allowed linkage between the Cry2Ab and Vip3A resistances to be investigated for H. punctigera. We show that dual resistant lines can be used to increase the efficiency of the F1 screen for recessive alleles, and that in H. punctigera there is no linkage between Cry2Ab and Vip3A resistance.

  15. Diet-delivered RNAi in Helicoverpa armigera--Progresses and challenges.

    Science.gov (United States)

    Lim, Zhi Xian; Robinson, Karl E; Jain, Ritesh G; Chandra, G Sharath; Asokan, R; Asgari, Sassan; Mitter, Neena

    2016-02-01

    Helicoverpa armigera (the cotton bollworm) is a significant agricultural pest endemic to Afro-Eurasia and Oceania. Gene suppression via RNA interference (RNAi) presents a potential avenue for management of the pest, which is highly resistant to traditional insecticide sprays. This article reviews current understanding on the fate of ingested double-stranded RNA in H. armigera. Existing in vivo studies on diet-delivered RNAi and their effects are summarized and followed by a discussion on the factors and hurdles affecting the efficacy of diet-delivered RNAi in H. armigera.

  16. Timeline and geographical distribution of Helicoverpa armigera (Hübner (Lepidoptera, Noctuidae: Heliothinae in Brazil

    Directory of Open Access Journals (Sweden)

    Daniel R. Sosa-Gómez

    2016-03-01

    Full Text Available ABSTRACT This study presents registers of Helicoverpa armigera (Hübner occurrence to assess its spatial and temporal distribution in Brazil. We used data from collections, especially from the Southern Region, systematic collections in Rio Grande do Sul, occasional collections of caterpillars and adults in different regions of Brazil, as well as literature registers. We conclude that the introduction of H. armigera in Brazil probably occurred before October 2008. We also register that in August 2012 H. armigera was already present from the extreme southern part (Rio Grande do Sul to the extreme northern part (Amapá of Brazil.

  17. 76 FR 46209 - Importation of Tomatoes From the Economic Community of West African States Into the Continental...

    Science.gov (United States)

    2011-08-02

    ... bollworm) H. assulta (cape gooseberry budworm) Leucinodes orbonalis (eggplant fruit borer) Three of the... mitigated. Harvesting Requirements The stem and calyx of each tomato would have to be removed. Removal of the stem and calyx would eliminate hiding places for small pests, thereby allowing the pests to...

  18. Modelling biological control with wild-type and genetically modified baculoviruses in the Helicoverpa armigera-cotton system

    NARCIS (Netherlands)

    Sun, X.; Werf, van der W.; Bianchi, F.J.J.A.; Hu, Z.; Vlak, J.M.

    2006-01-01

    A comprehensive model was developed to simulate virus epizootics in a stage structured insect population and analyse scenarios for the biological control of cotton bollworm (CBW), Helicoverpa armigera, in cotton, using wild-type or genetically modified baculoviruses. In simulations on dosage and tim

  19. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea

    Science.gov (United States)

    Newly emerged bollworm adults, Helicoverpa zea (Boddie) require carbohydrate source from plant exudates and nectars for reproduction. Adults actively seek such feeding sites upon eclosion in their natural habitat. We wanted to evaluate this nocturnal behavior of the bollworm for potential use as a p...

  20. Behaviour of wild-type and genetically modified baculoviruses in the Helicoverpa armigera - cotton system: a simulation approach

    NARCIS (Netherlands)

    Sun, X.

    2005-01-01

    Keywords:   Helicoverpa armigera , baculovirus, genetic modification, cotton,transmission«

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  1. Transmission of wild-type and recombinant HaSNPV among larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) on cotton.

    NARCIS (Netherlands)

    Georgievska, L.; Vries, R.S.M.; Gao, P.; Sun, X.; Cory, J.S.; Vlak, J.M.; Werf, van der W.

    2010-01-01

    Horizontal transmission of insect viruses is a key factor in their cycling in agro-ecosystems. Here we study the transmission of the baculovirus HaSNPV among larvae of Helicoverpa armigera (Hübner) in cotton. Transmission of three HaSNPV genotypes was studied from larvae infected with a single virus

  2. Data of in vitro synthesized dsRNAs on growth and development of Helicoverpa armigera

    Science.gov (United States)

    Chikate, Yojana R.; Dawkar, Vishal V.; Barbole, Ranjit S.; Tilak, Priyadarshini V.; Gupta, Vidya S.; Giri, Ashok P.

    2016-01-01

    The data presented in this article is related to the research article “RNAi of selected candidate genes interrupts growth and development of Helicoverpa armigera” (Chikate et al., 2016) [1]. RNA interference (RNAi) is emerging as a potent insect pest control strategy over current methods and their resistance by pest. In this study we tested 15 different in vitro synthesized dsRNAs for gene silencing in Helicoverpa armigera. These dsRNAs were specific against H. armigera enzymes/proteins such as proteases like trypsins (HaTry2, 3, 4 and 6), chymotrypsin (HaChy4) and cysteine proteases such as cathepsin (HaCATHL); glutathione S-transferases (HaGST1a, 6 and 8); esterases (HaAce4, HaJHE); catalase (HaCAT); super-oxide-dismutase (HaCu/ZnSOD); fatty acid binding protein (HaFabp) and chitin deacetylase (HaCda5b). These dsRNAs were fed to second instar larvae at an optimized dose (60 µg/day) for 3 days separately. Effects of dsRNA feeding were observed in terms of larval mass gain, percentage mortality and phenotypic abnormalities in later developmental stages of H. armigera. These findings might provide potential new candidates for designing sequence-specific dsRNA as pesticide in crop protection. PMID:27222861

  3. Analysis of the Genome of the Sexually Transmitted Insect Virus Helicoverpa zea Nudivius 2

    Directory of Open Access Journals (Sweden)

    Zhiqiang Lu

    2012-01-01

    Full Text Available The sexually transmitted insect virus Helicoverpa zea nudivirus 2 (HzNV-2 was determined to have a circular double-stranded DNA genome of 231,621 bp coding for an estimated 113 open reading frames (ORFs. HzNV-2 is most closely related to the nudiviruses, a sister group of the insect baculoviruses. Several putative ORFs that share homology with the baculovirus core genes were identified in the viral genome. However, HzNV-2 lacks several key genetic features of baculoviruses including the late transcriptional regulation factor, LEF-1 and the palindromic hrs, which serve as origins of replication. The HzNV-2 genome was found to code for three ORFs that had significant sequence homology to cellular genes which are not generally found in viral genomes. These included a presumed juvenile hormone esterase gene, a gene coding for a putative zinc-dependent matrix metalloprotease, and a major facilitator superfamily protein gene; all of which are believed to play a role in the cellular proliferation and the tissue hypertrophy observed in the malformation of reproductive organs observed in HzNV-2 infected corn earworm moths, Helicoverpa zea.

  4. Bioefficacy of Caesalpinia bonducella extracts against tobacco cutworm, Helicoverpa armigera (Hub.) (Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Backiyaraj Muthusamy; Elumalai Arumugam; Kasinathan Dhamodaran; Mathivanan Thangarasu; Krishnappa Kaliyamoorthy; Elumalai Kuppusamy

    2015-01-01

    Objective: To evaluate the antifeedant, oviposition deterrent, ovicidal and larvicidal activities of benzene, dichloromethane, diethylether, ethyl acetate and methanol extracts of Indian medicinal plant, Caesalpinia bonducella (C. bonducella) at different concentrations against Lepidopteran agricultural field pest Helicoverpa armigera (Lepidoptera: Noctuidae). Methods: Antifeedant activities of the selected plant extract were studied using leaf disc no-choice method and oviposition deterrent, ovicidal and larvicidal activities were also assessed by adapting the standard protocols. Results: The antifeedant activity of C. bonducella showed significant antifeedant activity in methanol extract. Oviposition deterrency is higher in methanol extract than the other solvent extracts. Similarly, maximum egg mortality was observed in methanol leaf extract of C. bonducella Lethal concentration, LC50 value of benzene, diethylether, dichloromethane, ethyl acetate and methanol extract of C. bonducella were 470.02, 469.00, 465.47, 460.52 and 443.87 mg/L respectively. The Chi-square values are significant at P< 0.05 level. Among five solventextracts, the methanol extract was responsible for strong lethal activity observed against selected pest species. Conclusions: Results of this study show that the selected Indian medicinal plant C. bonducella could be a potent source of natural antifeedant, oviposition deterrent, ovicidal and larvicidal agent against the field pest Helicoverpa armigera.

  5. Bioefficacy of Caesalpinia bonducella extracts against tobacco cutworm, Helicoverpa armigera (Hub. (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Backiyaraj Muthusamy

    2015-05-01

    Full Text Available Objective: To evaluate the antifeedant, oviposition deterrent, ovicidal and larvicidal activities of benzene, dichloromethane, diethylether, ethyl acetate and methanol extracts of Indian medicinal plant, Caesalpinia bonducella (C. bonducella at different concentrations against Lepidopteran agricultural field pest Helicoverpa armigera (Lepidoptera: Noctuidae. Methods: Antifeedant activities of the selected plant extract were studied using leaf disc nochoice method and oviposition deterrent, ovicidal and larvicidal activities were also assessed by adapting the standard protocols. Results: The antifeedant activity of C. bonducella showed significant antifeedant activity in methanol extract. Oviposition deterrency is higher in methanol extract than the other solvent extracts. Similarly, maximum egg mortality was observed in methanol leaf extract of C. bonducella Lethal concentration, LC50 value of benzene, diethylether, dichloromethane, ethyl acetate and methanol extract of C. bonducella were 470.02, 469.00, 465.47, 460.52 and 443.87 mg/L respectively. The Chi-square values are significant at P< 0.05 level. Among five solvent extracts, the methanol extract was responsible for strong lethal activity observed against selected pest species. Conclusions: Results of this study show that the selected Indian medicinal plant C. bonducella could be a potent source of natural antifeedant, oviposition deterrent, ovicidal and larvicidal agent against the field pest Helicoverpa armigera.

  6. Variation in susceptibility of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) (Lepidoptera: Noctuidae) in Australia to two Bacillus thuringiensis toxins.

    Science.gov (United States)

    Bird, Lisa J; Akhurst, Raymond J

    2007-02-01

    Intra-specific variation in susceptibility of Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) in Australia to the Cry1Ac and Cry2Ab delta-endotoxins from Bacillus thuringiensis (Berliner) (Bt) was determined to establish a baseline for monitoring changes that might occur with the use of Bt cotton. Strains of H. armigera and H. punctigera were established from populations collected primarily from commercial farms throughout the Australian cotton belts. Strains were evaluated for susceptibility using two bioassay methods (surface treatment and diet incorporation) by measuring the dose response for mortality (LC50) and growth inhibition (IC50). The variation in LC50 among H. armigera (n=17 strains) and H. punctigera (n=12 strains) in response to Cry1Ac was 4.6- and 3.2-fold, respectively. The variation in LC50 among H. armigera (n=19 strains) and H. punctigera (n=12 strains) to Cry2Ab was 6.6- and 3.5-fold, respectively. The range of Cry1Ac induced growth inhibition from the 3rd to 4th instar in H. armigera (n=15 strains) was 3.6-fold and in H. punctigera (n=13 strains) was 2.6-fold, while the range of Cry2Ab induced growth inhibition from neonate to 3rd instar in H. armigera (n=13 strains) was 4.3-fold and in H. punctigera (n=12 strains) was 6.1-fold. Variation in susceptibility was also evaluated for two age classes (neonates and 3rd instars) in laboratory strains of H. armigera and H. punctigera. Neonates of H. punctigera had the same or higher sensitivity to Bt than 3rd instars. Neonates of H. armigera were more sensitive to Cry2Ab than 3rd instars, while being less sensitive to Cry1Ac than 3rd instars. Differences in the two methods of bioassay used affected relative sensitivity of species to Bt toxins, highlighting the need to standardize bioassay protocols.

  7. Wood Anatomy and Insect Defoliator Systems: Is there an anatomical response to sustained feeding by the western spruce budworm (Choristoneura occidentalis) on Douglas-fir (Pseudotusga menziesii)?

    Science.gov (United States)

    Axelson, Jodi; Gärtner, Holger; Alfaro, René; Smith, Dan

    2013-04-01

    The western spruce budworm (Choristoneura occidentalis Freeman) is the most widespread and destructive defoliator of coniferous forests in western North America, and has a long-term coexistence with its primary host tree, Douglas-fir (Pseudotsuga menziesii Franco). Western spruce budworm (WSB) outbreaks usually last for several years, and cause reductions in annual growth, stem defects, and regeneration delays. In British Columbia, the WSB is the second most damaging insect after the mountain pine beetle, and sustained and/or severe defoliation can result in the mortality of host trees. Numerous studies have used tree rings to reconstruct WSB outbreaks across long temporal scales, to evaluate losses in stand productivity, and examine isotope ratios. Although some studies have looked at the impacts of artificial defoliation on balsam fir in eastern North America, there has been no prior research on how WSB outbreaks affect the anatomical structure of the stem as described by intra-annual wood density and potential cell size variations. The objective of this study was to anatomically examine the response of Douglas-fir to sustained WSB outbreaks in two regions of southern British Columbia. We hypothesize that the anatomical intra-annual characteristics of the tree rings, such as cell wall thickness, latewood cell size, and/or lumen area changes during sustained WSB outbreaks. To test this hypothesis we sampled four permanent sample plots in coastal and dry interior sites, which had annually resolved defoliation data collected over a 7-12 year period. At each site diameter-at-breast height (cm), height (m), and crown position were recorded and three increment cores were extracted from 25 trees. Increment cores were prepared to permit anatomical and x-ray density analyses. For each tree, a 15µm thick micro section was cut from the radial plane. Digital images of the micro sections were captured and processed. In each annual ring, features such as cell lumen area (µm2

  8. DNA synthesis in the imaginal wing discs of the American bollworm Helicoverpa armigera (Hübner)

    Indian Academy of Sciences (India)

    A Josephrajkumar; B Subrahmanyam

    2002-03-01

    The effect of two insect growth regulators of plant origin viz. plumbagin and azadirachtin and the ecdysteroids 20-hydroxyecdysone, makisterone A and a phytoecdysteroid on DNA synthesis in imaginal wing discs of day 4 final instar Helicoverpa armigera larvae was studied. DNA synthesis increased with increase in time of incubation up to 8 h and decreased later without the addition of moulting hormone. Addition of 20-hydroxyecdysone supported long term acquisition of competence for DNA synthesis in the wing discs. Both DNA synthesis and protein content were drastically reduced in plumbagin and azadirachtin-treated insects. Under in vitro conditions, plumbagin had a more pronounced inhibitory effect than azadirachtin. All the ecdysteroids tested, viz. makisterone A, 20-hydroxyecdysone and the ecdysteroidal fraction from the silver fern Cheilanthes farinosa enhanced DNA synthesis.

  9. Mitochondrial DNA COI characterization of Helicoverpa armigera (Lepidoptera: Noctuidae) from Paraguay and Uruguay.

    Science.gov (United States)

    Arnemann, J A; James, W J; Walsh, T K; Guedes, J V C; Smagghe, G; Castiglioni, E; Tay, W T

    2016-04-07

    Since its detection in Brazil in 2013, the Old World cotton bollworm Helicoverpa armigera has been reported in Argentina, Paraguay, and Bolivia. Here we present evidence extending the South American range of H. armigera to Uruguay, using polymerase chain reaction and sequencing of the partial mitochondrial DNA (mtDNA) cytochrome oxidase I region. Molecular characterization of this gene region from individuals from Paraguay also supports previous morphological identification of H. armigera in Paraguay. Shared mtDNA haplotypes in H. armigera from Brazil, Uruguay, and Paraguay were identified. Additional surveying of populations in this region will be imperative to better monitor and understand factors that are underpinning its presence and successful adaptation in these South American regions. We discuss our findings with respect to the development of resistance pest management strategies of this invasive insect pest in a predominantly monoculture soybean crop landscape in the Southern Cone region.

  10. Efficient isolation, purification, and characterization of the Helicoverpa zea VHDL receptor.

    Science.gov (United States)

    Persaud, Deryck R; Yousefi, Vandad; Haunerland, Norbert

    2003-12-01

    The study of fat body receptors (e.g., VHDL receptor) in Lepidoptera has been irksome due to the fact that isolation and purification of these proteins are difficult and resulted in extremely low yields. A rapid and efficient method is presented for the purification of Helicoverpa zea VHDL receptor by the use of VHDL-biotin ligand complexed to streptavidin coated magnetic beads. The technique can be easily applied to other ligands and allows for the purification of membrane proteins with higher yields compared to previously used methods involving immunopurification. Although the purified protein can be characterized by Western and non-radioactive ligand blots using enhanced chemiluminescence (ECL), a non-radioactive ligand blot method using VHDL-FITC is presented, which allows for the quick analysis of the receptor directly from the blot under standard UV light. Sufficient receptor protein has been derived for amino acid analysis, receptor-ligand and xenobiotic binding studies.

  11. Effects of a new microbial α-amylase inhibitor protein on Helicoverpa armigera larvae.

    Science.gov (United States)

    Zeng, Fanrong; Wang, Xiaojing; Cui, Jinjie; Ma, Yan; Li, Qiannan

    2013-03-06

    A new microbial α-amylase inhibitor gene was cloned and characterized. The encoded, recombinant, α-amylase inhibitor protein was induced and expressed by isopropyl β-d-1-thiogalactopyranoside (IPTG) in Escherichia coli M15 cells. The effects of the α-amylase inhibitor protein on Helicoverpa armigera larvae were studied. Compared to the control, the weight of H. armigera larvae fed the diet with recombinant α-amylase inhibitor protein added at a concentration of 20 μg/g was reduced by 49.8%. The total soluble protein of H. armigera larvae fed the diet with the α-amylase inhibitor protein added was also reduced by 36.8% compared to the control. The recombinant α-amylase inhibitor protein showed inhibition activity against α-amylase of H. armigera. These results suggested that this α-amylase inhibitor protein may be a promising bioinsecticide candidate for controlling H. armigera.

  12. Way toward "dietary pesticides": molecular investigation of insecticidal action of caffeic acid against Helicoverpa armigera.

    Science.gov (United States)

    Joshi, R S; Wagh, T P; Sharma, N; Mulani, F A; Sonavane, U; Thulasiram, H V; Joshi, R; Gupta, V S; Giri, A P

    2014-11-12

    Bioprospecting of natural molecules is essential to overcome serious environmental issues and pesticide resistance in insects. Here we are reporting insights into insecticidal activity of a plant natural phenol. In silico and in vitro screening of multiple molecules supported by in vivo validations suggested that caffeic acid (CA) is a potent inhibitor of Helicoverpa armigera gut proteases. Protease activity and gene expression were altered in CA-fed larvae. The structure-activity relationship of CA highlighted that all the functional groups are crucial for inhibition of protease activity. Biophysical studies and molecular dynamic simulations revealed that sequential binding of multiple CA molecules induces conformational changes in the protease(s) and thus lead to a significant decline in their activity. CA treatment significantly inhibits the insect's detoxification enzymes, thus intensifying the insecticidal effect. Our findings suggest that CA can be implicated as a potent insecticidal molecule and explored for the development of effective dietary pesticides.

  13. Draft Genome Sequence of Bacillus thuringiensis Serovar Tolworthi Strain Na205-3, an Isolate Toxic for Helicoverpa armigera

    Science.gov (United States)

    Palma, Leopoldo; Muñoz, Delia; Murillo, Jesús

    2014-01-01

    We report here the complete annotated 6,510,053-bp draft genome sequence of Bacillus thuringiensis serovar tolworthi strain Na205-3, which is toxic for Helicoverpa armigera. This strain potentially contains nine insecticidal toxin genes homologous to cry1Aa12, cry1Ab1, cry1Ab8, cry1Ba1, cry1Af1, cry1Ia10, vip1Bb1, vip2Ba2, and vip3Aa6. PMID:24625875

  14. Development of a Microbial-Based Integrated Pest Management Program for Helicoverpa spp. (Lepidoptera: Noctuidae and Beneficial Insects on Conventional Cotton Crops in Australia

    Directory of Open Access Journals (Sweden)

    Robert K. Mensah

    2015-04-01

    Full Text Available Entomopathogenic fungi, when used as a microbial control agent against cotton pests, such as Helicoverpa spp., may have the potential to establish and spread in the environment and to have an impact on both pests and beneficial insects. Information on the effect of entomopathogenic fungi on pests and beneficial insects is crucial for a product to be registered as a biopesticide. The effect of the entomopathogenic fungus BC 639 (Aspergillus sp. against Helicoverpa spp. and beneficial insects (mostly predatory insects was studied in the laboratory and in cotton field trials. The results show that when Helicoverpa spp. second instar larvae were exposed to increasing concentrations (from 102 to 109 of the entomopathogenic fungus BC 639, the optimum dose required to kill over 50% of the insects was 1.0 ´ 107 spores/mL. In the field trials, the number of Helicoverpa spp. per metre on plots treated with 1.0 or 0.50 L/ha of BC 639 was the same as on plots treated with the recommended rate of the commercial insecticide, Indoxacarb. However, when plots were treated with 0.25 L/ha of BC 639, this was not as effective at controlling Helicoverpa spp. as 1.0 or 0.5 L/ha BC 639 or Indoxacarb. BC 639 had less effect on predatory insects when applied at lower rates (0.50 and 0.25 L/ha than at higher rates (1.0 L/ha. Thus, BC 639 was more selective against predators when applied at lower rates than at the higher rate, but was also more selective than Indoxacarb. Thus, the ability of BC 639 to control Helicoverpa spp. effectively with a minimal effect on predatory insects indicates its potential for enhancing integrated pest management programs and to sustain cotton production.

  15. Development of a Microbial-Based Integrated Pest Management Program for Helicoverpa spp. (Lepidoptera: Noctuidae) and Beneficial Insects on Conventional Cotton Crops in Australia.

    Science.gov (United States)

    Mensah, Robert K; Young, Alison; Rood-England, Leah

    2015-04-09

    Entomopathogenic fungi, when used as a microbial control agent against cotton pests, such as Helicoverpa spp., may have the potential to establish and spread in the environment and to have an impact on both pests and beneficial insects. Information on the effect of entomopathogenic fungi on pests and beneficial insects is crucial for a product to be registered as a biopesticide. The effect of the entomopathogenic fungus BC 639 (Aspergillus sp.) against Helicoverpa spp. and beneficial insects (mostly predatory insects) was studied in the laboratory and in cotton field trials. The results show that when Helicoverpa spp. second instar larvae were exposed to increasing concentrations (from 10² to 10⁸) of the entomopathogenic fungus BC 639, the optimum dose required to kill over 50% of the insects was 1.0 ´ 10⁷ spores/mL. In the field trials, the number of Helicoverpa spp. per metre on plots treated with 1.0 or 0.50 L/ha of BC 639 was the same as on plots treated with the recommended rate of the commercial insecticide, Indoxacarb. However, when plots were treated with 0.25 L/ha of BC 639, this was not as effective at controlling Helicoverpa spp. as 1.0 or 0.5 L/ha BC 639 or Indoxacarb. BC 639 had less effect on predatory insects when applied at lower rates (0.50 and 0.25 L/ha) than at higher rates (1.0 L/ha). Thus, BC 639 was more selective against predators when applied at lower rates than at the higher rate, but was also more selective than Indoxacarb. Thus, the ability of BC 639 to control Helicoverpa spp. effectively with a minimal effect on predatory insects indicates its potential for enhancing integrated pest management programs and to sustain cotton production.

  16. Western Spruce Budworm Outbreaks Did Not Increase Fire Risk over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism

    Science.gov (United States)

    Flower, Aquila; G. Gavin, Daniel; Heyerdahl, Emily K.; Parsons, Russell A.; Cohn, Gregory M.

    2014-01-01

    warming, our records show no precedent that western spruce budworm outbreaks will increase future fire risk. PMID:25526633

  17. A Novel Neurotoxin Gene ar1b Recombination Enhances the Efficiency of Helicoverpa armigera Nucleopolyhedrovirus as a Pesticide by Inhibiting the Host Larvae Ability to Feed and Grow

    OpenAIRE

    Huan Yu; Jiao Meng; Jian Xu; Tong-Xian Liu; Dun Wang

    2015-01-01

    A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV), Ar1b-HearNPV, was constructed and identified as an improved bio-control agent of Helicoverpa armigera larvae. The HearNPV polyhedrin promoter was used to express the insect-specific neurotoxin gene, ar1b, which was originally isolated from the Australian funnel-web spider (Atrax robustus). RT-PCR and Western blotting analysis showed that both the ar1b transcript and protein were produced successfully in Ar1b-HearNPV-infected H...

  18. Bacterial Expression and Kinetic Analysis of Carboxylesterase 001D from Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Yongqiang Li

    2016-04-01

    Full Text Available Carboxylesterasesare an important class of detoxification enzymes involved in insecticide resistance in insects. A subgroup of Helicoverpa armigera esterases, known as Clade 001, was implicated in organophosphate and pyrethroid insecticide resistance due to their overabundance in resistant strains. In this work, a novel carboxylesterasegene 001D of H. armigera from China was cloned, which has an open reading frame of 1665 nucleotides encoding 554 amino acid residues. We used a series of fusion proteins to successfully express carboxylesterase 001D in Escherichia coli. Three different fusion proteins were generated and tested. The enzyme kinetic assay towards 1-naphthyl acetate showed all three purified fusion proteins are active with a Kcat between 0.35 and 2.29 s−1, and a Km between 7.61 and 19.72 μM. The HPLC assay showed all three purified fusion proteins had low but measurable hydrolase activity towards β-cypermethrin and fenvalerate insecticides (specific activities ranging from 0.13 to 0.67 μM·min−1·(μM−1·protein. The enzyme was stable up to 40 °C and at pH 6.0–11.0. The results imply that carboxylesterase 001D is involved in detoxification, and this moderate insecticide hydrolysis may suggest that overexpression of the gene to enhance insecticide sequestration is necessary to allow carboxylesterases to confer resistance to these insecticides in H. armigera.

  19. A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea.

    Science.gov (United States)

    Brévault, Thierry; Tabashnik, Bruce E; Carrière, Yves

    2015-05-07

    Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures versus separate blocks. Here we report results from greenhouse experiments with transgenic cotton producing Bt toxin Cry1Ac and the bollworm, Helicoverpa zea, showing that the dominance of resistance was significantly higher in a seed mixture relative to a block of Bt cotton. The proportion of larvae on non-Bt cotton plants in the seed mixture was also significantly higher than expected under the null hypothesis of random distribution. In simulations based on observed survival, resistance evolved 2- to 4.5-fold faster in the seed mixture relative to separate blocks of Bt and non-Bt cotton. These findings support previous modelling results indicating that block refuges may be more effective than seed mixtures for delaying resistance in pests with mobile larvae and inherently low susceptibility to the toxins in Bt crops.

  20. Resistance allele frequency to bt cotton in field populations of helicoverpa armigera (Lepidoptera: Noctuidae) in China.

    Science.gov (United States)

    Liu, Fengyi; Xu, Zhiping; Chang, Juhua; Chen, Jin; Meng, Fengxia; Zhu, Yu Cheng; Shen, Jinliang

    2008-06-01

    Resistance evolution in target insects to Bacillus thurningiensis (Bt) cotton, Gossypium hirsutum L., is a main threat to Bt cotton technology. An increasing trend of population density of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has been observed since 2001 in Qiuxian County (Hebei, China), where Bt cotton has been planted dominantly since 1998. This region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to Bt cotton by screening the F1 progeny from single-pair cross between field-collected male and laboratory female of the Bt-resistant strain of H. armigera (F1 screen). F1 offspring from each single-pair line were screened for resistance alleles based on larval growth, development, and survival on Bt cotton leaves for 5 d. Two-year results indicated that approximately equal to 20% of field-collected males carried resistance alleles. The conservative estimate of the resistance allele frequency was 0.094 (95% CI, 0.044-0.145) for 2006 and 0.107 (95% CI, 0.055-0.159) for 2007. This is the first report of resistance allele frequency increase to such a high level in the field in China. Long-term adoption of Bt sprays, dominant planting of single-toxin-producing Bt cotton, and lack of conventional cotton refuge system might accelerate the resistance evolution in the region.

  1. Mis-splicing of the ABCC2 gene linked with Bt toxin resistance in Helicoverpa armigera.

    Science.gov (United States)

    Xiao, Yutao; Zhang, Tao; Liu, Chenxi; Heckel, David G; Li, Xianchun; Tabashnik, Bruce E; Wu, Kongming

    2014-08-26

    Toxins from the bacterium Bacillus thuringiensis (Bt) are used widely for insect control in sprays and transgenic plants, but their efficacy is reduced when pests evolve resistance. Previous work showed that mutations in a gene encoding the transporter protein ABCC2 are linked with resistance to Bt toxins Cry1Ab, Cry1Ac or both in four species of Lepidoptera. Here we compared the ABCC2 gene of Helicoverpa armigera (HaABCC2) between susceptible strains and a laboratory-selected strain with >1,000-fold resistance to Cry1Ac relative its susceptible parent strain. We discovered a 73-base pair (bp) insertion in the cDNA of the resistant strain that generates a premature stop codon expected to yield a truncated ABCC2 protein. Sequencing of genomic DNA revealed that this insertion is an intron that is not spliced out because of a 6-bp deletion at its splicing site. Analysis of progeny from crosses revealed tight genetic linkage between HaABCC2 and resistance to Cry1Ac. These results provide the first evidence that mis-splicing of a gene encoding an ABCC2 protein confers resistance to a Bt toxin.

  2. New resistance mechanism in Helicoverpa armigera threatens transgenic crops expressing Bacillus thuringiensis Cry1Ac toxin.

    Science.gov (United States)

    Gunning, Robin V; Dang, Ho T; Kemp, Fred C; Nicholson, Ian C; Moores, Graham D

    2005-05-01

    In Australia, the cotton bollworm, Helicoverpa armigera, has a long history of resistance to conventional insecticides. Transgenic cotton (expressing the Bacillus thuringiensis toxin Cry1Ac) has been grown for H. armigera control since 1996. It is demonstrated here that a population of Australian H. armigera has developed resistance to Cry1Ac toxin (275-fold). Some 70% of resistant H. armigera larvae were able to survive on Cry1Ac transgenic cotton (Ingard) The resistance phenotype is inherited as an autosomal semidominant trait. Resistance was associated with elevated esterase levels, which cosegregated with resistance. In vitro studies employing surface plasmon resonance technology and other biochemical techniques demonstrated that resistant strain esterase could bind to Cry1Ac protoxin and activated toxin. In vivo studies showed that Cry1Ac-resistant larvae fed Cy1Ac transgenic cotton or Cry1Ac-treated artificial diet had lower esterase activity than non-Cry1Ac-fed larvae. A resistance mechanism in which esterase sequesters Cry1Ac is proposed.

  3. Insecticidal potential of defense metabolites from Ocimum kilimandscharicum against Helicoverpa armigera.

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    Priyanka Singh

    Full Text Available Genus Ocimum contains a reservoir of diverse secondary metabolites, which are known for their defense and medicinal value. However, the defense-related metabolites from this genus have not been studied in depth. To gain deeper insight into inducible defense metabolites, we examined the overall biochemical and metabolic changes in Ocimum kilimandscharicum that occurred in response to the feeding of Helicoverpa armigera larvae. Metabolic analysis revealed that the primary and secondary metabolism of local and systemic tissues in O. kilimandscharicum was severely affected following larval infestation. Moreover, levels of specific secondary metabolites like camphor, limonene and β-caryophyllene (known to be involved in defense significantly increased in leaves upon insect attack. Choice assays conducted by exposing H. armigera larvae on O. kilimandscharicum and tomato leaves, demonstrated that O. kilimandscharicum significantly deters larval feeding. Further, when larvae were fed on O. kilimandscharicum leaves, average body weight decreased and mortality of the larvae increased. Larvae fed on artificial diet supplemented with O. kilimandscharicum leaf extract, camphor, limonene and β-caryophyllene showed growth retardation, increased mortality rates and pupal deformities. Digestive enzymes of H. armigera - namely, amylase, protease and lipase- showed variable patterns after feeding on O. kilimandscharicum, which implies striving of the larvae to attain required nutrition for growth, development and metamorphosis. Evidently, selected metabolites from O. kilimandscharicum possess significant insecticidal activity.

  4. Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States.

    Science.gov (United States)

    Pan, Zaiqi; Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura

    2016-04-01

    We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton.

  5. Comparative toxicity of mycotoxins to navel orangeworm (Amyelois transitella) and corn earworm (Helicoverpa zea).

    Science.gov (United States)

    Niu, Guodong; Siegel, Joel; Schuler, Mary A; Berenbaum, May R

    2009-08-01

    Mycotoxins, such as aflatoxins and ochratoxins, are widely distributed in nature and are frequently problematic crop contaminants that cause millions of dollars of annual losses in the United States. Insect infestations of crop plants significantly exacerbate mycotoxin contamination. Damage to a variety of nut species by Amyelois transitella Walker (navel orangeworm, NOW) is associated with infection by Aspergillus species and concomitant production of aflatoxins and ochratoxins. Resistance to aflatoxins in this lepidopteran is compared here with the levels of resistance in Helicoverpa zea (corn earworm, CEW), another lepidopteran that routinely encounters aflatoxins in its diet, albeit at lower levels. Measured as the developmental delay caused by aflatoxin B1 (AFB1), it is apparent that the LC(50) (defined as the concentration preventing 50% of newly hatched larvae from entering the 2nd instar within 48 h) for AFB1 is 100 times greater for A. transitella than for H. zea. Similarly, A. transitella 1st instars display substantially higher tolerance to ochratoxin A, another mycotoxin contaminant produced by Aspergillus species, than do H. zea. Our studies indicate that A. transitella, although a hostplant generalist, may well be highly specialized for mycotoxin detoxification.

  6. Mitochondrial DNA and trade data support multiple origins of Helicoverpa armigera (Lepidoptera, Noctuidae) in Brazil

    Science.gov (United States)

    Tay, Wee Tek; Walsh, Thomas K.; Downes, Sharon; Anderson, Craig; Jermiin, Lars S.; Wong, Thomas K. F.; Piper, Melissa C.; Chang, Ester Silva; Macedo, Isabella Barony; Czepak, Cecilia; Behere, Gajanan T.; Silvie, Pierre; Soria, Miguel F.; Frayssinet, Marie; Gordon, Karl H. J.

    2017-01-01

    The Old World bollworm Helicoverpa armigera is now established in Brazil but efforts to identify incursion origin(s) and pathway(s) have met with limited success due to the patchiness of available data. Using international agricultural/horticultural commodity trade data and mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) gene markers, we inferred the origins and incursion pathways into Brazil. We detected 20 mtDNA haplotypes from six Brazilian states, eight of which were new to our 97 global COI-Cyt b haplotype database. Direct sequence matches indicated five Brazilian haplotypes had Asian, African, and European origins. We identified 45 parsimoniously informative sites and multiple substitutions per site within the concatenated (945 bp) nucleotide dataset, implying that probabilistic phylogenetic analysis methods are needed. High diversity and signatures of uniquely shared haplotypes with diverse localities combined with the trade data suggested multiple incursions and introduction origins in Brazil. Increasing agricultural/horticultural trade activities between the Old and New Worlds represents a significant biosecurity risk factor. Identifying pest origins will enable resistance profiling that reflects countries of origin to be included when developing a resistance management strategy, while identifying incursion pathways will improve biosecurity protocols and risk analysis at biosecurity hotspots including national ports. PMID:28350004

  7. X-ray radiation and development inhibition of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Kim, Junheon; Jung, Soon-Oh; Jang, Sin Ae; Kim, Jeongmin; Park, Chung Gyoo

    2015-10-01

    Effect of X-ray radiation on the development inhibition was evaluated for all stages of the life cycle of Helicoverpa armigera to determine a radiation dose for potential quarantine treatment against the insect. ED99 values for inhibition of hatching, pupation, and adult emergence from irradiated eggs were 413, 210, and 154 Gy, respectively. ED99 values for inhibition of pupation and adult emergence from irradiated larvae were 221 and 167 Gy, respectively. Pupa was the most tolerant to X-ray radiation. ED99 value for inhibition of adult emergence from irradiated pupae was as high as 2310 Gy, whereas that for inhibition of F1 egg hatching was only 66 Gy. ED99 value for inhibition of hatching of F1 eggs which were laid by irradiated adults was estimated to 194 Gy. X-ray irradiation against H. armigera is recommended as an alternative method to methyl bromide fumigation for phytosanitary treatments during quarantine. X-ray radiation dose of 200 Gy is proposed as a potential quarantine treatment dose for H. armigera eggs and larvae.

  8. Momordica charantia trypsin inhibitor Ⅱ inhibits growth and development of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Manasi Alok Telang; Prashant Pyati; Mohini Sainani; Vidya Shrikant Gupta; Ashok Prabhakar Giri

    2009-01-01

    Bitter gourd (Momordica charantia L.) seeds contain several squash-type serine proteinase inhibitors (PIs),which inhibit the digestive proteinases of the polyphagous insect pest Helicoverpa armigera.In the present work isolation of a DNA sequence encoding the mature peptide of a trypsin inhibitor McTI-Ⅱ,its cloning and expression as a recombinant protein using Pichia pastoris have been reported.Recombinant McTI-Ⅱinhibited bovine trypsin at 1:1 molar ratio,as expected,but did not inhibit chymotrypsin or elastase.McTI-Ⅱalso strongly inhibited trypsin-like proteinases (81% inhibition) as well as the total proteolytic activity of digestive proteinases (70% inhibition) from the midgut of H.armigera larvae.The insect larvae fed with McTI-Ⅱ-incorporated artificial diet suffered over 70% reduction in the average larval weight after 12 days of feeding.Moreover,ingestion of McTI-Ⅱresulted in 23% mortality in the larval population.The strong antimetabolic activity of McTI-Ⅱtoward H.armigera indicates its probable use in developing insect tolerance in susceptible plants.

  9. BIO-EFFICACY OF INSECTICIDES AGAINST FRUIT BORER (HELICOVERPA ARMIGERA IN TOMATO (LYCOPERSICON ESCULENTUM

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Katroju,

    2014-02-01

    Full Text Available Field experiment carried out during kharif, 2012 at Student’s Farm, College of Agriculture, Rajendranagar, Hyderabad to evaluate the efficacy of insecticides viz., emamectin benzoate 5 SG @11 g a.i. ha-1, emamectin benzoate 5 SG @ 22 g a.i. ha-1, profenophos 50 EC @ 500 g a.i. ha-1, profenophos 50 EC @1000 g a.i. ha-1, spinosad 45 SC @ 100 g a.i. ha-1, bifenthrin 10 EC @ 100 g a.i. ha-1 and Bacillus thuringiensis @ 25 g a.i. ha-1against tomato fruit borer (Helicoverpa armigera. Among all the insecticides, profenophos (1000 g a.i. ha-1 was found to be the most effective one with a maximum reduction in fruit borer population (65.20%, minimum per cent of fruit damage (28.80% and maximum yield (26.43 kg/20 m2 followed by bifenthrin @ 100 g a.i.ha-1 with reduced larval population of 64.51% and damaged fruits 32.60%.

  10. Genetic engineering of Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus as an improved pesticide.

    Science.gov (United States)

    Chen, X; Sun, X; Hu, Z; Li, M; O'Reilly, D R; Zuidema, D; Vlak, J M

    2000-08-01

    The Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HearNPV) has been registered and is commercially produced in China as a biopesticide to control the bollworm in cotton. However, the virus has a relatively slow speed of action. To improve its efficacy, recombinant HearNPVs were generated by deleting the ecdysteroid UDP-glucosyltransferase (egt) gene (HaCXW1 and HaLM2) or by inserting the insect-specific toxin gene AaIT in the egt locus (HaCXW2) of HearNPV using conventional recombination strategies in insect cell culture. The various recombinants remained genetically stable when cultured in HzAM1 insect cells. Bioassay data showed a significant reduction in the time required for all HearNPV recombinants to kill second instar H. armigera larvae. The LT(50) of the egt deletion recombinants HaCXW1 and HaLM2 was about 27% faster than that of wild-type HearNPV. The largest reduction in LT(50) was achieved by inserting the gene for the insect-specific neurotoxin, AaIT, in the egt locus, giving a reduction in LT(50) of 32% compared to wild-type HearNPV. The ability to genetically improve the properties of HearNPV as a biopesticide provides a further opportunity to develop this virus into a commercially viable product to control the bollworm in China.

  11. Bollworm responses to release of genetically modified Helicoverpa armigera nucleopolyhedroviruses in cotton.

    Science.gov (United States)

    Sun, Xiulian; Chen, Xinwen; Zhang, Zhongxin; Wang, Hualin; Bianchi, Felix J J A; Peng, Huiyin; Vlak, Just M; Hu, Zhihong

    2002-10-01

    Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) has been developed as a commercial biopesticide to control the cotton bollworm, H. armigera, in China. The major limitation to a broader application of this virus has been the relative long time to incapacitate the target insect. Two HaSNPV recombinants with improved insecticidal properties were released in bollworm-infested cotton. One recombinant (HaCXW1) lacked the ecdysteroid UDP-glucosyltransferase (egt) gene and in another recombinant (HaCXW2), an insect-selective scorpion toxin (AaIT) gene replaced the egt gene. In a cotton field situation H. armigera larvae treated with either HaCXW1 or HaCXW2 were killed faster than larvae in HaSNPV-wt treated plots. Second instar H. armigera larvae, which were collected from HaCXW1 and HaCXW2 treated plots and further reared on artificial diet, showed reduced ST(50) values of 15.3 and 26.3%, respectively, as compared to larvae collected from HaSNPV-wt treated plots. The reduction in consumed leaf area of field collected larvae infected with HaCXW1 and HaCXW2 was approximated 50 and 63%, respectively, as compared to HaSNPV-wt infected larvae at 108 h after treatment. These results suggest that in a cotton field situation the recombinants will be more effective control agents of the cotton bollworm than wild-type HaSNPV.

  12. Functional specificity of sex pheromone receptors in the cotton bollworm Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available Male moths can accurately perceive the sex pheromone emitted from conspecific females by their highly accurate and specific olfactory sensory system. Pheromone receptors are of special importance in moth pheromone reception because of their central role in chemosensory signal transduction processes that occur in olfactory receptor neurons in the male antennae. There are a number of pheromone receptor genes have been cloned, however, only a few have been functionally characterized. Here we cloned six full-length pheromone receptor genes from Helicoverpa armigera male antennae. Real-time PCR showing all genes exhibited male-biased expression in adult antennae. Functional analyses of the six pheromone receptor genes were then conducted in the heterologous expression system of Xenopus oocytes. HarmOR13 was found to be a specific receptor for the major sex pheromone component Z11-16:Ald. HarmOR6 was equally tuned to both of Z9-16: Ald and Z9-14: Ald. HarmOR16 was sensitively tuned to Z11-16: OH. HarmOR11, HarmOR14 and HarmOR15 failed to respond to the tested candidate pheromone compounds. Our experiments elucidated the functions of some pheromone receptor genes of H. armigera. These advances may provide remarkable evidence for intraspecific mating choice and speciation extension in moths at molecular level.

  13. Expression of Cry1Aa in cassava improves its insect resistance against Helicoverpa armigera.

    Science.gov (United States)

    Duan, Xiaoguang; Xu, Jia; Ling, Erjun; Zhang, Peng

    2013-09-01

    Lepidopteran insects affect cassava production globally, especially in intercropping system. The expression of Cry toxins in transgenic crops has contributed to an efficient control of insect pests, leading to a significant reduction in chemical insecticide usage. Helicoverpa armigera is a Lepidopteran pest that feeds on a wide range of plants like cotton and cassava. In the present study, transgenic cassava plants over-expressing Cry1Aa, which we named as Bt cassava, were developed and used to evaluate its efficacy against H. armigera as a model. Insect feeding assays were carried out to test the effects of Bt cassava leaves on the development and survival of H. armigera. Significant reduction (P cassava leaves in comparison with those fed with wild-type cassava leaves. The higher expression of Cry1Aa in transgenic cassava caused the lethal effect in larvae, in contrast to the normal growth and development of adults and pupation observed when fed with wild-type leaves. Morphological observation on the larval midguts showed that the consumption of Bt cassava affected the gut integrity of H. armigera. The columnar cells of the midgut epithelium were dramatically damaged and showed loose or disordered structure. Their cytoplasms become highly vacuolated and contained disorganized microvilli. Our study demonstrated that the transgenic cassava expressing the Cry1Aa is effective in controlling H. armigera. Our Bt transgenic cassava plant would provide a long-term beneficial effect on all crops in intercropping system, which in-turn, will be profitable to the farmers.

  14. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae—A 2D NMR Metabolomics Study

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    Fredd Vergara

    2016-09-01

    Full Text Available Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea. Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal, the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR and principal component analysis (PCA. Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of 1H-13C HSQC (Heteronuclear Single Quantum Coherence signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae.

  15. Cannibalism Affects Core Metabolic Processes in Helicoverpa armigera Larvae—A 2D NMR Metabolomics Study

    Science.gov (United States)

    Vergara, Fredd; Shino, Amiu; Kikuchi, Jun

    2016-01-01

    Cannibalism is known in many insect species, yet its impact on insect metabolism has not been investigated in detail. This study assessed the effects of cannibalism on the metabolism of fourth-instar larvae of the non-predatory insect Helicoverpa armigera (Lepidotera: Noctuidea). Two groups of larvae were analyzed: one group fed with fourth-instar larvae of H. armigera (cannibal), the other group fed with an artificial plant diet. Water-soluble small organic compounds present in the larvae were analyzed using two-dimensional nuclear magnetic resonance (NMR) and principal component analysis (PCA). Cannibalism negatively affected larval growth. PCA of NMR spectra showed that the metabolic profiles of cannibal and herbivore larvae were statistically different with monomeric sugars, fatty acid- and amino acid-related metabolites as the most variable compounds. Quantitation of 1H-13C HSQC (Heteronuclear Single Quantum Coherence) signals revealed that the concentrations of glucose, glucono-1,5-lactone, glycerol phosphate, glutamine, glycine, leucine, isoleucine, lysine, ornithine, proline, threonine and valine were higher in the herbivore larvae. PMID:27598144

  16. Alterations in the Helicoverpa armigera midgut digestive physiology after ingestion of pigeon pea inducible leucine aminopeptidase.

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    Purushottam R Lomate

    Full Text Available Jasmonate inducible plant leucine aminopeptidase (LAP is proposed to serve as direct defense in the insect midgut. However, exact functions of inducible plant LAPs in the insect midgut remain to be estimated. In the present investigation, we report the direct defensive role of pigeon pea inducible LAP in the midgut of Helicoverpa armigera (Lepidoptera: Noctuidae and responses of midgut soluble aminopeptidases and serine proteinases upon LAP ingestion. Larval growth and survival was significantly reduced on the diets supplemented with pigeon pea LAP. Aminopeptidase activities in larvae remain unaltered in presence or absence of inducible LAP in the diet. On the contrary, serine proteinase activities were significantly decreased in the larvae reared on pigeon pea LAP containing diet as compared to larvae fed on diet without LAP. Our data suggest that pigeon pea inducible LAP is responsible for the degradation of midgut serine proteinases upon ingestion. Reduction in the aminopeptidase activity with LpNA in the H. armigera larvae was compensated with an induction of aminopeptidase activity with ApNA. Our findings could be helpful to further dissect the roles of plant inducible LAPs in the direct plant defense against herbivory.

  17. Identification, isolation and characterization of the antifeedant constituent of Clausena anisata against Helicoverpa armigera (Lepidoptera: Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Olufemi O.R.Pitan; O.O.Ayelaagbe; Hong-Lei Wang; Chen-Zhu Wang

    2009-01-01

    Hexane, petroleum ether, chloroform, ethyl acetate, methanol and water extracts of Clausena anisata [(Willd.) Hook F. Ex Benth] leaves and roots were evaluated against Helicoverpa armigera (Hubner) for antifeedant activities. Antifeedant activity was confirmed, and was found to be higher in root extracts than those of the leaf. Chloroform and petroleum ether extracts of the root showed strongest antifeedant activities (DC50S [concentration (C) causing 50% deterrence compared with the control] 0.014% and 0.016% respectively), and root extracts were fractionated using silica gel column chromatography. One fraction of the chloroform and one of the petroleum ether root extracts was active; and on the basis of mass spectroscopy and 1H and 13C nuclear magnetic resonance spectral data, the active compounds in the two fractious were confirmed to be identical, and identified as osthol [2H-I-Benzopyran-2-one, 7-methoxy-8-(3-methyl-2-butenyl)]. The highest concentratiun of osthol was found in the chloroform root extract. Antifeedant activities of the root extracts, as measured by DC50 values, were highly correlated with their osthol contents. Approximately 99% of the variation in bioactivity of the root extracts could be accounted for by variation in osthol content; osthol therefore, appeared to be an antifeedant component of C. Anisata to H. Armigera. This may provide a new approach to managing this pest.

  18. Return migration of Helicoverpa armigera (Lepidoptera: Noctuidae) during autumn in northern China.

    Science.gov (United States)

    Feng, H-Q; Wu, K-M; Ni, Y-X; Cheng, D-F; Guo, Y-Y

    2005-08-01

    The autumn migration of Helicoverpa armigera (Hübner) was observed with radar and two types of light-trap at Langfang, Hebei province, China in 2001 and 2002. The sudden increase in the proportion of H. armigera moths in the searchlight trap indicated migration into the area and catches increased 10-fold during the second half of the night due to the landing of migrants before dawn. The moths' migratory flights took place at up to 2000 m above the ground, and moths flew differentially at times, and heights, when favourable (i.e. northerly) winds occurred. This facilitated the maximum displacement of moths towards the south during these 'return' migrations. The moths flew over the radar site at consistently high densities through the night, and the resulting flight durations of c. 10 h, at displacement speeds of 30-33 km h-1, would allow moths emerging in the far northeast of China (i.e. Liaoning and Jilin provinces and the Inner Mongolia autonomous region) to migrate into northern China (Hebei, Shandong and Henan provinces). The association of the seasonal migratory movements of H. armigera with crops in northern China is briefly discussed.

  19. Functional Characteristics of a Novel Chemosensory Protein in the Cotton Bollworm Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian-tao; WANG Wei-xuan; ZHANG Zi-ding; ZHANG Yong-jun; GUO Yu-yuan

    2013-01-01

    A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hübner) was obtained from antennal cDNA libraries and expressed in Escherichia coli. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isoborneol, nerolidol, 2-nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of sixα-helices located among residues 33-38 (α1), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trp101, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.

  20. Effect of the endoparasitoid Campoletis chlorideae on phenoloxidase activity in Helicoverpa armigera hemolymph

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Endoparasitoid wasps can develop inside permissive host due to their ability to overcome or to evade the host's cellular and humoral immune response. Oviposition of Campoletis chlorideae (Hymenoptera: Ichneumonidae) in larvae of Helicoverpa armigera (Lepidoptera) was accompanied by inhibition of phenoloxidase (PO) activity and melanization reaction in host hemolymph in vitro. PO activity in host plasma was decreased about 83% 48 h post parasitization. A similar result was found when the host insect was injected with 0.5 wasp equivalent calyx fluid. This indicated that the calyx fluid was concerned with suppression of PO activity after parasitization. Furthermore, the prophenoloxidase (proPO) in host haemocytes could be activated by bovine trypsin in unparasitized insects, while it could not be activated in parasitized or calyx fluid-injected host. The resuits suggested that inhibition of PO activity by parasitization was related to the calyx fluid of Campoletis chlorideae,and the components of calyx fluid (eg. polydnaviruses) perhaps suppressed the expression of proPO in hemolymph or accelerate the degradation of proPO.

  1. Parasitism of Helicoverpa armigera pupae (Lepidoptera: Noctuidae by Tetrastichus howardi and Trichospilus diatraeae (Hymenoptera: Eulophidae

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    Harley Nonato de Oliveira

    2016-02-01

    Full Text Available Helicoverpa armigera is a pest that was recently detected in Brazil, which causes significant losses in various crops in different regions of the country. Biological control has been reported to offer a promising alternative in the management of this pest. Thus, this study evaluated the ability of the parasitoids Tetrastichus howardi and Trichospilus diatraeae to parasitize pupae of H. armigera in the laboratory. H. armigera pupae were individually exposed to 15 female Trichospilus diatraeae or 15 female Tetrastichus howardi for 24 h. The pupae remained under observation until the emergence of parasitoids. Parasitism by both parasitoids was observed in 100% of the pupae. Further, 100% of Tetrastichus howardi and 90% of Trichospilus diatraeae emerged. The life cycle of Tetrastichus howardi parasitizing pupae of H. armigera was 15 ± 0.0 days, while that of Trichospilus diatraeae was 15.90 ± 0.10 days. The numbers of offspring from Tetrastichus howardi and Trichospilus diatraeae were 669.3 ± 33.47 and 816.11 ± 89.22 per pupae, with a sex ratio of 0.91 ± 0.01 and 0.94 ± 0.01, respectively. Tetrastichus howardi and Trichospilus diatraeae were shown to successfully parasitize H. armigera pupae in laboratory conditions, suggesting that this host could be used for rearing both parasitoids. However, further detailed studies of the host-parasitoid relationship are needed to assess the feasibility of including these parasitoids in integrated management programs of H. armigera.

  2. Differential antibiosis against Helicoverpa armigera exerted by distinct inhibitory repeat domains of Capsicum annuum proteinase inhibitors.

    Science.gov (United States)

    Joshi, Rakesh S; Gupta, Vidya S; Giri, Ashok P

    2014-05-01

    Plant defensive serine proteinase inhibitors (PIs) are known to have negative impact on digestive physiology of herbivore insects and thus have a crucial role in plant protection. Here, we have assessed the efficacy and specificity of three previously characterized inhibitory repeat domain (IRD) variants from Capsicum annuum PIs viz., IRD-7, -9 and -12 against gut proteinases from Helicoverpa armigera. Comparative study of in silico binding energy revealed that IRD-9 possesses higher affinity towards H. armigera serine proteinases as compared to IRD-7 and -12. H. armigera fed on artificial diet containing 5 TIU/g of recombinant IRD proteins exhibited differential effects on larval growth, survival rate and other nutritional parameters. Major digestive gut trypsin and chymotrypsin genes were down regulated in the IRD fed larvae, while few of them were up-regulated, this indicate alterations in insect digestive physiology. The results corroborated with proteinase activity assays and zymography. These findings suggest that the sequence variations among PIs reflect in their efficacy against proteinases in vitro and in vivo, which also could be used for developing tailor-made multi-domain inhibitor gene(s).

  3. Resurgence of the cotton bollworm Helicoverpa armigera in northern Greece associated with insecticide resistance.

    Science.gov (United States)

    Mironidis, George K; Kapantaidaki, Despina; Bentila, Maria; Morou, Evangelia; Savopoulou-Soultani, M; Vontas, John

    2013-08-01

    Helicoverpa armigera has been controlled effectively with chemical insecticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey (2007-2010), we examined the insecticide resistance status of H. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides (chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan). Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors (RF) were calculated, compared to a susceptible laboratory reference strain. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resistance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.

  4. Trichogramma chilotraeae PARASITOID TELUR Helicoverpa armigera (Hubner PADA POPULASI INANG RENDAH

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    - Sujak

    2011-03-01

    Full Text Available Helicoverpa armigera Hubner is an insect pest of corn and cotton crops. Eggs are laid by  H. armigera imago on corn silk and cotton crops often have high mortality, mainly caused by egg parasitoid. H. armigera egg on various agroecosystem reported can  be parasited by at least 12 species of  Trichogrammatidae. The purpose of this study was to determine the diversity of  Trichogrammatidae family as  parasitoid eggs of  H. armigera on  low population. H. armigera egg sample taken from Asembagus, Lamongan and Blora at 1 m2 field  both monoculture and intercropping. Observation of parasitoids and predators  done at the Laboratory of Biological Control Balittas Malang. Parasitoid that appears preserved in the Hoyer medium for identification purposes. low population of  H. armigera Egg in Asembagus is  4 eggs/m2 in both monoculture maize and intercropping with 86-100 days after transplanting (DAT cotton and  4.5 egg/m2 on cotton monoculture and intercropping with 75  DAT soybean, while 2 eggs/m2 in the Lamongan and Blora corn agroecosystem. The dominant egg parasitoid in Asembagus is T. chilotraea, as well as in Lamongan and Blora.

  5. A brave new world for an old world pest: Helicoverpa armigera (Lepidoptera: Noctuidae) in Brazil.

    Science.gov (United States)

    Tay, Wee Tek; Soria, Miguel F; Walsh, Thomas; Thomazoni, Danielle; Silvie, Pierre; Behere, Gajanan T; Anderson, Craig; Downes, Sharon

    2013-01-01

    The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA) cytochrome oxidase I (COI) and cytochrome b (Cyt b) partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta) within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC) markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas.

  6. A brave new world for an old world pest: Helicoverpa armigera (Lepidoptera: Noctuidae in Brazil.

    Directory of Open Access Journals (Sweden)

    Wee Tek Tay

    Full Text Available The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. armigera is thought to have colonised the American continents around 1.5 to 2 million years ago, leading to the current H. zea populations on the American continents. The relatively recent species divergence history is evident in mating compatibility between H. zea and H. armigera under laboratory conditions. Despite periodic interceptions of H. armigera into North America, this pest species is not believed to have successfully established significant populations on either continent. In this study, we provide molecular evidence via mitochondrial DNA (mtDNA cytochrome oxidase I (COI and cytochrome b (Cyt b partial gene sequences for the successful recent incursion of H. armigera into the New World, with individuals being detected at two sites (Primavera do Leste, Pedra Preta within the State of Mato Grosso in Brazil. The mtDNA COI and Cyt b haplotypes detected in the Brazilian H. armigera individuals are common throughout the Old World, thus precluding identification of the founder populations. Combining the two partial mtDNA gene sequences showed that at least two matrilines are present in Brazil, while the inclusion of three nuclear DNA Exon-Primed Intron-Crossing (EPIC markers identified a further two possible matrilines in our samples. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas.

  7. Incipient resistance of Helicoverpa punctigera to the Cry2Ab Bt toxin in Bollgard II cotton.

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    Sharon Downes

    Full Text Available Combinations of dissimilar insecticidal proteins ("pyramids" within transgenic plants are predicted to delay the evolution of pest resistance for significantly longer than crops expressing a single transgene. Field-evolved resistance to Bacillus thuringiensis (Bt transgenic crops has been reported for first generation, single-toxin varieties and the Cry1 class of proteins. Our five year data set shows a significant exponential increase in the frequency of alleles conferring Cry2Ab resistance in Australian field populations of Helicoverpa punctigera since the adoption of a second generation, two-toxin Bt cotton expressing this insecticidal protein. Furthermore, the frequency of cry2Ab resistance alleles in populations from cropping areas is 8-fold higher than that found for populations from non-cropping regions. This report of field evolved resistance to a protein in a dual-toxin Bt-crop has precisely fulfilled the intended function of monitoring for resistance; namely, to provide an early warning of increases in frequencies that may lead to potential failures of the transgenic technology. Furthermore, it demonstrates that pyramids are not 'bullet proof' and that rapid evolution to Bt toxins in the Cry2 class is possible.

  8. Diapause hormone in the corn earworm, Helicoverpa zea: Optimum temperature for activity, structure-activity relationships, and efficacy in accelerating flesh fly pupariation

    Science.gov (United States)

    Diapause hormone (DH) effectively terminated pupal diapause in Helicoverpa zea. This effect was temperature-dependent, with an optimum of 21 degrees C. The dose-response curve indicated an ED50 of DH for diapause termination of approximately 100 pmol. The core sequence and essential amino acids w...

  9. Helicoverpa armigera nucleopolyhedrovirus occlusion-derived virus-associated protein, HA100, affects oral infectivity in vivo but not virus replication in vitro

    NARCIS (Netherlands)

    Luo, S.; Zhang, Y.; Xu, X.; Westenberg, M.; Vlak, J.M.; Wang, H.; Hu, Z.; Deng, F.

    2011-01-01

    ORF100 (ha100) of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) has been reported as one of the unique genes of group II alphabaculoviruses encoding a protein located in the occlusion-derived virus (ODV) envelope and nucleocapsid. The protein consists of 510 aa with a predicted mass of 58.1 kD

  10. Estimation of long-terminal repeat element content in the Helicoverpa zea genome from next generation sequencing of reduced representation bacterial artificial chromosome (BAC) pools

    Science.gov (United States)

    The lepidopteran pest insect, Helicoverpa zea, feeds on cultivated corn and cotton crops in North America where control remains challenging due to evolution of resistance to chemical and transgenic insecticidal toxins, yet few genomic resources are available for this species. A bacterial artificial...

  11. Susceptibility of Helicoverpa zea and Heliothis virescens (Lepidoptera: noctuidae) to Vip3A insecticidal protein in VipCotTM cotton

    Science.gov (United States)

    Susceptibility of laboratory and field colonies of Helicoverpa zea (Boddie) and Heliothis virescens F. to Vip3A insecticidal protein was studied in diet incorporation and diet overlay assays from 2004 to 2008. Responses of field populations were compared to paired responses of University of Arkansas...

  12. Mitochondrial genome of the cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae) and comparison with other Lepidopterans.

    Science.gov (United States)

    Yin, Jiao; Hong, Gui-Yun; Wang, Ai-Min; Cao, Ya-Zhong; Wei, Zhao-Jun

    2010-10-01

    We present the complete sequence of the mitochondrial genome (mitogenome) of the cotton bollworm Helicoverpa armigera. The 15,347-bp mitogenome of H. armigera was arranged in the same order described for all other sequenced lepidopterans, which differs from the most common type found in insects, due to the movement of trnM to a position 5'-upstream of trnI. The gene overlap in the H. armigera mitogenome is totally 23 bp in six locations. The H. armigera mitogenome has a total of 175 bp of intergenic spacer sequences spread over 14 regions ranging in size from 1 to 45 bp. The nucleotide composition of the whole mitogenome of H. armigera is highly A+T biased, accounting for 80.97%, with a slightly positive AT skewness and negative GC skewness, indicating the occurrence of more A than T, C more than G. The protein-encoding genes have typical mitochondrial start codons, except for cox1, which contains the unusual CGA. The cox1, cox2, and nad4 genes have incomplete stop codons (T). The lrRNA and srRNA genes are 1395 and 794-bp long, respectively. All tRNAs have a typical cloverleaf structure of mitochondrial tRNAs, except for trnS1(AGN), the dihydrouridine arm of which could not form a stable stem-loop structure. The H. armigera A+T-rich region contains a conserved structure combining the motif ATAGA and a 19-bp poly-T stretch, but absence of the 9-bp poly-A element upstream of trnM.

  13. RNAi of selected candidate genes interrupts growth and development of Helicoverpa armigera.

    Science.gov (United States)

    Chikate, Yojana R; Dawkar, Vishal V; Barbole, Ranjit S; Tilak, Priyadarshini V; Gupta, Vidya S; Giri, Ashok P

    2016-10-01

    Helicoverpa armigera is one of the major crop pests and is less amenable to current pest control approaches. RNA interference (RNAi) is emerging as a potent arsenal for the insect pest control over current methods. Here, we examined the effect on growth and development in H. armigera by targeting various enzymes/proteins such as proteases like trypsins (HaTry2, 3, 4 and 6), chymotrypsin (HaChy4) and cysteine protease like cathepsin (HaCATHL); glutathione S-transferases (HaGST1a, 6 and 8); esterases (HaAce4, HaJHE); catalase (HaCAT); super-oxide-dismutase (HaCu/ZnSOD); fatty acid binding protein (HaFabp) and chitin deacetylase (HaCda5b) through dsRNA approach. Significant downregulation of cognate mRNA expression and reduced activity of trypsin and GST-like enzyme were evident upon feeding candidate dsRNAs to the larvae. Among these, the highest mortality was observed in HaAce4 dsRNA fed larvae followed by HaJHE; HaCAT; HaCuZnSOD; HaFabp and HaTry3 whereas remaining ones showed relatively lower mortality. Furthermore, the dsRNA fed larvae showed significant reduction in the larval mass and abnormalities at the different stages of H. armigera development compared to their control diets. For example, malformed larvae, pupae and moth at a dose of 60μg/day were evident in high number of individual insects fed on dsRNA containing diets. Moreover, the growth and development of insects and moths were retarded in dsRNA fed larvae. These findings might provide potential new candidates for designing effective dsRNA as pesticide in crop protection.

  14. Influences of insecticides on toxicity and cuticular penetration of abamectin in Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    QIANGWANG; JIA-ANCHENG; ZHONG-MINLIU; SHENG-GANWU; XUE-PINGZHAO; CHANG-XINGWU

    2005-01-01

    Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin+HMO (1:206)'. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin+HMO' or ‘abamectin+synergist', respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of 3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of 3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.

  15. Effect of electron beam irradiation on developmental stages of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Kim, Junheon; Chung, Soon-Oh; Jang, Sin Ae; Jang, Miyeon; Park, Chung Gyoo

    2015-07-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), is an economically important and polyphagous pest, which harms various kinds of food crops and important agricultural plants, such as cotton and paprika. Effects of electron beam irradiation at six dose levels between 50 and 350 Gy on the egg (24-48 h old), the larval (4-5th instar), and the pupal (7-d old for female, 5-d old for male) development, and on the adult (1-d old) reproduction were tested to identify a potential quarantine treatment dose. Increased doses of irradiation on eggs decreased egg hatchability, pupation and adult emergence and increased larval period. ED99 values for inhibition of hatching, pupation and emergence were 460.6, 236.9 and 197.8 Gy, respectively. When larvae were irradiated with more than 280 Gy, no larvae could develop into pupae. ED99 values for inhibition of pupation and adult emergence were 265.6 and 189.6 Gy, respectively. Even though the irradiation on pupa did not completely inhibit adult emergence, most of the pupae emerged to deformed adults. When adults were irradiated, fecundity was not affected. However, F1 egg hatching was completely inhibited at the dose of 350 Gy. ED99 value for inhibition of adult emergence was estimated at 366.5 Gy. Our results suggest that electron beam irradiation could be recommendable as an alternative to MB and as a phytosanitary treatment for quarantine. A treatment dose of less than or equal to 220 Gy is suggested as a potential quarantine treatment to H. armigera egg for prevention of pupation and to larva for prevention of adult emerge.

  16. Life table and consumption capacity of corn earworm, Helicoverpa armigera, fed asparagus, Asparagus officinalis.

    Science.gov (United States)

    Jha, Ratna Kumar; Tuan, Shu-Jen; Chi, Hsin; Tang, Li-Cheng

    2014-03-01

    The life table and consumption rate of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) reared on asparagus, Asparagus officinalis L. (Asparagales: Asparagaceae) were studied under laboratory conditions to assess their interaction. Development, survival, fecundity, and consumption data were analyzed by the age-stage, twosex life table. This study indicated that asparagus is a natural host of H. armigera. However, the poor nutritional content in asparagus foliage and the poor fitness of H. armigera that fed on asparagus indicated that asparagus is a suboptimal host in comparison to hybrid sweet corn. The uncertainty associated with life table parameters was estimated by using jackknife and bootstrap techniques, and the results were compared for statistical inference. The intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and mean generation time (T) were estimated by the jackknife technique to be 0.0780 day(-1), 1.0811 day(-1), 67.4 offspring, and 54.8 days, respectively, while those estimated by the bootstrap technique were 0.0752 day(-1), 1.0781 day(-1), 68.0 offspring, and 55.3 days, respectively. The net consumption rate of H. armigera, as estimated by the jackknife and bootstrap technique, was 1183.02 and 1132.9 mg per individual, respectively. The frequency distribution of sample means obtained by the jackknife technique failed the normality test, while the bootstrap results fit the normal distribution well. By contrast, the relationship between the mean fecundity and the net reproductive rate, as estimated by the bootstrap technique, was slightly inconsistent with the relationship found by mathematical proof. The application of the jackknife and bootstrap techniques in estimating population parameters requires further examination.

  17. Production and characterization of Bacillus thuringiensis Cry1Ac-resistant cotton bollworm Helicoverpa zea (Boddie).

    Science.gov (United States)

    Anilkumar, Konasale J; Rodrigo-Simón, Ana; Ferré, Juan; Pusztai-Carey, Marianne; Sivasupramaniam, Sakuntala; Moar, William J

    2008-01-01

    Laboratory-selected Bacillus thuringiensis-resistant colonies are important tools for elucidating B. thuringiensis resistance mechanisms. However, cotton bollworm, Helicoverpa zea, a target pest of transgenic corn and cotton expressing B. thuringiensis Cry1Ac (Bt corn and cotton), has proven difficult to select for stable resistance. Two populations of H. zea (AR and MR), resistant to the B. thuringiensis protein found in all commercial Bt cotton varieties (Cry1Ac), were established by selection with Cry1Ac activated toxin (AR) or MVP II (MR). Cry1Ac toxin reflects the form ingested by H. zea when feeding on Bt cotton, whereas MVP II is a Cry1Ac formulation used for resistance selection and monitoring. The resistance ratio (RR) for AR exceeded 100-fold after 11 generations and has been maintained at this level for nine generations. This is the first report of stable Cry1Ac resistance in H. zea. MR crashed after 11 generations, reaching only an RR of 12. AR was only partially cross-resistant to MVP II, suggesting that MVP II does not have the same Cry1Ac selection pressure as Cry1Ac toxin against H. zea and that proteases may be involved with resistance. AR was highly cross-resistant to Cry1Ab toxin but only slightly cross-resistant to Cry1Ab expressing corn leaf powder. AR was not cross-resistant to Cry2Aa2, Cry2Ab2-expressing corn leaf powder, Vip3A, and cypermethrin. Toxin-binding assays showed no significant differences, indicating that resistance was not linked to a reduction in binding. These results aid in understanding why this pest has not evolved B. thuringiensis resistance, and highlight the need to choose carefully the form of B. thuringiensis protein used in experiments.

  18. Efifciency of Different Methods for dsRNA Delivery in Cotton Bollworm (Helicoverpa armigera)

    Institute of Scientific and Technical Information of China (English)

    YANG Jing; HAN Zhao-jun

    2014-01-01

    RNAi trigged by dsRNA not only facilitates the development of molecular biology, but also initiates a new way for pest control by silence of fatal genes. However, one of the key limitations in pest control is lack of the convenient and efifcient method for dsRNA delivery. In this study, different dsRNA delivery methods at their own optimum conditions were evaluated comparatively for their efifciency with Helicoverpa armigera as test animal. It was found that the popular one-time injection of larvae with dsRNA could reduce the pupation rate by 43.0%and enhance larva mortality by 11.7%. One-time ingestion of dsRNA did not result in any signiifcant effect on phenotype. Continuous ingestion of in vitro synthesized dsRNA by refreshing the bait diet every day caused 40.4% decrease in successful pupation and 10.0% increase in larval mortality, which was similar as one-time injection. The most efifcient method was found to be the continuous ingestion of the bacteria containing dsRNA expressed, which reduced the rate of pupation by 68.7%and enhanced the larval mortality by 34.1%. Further analysis found that dsRNA was degraded faster in midgut juice than in hemolymph. However, the cell of bacteria could protect dsRNA and delay the degradation in the midgut juice of H. armigera. These results throw light on the application of dsRNA in pest management with proper ways.

  19. Biology, Ecology, and Evolving Management of Helicoverpa zea (Lepidoptera: Noctuidae) in Sweet Corn in the United States.

    Science.gov (United States)

    Olmstead, Daniel L; Nault, Brian A; Shelton, Anthony M

    2016-08-01

    The corn earworm, Helicoverpa zea (Boddie), is a polyphagous pest found throughout the United States, where it attacks many field and vegetable crops. Although H. zea has long been a traditional pest of sweet corn, its importance to this crop has increased dramatically over the past two decades. In this review, we summarize information critical for current and future management of H. zea in sweet corn production in the United States. First, we discuss the pest status of H. zea and its life history, including migration, infestation and larval development, diapause, overwintering, and abiotic factors that affect its biology. Next we describe monitoring methods, crop protection decision-making processes, chemical control options, and the use of genetic technologies for control of H. zea Alternative H. zea management options including biological control, cultural controls, host plant resistance, and pheromone disruption are also reviewed. The role of climate change and its effects on H. zea and its ecology are discussed, as well as the recent invasion of its relative, Helicoverpa armigera (Hübner), which is a major pest of corn in other parts of the world. To conclude, we suggest future research opportunities for H. zea and H. armigera management in sweet corn.

  20. Cantharidin Impedes Activity of Glutathione S-Transferase in the Midgut of Helicoverpa armigera Hübner

    Directory of Open Access Journals (Sweden)

    Ya Lin Zhang

    2013-03-01

    Full Text Available Previous investigations have implicated glutathione S-transferases (GSTs as one of the major reasons for insecticide resistance. Therefore, effectiveness of new candidate compounds depends on their ability to inhibit GSTs to prevent metabolic detoxification by insects. Cantharidin, a terpenoid compound of insect origin, has been developed as a bio-pesticide in China, and proves highly toxic to a wide range of insects, especially lepidopteran. In the present study, we test cantharidin as a model compound for its toxicity, effects on the mRNA transcription of a model Helicoverpa armigera glutathione S-transferase gene (HaGST and also for its putative inhibitory effect on the catalytic activity of GSTs, both in vivo and in vitro in Helicoverpa armigera, employing molecular and biochemical methods. Bioassay results showed that cantharidin was highly toxic to H. armigera. Real-time qPCR showed down-regulation of the HaGST at the mRNA transcript ranging from 2.5 to 12.5 folds while biochemical assays showed in vivo inhibition of GSTs in midgut and in vitro inhibition of rHaGST. Binding of cantharidin to HaGST was rationalized by homology and molecular docking simulations using a model GST (1PN9 as a template structure. Molecular docking simulations also confirmed accurate docking of the cantharidin molecule to the active site of HaGST impeding its catalytic activity.

  1. Specific binding of Bacillus thuringiensis Cry2A insecticidal proteins to a common site in the midgut of Helicoverpa species.

    Science.gov (United States)

    Hernández-Rodríguez, Carmen Sara; Van Vliet, Adri; Bautsoens, Nadine; Van Rie, Jeroen; Ferré, Juan

    2008-12-01

    For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with (125)I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera. Homologous-competition assays with (125)I-Cry2Ab demonstrated that this toxin binds with high affinity to binding sites in H. armigera and Helicoverpa zea midgut. Heterologous-competition assays showed a common binding site for three toxins belonging to the Cry2A family (Cry2Aa, Cry2Ab, and Cry2Ae), which is not shared by Cry1Ac. Estimation of K(d) (dissociation constant) values revealed that Cry2Ab had around 35-fold less affinity than Cry1Ac for BBMV binding sites in both insect species. Only minor differences were found regarding R(t) (concentration of binding sites) values. This study questions previous interpretations from other authors performing binding assays with Cry2A toxins and establishes the basis for the mode of action of Cry2A toxins.

  2. Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species▿

    Science.gov (United States)

    Hernández-Rodríguez, Carmen Sara; Van Vliet, Adri; Bautsoens, Nadine; Van Rie, Jeroen; Ferré, Juan

    2008-01-01

    For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with 125I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera. Homologous-competition assays with 125I-Cry2Ab demonstrated that this toxin binds with high affinity to binding sites in H. armigera and Helicoverpa zea midgut. Heterologous-competition assays showed a common binding site for three toxins belonging to the Cry2A family (Cry2Aa, Cry2Ab, and Cry2Ae), which is not shared by Cry1Ac. Estimation of Kd (dissociation constant) values revealed that Cry2Ab had around 35-fold less affinity than Cry1Ac for BBMV binding sites in both insect species. Only minor differences were found regarding Rt (concentration of binding sites) values. This study questions previous interpretations from other authors performing binding assays with Cry2A toxins and establishes the basis for the mode of action of Cry2A toxins. PMID:18931285

  3. UJI KETAHANAN BEBERAPA GALUR KAPAS (Gossypium hirsutum HASIL RADIASI TERHADAP SERANGGA HAMA PENGGEREK BUAH Helicoverpa armigera(Hǖbner

    Directory of Open Access Journals (Sweden)

    Dwi Sunarto

    2015-09-01

    Full Text Available Uji  ketahanan beberapa galur kapas (Gossypium hirsutum terhadap  penggerek buah Helicoverpa armigera (Hǖbner dilaksanakan di laboratorium Entomologi Balai Penelitian Tanaman Pemanis dan Serat Malang pada bulan Januari sampai dengan Mei 2011. Penelitian bertujuan untuk mengevaluasi ketahanan beberapa galur kapas hasil radiasi terhadap penggerek buah H. armigera.  Perlakuan disusun menggunakan Rancangan Acak Kelompok (RAK yang terdiri atas empat galur hasil radiasi yaitu galur IA, 2A, 4A, dan 2C, dua varietas hasil radiasi yaitu Karisma, NIAB, dan dua varietas hasil pemuliaan konvensional yaitu Kanesia 10 dan Kanesia 15.  Setiap perlakuan diulang 3 kali.  Pengujian dilakukan dengan cara uji pakan (feeding assay daun, kuncup daun, dan buah muda sesuai dengan perkembangan larva H. armigera.  Larva instar I, instar II-III, dan instar IV-V berturut-turut diberikan daun muda, kuncup bunga, dan buah muda. Hasil penelitian menunjukkan bahwa galur kapas nomor 1A, 2A, 4A, dan 4C merupakan galur yang toleran terhadap H. armigera.  Kata kunci : Gossypium hirsutum, Helicoverpa armigera,   ketahanan  varietas.

  4. Occurrence of Cystosporogenes sp. (Protozoa, Microsporidia) in a multi-species insect production facility and its elimination from a colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae).

    Science.gov (United States)

    van Frankenhuyzen, Kees; Ebling, Peter; McCron, Bob; Ladd, Tim; Gauthier, Debbie; Vossbrinck, Charles

    2004-09-01

    We have isolated a microsporidium from a laboratory colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae). Light and electron microscopic investigations showed that gross pathology and ultrastructure of our isolate are similar to those described for Cystosporogenes legeri from the European grape vine moth, Lobesia botrana. Comparative phylogenetic analysis of the small subunit rDNA using maximum likelihood, maximum parsimony, and neighbour joining distance methods revealed perfect homology with the C. legeri sequence. The microsporidian was infectious to other Choristoneura species, as well as Malacosoma disstria, Lymantria dispar, and Lambdina fiscellaria. Incubation of infected egg masses at 41 degrees C for 20 min followed by 30 min in 33% formaldehyde did not reduce disease incidence in larval offspring. Exposure of one or two generations to fumagillin at 6000 ppm or higher eliminated infection in adult moths, but also reduced colony fitness. A clean colony was established by conducting individual matings and selecting disease-free offspring.

  5. Monitoring larval populations of the douglas-fir tussock moth and the western spruce budworm on permanent plots: Sampling methods and statistical properties of data. Forest Service general technical report

    Energy Technology Data Exchange (ETDEWEB)

    Mason, R.R.; Paul, H.G.

    1994-05-01

    Procedures for monitoring Larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience of sample these species in eastern Oregon and Washington. It is shown that statistically reliable estimates of larval density can be made for a population by sampling host trees in a series of permanent plots in a geographical monitoring unit. The most practical method is to estimate densities of both insect species simultaneously on a plot by the nondestructive sampling of foliage on lower crown branches of host trees. For best results, sampling methods need to be consistent with monitoring done annually to accumulate continuous databases that reflect the behavior of defoliator populations over a long period of time.

  6. Cross-resistance to alpha-cypermethrin after xanthotoxin ingestion in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Li, X; Zangerl, A R; Schuler, M A; Berenbaum, M R

    2000-02-01

    Cytochrome P450 monooxygenases (P450) are membrane-bound hemoproteins that play important roles in conferring protection against both naturally occurring phytochemicals and synthetic organic insecticides. Despite the potential for common modes of detoxification, cross-resistance between phytochemicals and synthetic organic insecticides has rarely been documented. In this study, we examined the responses of a susceptible strain of corn earworm, Helicoverpa zea (Boddie), a polyphagous noctuid, to exposure by an allelochemical infrequently encountered in its host plants and by an insecticide widely used for control purposes. Within a single generation, survivors of xanthotoxin exposure displayed higher levels of tolerance to alpha-cypermethrin than did unexposed control larvae. The F1 offspring of xanthotoxin-exposed survivors also displayed higher alpha-cypermethrin tolerance than did offspring of unexposed control larvae, suggesting that increased alpha-cypermethrin tolerance after xanthotoxin exposure represents, at least in part, heritable resistance. Administration of piperonyl butoxide, a P450 synergist, demonstrated that resistance to both xanthotoxin and alpha-cypermethrin is P450-mediated. Alpha-cypermethrin-exposed survivors, however, failed to show superior growth on xanthotoxin diets. Assays with control larvae, larvae induced by both xanthotoxin and alpha-cypermethrin, and survivors of LD50 doses of both compounds indicated that H. zea midgut P450s are capable of metabolizing both xanthotoxin and alpha-cypermethrin. Metabolism of each compound is significantly inhibited by the presence of the other compound, suggesting that at least one form of P450 in H. zea midguts degrades both compounds and may constitute the biochemical basis for possible cross-resistance. Compared with control larvae, xanthotoxin- and alpha-cypermethrin-induced larvae displayed 2- to 4-fold higher P450-mediated metabolism of both compounds. However, xanthotoxin- and alpha

  7. Influência da idade dos ovos de Helicoverpa zea (Boddie no parasitismo de Trichogramma pretiosum Riley Influence of egg age of Helicoverpa zea (Boddie on the parasitism by Trichogramma pretiosum Riley

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    1999-05-01

    Full Text Available Entre os agentes de controle biológico, os parasitóides do gênero Trichogramma representam um dos mais importantes grupos, pois controlam diversas pragas na agricultura. Este trabalho teve por objetivo determinar a melhor idade dos ovos de Helicoverpa zea (Boddie para que Trichogramma pretiosum Riley tenha uma melhor eficiência no controle dessa praga. Ovos com um, dois, três e quatro dias foram oferecidos para o parasitismo, por um período de 24 horas a 25 ± 1ºC, umidade relativa de 70 ± 10% e fotofase de 14 horas. Ovos de um dia de idade apresentaram a maior taxa de parasitismo, viabilidade e número de descendentes por fêmea. A mais alta eficiência de T. pretiosum será alçancada no campo, quando for observado maior densidade de ovos de H. zea com, no máximo, dois dias de desenvolvimento embrionário.Among the agents of biological control, the parasitoids of the genus Trichogramma represent one of the most important groups, as they are able to control many pests in agriculture. The objective of this work was to determine the best age of the Helicoverpa zea (Boddie eggs so that the Trichogramma pretiosum Riley could have the best efficiency against this pest. One, two, three and four-days-old eggs were offered for the parasitism during 24 hours, at 25 ± 1ºC, relative humidity 70 ± 10% and photofase of 14 hours. One-day-old eggs showed the highest rates of parasitism, viability, and number of descendants for each female. The highest efficiency with T. pretiosum will be reached in the field conditions, when observed a great density of H. zea eggs until two days of embryonic development.

  8. Insecticidal activity of venomous saliva from Rhynocoris fuscipes (Reduviidae against Spodoptera litura and Helicoverpa armigera by microinjection and oral administration

    Directory of Open Access Journals (Sweden)

    K Sahayaraj

    2011-01-01

    Full Text Available Rhynocoris fuscipes is a potential predator of many economically important pests in India. In the present study, its venomous saliva (VS was collected by milking and diluted with HPLC grade water to different concentrations (200, 400, 600, 800 and 1000 ppm. Microinjection of Rhynocoris fuscipes VS was more toxic than its oral administration in Helicoverpa armigera (cotton bollworm and Spodoptera litura (tobacco cutworm. Thus, R. fuscipes VS was found to be toxic to third instar S. litura and H. armigera with respective LD50s of 846.35 and 861.60 ppm/larva at 96 hours after microinjection. The current results showed that VS of Rhynocoris fuscipes caused mortality of H. armigera and S. litura. Active peptides from VS may be isolated, identified and assessed for their impact in order to ascertain how they alter the physiology of these pests, information that could be applicable in pest management programs.

  9. Determination of lethal concentration (LC50 for different insecticides against third instar larvae of Helicoverpa armigera (Hubner (LEPIDOPTERA:NOCTUIDAE

    Directory of Open Access Journals (Sweden)

    M. Hamed

    2006-03-01

    Full Text Available The efficacy of LorsbanTM, Alpha-cypermethrinTM and KarateTM was assessed by larval dip bioassay against third instar larvae of American bollworm, Helicoverpa armigera (Hub. collected from a cotton field at Faisalabad and reared in the laboratory until F1 generation. Third instar larvae were used to assess the toxicity of insecticides after 48 hrs of insecticide treatments. Results showed that toxicity of Karate was above all with LC50 of 71.31ppm followed by Alpha-cypermethrin with LC50 287.87 and Lorsban 464.85, respectively. These results showed the increased resistance of H. armigera against Lorsban in F1 generation under laboratory conditions.

  10. Interaction of plant cell signaling molecules, salicylic acid and jasmonic acid, with the mitochondria of Helicoverpa armigera.

    Science.gov (United States)

    Akbar, S M D; Sharma, H C; Jayalakshmi, S K; Sreeramulu, K

    2012-02-01

    The cotton bollworm, Helicoverpa armigera is a polyphagous pest in Asia, Africa, and the Mediterranean Europe. Salicylic acid (SA) and jasmonic acid (JA) are the cell signaling molecules produced in response to insect attack in plants. The effect of these signaling molecules was investigated on the oxidative phosphorylation and oxidative stress of H. armigera. SA significantly inhibited the state III and state IV respiration, respiratory control index (RCI), respiratory complexes I and II, induced mitochondrial swelling, and cytochrome c release in vitro. Under in vivo conditions, SA induced state IV respiration as well as oxidative stress in time- and dose-dependent manner, and also inhibited the larval growth. In contrast, JA did not affect the mitochondrial respiration and oxidative stress. SA affected the growth and development of H. armigera, in addition to its function as signaling molecules involved in both local defense reactions at feeding sites and the induction of systemic acquired resistance in plants.

  11. Bioactivity of Pseudocalymma alliaceum (Lam.) Sandwith (Bignoniaceae) against Spodoptera litura Fabricius and Helicoverpa armigera Hübner (Lepidotera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Alagarmalai Jeyasankar; Tamilarasu Chinnamani

    2014-01-01

    Objective: To evaluate the antifeedant, larvicidal and insect growth inhibitory activities of crude extracts of Pseudocalymma alliaceum tested against fourth instar larvae of Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). Methods: Hexane, chloroform and ethyl acetate extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera.Results:Ethyl acetate extract showed promising antifeedant, insecticidal activity against S. litura and H. armigera. Maximum percentage of deformed larvae, pupae and adults were found on treatment with ethyl acetate extract. Percentage of successful adult emergence was deteriorated by extract treated larvae. Ethyl acetate extracts of Pseudocalymma alliaceum, showed higher percentage of antifeedant, insecticidal and growth inhibition activities.Conclusions:This is the first report on S. litura and H. armigera. Further, the active compounds isolated from the ethyl acetate extracts will be useful for controlling economically important insect pests.

  12. Insecticidal Efficacy of Azadirachta indica, Nucleopolyhedrovirus and Chlorantraniliprole Singly or Combined against Field Populations fo Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) Eficacia Insecticida de Azadirachta indica, Nucleopolihedrovirus y Clorantraniliprol solo y sus Aplicaciones Integradas contra Poblaciones de Campo de Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

    OpenAIRE

    2012-01-01

    The development of resistance in cosmopolitan insect Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) forced the researchers for alternative control measures. In the present study, insecticidal efficacy of formulations of Azadirachta indica, a Nucleopolyhedrovirus (NPV), and new anthranilic diamide insecticide (chlorantraniliprole) formulations was determined against 2nd, through 5th larval instars of H. armigera collected from diverse geographical locations in the Punjab province, Pakist...

  13. Molecular characterization and expression of prothoracicotropic hormone during development and pupal diapause in the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Wei, Zhao-Jun; Zhang, Qi-Rui; Kang, Le; Xu, Wei-Hua; Denlinger, David L

    2005-06-01

    Using a strategy of rapid amplification of cDNA ends, the cDNA encoding prothoracicotropic hormone (PTTH) was cloned from the brain of Helicoverpa armigera (Hearm). The Hearm-PTTH cDNA contains an open reading frame encoding a 226-amino acid preprohormone, which shows high identity with the closely related noctuid moths, Helicoverpa zea (98%) and Heliothis virescens (94%), and low identity with five species of Bombycoidea: Bombyx mori (57%), Manduca sexta (55%), Hyalophora cecropia (52%), Samia cynthia ricini (49%) and Antheraea peryni (48%). Hearm-PTTH cDNA shares important structural characterization known from other PTTHs, such as seven cysteine residues, proteolytic cleavage site, glycosylation site, and hydrophobic regions within the mature peptides. Northern blot analysis indicated a 0.9kb transcript present only in the brain. Using the more sensitive technique of RT-PCR, PTTH mRNA was also detected in the subesophageal ganglion, thoracic ganglion, abdominal ganglion, midgut and fat body. During the pupal stage, PTTH mRNA in the brain remained at a constant high level in nondiapausing individuals, was low in diapausing pupae, but increased again at diapause termination. The PTTH protein was detected only in the brain by Western blot analysis. Immunocytochemical results revealed that Hearm-PTTH is localized in two pairs of dorsolateral neurosecretory cells within the brain. Recombinant Hearm-PTTH was successfully expressed in E. coli, and purified recombinant-PTTH was effective in breaking pupal diapause. The results are consistent with a role for PTTH in the regulation of diapause in this species.

  14. Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions

    OpenAIRE

    2011-01-01

    Transgenic cotton (Gossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects. the Cry1Ac gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in conferring resistance to cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was studied in laboratory and field experiments. In each experiment, performance of Bt+CpTI cotton was c...

  15. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop

    Directory of Open Access Journals (Sweden)

    Bhavna Bharucha

    2010-04-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea and sorghum can be used as mixed crops to protect the crop from

  16. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop

    Directory of Open Access Journals (Sweden)

    Bharucha Bhavna

    2010-06-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea

  17. Molecular identification of three novel glutaredoxin genes that play important roles in antioxidant defense in Helicoverpa armigera.

    Science.gov (United States)

    Zhang, Song-Dou; Shen, Zhong-Jian; Liu, Xiao-Ming; Li, Zhen; Zhang, Qing-Wen; Liu, Xiao-Xia

    2016-08-01

    Glutaredoxins (Grxs), also known as thioltransferases, play key roles in maintaining intracellular redox balance and protecting cells from oxidative damage in plants and mammals. We tested whether Grxs play important roles in antioxidant defense in insects using the moth, Helicoverpa armigera. We obtained the full-length cDNA sequences of three novel Grx genes, named HaGrx, HaGrx3, and HaGrx5. Sequence analysis indicated that HaGrx shared a high amino acid identity (58%-78%) and a CPYC motif of conserved redox activity with homologues from other selected insect species. In contrast, HaGrx3 and HaGrx5 both shared a CGF(S/G) motif, a conserved catalytic domain, with other orthologous genes. Quantitative real-time PCR results revealed that HaGrx, HaGrx3, and HaGrx5 exhibited temporally- and spatially-dependent patterns of expression. The mRNA expression of HaGrx, HaGrx3, and HaGrx5 was induced by various temperature stresses and H2O2 treatments. We further investigated the knockdown of HaGrx, HaGrx3, and HaGrx5 in H. armigera larvae and found that most of the selected antioxidant genes were up regulated. However, Tpx was down regulated, and further interpretation of the complementary functions of these antioxidant genes is still required. We also determined the effect of HaGrx, HaGrx3, and HaGrx5 knockdown on antioxidant enzymatic activity and metabolite content. The enzymatic activities of SOD, CAT, and POD, and the metabolite contents of hydrogen peroxide, ascorbate, protein carbonyl, and total GSH increased after RNAi mediated knockdown of HaGrx, HaGrx3, and HaGrx5. These results supported our hypothesis that HaGrx, HaGrx3, and HaGrx5 play important roles in antioxidant defense of Helicoverpa armigera and provided a theoretical basis for further in-depth study of physiological function in the insect glutaredoxin family genes.

  18. Molecular Cloning, Expression, and Identification of Bre Genes Involved in Glycosphingolipids Synthesis in Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Zhang, Dandan; Xiao, Yutao; Hussain Dhiloo, Khalid; Soberon, Mario; Bravo, Alejandra; Wu, Kongming

    2016-05-17

    Glycosphingolipids (GSLs) play important roles in the cellular biology of vertebrate and invertebrate organisms, such as cell differentiation, tumor metastasis, and cell coordination. GSLs also serve as receptors for different bacterial toxins. For example, in the nematode Caenorhabditis elegans, GSLs function as receptors of the insecticidal Cry toxins produced by Bacillus thuringiensis (Bt), and mutations in bre genes involved in GSLs synthesis resulted in resistance to Cry5 toxin in this organism. However, the information of GSLs function in insects is still limited. In this study, three genes for glycosyltransferases, bre2, bre3, and bre4, from Helicoverpa armigera were identified and cloned. The previously reported bre5 gene from H. armigera was also analyzed. Protein sequence alignments revealed that proteins codified by H. armigera Bre shared high identity with homologous proteins from other organisms. Expression profile analysis revealed that the expressions of bre genes varied in the different tissues and also in the different developmental stages of H. armigera. Finally, the heterologous expression of bre genes in Trichoplusia ni Hi5 cell line showed that the corresponding translated proteins were localized in the cytoplasm of Hi5 cells. These results provide the bases for further functional studies of bre genes and analyzing potential roles of GSLs in mode of action of Cry1A toxin in H. armigera.

  19. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Science.gov (United States)

    Chen, Wenbo; Liu, Chenxi; Xiao, Yutao; Zhang, Dandan; Zhang, Yongdong; Li, Xianchun; Tabashnik, Bruce E; Wu, Kongming

    2015-01-01

    Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry) proteins from the bacterium Bacillus thuringiensis (Bt) in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50) of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f) was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.

  20. Densovirus is a mutualistic symbiont of a global crop pest (Helicoverpa armigera and protects against a baculovirus and Bt biopesticide.

    Directory of Open Access Journals (Sweden)

    Pengjun Xu

    2014-10-01

    Full Text Available Mutualistic associations between symbiotic bacteria and their hosts are common within insect systems. However, viruses are often considered as pathogens even though some have been reported to be beneficial to their hosts. Herein, we report a novel densovirus, Helicoverpa armigera densovirus-1 (HaDNV-1 that appears to be beneficial to its host. HaDNV-1 was found to be widespread in wild populations of H. armigera adults (>67% prevalence between 2008 and 2012. In wild larval populations, there was a clear negative interaction between HaDNV-1 and H. armigera nucleopolyhedrovirus (HaNPV, a baculovirus that is widely used as a biopesticide. Laboratory bioassays revealed that larvae hosting HaDNV-1 had significantly enhanced resistance to HaNPV (and lower viral loads, and that resistance to Bacillus thuringiensis (Bt toxin was also higher at low doses. Laboratory assays indicated that the virus was mainly distributed in the fat body, and could be both horizontally- and vertically-transmitted, though the former occurred only at large challenge doses. Densovirus-positive individuals developed more quickly and had higher fecundity than uninfected insects. We found no evidence for a negative effect of HaDNV-1 infection on H. armigera fitness-related traits, strongly suggesting a mutualistic interaction between the cotton bollworm and its densovirus.

  1. Helicoverpa armigera baseline susceptibility to Bacillus thuringiensis Cry toxins and resistance management for Bt cotton in India.

    Science.gov (United States)

    Gujar, G T; Kalia, V; Kumari, A; Singh, B P; Mittal, A; Nair, R; Mohan, M

    2007-07-01

    Transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt), often referred to as Bt cotton, is widely grown in many countries. Bt cotton with a single cry1A gene and stacked also with cry2A gene has provided satisfactory protection against the damage by the lepidopteran bollworms, especially the cotton bollworm, Helicoverpa armigera (Hübner) which is considered as a key pest. The baseline susceptibility of the larvae of H. armigera to Cry1Ac and other toxins carried out in many countries has provided a basis for monitoring resistance. There is no evidence of development of field-level resistance in H. armigera leading to the failure of Bt cotton crop anywhere in the world, despite the fact that Bt cotton was grown on the largest ever area of 12.1 million hectares in 2006 and its cumulative cultivation over the last 11 years has surpassed the annual cotton area in the world. Nevertheless, the Bt resistance management has become a necessity to sustain Bt cotton and other transgenic crops in view of potential of the target insects to evolve Cry toxin resistance.

  2. In vivo and in vitro effect of Acacia nilotica seed proteinase inhibitors on Helicoverpa armigera (Hübner) larvae

    Indian Academy of Sciences (India)

    S Ramesh Babu; B Subrahmanyam; Srinivasan; I M Santha

    2012-06-01

    Acacia nilotica proteinase inhibitor (AnPI) was isolated by ammonium sulphate precipitation followed by chromatography on DEAE-Sephadex A-25 and resulted in a purification of 10.68-fold with a 19.5% yield. Electrophoretic analysis of purified AnPI protein resolved into a single band with molecular weight of approximately 18.6+1.00 kDa. AnPI had high stability at different pH values (2.0 to 10.0) except at pH 5.0 and are thermolabile beyond 80°C for 10 min. AnPI exhibited effective against total proteolytic activity and trypsin-like activity, but did not show any inhibitory effect on chymotrypsin activity of midgut of Helicoverpa armigera. The inhibition kinetics studies against H. armigera gut trypsin are of non-competitive type. AnPI had low affinity for H. armigera gut trypsin when compared to SBTI. The partially purified and purified PI proteins-incorporated test diets showed significant reduction in mean larval and pupal weight of H. armigera. The results provide important clues in designing strategies by using the proteinase inhibitors (PIs) from the A. nilotica that can be expressed in genetically engineered plants to confer resistance to H. armigera.

  3. Effects of dietary quercetin on performance and cytochrome P450 expression of the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Liu, D; Yuan, Y; Li, M; Qiu, X

    2015-12-01

    Quercetin is ubiquitous in terrestrial plants. The cotton bollworm Helicoverpa armigera as a highly polyphagous insect has caused severe crop losses. Until now, interactions between this pest and quercetin are poorly understood at the biochemical and molecular levels. In this study, we investigated the in vivo effects of quercetin on performance of cotton bollworm and on cytochrome P450 (P450) expression. Deleterious effects of quercetin on the performance of the cotton bollworm, including growth, survival, pupation and adult emergence were observed after oral administration of 3 and 10 mg g(-1) quercetin to larvae since the third instar, whereas no significant toxic effect was found at 0.1 mg g(-1) quercetin treatment. Piperonyl butoxide treatment enhanced the toxicity of quercetin. In vitro metabolism studies showed that quercetin was rapidly transformed by gut enzymes of fifth instar larvae of the cotton bollworm. qRT-PCR results revealed that the effect of quercetin on P450 expression was tissue- and dose-specific. Quercetin regulated P450 expression in a mild manner, and it could serve as P450 inducer (CYP337B1, CYP6B6) or repressor (CYP337B1, CYP6B7, CYP6B27, CYP9A14, CYP6AE11, and CYP4M7). These findings are important for advancing our understanding of the biochemical and molecular response of insects to plant toxins and have implications for a smart pest control.

  4. Dynamic transcriptome analysis and volatile profiling of Gossypium hirsutum in response to the cotton bollworm Helicoverpa armigera.

    Science.gov (United States)

    Huang, Xin-Zheng; Chen, Jie-Yin; Xiao, Hai-Jun; Xiao, Yu-Tao; Wu, Juan; Wu, Jun-Xiang; Zhou, Jing-Jiang; Zhang, Yong-Jun; Guo, Yu-Yuan

    2015-07-07

    In response to insect herbivory, plants emit elevated levels of volatile organic compounds for direct and indirect resistance. However, little is known about the molecular and genomic basis of defense response that insect herbivory trigger in cotton plants and how defense mechanisms are orchestrated in the context of other biological processes. Here we monitored the transcriptome changes and volatile characteristics of cotton plants in response to cotton bollworm (CBW; Helicoverpa armigera) larvae infestation. Analysis of samples revealed that 1,969 transcripts were differentially expressed (log2|Ratio| ≥ 2; q ≤ 0.05) after CBW infestation. Cluster analysis identified several distinct temporal patterns of transcriptome changes. Among CBW-induced genes, those associated with indirect defense and jasmonic acid pathway were clearly over-represented, indicating that these genes play important roles in CBW-induced defenses. The gas chromatography-mass spectrometry (GC-MS) analyses revealed that CBW infestation could induce cotton plants to release volatile compounds comprised lipoxygenase-derived green leaf volatiles and a number of terpenoid volatiles. Responding to CBW larvae infestation, cotton plants undergo drastic reprogramming of the transcriptome and the volatile profile. The present results increase our knowledge about insect herbivory-induced metabolic and biochemical processes in plants, which may help improve future studies on genes governing processes.

  5. Integrated proteomic and metabolomic analysis of larval brain associated with diapause induction and preparation in the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhang, Qi; Lu, Yu-Xuan; Xu, Wei-Hua

    2012-02-03

    Diapause is a developmental arrest that allows an organism to survive unfavorable environmental conditions and is induced by environmental signals at a certain sensitive developmental stage. In Helicoverpa armigera, the larval brain receives the environmental signals for diapause induction and then regulates diapause entry at the pupal stage. Here, combined proteomic and metabolomic differential display analysis was performed on the H. armigera larval brain. Using two-dimensional electrophoresis, it was found that 22 proteins were increased and 27 proteins were decreased in the diapause-destined larval brain, 37 of which were successfully identified by MALDI-TOF/TOF mass spectrometry. RT-PCR and Western blot analyses showed that the expression levels of the differentially expressed proteins were consistent with the 2-DE results. Furthermore, a total of 49 metabolites were identified in the larval brain by GC-MS analysis, including 4 metabolites at high concentrations and 14 metabolites at low concentrations. The results gave us a clue to understand the governing molecular events of the prediapause phase. Those differences that exist in the induction phase of diapause-destined individuals are probably relevant to a special memory mechanism for photoperiodic information storage, and those differences that exist in the preparation phase are likely to regulate accumulation of specific energy reserves in diapause-destined individuals.

  6. Targeting chitinase gene of Helicoverpa armigera by host-induced RNA interference confers insect resistance in tobacco and tomato.

    Science.gov (United States)

    Mamta; Reddy, K R K; Rajam, M V

    2016-02-01

    Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a devastating agricultural insect pest with broad spectrum of host range, causing million dollars crop loss annually. Limitations in the present conventional and transgenic approaches have made it crucial to develop sustainable and environmental friendly methods for crop improvement. In the present study, host-induced RNA interference (HI-RNAi) approach was used to develop H. armigera resistant tobacco and tomato plants. Chitinase (HaCHI) gene, critically required for insect molting and metamorphosis was selected as a potential target. Hair-pin RNAi construct was prepared from the conserved off-target free partial HaCHI gene sequence and was used to generate several HaCHI-RNAi tobacco and tomato plants. Northern hybridization confirmed the production of HaCHI gene-specific siRNAs in HaCHI-RNAi tobacco and tomato lines. Continuous feeding on leaves of RNAi lines drastically reduced the target gene transcripts and consequently, affected the overall growth and survival of H. armigera. Various developmental deformities were also manifested in H. armigera larvae after feeding on the leaves of RNAi lines. These results demonstrated the role of chitinase in insect development and potential of HI-RNAi for effective management of H. armigera.

  7. RNAi silencing of the HaHMG-CoA reductase gene inhibits oviposition in the Helicoverpa armigera cotton bollworm.

    Science.gov (United States)

    Wang, Zhijian; Dong, Yongcheng; Desneux, Nicolas; Niu, Changying

    2013-01-01

    RNA interference (RNAi) has considerable promise for developing novel pest control techniques, especially because of the threat of the development of resistance against current strategies. For this purpose, the key is to select pest control genes with the greatest potential for developing effective pest control treatments. The present study demonstrated that the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase; HMGR) gene is a potential target for insect control using RNAi. HMGR is a key enzyme in the mevalonate pathway in insects. A complete cDNA encoding full length HMGR (encoding an 837-aa protein) was cloned from Helicoverpa armigera (Lepidoptera: Noctuidae). The HaHMGR (H. armigera HMGR) knockdown using systemic RNAi in vivo inhibited the fecundity of the females, effectively inhibited ovipostion, and significantly reduced vitellogenin (Vg) mRNA levels. Moreover, the oviposition rate of the female moths was reduced by 98% by silencing HaHMGR compared to the control groups. One-pair experiments showed that both the proportions of valid mating and fecundity were zero. Furthermore, the HaHMGR-silenced females failed to lay eggs (approximate 99% decrease in oviposition) in the semi-field cage performance. The present study demonstrated the potential implications for developing novel pest management strategies using HaHMGR RNAi in the control of H. armigera and other insect pests.

  8. Mitochondrial P-glycoprotein ATPase contributes to insecticide resistance in the cotton bollworm, Helicoverpa armigera (Noctuidae: Lepidoptera).

    Science.gov (United States)

    Akbar, S Md; Aurade, Ravindra M; Sharma, H C; Sreeramulu, K

    2014-09-01

    Cotton bollworm, Helicoverpa armigera, is one of the most damaging polyphagous pests worldwide, which has developed high levels of resistance to commonly applied insecticides. Mitochondrial P-glycoprotein (Pgp) was detected in the insecticide-resistant strain of H. armigera using C219 antibodies, and its possible role was demonstrated in the efflux of xenobiotic compounds using spectrofluorometer. The TMR accumulated in mitochondria in the absence of ATP, and effluxed out in presence of ATP; the process of efflux was inhibited in the presence of ortho-vandate, an inhibitor of Pgp, in insecticide-resistant larvae of H. armigera. The mitochondria isolated from insecticide-resistant larvae were resistant to insecticide-induced inhibition of oxygen consumption and cytochrome c release. Membrane potential decreased in a dose-dependent manner in the presence of higher concentration of insecticides (>50 µM) in mitochondria of insecticide-resistant larvae. In conclusion, mitochondrial Pgp ATPase detected in the insecticide-resistant larvae influenced the efflux of xenobiotic compounds. Pgp might be involved in protecting the mitochondrial DNA and the components of the electron transport chain from damage due to insecticides, and contributing to the resistance to the deleterious effects of insecticides on the growth of insecticide-resistant H. armigera larvae.

  9. Ovicidal activity of botanical oil formulations against Helicoverpa armigera Hubner and Spodoptera litura Fabricius (Lepidoptera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Susaimanickam Maria Packiam; Kathirvelu Baskar; Savarimuthu Ignacimuthu

    2012-01-01

    Objective: To evaluate the ovicidal activity of different botanical oil formulations againstHelicoverpa armigera and Spodoptera litura. Methods: Different botanical oils were formulated with different ratio to evaluate the ovicidal activity against H. armigera and S. litura at 5, 10, 15 and 20μl/L concentrations. Results: All the oil formulations showed the ovicidal activity against H. armigera and S. litura. The maximum ovicidal actvity of 76.74 and 69.36% was noticed at 20μl/L concentration in formulation 3 PONNEEM. Formulation 4 Pongam oil showed lower ovicidal activity of 31.34 and 24.76% against H. armigera and S. litura respectively. Among the formulations, PONNEEM exhibited statistically superior ovicidal activity against both insect pests. Conclusions: the present study clearly showed PONNEEM as a pontenial biopesticide to control the egg stage of economically important pests of H. armigera and S. litura. This is the first report for the ovicidal activity of PONNEEM against these two insect pests.

  10. A toxin-binding alkaline phosphatase fragment synergizes Bt toxin Cry1Ac against susceptible and resistant Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Wenbo Chen

    Full Text Available Evolution of resistance by insects threatens the continued success of pest control using insecticidal crystal (Cry proteins from the bacterium Bacillus thuringiensis (Bt in sprays and transgenic plants. In this study, laboratory selection with Cry1Ac yielded five strains of cotton bollworm, Helicoverpa armigera, with resistance ratios at the median lethal concentration (LC50 of activated Cry1Ac ranging from 22 to 1700. Reduced activity and reduced transcription of an alkaline phosphatase protein that binds Cry1Ac was associated with resistance to Cry1Ac in the four most resistant strains. A Cry1Ac-binding fragment of alkaline phosphatase from H. armigera (HaALP1f was not toxic by itself, but it increased mortality caused by Cry1Ac in a susceptible strain and in all five resistant strains. Although synergism of Bt toxins against susceptible insects by toxin-binding fragments of cadherin and aminopeptidase N has been reported previously, the results here provide the first evidence of synergism of a Bt toxin by a toxin-binding fragment of alkaline phosphatase. The results here also provide the first evidence of synergism of a Bt toxin by any toxin-binding peptide against resistant insects.

  11. Genetic engineering of cotton with a novel cry2AX1 gene to impart insect resistance against Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Karunamurthy Dhivya

    2016-09-01

    Full Text Available Embryogenic calli of cotton (Coker310 were cocultivated with the Agrobacterium tumefaciens strain LBA4404 harbouring the codon-optimised, chimeric cry2AX1 gene consisting of sequences from cry2Aa and cry2Ac genes isolated from Indian strains of Bacillus thuringiensis. Forty-eight putative transgenic plants were regenerated, and PCR analysis of these plants revealed the presence of the cry2AX1 gene in 40 plants. Southern blot hybridisation analysis of selected transgenic plants confirmed stable T-DNA integration in the genome of transformed plants. The level of Cry2AX1 protein expression in PCR positive plants ranged from 4.9 to 187.5 ng g-1 of fresh tissue. A transgenic cotton event, TP31, expressing the cry2AX1 gene showed insecticidal activity of 56.66 per cent mortality against Helicoverpa armigera in detached leaf disc bioassay. These results indicate that the chimeric cry2AX1 gene expressed in transgenic cotton has insecticidal activity against H. armigera.

  12. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea.

    Science.gov (United States)

    Persaud, Deryck R; Haunerland, Norbert H

    2004-01-01

    In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL). Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, approximately 80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3' and 5' RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL.

  13. Cloning and expression of the VHDL receptor from fat body of the corn ear worm, Helicoverpa zea

    Directory of Open Access Journals (Sweden)

    Deryck R. Persaud

    2004-02-01

    Full Text Available In Noctuids, storage proteins are taken up into fat body by receptor-mediated endocytosis. These include arylphorin and a second, structurally unrelated very high-density lipoprotein (VHDL. Previously, we have isolated a single storage protein receptor from the corn earworm, Helicoverpa zea, which binds both VHDL and arylphorin. The receptor protein is a basic, N-terminally blocked, ?80 kDa protein that is associated with fat body membranes. Microsequencing of proteolytic fragments of the isolated receptor protein revealed internal sequences that were used to clone the complete cDNA of the VHDL receptor by 3' and 5' RACE techniques. The receptor protein, when expressed in vitro via a suitable insect expression vector, reacted with antibodies against the native VHDL receptor and bound strongly to its ligand VHDL, thus confirming that the cloned cDNA represents indeed the previously purified VHDL receptor. The receptor protein and a second, similar protein also found associated with the fat body membrane show considerable homology to putative basic juvenile hormone suppressible proteins cloned previously from other Noctuid species. Sequence analysis revealed that the receptor is likely a peripheral membrane protein that may mediate the selective uptake of VHDL.

  14. VHDL, a larval storage protein from the corn earworm, Helicoverpa zea, is a member of the vitellogenin gene family.

    Science.gov (United States)

    Sum, Herbert; Haunerland, Norbert H

    2007-10-01

    The hemolymph of last instar larvae of the corn earworm, Helicoverpa zea contains a blue very high-density lipoprotein (VHDL) that is selectively taken up into fat body prior to pupation. Its amino-terminal sequence was determined by Edman degradation, and used to design a degenerate primer for PCR amplification. With 5' and 3' RACE techniques, the entire cDNA coding for VHDL was amplified and sequenced. Conceptual translation reveals a 173 kDa protein that contains a 15 amino acid signal sequence immediately before the experimentally determined N-terminus of the mature protein. The protein contains a typical lipoprotein N-terminal domain, and shows high sequence similarity to vitellogenins from Lepidoptera and other insect species. VHDL mRNA was not detectable in adult H. zea, and antibodies raised against VHDL did not react with adult hemolymph or yolk proteins. Therefore VHDL, although a member of the vitellogenin gene family, seems to be distinct from the vitellogenin expressed in adult females.

  15. Comparison of Leg Regeneration Potency Between Holometabolous Helicoverpa armigera (Lepidoptera: Noctuidae) and Hemimetabolous Locusta migratoria manilensis (Orthoptera: Acrididae).

    Science.gov (United States)

    Yang, Qingpo; Li, Zhen; Li, Hui; Li, Yanrong; Yang, Yuhui; Zhang, Qingwen; Liu, Xiaoxia

    2016-12-01

    After injury many insects could regenerate lost limb. In this study, Helicoverpa armigera Hubner and Locusta migratoria manilensis (Meyen, 1835) were chosen to compare the regeneration potency of holometabolous and hemimetabolous insects. We employed the classical approach of surgical excision to verify the regeneration ability and to investigate the factors that affect the extent of regeneration. The results found that H. armigera could regenerate intact legs when the larval legs were excised at the first and second instar and that legs of adult H. armigera had a close relationship with their larval counterparts. However, the adult legs became malformed or disappeared when excised at other older instars. For the L. migratoria, we found the legs have weak partial regeneration ability when amputation was conducted at the joint of two segments. The regeneration potency might be stronger the more proximal the operation. Regeneration process had a negative impact on the larval development. This is the first report of complete leg regeneration capacity having a strong correlation with the instar but not with the position where amputation occurred for H. armigera, while for the L. migratoria, partial regenerative ability had a close relationship with the position where amputation occurred but not with instars.

  16. Forecasting Helicoverpa populations in Australia: A comparison of regression based models and a bioclimatic based modelling approach

    Institute of Scientific and Technical Information of China (English)

    MYRONP.ZALUCKI; MICHAELJ.FURLONG

    2005-01-01

    Long-term forecasts of pest pressure are central to the effective management of many agricultural insect pests. In the eastern cropping regions of Australia, serious infestations of Helicoverpa punctigera (Wallenglen) and H. armigera (Hübner)(Lepidoptera:Noctuidae) are experienced annually. Regression analyses of a long series of light-trap catches of adult moths were used to describe the seasonal dynamics of both species. The size of the spring generation in eastern cropping zones could be related to rainfall in putative source areas in inland Australia. Subsequent generations could be related to the abundance of various crops in agricultural areas, rainfall and the magnitude of the spring population peak. As rainfall figured prominently as a predictor variable, and can itself be predicted using the Southern Oscillation Index (SOI), trap catches were also related to this variable. The geographic distribution of each species was modelled in relation to climate and CLIMEX was used to predict temporal variation in abundance at given putative source sites in inland Australia using historical meteorological data. These predictions were then correlated with subsequent pest abundance data in a major cropping region. The regression-based and bioclimatic-based approaches to predicting pest abundance are compared and their utility in predicting and interpreting pest dynamics are discussed.

  17. Detection and evolution of resistance to the pyrethroid cypermethrin in Helicoverpa zea (Lepidoptera: Noctuidae) populations in Texas.

    Science.gov (United States)

    Pietrantonio, P V; Junek, T A; Parker, R; Mott, D; Siders, K; Troxclair, N; Vargas-Camplis, J; Westbrook, J K; Vassiliou, V A

    2007-10-01

    The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

  18. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Zhuoya Zhao

    2016-07-01

    Full Text Available Crystal (Cry proteins derived from Bacillus thuringiensis (Bt have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  19. Identification of gene expression changes associated with the initiation of diapause in the brain of the cotton bollworm, Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Xu Wei-Hua

    2011-05-01

    Full Text Available Abstract Background Diapause, a state of arrested development accompanied by a marked decrease of metabolic rate, helps insects to overcome unfavorable seasons. Helicoverpa armigera (Har undergoes pupal diapause, but the molecular mechanism of diapause initiation is unclear. Using suppression subtractive hybridization (SSH, we investigated differentially expressed genes in diapause- and nondiapause-destined pupal brains at diapause initiation. Results We constructed two SSH libraries (forward, F and reverse, R to isolate genes that are up-regulated or down-regulated at diapause initiation. We obtained 194 unique sequences in the F library and 115 unique sequences in the R library. Further, genes expression at the mRNA and protein level in diapause- and nondiapause-destined pupal brains were confirmed by RT-PCR, Northern blot or Western blot analysis. Finally, we classified the genes and predicted their possible roles at diapause initiation. Conclusion Differentially expressed genes at pupal diapause initiation are possibly involved in the regulation of metabolism, energy, stress resistance, signaling pathways, cell cycle, transcription and translation.

  20. Functional analysis of the ABCs of eye color in Helicoverpa armigera with CRISPR/Cas9-induced mutations

    Science.gov (United States)

    Khan, Sher Afzal; Reichelt, Michael; Heckel, David G.

    2017-01-01

    Many insect pigments are localized in subcellular pigment granules, and transport of pigment precursors from the cytoplasm is accomplished by ABC proteins. Drosophila melanogaster has three half-transporter genes (white, scarlet, and brown, all affecting eye pigments) and Bombyx mori has a fourth (ok). The White, Brown, Scarlet and Ok proteins each have one transmembrane and one cytoplasmic domain and they heterodimerize to form functional transporters with different substrate specificities. We used CRISPR/Cas9 to create somatic and germ-line knockout mutations of these four genes in the noctuid moth Helicoverpa armigera. Somatic knockouts of white block pigmentation of the egg, first instar larva and adult eye, but germ-line knockouts of white are recessive lethal in the embryo. Knockouts of scarlet are viable and produce pigmentless first instar larvae and yellow adult eyes lacking xanthommatin. Knockouts of brown show no phenotypic effects on viability or pigmentation. Knockouts of ok are viable and produce translucent larval cuticle and black eyes. CRISPR/Cas9-induced mutations are a useful tool for analyzing how essential and non-essential genes interact to produce the diversity of insect pigmentation patterns found in nature. PMID:28053351

  1. Brush border membrane binding properties of Bacillus thuringiensis Vip3A toxin to Heliothis virescens and Helicoverpa zea midguts.

    Science.gov (United States)

    Lee, Mi Kyong; Miles, Paul; Chen, Jeng-Shong

    2006-01-27

    The binding properties of Vip3A, a new family of Bacillus thuringiensis insecticidal toxins, have been examined in the major cotton pests, Heliothis virescens and Helicoverpa zea. Vip3A bound specifically to brush border membrane vesicles (BBMV) prepared from both insect larval midguts. In order to examine the cross-resistance potential of Vip3A to the commercially available Cry1Ac and Cry2Ab2 toxins, the membrane binding site relationship among these toxins was investigated. Competition binding assays demonstrated that Vip3A does not inhibit the binding of either Cry1Ac or Cry2Ab2 and vice versa. BBMV protein blotting experiments showed that Vip3A does not bind to the known Cry1Ac receptors. These distinct binding properties and the unique protein sequence of Vip3A support its use as a novel insecticidal agent. This study indicates a very low cross-resistance potential between Vip3A and currently deployed Cry toxins and hence supports its use in an effective resistance management strategy in cotton.

  2. Specific binding of activated Vip3Aa10 to Helicoverpa armigera brush border membrane vesicles results in pore formation.

    Science.gov (United States)

    Liu, Jing-Guo; Yang, Ai-Zhen; Shen, Xiao-Hong; Hua, Bao-Guang; Shi, Guang-Lu

    2011-10-01

    Helicoverpa armigera is one of the most harmful pests in China. Although it had been successfully controlled by Cry1A toxins, some H. armigera populations are building up resistance to Cry1A toxins in the laboratory. Vip3A, secreted by Bacillus thuringiensis, is another potential toxin against H. armigera. Previous reports showed that activated Vip3A performs its function by inserting into the midgut brush border membrane vesicles (BBMV) of susceptible insects. To further investigate the binding of Vip3A to BBMV of H. armigera, the full-length Vip3Aa10 toxin expressed in Escherichia coli was digested by trypsin or midgut juice extract, respectively. Among the fragments of digested Vip3Aa10, only a 62kDa fragment (Vip3Aa10-T) exhibited binding to BBMV of H. armigera and has insecticidal activity. Moreover, this interaction was specific and was not affected by the presence of Cry1Ab toxin. Binding of Vip3Aa10-T to BBMV resulted in the formation of an ion channel. Unlike Cry1A toxins, Vip3Aa10-T was just slightly associated with lipid rafts of BBMV. These data suggest that although activated Vip3Aa10 specifically interacts with BBMV of H. armigera and forms an ion channel, the mode of action of it may be different from that of Cry1A toxins.

  3. Cannibalism of Helicoverpa zea (Lepidoptera: Noctuidae) from Bacillus thuringiensis (Bt) transgenic corn versus non-Bt corn.

    Science.gov (United States)

    Chilcutt, Charles F

    2006-06-01

    Because of the importance of cannibalism in population regulation of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in corn, Zea mays L., it is useful to understand the interactions between Bacillus thuringiensis (Bt) transgenic corn and cannibalism. To determine the effects of Bt corn on cannibalism in H. zea, pairs of the same or different instars were taken from Bt or non-Bt corn and placed on artificial diet in proximity. Cannibalism occurred in 91% of pairs and was approximately 7% greater for pairs of larvae reared from Bt transgenic corn (95%) than from non-Bt corn (88%). Also, first instar by first instar pairs had a lower rate of cannibalism than other pairs. Time until cannibalism was not different for larvae from Bt corn versus non-Bt corn. Pupation rate of cannibals and surviving victims was not different for pairs from Bt corn versus non-Bt corn. Finally, cannibalism increased pupation rate of cannibals from both Bt and non-Bt corn by approximately 23 and 12%, respectively, although the increases were not significant. Thus, negative effects of Bt on larvae were compensated by increased cannibalism in comparison with larvae reared on non-Bt corn, which increased larval survival to levels comparable with larvae reared on non-Bt plants.

  4. Feeding deterrent and growth inhibitory activities of PONNEEM, a newly developed phytopesticidal formulation against Helicoverpa armigera (Hubner)

    Institute of Scientific and Technical Information of China (English)

    Soosaimanickam Maria Packiam; Kathirvelu Baskar; Savarimuthu Ignacimuthu

    2014-01-01

    Objective: To assess the feeding deterrent, growth inhibitory and egg hatchability effects of PONNEEM on Helicoverpa armigera (H. armigera).Methods:growth inhibitory and egg hatchability effects on H. armigera.Results:Invariably all the newly formulated phytopesticidal oil formulations showed the feeding Five oil formulations were prepared at different ratios to assess the feeding deterrent, deterrent and growth inhibitory activities against H. armigera. The maximum feeding deterrent activity of 88.44% was observed at 15 µL/L concentration of PONNEEM followed by formulation A (74.54%). PONNEEM was found to be effective in growth inhibitory activities and egg hatchability at 10 µL/L concentration. It exhibited statistically significant feeding deterrent activity and growth inhibitory activity compared with all the other treatments.Conclusions:PONNEEM was found to be effective phytopesticidal formulation to control the larval stage of H. armigera. This is the first report for the feeding deterrent activity of PONNEEM against H.armigera. This newly formulated phytopesticide was patented in India.

  5. Evaluation of the role of CYP6B cytochrome P450s in pyrethroid resistant Australian Helicoverpa armigera.

    Science.gov (United States)

    Grubor, Vladimir D; Heckel, David G

    2007-02-01

    The AN02 strain of Helicoverpa armigera from eastern Australia exhibits 50-fold, PBO-suppressible resistance to the pyrethroid insecticide fenvalerate. The semidominant resistance gene RFen1 was previously mapped to AFLP Linkage Group 13. In evaluating the cytochrome P450 genes CYP6B7, CYP6B6, and CYP6B2 as candidates for RFen1, we found that they occur in a tandem array in the genome, next to the gene encoding the para-type sodium channel; the target of pyrethroid insecticides. We mapped these genes to AFLP Linkage Group 14, thus rejecting mutations within the P450 cluster or para as candidates for RFen1. RFen1 genotypes produced slightly different mRNA levels of the three P450s, but the differences were too small to convincingly account for resistance. We conclude that even if one or more of these P450s metabolize fenvalerate, they are unlikely to be responsible for the resistance in AN02.

  6. The expression of proteins involved in digestion and detoxification are regulated in Helicoverpa armigera to cope up with chlorpyrifos insecticide.

    Science.gov (United States)

    Dawkar, Vishal V; Chikate, Yojana R; More, Tushar H; Gupta, Vidya S; Giri, Ashok P

    2016-02-01

    Helicoverpa armigera is a key pest in many vital crops, which is mainly controlled by chemical strategies. To manage this pest is becoming challenging due to its ability and evolution of resistance against insecticides. Further, its subsequent spread on nonhost plant is remarkable in recent times. Hence, decoding resistance mechanism against phytochemicals and synthetic insecticides is a major challenge. The present work describes that the digestion, defense and immunity related enzymes are associated with chlorpyrifos resistance in H. armigera. Proteomic analysis of H. armigera gut tissue upon feeding on chlorpyrifos containing diet (CH) and artificial diet (AD) using nano-liquid chromatography-mass spectrometry identified upregulated 23-proteins in CH fed larvae. Database searches combined with gene ontology analysis revealed that the identified gut proteins engrossed in digestion, proteins crucial for immunity, adaptive responses to stress, and detoxification. Biochemical and quantitative real-time polymerase chain reaction analysis of candidate proteins indicated that insects were struggling to get nutrients and energy in presence of CH, while at the same time endeavoring to metabolize chlorpyrifos. Moreover, we proposed a potential processing pathway of chlorpyrifos in H. armigera gut by examining the metabolites using gas chromatography-mass spectrometry. H. armigera exhibit a range of intriguing behavioral, morphological adaptations and resistance to insecticides by regulating expression of proteins involved in digestion and detoxification mechanisms to cope up with chlorpyrifos. In these contexts, as gut is a rich repository of biological information; profound analysis of gut tissues can give clues of detoxification and resistance mechanism in insects.

  7. Distribution and Metabolism of Bt-Cry1Ac Toxin in Tissues and Organs of the Cotton Bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Zhao, Zhuoya; Li, Yunhe; Xiao, Yutao; Ali, Abid; Dhiloo, Khalid Hussain; Chen, Wenbo; Wu, Kongming

    2016-01-01

    Crystal (Cry) proteins derived from Bacillus thuringiensis (Bt) have been widely used in transgenic crops due to their toxicity against insect pests. However, the distribution and metabolism of these toxins in insect tissues and organs have remained obscure because the target insects do not ingest much toxin. In this study, several Cry1Ac-resistant strains of Helicoverpa armigera, fed artificial diets containing high doses of Cry1Ac toxin, were used to investigate the distribution and metabolism of Cry1Ac in their bodies. Cry1Ac was only detected in larvae, not in pupae or adults. Also, Cry1Ac passed through the midgut into other tissues, such as the hemolymph and fat body, but did not reach the larval integument. Metabolic tests revealed that Cry1Ac degraded most rapidly in the fat body, followed by the hemolymph, peritrophic membrane and its contents. The toxin was metabolized slowly in the midgut, but was degraded in all locations within 48 h. These findings will improve understanding of the functional mechanism of Bt toxins in target insects and the biotransfer and the bioaccumulation of Bt toxins in arthropod food webs in the Bt crop ecosystem.

  8. Putative Phosphorylation Sites On WCA Domain of HA2 Is Essential For Helicoverpa armigera Single Nucleopolyhedrovirus Replication

    Institute of Scientific and Technical Information of China (English)

    Yi-pin Lv; Qian Wang; Chun-chen Wu; Rong Juan Pei; Yuan Zhou; Yun Wang; Xin-wen Chen

    2011-01-01

    Protein phosphorylation is one of the most common post-translational modification processes that play an essential role in regulating protein functionality.The Helicoverpa armigera single nucleopolyhedrovirus (HearNPv) orf2-encoded nucleocapsid protein HA2 participates in orchestration of virus-induced actin polymerization through its WCA domain,in which phosphorylation status are supposed to be critical in respect to actin polymerization.In the present study,two putative phosphorylation sites (232Thr and 250Ser) and a highly conserved Serine (245Ser) on the WCA domain of HA2 were mutated,and their phenotypes were characterized by reintroducing the mutated HA2 into the HearNPV genome.Viral infectivity assays demonstrated that only the recombinant HearNPV bearing HA2 mutation at 245Ser can produce infectious virions,both 232Tbr and 250Ser mutations were lethal to the virus.However,actin polymerization assay demonstrated that all the three viruses bearing HA2 mutations were still capable of initiating actin polymerization in the host nucleus,which indicated the putative phosphorylation sites on HA2 may contribute to HearNPV replication through another unidentified pathway.

  9. EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone

    Institute of Scientific and Technical Information of China (English)

    邓建宇; 黄永平; 魏洪义; 杜家纬

    2004-01-01

    Electroantennogram (EAG) evaluation of selected compounds from wilted leaves ofblack poplar,Populus nigra,showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol,phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%,50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles should modify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

  10. EAG and behavioral responses of Helicoverpa armigera males to volatiles from poplar leaves and their combinations with sex pheromone

    Institute of Scientific and Technical Information of China (English)

    邓建宇; 黄永平; 魏洪义

    2004-01-01

    Electroantennogram (EAG) evaluation of selected compounds from wilted leaves of black poplar, Populus nigra, showed that phenyl acetaldehyde, methyl salicylate, (E)-2-hexenal elicited strong responses from male antennae of Helicoverpa armigera. When mixed with sex pheromone (Ph), some volatiles, e.g. phenyl acetaldehyde, benzyl alcohol, phenylethanol, methylsalicylate, linalool, benzaldehyde, (Z)-3-hexenol, (Z)-3-hexenylacetate, (Z)-6-nonenol, cineole, (E)-2-hexenal, and geraniol elicited stronger responses from male antennae than Ph alone. Wind tunnel bioassay demonstrated that various volatiles could either enhance or inhibit the effect of synthetic sex pheromone. (E)-2-hexenal, (Z)-3-hexenol and linalool in combination with Ph could not induce any male to land on source at all, whereas phenyl acetaldehyde, benzaldehyde, (Z)-6-nonenol and salicylaldehyde combined with Ph enhanced male response rates by 58.63%, 50.33%, 51.85% and 127.78%, respectively, compared to Ph alone. These results suggested that some volatiles shouldmodify sex pheromone caused behavior and that some of them could possibly be used as a tool for disrupting mating or for enhancing the effect of synthetic sex pheromone in the field.

  11. Binding site alteration is responsible for field-isolated resistance to Bacillus thuringiensis Cry2A insecticidal proteins in two Helicoverpa species.

    Directory of Open Access Journals (Sweden)

    Silvia Caccia

    Full Text Available BACKGROUND: Evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing Bacillus thuringiensis (Bt insecticidal proteins. Cry2 proteins play a pivotal role in current Bt spray formulations and transgenic crops and they complement Cry1A proteins because of their different mode of action. Their presence is critical in the control of those lepidopteran species, such as Helicoverpa spp., which are not highly susceptible to Cry1A proteins. In Australia, a transgenic variety of cotton expressing Cry1Ac and Cry2Ab (Bollgard II comprises at least 80% of the total cotton area. Prior to the widespread adoption of Bollgard II, the frequency of alleles conferring resistance to Cry2Ab in field populations of Helicoverpa armigera and Helicoverpa punctigera was significantly higher than anticipated. Colonies established from survivors of F(2 screens against Cry2Ab are highly resistant to this toxin, but susceptible to Cry1Ac. METHODOLOGY/PRINCIPAL FINDINGS: Bioassays performed with surface-treated artificial diet on neonates of H. armigera and H. punctigera showed that Cry2Ab resistant insects were cross-resistant to Cry2Ae while susceptible to Cry1Ab. Binding analyses with (125I-labeled Cry2Ab were performed with brush border membrane vesicles from midguts of Cry2Ab susceptible and resistant insects. The results of the binding analyses correlated with bioassay data and demonstrated that resistant insects exhibited greatly reduced binding of Cry2Ab toxin to midgut receptors, whereas no change in (125I-labeled-Cry1Ac binding was detected. As previously demonstrated for H. armigera, Cry2Ab binding sites in H. punctigera were shown to be shared by Cry2Ae, which explains why an alteration of the shared binding site would lead to cross-resistance between the two Cry2A toxins. CONCLUSION/SIGNIFICANCE: This is the first time that a mechanism of resistance to the Cry2 class of insecticidal proteins has been reported

  12. An analysis of structure fitting and bioactivity between sex pheromone of cotton bollworm, Helicoverpa armigera (H(u)bner) and its fluorinated analogs

    Institute of Scientific and Technical Information of China (English)

    KAN Wei; ZHANG Zhongning; YANG Xinling; FANG Yuling; XIAO Chun

    2005-01-01

    A study on the structure-activty relationship between (Z)-hexadec-9-enal (Z-9-16:Ald) and its analog was conducted by comparing the structures of the sex pheromone of cotton bollworm, Helicoverpa armigera (Hübner) with its fluorinated analog using computer molecular fitting. It is demonstrated that the structure of analog substituting for hydrogen atom on the terminal carbon atom is similar to Z-9-16:Ald. The EAG result showed that there is no significant difference in activities between Z-9-16:Ald and its fluorinated analog synthesized.

  13. Antifeedant, larvicidal and growth inhibitory effects of ononitol monohydrate isolated from Cassia tora L. against Helicoverpa armigera (Hub.) and Spodoptera litura (Fab.) (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Baskar, Kathirvelu; Ignacimuthu, Savarimuthu

    2012-07-01

    Ononitol monohydrate isolated from the ethyl acetate extract of Cassia tora L. using column chromatography was evaluated for its antifeedant, larvicidal and growth inhibitory activities against Helicoverpa armigera and Spodoptera litura at different concentrations of 125, 250, 500 and 1000 ppm. Leaf disc no-choice method was used for the bioassay. The compound showed significant antifeedant, larvicidal and pupicidal activities against H. armigera and S. litura. The compound also prolonged the larval-pupal duration of the insect at all the tested concentrations. The activities were concentration dependent for both the insects. Ononitol could be used as an agent to prepare botanical new pesticidal formulations.

  14. Resistance to Bacillus thuringiensis toxin Cry2Ab in a strain of Helicoverpa armigera (Lepidoptera: Noctuidae) in Australia.

    Science.gov (United States)

    Mahon, R J; Olsen, K M; Garsia, K A; Young, S R

    2007-06-01

    Transgenic cotton, Gossypium hirsutum L., expressing the crylAc and cry2Ab genes from Bacillus thuringiensis (Bt) Berliner variety kurstaki in a pyramid (Bollgard II) was widely planted for the first time in Australia during the 2004-2005 growing season. Before the first commercial Bollgard II crops, limited amounts of cotton expressing only the crylAc gene (Ingard) was grown for seven seasons. No field failures due to resistance to CrylAc toxin were observed during that period and a monitoring program indicated that the frequency of genes conferring high level resistance to the CrylAc toxin were rare in the major pest of cotton, Helicoverpa armigera (Htibner) (Lepidoptera: Noctuidae). Before the deployment of Bollgard II, an allele conferring resistance to Cry2Ab toxin was detected in field-collected H. armigera. We established a colony (designated SP15) consisting of homozygous resistant individuals and examined their characteristics through comparison with individuals from a Bt-susceptible laboratory colony (GR). Through specific crosses and bioassays, we established that the resistance present in SP15 was due to a single autosomal gene. The resistance was recessive. Homozygotes were highly resistant to Cry2Ab toxin, so much so, that we were unable to induce significant mortality at the maximum concentration of toxin available. Homozygotes also were unaffected when fed leaves of a cotton variety expressing the cry2Ab gene. Although cross-resistant to Cry2Aa toxin, SP15 was susceptible to CrylAc and to the Bt product DiPel.

  15. Elevated CO2 reduces the resistance and tolerance of tomato plants to Helicoverpa armigera by suppressing the JA signaling pathway.

    Directory of Open Access Journals (Sweden)

    Huijuan Guo

    Full Text Available Both resistance and tolerance, which are two strategies that plants use to limit biotic stress, are affected by the abiotic environment including atmospheric CO(2 levels. We tested the hypothesis that elevated CO(2 would reduce resistance (i.e., the ability to prevent damage but enhance tolerance (i.e., the ability to regrow and compensate for damage after the damage has occurred of tomato plants to the cotton bollworm, Helicoverpa armigera. The results showed that elevated CO(2 reduced resistance by decreasing the jasmonic acid (JA level and activities of lipoxygenase, proteinase inhibitors, and polyphenol oxidase in wild-type (WT plants infested with H. armigera. Consequently, the activities of total protease, trypsin-like enzymes, and weak and active alkaline trypsin-like enzymes increased in the midgut of H. armigera when fed on WT plants grown under elevated CO(2. Unexpectedly, the tolerance of the WT to H. armigera (in terms of photosynthetic rate, activity of sucrose phosphate synthases, flower number, and plant biomass and height was also reduced by elevated CO(2. Under ambient CO(2, the expression of resistance and tolerance to H. armigera was much greater in wild type than in spr2 (a JA-deficient genotype plants, but elevated CO(2 reduced these differences of the resistance and tolerance between WT and spr2 plants. The results suggest that the JA signaling pathway contributes to both plant resistance and tolerance to herbivorous insects and that by suppressing the JA signaling pathway, elevated CO(2 will simultaneously reduce the resistance and tolerance of tomato plants.

  16. The potential distribution of invading Helicoverpa armigera in North America: is it just a matter of time?

    Directory of Open Access Journals (Sweden)

    Darren J Kriticos

    Full Text Available Helicoverpa armigera has recently invaded South and Central America, and appears to be spreading rapidly. We update a previously developed potential distribution model to highlight the global invasion threat, with emphasis on the risks to the United States. The continued range expansion of H. armigera in Central America is likely to change the invasion threat it poses to North America qualitatively, making natural dispersal from either the Caribbean islands or Mexico feasible. To characterise the threat posed by H. armigera, we collated the value of the major host crops in the United States growing within its modelled potential range, including that area where it could expand its range during favourable seasons. We found that the annual value of crops that would be exposed to H. armigera totalled approximately US$78 billion p.a., with US$843 million p.a. worth growing in climates that are optimal for the pest. Elsewhere, H. armigera has developed broad-spectrum pesticide resistance; meaning that if it invades the United States, protecting these crops from significant production impacts could be challenging. It may be cost-effective to undertake pre-emptive biosecurity activities such as slowing the spread of H. armigera throughout the Americas, improving the system for detecting H. armigera, and methods for rapid identification, especially distinguishing between H. armigera, H. zea and potential H. armigera x H. zea hybrids. Developing biological control programs, especially using inundative techniques with entomopathogens and parasitoids could slow the spread of H. armigera, and reduce selective pressure for pesticide resistance. The rapid spread of H. armigera through South America into Central America suggests that its spread into North America is a matter of time. The likely natural dispersal routes preclude aggressive incursion responses, emphasizing the value of preparatory communication with agricultural producers in areas suitable for

  17. Isotopes and trace elements as natal origin markers of Helicoverpa armigera--an experimental model for biosecurity pests.

    Science.gov (United States)

    Holder, Peter W; Armstrong, Karen; Van Hale, Robert; Millet, Marc-Alban; Frew, Russell; Clough, Timothy J; Baker, Joel A

    2014-01-01

    Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150-3000 km apart). Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The geographic resolution

  18. Functional response of Chrysoperla carnea (Neuroptera: Chrysopidae) to Helicoverpa armigera (Lepidoptera: Noctuidae): Effect of prey and predator stages

    Institute of Scientific and Technical Information of China (English)

    Mehdi Hassanpour; Jafar Mohaghegh; Shahzad Iranipour; Gadir Nouri-Ganbalani; Annie Enkegaard

    2011-01-01

    Understanding predator-prey interactions has a pivotal role in biological control programs. This study evaluated the functional response of three larval instars of the green lacewing, Chrysoperla carnea (Stephens), preying upon eggs and first instar larvae of the cotton bollworm, Helicoverpa armigera Hilbner. The first and second instar larvae of C. carnea exhibited typeⅡ functional responses against both prey stages. However, the third instar larvae of C. carnea showed a typeⅡ functional response to the first instar larvae of H. armigera, but a typeⅢ functional response to the eggs. For the first instar larvae of C. carnea, the attack rate on H. armigera eggs was significantly higher than that on the larvae, whereas the attack rate of the second instar C. carnea on H. armigera larvae was significantly higher than that on the eggs. For the third instar larvae of C. carnea, the attack rate on the larvae was 1.015± 0.278/h, and the attack coefficient on the eggs was 0.036± 0.005. The handling times of the third instar larvae on larvae and eggs were 0.087± 0.009 and 0.071± 0.001 h, respectively. The highest predation rate was found for the third instar larvae of C. carnea on H. armigera eggs. Results of this study revealed that the larvae of C. carnea, especially the third instar, had a good predation potential in controlling H. armigera eggs and larvae. However, for a comprehensive estimation of the bio-control abilities of C. carnea toward//, armigera, further field-based studies are needed.

  19. Mutagenesis and nuclear magnetic resonance analyses of the fusion peptide of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus F protein.

    Science.gov (United States)

    Tan, Ying; Jiang, Ling; Wang, Manli; Yin, Feifei; Deng, Fei; Liu, Maili; Hu, Zhihong; Wang, Hualin

    2008-08-01

    The entry of enveloped viruses into cells is normally mediated by fusion between viral and cellular membranes, in which the fusion peptide plays a crucial role. The fusion peptides of group II nucleopolyhedrovirus (NPV) F proteins are quite conserved, with a hydrophobic region located at the N terminal of the F(1) fragment. For this report, we used mutagenesis and nuclear magnetic resonance (NMR) to study the structure and function of the fusion peptide of the Helicoverpa armigera single-nucleocapsid NPV (HearNPV) F protein (HaF). Five mutations in the fusion peptide of HaF, N(1)G, N(1)L, I(2)N, G(3)L, and D(11)L, were generated separately, and the mutated f genes were transformed into the f-null HearNPV bacmid. The mutations N(1)L, I(2)N, and D(11)L were found to completely abolish the ability of the recombinant bacmids to produce infectious budded virus, while the mutations N(1)G and G(3)L did not. The low-pH-induced envelope fusion assay demonstrated that the N(1)G substitution increased the fusogenicity of HaF, while the G(3)L substitution reduced its fusogenicity. NMR spectroscopy was used to determine the structure of a synthetic fusion peptide of HaF in the presence of sodium dodecyl sulfate micelles at pH 5.0. The fusion peptide appeared to be an amphiphilic structure composed of a flexible coil in the N terminus from N(1) to N(5), a 3(10)-helix from F(6) to G(8), a turn at S(9), and a regular alpha-helix from V(10) to D(19). The data provide the first NMR structure of a baculovirus fusion peptide and allow us to further understand the relationship of structure and function of the fusion peptide.

  20. Wnt/β-catenin signaling regulates Helicoverpa armigera pupal development by up-regulating c-Myc and AP-4.

    Science.gov (United States)

    Chen, Wei; Xu, Wei-Hua

    2014-10-01

    Seasonally changing environmental conditions perceived by insect brains can be converted into hormonal signals that prompt insects to make a decision to develop or enter developmental arrest (diapause). Diapause is a complex physiological response, and many signaling pathways may participate in its regulation. However, little is known about these regulatory pathways. In this study, we cloned four genes related to the Wnt/β-catenin signaling pathway from Helicoverpa armigera, a pupal diapause species. Western blotting shows that expression of Har-Wnt1, Har-β-catenin, and Har-c-Myc are higher in non-diapause pupal brains than in diapause-destined brains. Har-Wnt1 can promote the accumulation of Har-β-catenin in the nucleus, and Har-β-catenin in turn increases the expression of Har-c-Myc. The blockage of Wnt/β-catenin signaling by the inhibitor XAV939 significantly down-regulates Har-β-catenin and Har-c-Myc expression and delays pupal development, suggesting that the Wnt/β-catenin pathway functions in insect development. Furthermore, Har-c-Myc binds to the promoter of Har-AP-4 and regulates its expression. It has been reported that Har-AP-4 activates diapause hormone (DH) expression and that DH up-regulates the growth hormone ecdysteroid for pupal development. Thus, pupal development is regulated by Wnt/β-catenin signaling through the pathway Wnt-β-catenin-c-Myc-AP-4-DH-ecdysteroid. In contrast, the down-regulation of Wnt/β-catenin signaling is likely to induce insects to enter diapause.

  1. Development of neuropeptide analogs capable of traversing the integument: A case study using diapause hormone analogs in Helicoverpa zea.

    Science.gov (United States)

    Zhang, Qirui; Nachman, Ronald J; Kaczmarek, Krzysztof; Kierus, Krzysztof; Zabrocki, Janusz; Denlinger, David L

    2015-12-01

    Diapause hormone and its analogs terminate pupal diapause in Helicoverpa zea when injected, but if such agents are to be used as effective diapause disruptors it will be essential to develop simple techniques for administering active compounds that can exert their effect by penetrating the insect epidermis. In the current study, we used two molecules previously shown to have high diapause-terminating activity as lead molecules to rationally design and synthesize new amphiphilic compounds with modified hydrophobic components. An assay for diapause termination identified 13 active compounds with EC50's ranging from 0.9 to 46.0 pmol per pupa. Three compounds, Decyl-1963, Dodecyl-1967, and Heptyl-1965, selected from the 13 compounds most active in breaking diapause following injection, also successfully prevented newly-formed pupae from entering diapause when applied topically. These compounds feature straight-chain, aliphatic hydrocarbons from 7 to 12 carbons in length; DH analogs with either a short-chain length of 4 or an aromatic phenethyl group failed to act topically. Compared to a high diapause incidence of 80-90% in controls, diapause incidence in pupae receiving a 10 nmole topical application of Decyl-1963, Dodecyl-1967, or Heptyl-1965 dropped to 30-45%. Decyl-1963 and Dodecyl-1967 also remained effective when topically applied at the 1 nmole level. These results suggest the feasibility of developing DH agonists that can be applied topically and suggest the identity of new lead molecules for development of additional topically-active DH analogs. The ability to penetrate the insect epidermis and/or midgut lining is critical if such agents are to be considered for future use as pest management tools.

  2. Isotopes and trace elements as natal origin markers of Helicoverpa armigera--an experimental model for biosecurity pests.

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    Peter W Holder

    Full Text Available Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150-3000 km apart. Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The

  3. Isolation and Characterization of Gut Bacterial Proteases Involved in Inducing Pathogenicity of Bacillus thuringiensis Toxin in Cotton Bollworm, Helicoverpa armigera

    Science.gov (United States)

    Regode, Visweshwar; Kuruba, Sreeramulu; Mohammad, Akbar S.; Sharma, Hari C.

    2016-01-01

    Bacillus thuringiensis toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac) to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation toward pro-Cry1Ac. Among 12 gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2, and IVS3) were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2, and IVS3 isolates were purified to 11.90-, 15.50-, and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40°C. Maximum inhibition of total proteolytic activity was exerted by phenylmethane sulfonyl fluoride followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65, and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity toward H. armigera. The gut bacterial isolates IVS1, IVS2, and IVS3 showed homology with B. thuringiensis (CP003763.1), Vibrio fischeri (CP000020.2), and Escherichia coli (CP011342.1), respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of B. thuringiensis protoxin and play a major role in inducing pathogenicity of B. thuringiensis toxins in H. armigera. PMID:27766093

  4. Isolation and characterization of gut bacterial proteases involved in inducing pathogenicity of Bacillus thuringiensis toxin in cotton bollworm, Helicoverpa armigera

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    Visweshwar Regode

    2016-10-01

    Full Text Available Bacillus thuringiensis (Bt toxin proteins are deployed in transgenic plants for pest management. The present studies were aimed at characterization of gut bacterial proteases involved in activation of inactive Cry1Ac protoxin (pro-Cry1Ac to active toxin in Helicoverpa armigera. Bacterial strains were isolated from H. armigera midgut and screened for their proteolytic activation towards pro-Cry1Ac. Among twelve gut bacterial isolates seven isolates showed proteolytic activity, and proteases from three isolates (IVS1, IVS2 and IVS3 were found to be involved in the proteolytic conversion of pro-Cry1Ac into active toxin. The proteases from IVS1, IVS2 and IVS3 isolates were purified to 11.90-, 15.50- and 17.20-fold, respectively. The optimum pH and temperature for gut bacterial protease activity was 8.0 and 40 oC. Maximum inhibition of total proteolytic activity was exerted by PMSF followed by EDTA. Fluorescence zymography revealed that proteases from IVS1, IVS2, and IVS3 were chymotrypsin-like and showing protease band at ~15, 65 and 15 kDa, respectively. Active Cry1Ac formed from processing pro-Cry1Ac by gut bacterial proteases exhibited toxicity towards H. armigera. The gut bacterial isolates IVS1, IVS2 and IVS3 showed homology with Bacillus thuringiensis (CP003763.1, Vibrio fischeri (CP000020.2 and Escherichia coli (CP011342.1, respectively. Proteases produced by midgut bacteria are involved in proteolytic processing of Bt protoxin and play a major role in inducing pathogenicity of Bt toxins in H. armigera.

  5. PELEPASAN DAN PEMANGSAAN KUMBANG JELAJAH PAEDERUSFUSCIPES (COLEOPTERA:STAPHYLINIDAE TERHADAP TELUR DAN LARVA HELICOVERPA ARMIGERA (LEPIDOPTERA: NOCTUIDAE

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    I Wayan Winasa

    2007-12-01

    Full Text Available Paederus fuscipes is an important predators in soybean fields, including toward Helicoverpa armigera. Predation evaluation using a cage are very common, giving significant suppressed the exposed pest population. However, predation evaluation in open space is rarely conducted. This study was to investigate the dispersal capability of P. fuscipes, and to evaluate the effectiveness of the beetle release in the predation on H. Armigera eggs and larvae. Observations were made in a soybean field in Mekarwangi Village, Cianjur, during soybean planting season in 2005 and 2006. In the dispersal study, all beetles were collected from the field and tagged on the elitra. As many as 1187 tagged beetle were released. The dispersal was observed in the area within a radius of 40 m from the release point. In the predation study, eggs and larvae of H.armigera from laboratory rearing were used as the prey. Soybean plots with exposed prey were treated by releasing the beetle with different densities, i. e., 100-400 beetles, and a control. The released beetles were from laboratory rearing and beetles were collected from the field. The study indicated that the tagged beetles that were released to the soybean field actively move but their dispersal were relatively slow. Until 5 days after release, most beetles were remain in the area surrounding release point, within a radius of 5 m. Release of predators to the soybean field, suppressed H. armigera egg and larva populations for both vegetative and generative stages, but were not significantly different between treatment and control plots, except for the egg population on vegetative stage. It indicates that population of the natural predator in soybean field were very complex and potential to be used for controling pest populations. Thus, it is important to manage soybean field that can support the role of predators in the field.

  6. Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines.

    Science.gov (United States)

    Dowd, Patrick F; Sattler, Scott E

    2015-01-01

    The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production.

  7. Identification of a thioredoxin peroxidase gene involved in resistance to nucleopolyhedrovirus infection in Helicoverpa armigera with RNA interference.

    Science.gov (United States)

    Zhang, Songdou; Shen, Zhongjian; Li, Zhen; Wu, Fengming; Zhang, Boyu; Liu, Yanjun; Zhang, Qingwen; Liu, Xiaoxia

    2015-11-01

    Thioredoxin peroxidases (Tpxs) play a crucial role in protection against oxidative damage in several insect species. However, studies on the characteristics and functions of Tpxs in Helicoverpa armigera are lacking. In this study, a novel 2-Cys Tpx gene from H. armigera (HaTpx) was identified. Sequence analysis revealed that HaTpx is highly conserved and shares two catalysis regions (VCP) with other insect species. HaTpx mRNA was found to be expressed in an age-dependent manner and was ubiquitous in all tissues examined. Hormone treatment showed that the expression of HaTpx is clearly induced by 20-hydroxyecdysone but repressed by Juvenile hormone. Additionally, extreme temperature, ultraviolet light, mechanical injury, Escherichia coli, Metarhizium anisopliae, nucleopolyhedrovirus (NPV) infection, and H2O2 treatment markedly induced HaTpx gene expression. Reactive oxygen species (ROS) levels in hemocytes and MDA concentrations in the hemolymph after NPV infection were evaluated, and the results indicated that NPV infection causes excessive ROS generation. After knockdown of HaTpx by RNA interference, the expression of three antioxidant genes (Cu/ZnSOD, Trx, and TrxR) was increased, whereas two antioxidant genes (CAT and GPX) showed decreased expression. Moreover, the susceptibility of H. armigera to NPV infection increased after HaTpx knockdown. These results indicated that HaTpx contributes to the susceptibility of H. armigera to NPV, and the results also provide a theoretical basis for a novel strategy for developing new chemicals and microbial pesticides that target HaTpx gene for controlling H. armigera.

  8. Next-generation sequencing-based transcriptome analysis of Helicoverpa armigera Larvae immune-primed with Photorhabdus luminescens TT01.

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    Zengyang Zhao

    Full Text Available Although invertebrates are incapable of adaptive immunity, immunal reactions which are functionally similar to the adaptive immunity of vertebrates have been described in many studies of invertebrates including insects. The phenomenon was termed immune priming. In order to understand the molecular mechanism of immune priming, we employed Illumina/Solexa platform to investigate the transcriptional changes of the hemocytes and fat body of Helicoverpa armigera larvae immune-primed with the pathogenic bacteria Photorhabdus luminescens TT01. A total of 43.6 and 65.1 million clean reads with 4.4 and 6.5 gigabase sequence data were obtained from the TT01 (the immune-primed and PBS (non-primed cDNA libraries and assembled into 35,707 all-unigenes (non-redundant transcripts, which has a length varied from 201 to 16,947 bp and a N50 length of 1,997 bp. For 35,707 all-unigenes, 20,438 were functionally annotated and 2,494 were differentially expressed after immune priming. The differentially expressed genes (DEGs are mainly related to immunity, detoxification, development and metabolism of the host insect. Analysis on the annotated immune related DEGs supported a hypothesis that we proposed previously: the immune priming phenomenon observed in H. armigera larvae was achieved by regulation of key innate immune elements. The transcriptome profiling data sets (especially the sequences of 1,022 unannotated DEGs and the clues (such as those on immune-related signal and regulatory pathways obtained from this study will facilitate immune-related novel gene discovery and provide valuable information for further exploring the molecular mechanism of immune priming of invertebrates. All these will increase our understanding of invertebrate immunity which may provide new approaches to control insect pests or prevent epidemic of infectious diseases in economic invertebrates in the future.

  9. Vip3Aa tolerance response of Helicoverpa armigera populations from a Cry1Ac cotton planting region.

    Science.gov (United States)

    An, Jingjie; Gao, Yulin; Wu, Kongming; Gould, Fred; Gao, Jianhua; Shen, Zhicheng; Lei, Chaoliang

    2010-12-01

    Transgenic cotton, Gossypium hirsutum L., that expresses the Bacillus thuringiensis (Bt) Cry1Ac toxin, holds great promise in controlling target insect pests. Evolution of resistance by target pests is the primary threat to the continued efficacy of Bt cotton. To thwart pest resistance evolution, a transgenic cotton culitvar that produces two different Bt toxins, cry1Ac and vip3A genes, was proposed as a successor of cry1Ac cotton. This article reports on levels of Vip3Aa tolerance in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) populations from the Cry1Ac cotton planting region in China based on bioassays of the F1 generation of isofemale lines. In total, 80 isofemale families of H. armigera from Xiajin county of Shandong Province (an intensive Bt cotton planting area) and 93 families from Anci county of Hebei Province (a multiple-crop system including corn [Zea mays L.] , soybean [Glycine max (L.) Merr.], peanut (Arachis hypogaea L.), and Bt cotton) were screened with a discriminating concentration of both Cry1Ac- and Vip3A-containing diets in 2009. From data on the relative average development rates and percentage of larval weight inhibition of F1 full-sib families tested simultaneously on Cry1Ac and Vip3Aa, results indicate that responses to Cry1Ac and Vip3Aa were not genetically correlated in field population ofH. armigera. This indicates that the threat of cross-resistance between Cry1Ac and Vip3A is low in field populations of H. armigera. Thus, the introduction of Vip3Aa/Cry1Ac-producing lines could delay resistance evolution in H. armigera in Bt cotton planting area of China.

  10. Molecular and insecticidal characterization of Vip3A protein producing Bacillus thuringiensis strains toxic against Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Lone, Showkat Ahmad; Yadav, Radha; Malik, Abdul; Padaria, Jasdeep Chatrath

    2016-02-01

    Vegetative insecticidal proteins (Vip) represent the second generation of insecticidal proteins produced by Bacillus thuringiensis (Bt) during the vegetative growth stage of growth. Bt-based biopesticides are recognized as viable alternatives to chemical insecticides; the latter cause environmental pollution and lead to the emergence of pest resistance. To perform a systematic study of vip genes encoding toxic proteins, a total of 30 soil samples were collected from diverse locations of Kashmir valley, India, and characterized by molecular and analytical methods. Eighty-six colonies showing Bacillus-like morphology were selected. Scanning electron microscopy observations confirmed the presence of different crystal shapes, and PCR analysis of insecticidal genes revealed a predominance of the lepidopteran-specific vip3 (43.18%) gene followed by coleopteran-specific vip1 (22.72%) and vip2 (15.90%) genes in the isolates tested. Multi-alignment of the deduced amino acid sequences revealed that vip3 sequences were highly conserved, whereas vip1 and vip2 showed adequate differences in amino acid sequences compared with already reported sequences. Screening for toxicity against Helicoverpa armigera larvae was performed using partially purified soluble fractions containing Vip3A protein. The mortality levels observed ranged between 70% and 96.6% in the isolates. The LC50 values of 2 of the native isolates, JK37 and JK88, against H. armigera were found to be on par with that of Bt subsp. kurstaki HD1, suggesting that these isolates could be developed as effective biopesticides against H. armigera.

  11. Bt Maize Seed Mixtures for Helicoverpa zea (Lepidoptera: Noctuidae): Larval Movement, Development, and Survival on Non-transgenic Maize.

    Science.gov (United States)

    Burkness, Eric C; Cira, T M; Moser, S E; Hutchison, W D

    2015-12-01

    In 2012 and 2013, field trials were conducted near Rosemount, MN, to assess the movement and development of Helicoverpa zea (Boddie) larvae on non-Bt refuge corn plants within a seed mixture of non-Bt and Bt corn. The Bt corn hybrid expressed three Bt toxins-Cry1Ab, Cry1F, and Vip3A. As the use of seed mixtures for insect resistance management (IRM) continues to be implemented, it is necessary to further characterize how this IRM approach impacts resistance development in ear-feeding Lepidopteran pests. The potential for Bt pollen movement and cross pollination of the non-Bt ears in a seed mixture may lead to Bt toxin exposure to larvae developing on those refuge ears. Larval movement and development by H. zea, feeding on non-Bt refuge plants adjacent to either transgenic Bt or non-Bt plants, were measured to investigate the potential for unintended Bt exposure. Non-Bt plants were infested with H. zea eggs and subplots were destructively sampled twice per week within each treatment to assess larval development, location, and kernel injury. Results indicate that H. zea larval movement between plants is relatively low, ranging from 2-16% of larvae, and occurs mainly after reaching the second instar. Refuge plants in seed mixtures did not produce equivalent numbers of H. zea larvae, kernel injury, and larval development differed as compared with a pure stand of non-Bt plants. This suggests that there may be costs to larvae developing on refuge plants within seed mixtures and additional studies are warranted to define potential impacts.

  12. Risk assessment for Helicoverpa zea (Lepidoptera: Noctuidae) resistance on dual-gene versus single-gene corn.

    Science.gov (United States)

    Edwards, Kristine T; Caprio, Michael A; Allen, K Clint; Musser, Fred R

    2013-02-01

    Recent Environmental Protection Agency (EPA) decisions regarding resistance management in Bt-cropping systems have prompted concern in some experts that dual-gene Bt-corn (CrylA.105 and Cry2Ab2 toxins) may result in more rapid selection for resistance in Helicoverpa zea (Boddie) than single-gene Bacillus thuringiensis (Bt)-corn (CrylAb toxin). The concern is that Bt-toxin longevity could be significantly reduced with recent adoption of a natural refuge for dual-gene Bt-cotton (CrylAc and Cry2Ab2 toxins) and concurrent reduction in dual-gene corn refuge from 50 to 20%. A population genetics framework that simulates complex landscapes was applied to risk assessment. Expert opinions on effectiveness of several transgenic corn and cotton varieties were captured and used to assign probabilities to different scenarios in the assessment. At least 350 replicate simulations with randomly drawn parameters were completed for each of four risk assessments. Resistance evolved within 30 yr in 22.5% of simulations with single-gene corn and cotton with no volunteer corn. When volunteer corn was added to this assessment, risk of resistance evolving within 30 yr declined to 13.8%. When dual-gene Bt-cotton planted with a natural refuge and single-gene corn planted with a 50% structured refuge was simulated, simultaneous resistance to both toxins never occurred within 30 yr, but in 38.5% of simulations, resistance evolved to toxin present in single-gene Bt-corn (CrylAb). When both corn and cotton were simulated as dual-gene products, cotton with a natural refuge and corn with a 20% refuge, 3% of simulations evolved resistance to both toxins simultaneously within 30 yr, while 10.4% of simulations evolved resistance to CrylAb/c toxin.

  13. Influence of Dual-Bt Protein Corn on Bollworm, Helicoverpa zea (Boddie), Survivorship on Bollgard II Cotton.

    Science.gov (United States)

    Von Kanel, M B; Gore, J; Catchot, A; Cook, D; Musser, F; Caprio, M

    2016-04-01

    Similar Cry proteins are expressed in both Bt corn, Zea mays L., and cotton, Gossypium hirsutum (L.), commercial production systems. At least one generation of corn earworm, Helicoverpa zea (Boddie), completes development on field corn in the Mid-South before dispersing across the landscape into other crop hosts like cotton. A concern is that Bt corn hybrids may result in selection for H. zea populations with a higher probability of causing damage to Bt cotton. The objective of this study was to determine the susceptibility of H. zea offspring from moths that developed on non-Bt and VT Triple Pro (VT3 PRO) field corn to lyophilized Bollgard II cotton tissue expressing Cry1Ac and Cry2Ab. Offspring of individuals reared on VT3 PRO expressing Cry1A.105 and Cry2Ab had a significantly higher LC50 two out of the three years this study was conducted. Excess larvae were placed on artificial diet and allowed to pupate to determine if there were any inheritable fitness costs associated with parental development on VT3 PRO corn. Offspring resulting from males collected from VT3 PRO had significantly lower pupal weight and longer pupal duration compared with offspring of individuals collected from non-Bt corn. However, offspring from females collected from VT3 PRO were not different from non-Bt offspring. Paternal influence on offspring in insects is not commonly observed, but illustrates the side effects of development on a transgenic plant expressing less than a high dose, 25 times the concentration needed to kill susceptible larvae.

  14. Isotopes and Trace Elements as Natal Origin Markers of Helicoverpa armigera – An Experimental Model for Biosecurity Pests

    Science.gov (United States)

    Holder, Peter W.; Armstrong, Karen; Van Hale, Robert; Millet, Marc-Alban; Frew, Russell; Clough, Timothy J.; Baker, Joel A.

    2014-01-01

    Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150–3000 km apart). Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The geographic resolution

  15. Introgression of Helicoverpa armigera Resistance from Cajanus acutifolius-a Wild Relative from Secondary Gene Pool of Pigeon Pea (Cajanus cajan

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    Deepak R. Jadhav

    2012-07-01

    Full Text Available The aim of the study was to introgress Helicoverpa armigera resistance from wild relative Cajanus acutifolius into pigeonpea, (Cajanus cajan L., an important grain legume in South Asia, East Africa and the West Indies. Pigeonpea grain yields on farmer’s fields are quite low, largely because of damage by insect pests, of which legume pod borer Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae is the important pest worldwide. Pod borer has developed high levels of resistance to chemical insecticides. Currently, there are no cultivars of pigeonpea with high levels of resistance to H. armigera. Therefore, there is a need to identify and introgress resistance genes from the wild relatives of this crop. Wild relative of pigeonpea, Cajanus acutifolius (ICPW 15613 and the interspecific derivatives C. acutifolius x C. cajan have shown resistance to H. armigera. The results showed that all the test lines and C. acutifolius had high levels of flavonoids such as chlorogenic acid, quercetin and rutin in the flowers and buds, which may have resulted in less damage due to H. armigera larvae. Most of the test lines had more than 15.00 g of seed weight (100 seed weight and beige seed color. These lines can be used for pigeonpea improvement for resistance to H. armigera.

  16. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Science.gov (United States)

    Sengupta, Anindita; Sarkar, Anindya; Priya, Prerna; Ghosh Dastidar, Shubhra; Das, Sampa

    2013-01-01

    Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  17. Assessment of beneficial role of an insectivorous bird, jungle babbler (Turdoides striatus predation, on Helicoverpa armigera infesting pigeon pea (Cajanus cajan crop Evaluación del rol benéfico de Turdoides striatus como predator de Helicoverpa armigera en el cultivo de guandul (Cajanus cajan

    Directory of Open Access Journals (Sweden)

    Bhavna Bharucha

    2010-04-01

    Full Text Available Jungle babbler (Turdoides striatus, a widely spread sub-tropical insectivorous passerine is considered beneficial to agro-ecosystem, as they devour voraciously on insect matter especially Helicoverpa armigera, the gram pod borer, a notorious pest infesting and causing heavy loses to crops like pigeon pea (Cajanus cajan which is a vital crop of semi-arid tropical and subtropical farming system, providing high quality vegetable protein. Helicoverpa is known to feed on flowers, pods, and seeds and is the most important biotic constraint affecting pigeon pea yields. Jungle babblers have a peculiar foraging style which helps expose the Helicoverpa larvae as well as pupae through various phenological stages of pigeon pea. For comparative assessment of their beneficial role and as a possible bio control agent, in Baroda city (State of Gaujarat, India, was studied, two crops of pigeon pea (insecticide treated and untreated (control were selected. In both treated and control crops, the number of jungle babblers were maximum in pigeon pea fields during october and november in both small pod stage and large pod stage which had heavy infestation of Helicoverpa. Least number of birds was seen during the flowering stage in September. Later in treatment crop three applications of Dunnate and Monocrotophos insecticide spray was done after which the pest population decreased which is reflected in number of birds in the field, while the bird number in control crops grew since insecticide spray was not done and number of larvae increased with the stage of the crop. Along with the main crop pigeon pea, comparative study was also done to see the food preference by these birds in crops like sorghum, maize, cow pea and ploughed and unploughed fields. Maximum number of birds was seen in unploughed field and least in sorghum suggesting that Helicoverpa is preferred food over sorghum grains thus pigeon pea and sorghum can be used as mixed crops to protect the crop from

  18. Gene cloning and expression of cadherin in midgut of Helicoverpa armigera and its Cry1A binding region

    Institute of Scientific and Technical Information of China (English)

    WANG Guirong; WU Kongming; LIANG Gemei; GUO Yuyuan

    2005-01-01

    Cadherins belong to one of the families of animal glycoproteins responsible for calcium-dependent cell-cell adhesion. Recent literatures showed that the cadherin-like in midgut of several insects served as the receptor of Bt toxin Cry1A and the variation of cadherin-like is related to insect's resistance to Cry1A. The full-length cDNA encoding cadherin-like of Helicoverpa armigera is cloned by degenerate PCR and RACE techniques and the gene was designated as BtR-harm, which is 5581 bp in full-length, encoding 1730 amino acid residues (BtR-harm was deposited in GenBank and the accession number is AF519180). Its predicted molecular weight and isoelectric point were 195.39 kDa and 4.23, respectively. The inferred amino acid sequence includes a signal sequence, 11 cadherin repeats, a membrane-proximal region, a transmembrane region and a cytoplasmic region. Sequence analysis indicated that the deduced protein sequence was most similar to the cadherin-like from Heliothis virescens with 84.2% identity and highly similar to three other lepidopteran cadherin from Bombyx mori, Manduca sexta and Pectinophora gossypiella, with the sequence identities of 60.3.6%, 57.5% and 51.0%, respectively. The cDNA encoding cadherin gene was expressed successfully in E. coli and the recombinant proteins can bind with Cry1Ac. Truncation analysis and binding experiment of BtR-harm revealed that the Cry1A binding region was a contiguous 244-amino acid sequence, which located between amino acid 1217 and 1461. Semi-quantitative RT-PCR analysis showed that BtR-harm was highly expressed in midgut of H. armigera, very low expressed in foregut and hindgut and was not expressed in other tissues. After H. armigera producing resistance to Cry1Ac, the expression quantity of BtR-harm significantly decreased in midgut of H. armigera. It is the first confirmation that BtR-harm can function as receptor of Cry1Ac in H. armigera and the binding region was located on a contiguous 244 amino acid sequence

  19. Effects of climate change on overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Huang, Jian; Li, Jing

    2015-07-01

    Climate change significantly affects insects' behaviors. Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most serious insect pests in the world. Much is known about the survival of the overwintering population and spring emergence of H. armigera. However, little is known about the effects of climate change on overwintering and spring emergence of H. armigera. This study investigated the effects of changes of air and soil temperatures and precipitation on overwintering pupae of H. armigera by analyzing historical data from Magaiti County in northwest China using statistical methods. The results showed that during the period of 1989-2006, the climate warming advanced the first-appearance date of overwintering pupae eclosion (FD) and end date of overwintering pupae eclosion (ED) by 1.276 and 0.193 days per year, respectively; the duration between the FD and ED (DFEPE) was prolonged by 1.09 days per year, which resulted in more eclosion of overwintering pupae. For a 1 °C increase in the maximum air temperature ( T max) in winter, the FD became earlier by 3.234 days. Precipitation in winter delayed the FD and ED and produced little relative influence on DFEPE. A 1-mm increase of precipitation in winter delayed the FD and ED by 0.850 and 0.494 days, respectively. Mean air temperature ( T mean) in March, with a 41.3 % relative influence, precipitation in winter, with a 49.0 % relative influence, and T mean in March, with a 37.5 % relative influence, were the major affecting factors on FD, ED, and DFEPE, respectively. T max in February with a 53.0 % relative influence was the major affecting factor on the mortality of overwintering pupae (MOP). Increased soil temperatures in October and November and autumn and air temperatures in winter could decrease the MOP, though the relative influences were lower than T max in February. Increased precipitation in winter increased the MOP, but the relative influence was only 4.2 % because of little precipitation

  20. Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea.

    Science.gov (United States)

    López, Juan D; Latheef, M A; Hoffmann, W C

    2010-01-01

    Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC(50) values (95% CL) being 0.718 (0.532-0.878), 0.525 (0.316-0.751), and 0.182 (0.06-0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of

  1. Bacillus thuringiensis insecticidal crystal proteins affect lifespan and reproductive performance of Helicoverpa armigera and Spodoptera exigua adults.

    Science.gov (United States)

    Zhang, Ying; Ma, Yan; Wan, Pin-Jun; Mu, Li-Li; Li, Guo-Qing

    2013-04-01

    Being delivered as sprays or expressed in plant, Bacillus thuringiensis (Bt) crystalline proteins (Cry toxins) display insecticidal activities against numerous Lepidopteran, Dipteran, and Coleopteran larvae. Comparative study of toxicities of Bt Cry toxins between larvae and adults may afford important new insights into the interactions of the toxins with receptor proteins in host insect, and represent intriguing targets for the control of insect pests. However, the effectiveness of Bt Cry toxins in insect adults has paid less attention. In the present article, the effectiveness of Cry1Ac and Cry1Ca on lifespans and reproductive performance of Helicoverpa armigera (Hübner) and Spodoptera exigua (Hübner) adults were evaluated by in vivo experiments. Considering transgenic plants express modified, truncated versions of cry genes yielding active toxin fragment, we used activated Bt toxins at the concentration of 500, 100, and 20 microg/ml in a 10% sucrose aquous solution. At the highest concentration, Cry1Ac and Cry1Ca shortened 48.1 and 48.9% of H. armigera female lifespan, and 43.5 and 38.5% of S. exigua female lifespan, and they reduced 37.8 and 40.3%, and 50.5 and 47.4% of H. armigera and S. exigua male lifespans respectively. Bt toxins negatively affected copulation. Exposure to 500 microg/ml of Cry1Ac and Cry1Ca greatly reduced 50.0 and 46.8%, and 58.7 and 57.3% spermatophore acceptance by H. armigera and S. exigua females, respectively. Similarly, Cry1Ac and Cry1Ca exposure decreased 40.0 and 50.3%, and 61.3 and 60.0% of spermatophore transfer by H. armigera and S. exigua males, respectively. Moreover, exposure females rather than males to 500 microg/ml of Cry1Ac and Cry1Ca significantly dropped 57.5 and 57.5% of the number of eggs laid by H. armigera, and 35.4 and 45.8% of the number of egg masses deposited by S. exigua. In contrast, both Cry1Ac and Cry1Ca did not negatively influence the egg hatchability. At the middle and the lowest concentrations, however

  2. Cross-resistance to toxins used in pyramided Bt crops and resistance to Bt sprays in Helicoverpa zea.

    Science.gov (United States)

    Welch, Kara L; Unnithan, Gopalan C; Degain, Ben A; Wei, Jizhen; Zhang, Jie; Li, Xianchun; Tabashnik, Bruce E; Carrière, Yves

    2015-11-01

    To delay evolution of resistance by insect pests, farmers are rapidly increasing their use of transgenic crops producing two or more Bacillus thuringiensis (Bt) toxins that kill the same pest. A key condition favoring durability of these "pyramided" crops is the absence of cross-resistance between toxins. Here we evaluated cross-resistance in the major lepidopteran pest Helicoverpa zea (Boddie) to Bt toxins used in pyramids. In the laboratory, we selected a strain of this pest with Bt toxin Cry1Ac followed by selection with MVP II, a formulation containing a hybrid protoxin that is identical to Cry1Ac in the active portion of the toxin and 98.5% identical overall. We calculated the resistance ratio as the EC50 (concentration causing mortality or failure to develop beyond the first instar of 50% of larvae) for the laboratory-selected strain divided by the EC50 for its field-derived parent strain that was not selected in the laboratory. The resistance ratio was 20.0-33.9 (mean=27.0) for MVP II, 57.0 for Cry1Ac, 51.3 for Cry1A.105, 22.4 for Cry1Ab, 3.3 for Cry2Ab, 1.8 for Cry1Fa, and 1.6 for Vip3Aa. Resistance ratios were 2.9 for DiPel ES and 2.0 for Agree VG, which are commercial Bt spray formulations containing Cry1Ac, other Bt toxins, and Bt spores. By the conservative criterion of non-overlap of 95% fiducial limits, the EC50 was significantly higher for the selected strain than its parent strain for MVP II, Cry1Ac, Cry1A.105, Cry1Ab, Cry2Ab and DiPel ES. For Cry1Fa, Vip3Aa, and Agree VG, significantly lower susceptibility to a high concentration indicated low cross-resistance. The resistance ratio for toxins other than Cry1Ac was associated with their amino acid sequence similarity to Cry1Ac in domain II. Resistance to Cry1Ac and the observed cross-resistance to other Bt toxins could accelerate evolution of H. zea resistance to currently registered Bt sprays and pyramided Bt crops.

  3. Isovitexin-2'-O-beta-[6-O-E-p-coumaroylglucopyranoside] from UV-B irradiated leaves of rice, Oryza sativa L. inhibits fertility of Helicoverpa armigera.

    Science.gov (United States)

    Caasi-Lit, Merdelyn T; Tanner, Gregory J; Nayudu, Murali; Whitecross, Malcolm I

    2007-01-01

    UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1x concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (Pisoorientin-2''-O-beta-[6-O-E-p-coumaroylglucopyranoside] or isoorientin-2''-O-beta-[6-O-E-p-feruloylglucopyranoside], were not significantly different to control diets.

  4. Vip3A is responsible for the potency of Bacillus thuringiensis 9816C culture supernatant against Helicoverpa armigera and Spodoptera exigua.

    Science.gov (United States)

    Cai, Jun; Xiao, Liang; Yan, Bing; Bin, Guan; Chen, Yuehua; Ren, Gaixin

    2006-04-01

    Culture supernatant of Bacillus thuringiensis 9816C had high toxicity against Helicoverpa armigera and Spodoptera exigua. However, it lost insecticidal activities after being bathed in boiling water for 5 min. Acrystalliferous mutants of Bt9816C (Bt9816C-NP1 and Bt9816C-NP2) cured of its endogenous plasmids no longer possessed vip3A gene and toxicity. The 89 kD protein which existed in Bt9816C supernatant disappeared in the two mutants' supernatant; nevertheless, the two mutants still exhibited hemolytic and phospholipase C activity as Bt9816C did. The vip3A gene of Bt9816C, vip3Aa18, was cloned and expressed in Escherichia coli BL21. Bioassay demonstrated that the recombinant E. coli had high toxicity against S. exigua. Taken together, it suggested that Vip3A protein was responsible for the toxicity of Bt9816C culture supernatants.

  5. Biological activities of Solanum pseudocapsicum (Solanaceae) against cotton bollworm, Helicoverpa armigera Hübner and armyworm, Spodoptera litura Fabricius (Lepidotera:Noctuidae)

    Institute of Scientific and Technical Information of China (English)

    Alagarmalai Jeyasankar; Selvaraj Premalatha; Kuppusamy Elumalai

    2012-01-01

    Objective:To evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). Methods:Hexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera. Results:Ethyl acetate extract showed promising antifeedant and insecticidal activities against S. litura and H. armigera. Percentage of deformed larvae, pupae and adults were maximum in treatment of ethyl acetate extract. Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae. Conclusions: Ethyl acetate extracts of S. pseudocapsicum, showed higher efficiency of antifeedant, insecticidal and growth inhibition activities. Hence, it can be used to controll agricultural insect pests, S. litura and H. armigera.

  6. A Novel Neurotoxin Gene ar1b Recombination Enhances the Efficiency of Helicoverpa armigera Nucleopolyhedrovirus as a Pesticide by Inhibiting the Host Larvae Ability to Feed and Grow.

    Directory of Open Access Journals (Sweden)

    Huan Yu

    Full Text Available A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV, Ar1b-HearNPV, was constructed and identified as an improved bio-control agent of Helicoverpa armigera larvae. The HearNPV polyhedrin promoter was used to express the insect-specific neurotoxin gene, ar1b, which was originally isolated from the Australian funnel-web spider (Atrax robustus. RT-PCR and Western blotting analysis showed that both the ar1b transcript and protein were produced successfully in Ar1b-HearNPV-infected HzAM1 cells. In order to investigate the influence of foreign gene insertion in HearNPV, including the ar1b gene, chloramphenicol resistance gene, lacZ, kanamycin resistance gene, and the gentamicin resistance gene, two virus strains (HZ8-HearNPV and wt-HearNPV were used as controls in the cell transfection analysis. As expected, foreign gene insertion had no impact on budded virus production and viral DNA replication. Both optical microscopy and electron microscopy observations indicated that the formation of the occlusion bodies of recombinant virus was similar to wild type virus. The Ar1b-HearNPV-infected H. armigera larvae exhibited paralysis and weight loss before dying. This recombinant virus also showed a 32.87% decrease in LT50 assays compared with the wild type virus. Besides, Ar1b-HearNPV also inhibited host larval growth and diet consumption. This inhibition was still significant in the older instar larvae treated with the recombinant virus. All of these positive properties of this novel recombinant HearNPV provide a further opportunity to develop this virus strain into a commercial product to control the cotton bollworm.

  7. Characteristics of resistance to Bacillus thuringiensis toxin Cry2Ab in a strain of Helicoverpa punctigera (Lepidoptera: Noctuidae) isolated from a field population.

    Science.gov (United States)

    Downes, S; Parker, T L; Mahon, R J

    2010-12-01

    In 1996, the Australian cotton industry adopted Ingard that expresses the Bacillus thuringiensis (Bt) toxin gene cry1Ac and was planted at a cap of 30%. In 2004-2005, Bollgard II, which expresses cry1Ac and cry2Ab, replaced Ingard in Australia, and subsequently has made up >80% of the area planted to cotton, Gossypium hirsutum L. The Australian target species Helicoverpa armigera (Hübner) and Helicoverpa punctigera (Wallengren) are innately moderately tolerant to Bt toxins, but the absence of a history of insecticide resistance indicates that the latter species is less likely to develop resistance to Bt cotton. From 2002-2003 to 2006-2007, F2 screens were deployed to detect resistance to CrylAc or Cry2Ab in natural populations of H. punctigera. Alleles that conferred an advantage against CrylAc were not detected, but those that conferred resistance to Cry2Ab were present at a frequency of 0.0018 (n = 2,192 alleles). Importantly, the first isolation of Cry2Ab resistance in H. punctigera occurred before significant opportunities to develop resistance in response to Bollgard II. We established a colony (designated Hp4-13) consisting of homozygous resistant individuals and examined their characteristics through comparison with individuals from a Bt-susceptible laboratory colony. Through specific crosses and bioassays, we established that the resistance present in Hp4-13 is due to a single autosomal gene. The resistance is fully recessive. Homozygotes are able to survive a dose of Cry2Ab toxin that is 15 times the reported concentration in field grown Bollgard II in Australia (500 microg/ml) and are fully susceptible to Cry1Ac and to the Bt product DiPel. These characteristics are the same as those described for the first Cry2Ab resistant strain of H. armigera isolated from a field population in Australia.

  8. Diapause hormone in the Helicoverpa/Heliothis complex: A review of gene expression, peptide structure and activity, analog and antagonist development, and the receptor.

    Science.gov (United States)

    Zhang, Qirui; Nachman, Ronald J; Denlinger, David L

    2015-10-01

    This review summarizes recent studies focusing on diapause hormone (DH) in the Helicoverpa/Heliothis complex of agricultural pests. Moths in this complex overwinter in pupal diapause, a form of developmental arrest used to circumvent unfavorable seasons. DH was originally reported in the silkmoth Bombyx mori, a species that relies on DH to induce an embryonic diapause. But, in the case of Helicoverpa/Heliothis, levels of dh transcripts and DH peptides are more abundant in nondiapausing pupae than in diapausing individuals, and DH effectively terminates diapause within a specific temperature range. A structure activity relationship study indicated that the active core of DH is the C-terminal hepta-peptide, LWFGPRLa. We designed and synthesized a first generation of DH agonists and identified two agonists (PK-2Abf and PK-Etz) that were nearly 50- and 13-fold more potent than the native hormone. These studies revealed two structural characteristics of DH and its agonists that are essential for interaction with the receptor: a trans-Pro configuration to form a type I β-turn and a hydrophobic moiety involved in ligand binding. Modification of DH at the active core yielded a potent DH antagonist (DH-Jo, acetyl-GLWA[Jo]RLa) as well as an agonist (DH-2Abf-K). Three compounds (Decyl-1963, Dodecyl-1967, Heptyl-1965) were identified as agents capable of penetrating the cuticle of young pupae and thereby preventing the entry into diapause. DH receptor cDNA was cloned and an effective in vitro high throughput screen system was established for future use. This work sets the stage for further development of DH analogs and antagonists that have the potential to disrupt insect diapause as a tool for pest management.

  9. Negative Effects of a Nonhost Proteinase Inhibitor of ~19.8 kDa from Madhuca indica Seeds on Developmental Physiology of Helicoverpa armigera (Hübner

    Directory of Open Access Journals (Sweden)

    Farrukh Jamal

    2014-01-01

    Full Text Available An affinity purified trypsin inhibitor from the seed flour extracts of Madhuca indica (MiTI on denaturing polyacrylamide gel electrophoresis showed that MiTI consisted of a single polypeptide chain with molecular mass of ~19.8 kDa. MiTI inhibited the total proteolytic and trypsin-like activities of the midgut proteinases of Helicoverpa armigera larvae by 87.51% and 76.12%, respectively, at concentration of 5 µg/mL with an IC50 of 1.75 µg/mL against trypsin like midgut proteinases. The enzyme kinetic studies demonstrated that MiTI is a competitive inhibitor with a Ki value of 4.1×10−10 M for Helicoverpa trypsin like midgut proteinases. In vivo experiments with different concentrations of MiTI in artificial diet (0.5, 1.0, and 1.5% w/w showed an effective downfall in the larval body weight and an increase in larval mortality. The concentration of MiTI in the artificial diet to cause 50% mortality (LD50 of larvae was 1.5% w/w and that to cause reduction in mass of larvae by 50% (ED50 was 1.0% w/w. Nutritional indices observations suggest the toxic and adverse effects of MiTI on the growth and development of H. armigera larvae. The results suggest a strong bioinsecticidal potential of affinity purified MiTI which can be exploited in insect pest management of crop plants.

  10. A Novel Neurotoxin Gene ar1b Recombination Enhances the Efficiency of Helicoverpa armigera Nucleopolyhedrovirus as a Pesticide by Inhibiting the Host Larvae Ability to Feed and Grow.

    Science.gov (United States)

    Yu, Huan; Meng, Jiao; Xu, Jian; Liu, Tong-Xian; Wang, Dun

    2015-01-01

    A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV), Ar1b-HearNPV, was constructed and identified as an improved bio-control agent of Helicoverpa armigera larvae. The HearNPV polyhedrin promoter was used to express the insect-specific neurotoxin gene, ar1b, which was originally isolated from the Australian funnel-web spider (Atrax robustus). RT-PCR and Western blotting analysis showed that both the ar1b transcript and protein were produced successfully in Ar1b-HearNPV-infected HzAM1 cells. In order to investigate the influence of foreign gene insertion in HearNPV, including the ar1b gene, chloramphenicol resistance gene, lacZ, kanamycin resistance gene, and the gentamicin resistance gene, two virus strains (HZ8-HearNPV and wt-HearNPV) were used as controls in the cell transfection analysis. As expected, foreign gene insertion had no impact on budded virus production and viral DNA replication. Both optical microscopy and electron microscopy observations indicated that the formation of the occlusion bodies of recombinant virus was similar to wild type virus. The Ar1b-HearNPV-infected H. armigera larvae exhibited paralysis and weight loss before dying. This recombinant virus also showed a 32.87% decrease in LT50 assays compared with the wild type virus. Besides, Ar1b-HearNPV also inhibited host larval growth and diet consumption. This inhibition was still significant in the older instar larvae treated with the recombinant virus. All of these positive properties of this novel recombinant HearNPV provide a further opportunity to develop this virus strain into a commercial product to control the cotton bollworm.

  11. New insight to structure-function relationship of GalNAc mediated primary interaction between insecticidal Cry1Ac toxin and HaALP receptor of Helicoverpa armigera.

    Directory of Open Access Journals (Sweden)

    Anindita Sengupta

    Full Text Available Over the last few decades Cry1Ac toxin has been widely used in controlling the insect attack due to its high specificity towards target insects. The pore-forming toxin undergoes a complex mechanism in the insect midgut involving sequential interaction with specific glycosylated receptors in which terminal GalNAc molecule plays a vital role. Recent studies on Cry toxins interactions with specific receptors revealed the importance of several amino acid residues in domain III of Cry1Ac, namely Q509, N510, R511, Y513 and W545, serve as potential binding sites that surround the putative GalNAc binding pocket and mediate the toxin-receptor interaction. In the present study, alanine substitution mutations were generated in the Cry1Ac domain III region and functional significance of those key residues was monitored by insect bioassay on Helicoverpa armigera larvae. In addition, ligand blot analysis and SPR binding assay was performed to monitor the binding characteristics of Cry1Ac wild type and mutant toxins towards HaALP receptor isolated from Helicoverpa armigera. Mutagenesis data revealed that, alanine substitutions in R511, Y513 and W545 substantially impacted the relative affinity towards HaALP receptor and toxicity toward target insect. Furthermore, in silico study of GalNAc-mediated interaction also confirmed the important roles of these residues. This structural analysis will provide a detail insight for evaluating and engineering new generation Cry toxins to address the problem of change in insect behavioral patterns.

  12. Effects of Soil Salinity on the Expression of Bt Toxin (Cry1Ac) and the Control Efficiency of Helicoverpa armigera in Field-Grown Transgenic Bt Cotton

    Science.gov (United States)

    Luo, Jun-Yu; Zhang, Shuai; Peng, Jun; Zhu, Xiang-Zhen; Lv, Li-Min; Wang, Chun-Yi; Li, Chun-Hua; Zhou, Zhi-Guo; Cui, Jin-Jie

    2017-01-01

    An increasing area of transgenic Bacillus thuringiensis (Bt) cotton is being planted in saline-alkaline soil in China. The Bt protein level in transgenic cotton plants and its control efficiency can be affected by abiotic stress, including high temperature, water deficiency and other factors. However, how soil salinity affects the expression of Bt protein, thus influencing the control efficiency of Bt cotton against the cotton bollworm (CBW) Helicoverpa armigera (Hübner) in the field, is poorly understood. Our objective in the present study was to investigate the effects of soil salinity on the expression of Bt toxin (Cry1Ac) and the control efficiency of Helicoverpa armigera in field-grown transgenic Bt cotton using three natural saline levels (1.15 dS m-1 [low soil-salinity], 6.00 dS m-1 [medium soil-salinity] and 11.46 dS m-1 [high soil-salinity]). We found that the Bt protein content in the transgenic Bt cotton leaves and the insecticidal activity of Bt cotton against CBW decreased with the increasing soil salinity in laboratory experiments during the growing season. The Bt protein content of Bt cotton leaves in the laboratory were negatively correlated with the salinity level. The CBW populations were highest on the Bt cotton grown in medium-salinity soil instead of the high-salinity soil in field conditions. A possible mechanism may be that the relatively high-salinity soil changed the plant nutritional quality or other plant defensive traits. The results from this study may help to identify more appropriate practices to control CBW in Bt cotton fields with different soil salinity levels. PMID:28099508

  13. Influence of Two Kinds of Insecticides on Helicoverpa armigera Hubner and its Natural Enemies%2种药剂对棉花棉铃虫及其天敌的影响

    Institute of Scientific and Technical Information of China (English)

    张曦

    2013-01-01

    研究2种药剂对棉花棉铃虫及其天敌的影响,结果表明:14%氯虫-高氯氟和1.1%甲氨基阿维菌素苯甲酸盐对棉铃虫均有很好的防治效果,同时对天敌瓢虫和草蛉无较大影响。%Influence of two kinds of insecticides on Helicoverpa armigera Hubner and its natural enemies was studied.The results showed that 14% chlorantraniliprole-high chlorine fluorine and 1.1% emamectin benzoate had good control effect on Helicoverpa armigera Hubner.At the same time,they had no significant impact on natural enemy ladybug and lacewing.

  14. Tradeoff between reproduction and resistance evolution to Bt-toxin in Helicoverpa armigera: regulated by vitellogenin gene expression.

    Science.gov (United States)

    Zhang, W N; Xiao, H J; Liang, G M; Guo, Y Y; Wu, K M

    2014-08-01

    Evolution of resistance to insecticides usually has fitness tradeoffs associated with adaptation to the stress. The basic regulation mechanism of tradeoff between reproduction and resistance evolution to Bacillus thuringiensis (Bt) toxin in the cotton bollworm, Helicoverpa armigera (Ha), based on the vitellogenin (Vg) gene expression was analyzed here. The full-length cDNA of the Vg gene HaVg (JX504706) was cloned and identified. HaVg has 5704 base pairs (bp) with an open reading frame (ORF) of 5265 bp, which encoded 1756 amino acid protein with a predicted molecular mass of 197.28 kDa and a proposed isoelectric point of 8.74. Sequence alignment analysis indicated that the amino acid sequence of HaVg contained all of the conserved domains detected in the Vgs of the other insects and had a high similarity with the Vgs of the Lepidoptera insects, especially Noctuidae. The resistance level to Cry1Ac Bt toxin and relative HaVg mRNA expression levels among the following four groups: Cry1Ac-susceptible strain (96S), Cry1Ac-resistant strain fed on artificial diet with Bt toxin for 135 generations (BtR stands for the Cry1Ac Bt resistance), progeny of the Cry1Ac-resistant strain with a non-Bt-toxin artificial diet for 38 generations (CK1) and the direct descendants of the 135th-generation resistant larvae which were fed on an artificial diet without the Cry1Ac protein (CK2) were analyzed. Compared with the 96S strain, the resistance ratios of the BtR strain, the CK1 strain and the CK2 strain were 2917.15-, 2.15- and 2037.67-fold, respectively. The maximum relative HaVg mRNA expression levels of the BtR strain were approximately 50% less than that of the 96S strain, and the coming of maximum expression was delayed for approximately 4 days. The overall trend of the HaVg mRNA expression levels in the CK1 strain was similar to that in the 96S strain, and the overall trend of the HaVg mRNA expression levels in the CK2 strain was similar to that in the BtR strain. Our results

  15. Frequency of alleles conferring resistance to the Bt toxins Cry1Ac and Cry2Ab in Australian populations of Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Mahon, R J; Olsen, K M; Downes, S; Addison, S

    2007-12-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is an important lepidopteran pest of cotton (Gossypium spp.) in Australia and the Old World. From 2002, F2 screens were used to examine the frequency of resistance alleles in Australian populations of H. armigera to Bacillus thuringiensis (Bt) CrylAc and Cry2Ab, the two insecticidal proteins present in the transgenic cotton Bollgard II. At that time, Ingard (expressing Cry1Ac) cotton had been grown in Australia for seven seasons, and Bollgard II was about to be commercially released. The principal objective of our study was to determine whether sustained exposure caused an elevated frequency of alleles conferring resistance to Cry1Ac in a species with a track record of evolving resistance to conventional insecticides. No major alleles conferring resistance to Cry1Ac were found. The frequency of resistance alleles for Cry1Ac was <0.0003, with a 95% credibility interval between 0 and 0.0009. In contrast, alleles conferring resistance to Cry2Ab were found at a frequency of 0.0033 (0.0017, 0.0055). The first isolation of this allele was found before the widespread deployment of Bollgard II. For both toxins the experiment-wise detection probability was 94.4%. Our results suggest that alleles conferring resistance to Cry1Ac are rare and that a relatively high baseline frequency of alleles conferring resistance to Cry2Ab existed before the introduction of Bt cotton containing this toxin.

  16. Broad-scale suppression of cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae), associated with Bt cotton crops in Northern New South Wales, Australia.

    Science.gov (United States)

    Baker, G H; Tann, C R

    2017-04-01

    The cotton bollworm, Helicoverpa armigera, is a major pest of many agricultural crops in several countries, including Australia. Transgenic cotton, expressing a single Bt toxin, was first used in the 1990s to control H. armigera and other lepidopteran pests. Landscape scale or greater pest suppression has been reported in some countries using this technology. However, a long-term, broad-scale pheromone trapping program for H. armigera in a mixed cropping region in eastern Australia caught more moths during the deployment of single Bt toxin cotton (Ingard®) (1996-2004) than in previous years. This response can be attributed, at least in part, to (1) a precautionary cap (30% of total cotton grown, by area) being applied to Ingard® to restrict the development of Bt resistance in the pest, and (2) during the Ingard® era, cotton production greatly increased (as did that of another host plant, sorghum) and H. armigera (in particular the 3rd and older generations) responded in concert with this increase in host plant availability. However, with the replacement of Ingard® with Bollgard II® cotton (containing two different Bt toxins) in 2005, and recovery of the cotton industry from prevailing drought, H. armigera failed to track increased host-plant supply and moth numbers decreased. Greater toxicity of the two gene product, introduction of no cap on Bt cotton proportion, and an increase in natural enemy abundance are suggested as the most likely mechanisms responsible for the suppression observed.

  17. A Nonhost Peptidase Inhibitor of ~14 kDa from Butea monosperma (Lam. Taub. Seeds Affects Negatively the Growth and Developmental Physiology of Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Prabhash K. Pandey

    2014-01-01

    Full Text Available Helicoverpa armigera is one of the major devastating pests of crop plants. In this context a serine peptidase inhibitor purified from the seeds of Butea monosperma was evaluated for its effect on developmental physiology of H. armigera larvae. B. monosperma peptidase inhibitor on 12% denaturing polyacrylamide gel electrophoresis exhibited a single protein band of ~14 kDa with or without reduction. In vitro studies towards total gut proteolytic enzymes of H. armigera and bovine trypsin indicated measurable inhibitory activity. B. monosperma peptidase inhibitor dose for 50% mortality and weight reduction by 50% were 0.5% w/w and 0.10% w/w, respectively. The IC50 of B. monosperma peptidase inhibitor against total H. armigera gut proteinases activity was 2.0 µg/mL. The larval feeding assays suggested B. monosperma peptidase inhibitor to be toxic as reflected by its retarded growth and development, consequently affecting fertility and fecundity of pest and prolonging the larval-pupal duration of the insect life cycle of H. armigera. Supplementing B. monosperma peptidase inhibitor in artificial diet at 0.1% w/w, both the efficiencies of conversion of ingested as well as digested food were downregulated, whereas approximate digestibility and metabolic cost were enhanced. The efficacy of Butea monosperma peptidase inhibitor against progressive growth and development of H. armigera suggest its usefulness in insect pest management of food crops.

  18. 早熟素对棉铃虫滞育的终止作用%TERMINATION OF PUPAL DIAPAUSE IN THE BOLLWORM HELICOVERPA ARMIGERA BY PRECOCENE Ⅱ

    Institute of Scientific and Technical Information of China (English)

    王方海; 龚和

    2001-01-01

    用外源激素和某些化合物处理棉铃虫的滞育蛹,结果发现早熟素与蜕皮素-样可终止棉铃虫蛹的滞育,使其进入到发育阶段.而保幼激素类似物ZR-515,环腺氨酸(cAMP)和色氨类化合物(5-HT)则完全不具有终止棉铃虫滞育的作用.结合早熟素还可终止蚜虫寄生蜂Aphidius matricariae Haliday和Praon volucre Haliday的预蛹滞育的报道,建议早熟素应具有终止多种类昆虫滞育的功能.%Precocene Ⅱ terminated pupal diapause in the bollworm Helicoverpa armigera as 20-hydroxyecdysterone did, whereas juvenile hormone analog ZR-515, cyclic adenosine monophosphate (cAMP), and 5-hydroxytryptamine (5-HT) did not. The results indicate that precocene Ⅱ affects diapausing pupae in the similar way as what was found in the prepupae of the aphid parasitoids, Aphidius matricariae Haliday and Praon volucre Haliday (Hymenoptera: Aphidiidae). It is suggested that precocene Ⅱ may affect different kinds of termination of diapause in insects.

  19. The diapause hormone-pheromone biosynthesis activating neuropeptide gene of Helicoverpa armigera encodes multiple peptides that break, rather than induce, diapause.

    Science.gov (United States)

    Zhang, Tian-Yi; Sun, Jiu-Song; Zhang, Qi-Rui; Xu, Jun; Jiang, Rong-Jing; Xu, Wei-Hua

    2004-06-01

    FXPRLamide peptides encoded by the DH-PBAN (diapause hormone-pheromone biosynthesis activating neuropeptide) gene induce embryonic diapause in Bombyx mori, but terminate pupal diapause in Helicoverpa armigera (Har). Here, we explore the mechanisms of terminating pupal diapause by the FXPRLamide peptides. Using quantitative RT-PCR, we observed that expression of Har-DH-PBAN mRNA in the SG of nondiapause-type pupae was significantly higher than in diapause-type pupae. Immunocytochemical results indicated that the level of FXPRLamide peptides and axonal release are related to the diapause decision. Ecdysteroidogenesis in prothoracic glands (PGs) was stimulated by synthetic Har-DH in vivo and in vitro, and labeled Har-DH bound to the membrane of the PG, thus suggesting that DH breaks diapause by activating the PG to synthesize ecdysone. Furthermore, the response of DH in terminating diapause was temperature dependent. Decerebration experiments showed that the brain can control pupal development through the regulation of DH, and DH can terminate diapause and promote development without the brain. This result suggests a possible mechanism of response for the signals of DH and other FXPRLamide peptides in H. armigera.

  20. Evaluation of fractions and 5,7-dihydroxy-4',6-dimethoxy-flavone fromClerodendrum phlomidis Linn. F. against Helicoverpa armigera Hub.

    Directory of Open Access Journals (Sweden)

    Veeramuthu Duraipandiyan

    2015-04-01

    Full Text Available Twelve fractions from chloroform extract of Clerodendrum phlomidis and 5,7-dihydroxy- 4',6-dimethoxy-flavone (pectolinaringenin were evaluated against Helicoverpa armigera. Maximum antifeedant (89.41%, larvicidal (83.77% and ovicidal (69.25% activities were observed in fraction 5. The least LC50 value for antifeedant (178.09 ppm and larvicidal (198.23 ppm were observed in fraction 5. No adult emergence was recorded in fractions 4-6 at 1000 ppm. The oviposition deterrent activity was 100% in fraction 5 at all the concentrations. Pectolinaringenin recorded maximum antifeedant (74.68% and larvicidal (81.11% activities at 100 ppm; it completely prevented the adult emergence of H. armigera at 100 ppm. Maximum ovicidal activity at 100 ppm concentration was 67.95%. The oviposition deterrent activity was 100% in 100 and 50 ppm concentrations. C. phlomidis could be effectively used to develop a new formulation to control the economically important pests.

  1. Growth inhibitory activity of fatty acid methyl esters in the whole seed oil of madagascar periwinkle (Apocyanaceae) against Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Satyan, R S; Malarvannan, S; Eganathan, P; Rajalakshmi, S; Parida, Ajay

    2009-06-01

    Crude hexane and water extracts of Catharanthus roseus Linn. (Syn: Vinca rosea) (Apocyanaceae) stem, leaf, and seed exhibited pesticidal activity against Helicoverpa armigera (Hübner) (Lepidoptera Noctuidae). The extracts differed significantly in their efficacy, with the crude hexane extract of whole seed being the most effective in curtailing pupal survivorship to 18% followed by the hexane extracts of leaf (21%) and stem (24%). Average pupal weight (68.2 mg) and length (1.5 cm) in the whole seed treatment were drastically reduced, compared with the controls (415.2 mg and 2.72 cm), subsequently reducing adult emergence to 15.7%. SiO2 column purification yielded eight fractions of which fraction 1 exhibited 90% larval mortality, with severe reduction of the larvae weight (12.7 mg) and length (1.5 cm). Gas chromatographic-mass spectrometric analysis of fraction 1 suggested the presence of 16 compounds, among which oleic, linoleic, palmitic, and margaric acids were detected as major constituents. Presence of the alkane hydrocarbons triacontane, tetracosane, and heptacosane also was noted.

  2. Effects of UV-A exposures on longevity and reproduction in Helicoverpa armigera, and on the development of its F1 generation

    Institute of Scientific and Technical Information of China (English)

    Chang-Yu Zhang; Jian-Yu Meng; Xiao-Ping Wang; Fen Zhu; Chao-Liang Lei

    2011-01-01

    Helicoverpa armigera adults display a conspicuous positive phototacdc behavior to light stimuli,and are especially sensitive to ultraviolet (UV) light.The effects of UV-A (longwave) exposures on adult longevity and reproduction in H.armigera were investigated,as well as the development of the F1 generation.Paired adults were exposed to UV-A for various time periods (0,1,5 and 9 h/day),until the end of adult life.The results showed that adult longevity decreased with increasing exposure time for both sexes,and a significant decrease was observed after exposure for 5 and 9 h/day.Fecundity increased when adults were exposed for 1 and 5 h/day,and a significant difference was observed in the 5 h/day group.Oviposition rates of females in all treatments were significantly higher than in the control.Exposure to UV-A for longer periods (5 and 9 h/day) caused a decline in cumulative survival of F1 immature stages,but no significant differences were found in egg hatch,pupation and eclosion.The developmental periods of F1 larvae were significantly prolonged after exposure to UV-A for 5 and 9 h/day.UV-A radiation had no significant effects on F1 pupal period.

  3. Expression of Aminopeptidase N1(APN1),the Main Receptor Protein for Bacillus thuringiensis Cry1A Toxin from Helicoverpa armigera Larval Midgut in Trichoplusia ni cells

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong-lei; LIANG Ge-mei; WANG Gui-rong; YU Hong-kun; GUO Yu-yuan; WU Kong-ming

    2008-01-01

    The aim of this article is to successfully express the Bt(Bacillus thuringiensis)toxin receptor protein located on the internal membrane of larval midgut of cotton bollworm(Helicoverpa armigera Hiibner)within eukaryotic expression system,which is one of the key links for clarifying the relationship between receptor and Bt resistance.The fragments of aminopeptidase N1(APN1)gene without signal peptide in the susceptible and the resistant H. armigera were cloned separately using PCR method,and were separately cloned into pUC 19 vector.After sequencing the gene,the fragments encoding for APN1 without signal peptide were cloned into the Bac-to-Bac baculovirus expression system with transfer vector pFastBacHTB under the polyhedron gene promoter.The recombinant transposing plasmid pFastBacHTB/APN1 was screened and then transformed into Escherichia coli DH10Bac.It was cultured in LB medium,which contained Te, Kan,Ge,X-gal,and IPTG.The resulting recombinant bacmid was transfected into cells of the insect Trichoplusia ni and recombinant baculoviruse was obtained.The lysate of cells infected with recombinant baculoviruse was analyzed by SDS-PAGE and blot analysis.The results showed that the recombinant baculoviruse was fully capable of expressing APN1.The APN1 gene successfully expressed in T. ni cell established the base for continuing the research on its function and relationship of resistance with Bt.

  4. Toxicidade e capacidade de ligação de proteínas Cry1 a receptores intestinais de Helicoverpa armigera (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Isis Sebastião

    2015-11-01

    Full Text Available Resumo: O objetivo deste trabalho foi avaliar a toxicidade e a capacidade de ligação das proteínas Cry1Aa, Cry1Ab, Cry1Ac e Cry1Ca, de Bacillus thuringiensis, a receptores intestinais de Helicoverpa armigera. Realizou-se análise de ligação das proteínas ativadas às vesículas de membrana da microvilosidade apical (VMMA do intestino médio deH. armigera, além de ensaios de competição heteróloga para avaliar sua capacidade de ligação. Cry1Ac destacou-se como a proteína mais tóxica, seguida por Cry1Ab e Cry1Aa. A proteína Cry1Ca não foi tóxica às lagartas e, portanto, não foi possível determinar os seus parâmetros de toxicidade CL50 e CL90. As proteínas Cry1Aa, Cry1Ab e Cry1Ac são capazes de se ligar a um mesmo receptor nas membranas intestinais, o que aumenta o risco do desenvolvimento de resistência cruzada. Portanto, a utilização conjunta dessas proteínas deve ser evitada.

  5. Functional validation of cadherin as a receptor of Bt toxin Cry1Ac in Helicoverpa armigera utilizing the CRISPR/Cas9 system.

    Science.gov (United States)

    Wang, Jing; Zhang, Haonan; Wang, Huidong; Zhao, Shan; Zuo, Yayun; Yang, Yihua; Wu, Yidong

    2016-09-01

    Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out. A single positive CRISPR event with a frame shift deletion of 4 nucleotides was identified and made homozygous to create a knockout line named SCD-Cad. Western blotting confirmed that HaCad was no longer expressed in the SCD-Cad line while an intact HaCad of 210 kDa was present in the parental SCD strain. Insecticide bioassays were used to show that SCD-Cad exhibited 549-fold resistance to Cry1Ac compared with SCD, but no significant change in susceptibility to Cry2Ab. Our results not only provide strong reverse genetics evidence for HaCad as a functional receptor of Cry1Ac, but also demonstrate that the CRISPR/Cas9 technique can act as a powerful and efficient genome editing tool to study gene function in a global agricultural pest, H. armigera.

  6. A novel bio-engineering approach to generate an eminent surface-functionalized template for selective detection of female sex pheromone of Helicoverpa armigera

    Science.gov (United States)

    Moitra, Parikshit; Bhagat, Deepa; Pratap, Rudra; Bhattacharya, Santanu

    2016-11-01

    Plant pests exert serious effects on food production due to which the global crop yields are reduced by ~20–40 percent per year. Hence to meet the world’s food needs, loses of food due to crop pests must be reduced. Herein the silicon dioxide based MEMS devices are covalently functionalized for robust and efficient optical sensing of the female sex pheromones of the pests like Helicoverpa armigera for the first time in literature. The functionalized devices are also capable of selectively measuring the concentration of this pheromone at femtogram level which is much below the concentration of pheromone at the time of pest infestation in an agricultural field. Experiments are also performed in a confined region in the presence of male and female pests and tomato plants which directly mimics the real environmental conditions. Again the reversible use and absolutely trouble free transportation of these pheromone nanosensors heightens their potentials for commercial use. Overall, a novel and unique approach for the selective and reversible sensing of female sex pheromones of certain hazardous pests is reported herein which may be efficiently and economically carried forward from the research laboratory to the agricultural field.

  7. Toxicity and binding analyses of Bacillus thuringiensis toxin Vip3A in Cry1Ac-resistant and-susceptible strains of Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qian; CHEN Li-zhen; LU Qiong; ZHANG Yan; LIANG Ge-mei

    2015-01-01

    The Bacil us thuringiensis vegetative insecticidal protein, Vip3A, represents a new family of Bt toxin and is currently ap-plied to commercial transgenic cotton. To determine whether the Cry1Ac-resistant Helicoverpa armigera is cross-resistant to Vip3Aa protein, insecticidal activities, proteolytic activations and binding properties of Vip3Aa toxin were investigated using Cry1Ac-susceptible (96S) and Cry1Ac-resistant H. armigera strain (Cry1Ac-R). The toxicity of Vip3Aa in Cry1Ac-R slightly reduced compared with 96S, the resistance ratio was only 1.7-fold. The digestion rate of ful-length Vip3Aa by gut juice extracts from 96S was little faster than that from Cry1Ac-R. Surface plasmon resonance (SPR) showed there was no signiifcant difference between the binding afifnity of Vip3Aa and BBMVs between 96S and Cry1Ac-R strains, and there was no signiifcant competitive binding between Vip3Aa and Cry1Ac in susceptible or resistant strains. So there had little cross-resistance between Vip3Aa and Cry1Ac,Vip3A+Cry proteins maybe the suitable pyramid strategy to control H. armigera in China in the future.

  8. Diversity in gut microflora of Helicoverpa armigera populations from different regions in relation to biological activity of Bacillus thuringiensis δ-endotoxin Cry1Ac.

    Science.gov (United States)

    Paramasiva, Inakarla; Shouche, Yogesh; Kulkarni, Girish Jayant; Krishnayya, Pulipaka Venkata; Akbar, Shaik Mohammed; Sharma, Hari Chand

    2014-12-01

    Transgenic crops expressing toxin proteins from Bacillus thuringiensis (Bt) have been deployed on a large scale for management of Helicoverpa armigera. Resistance to Bt toxins has been documented in several papers, and therefore, we examined the role of midgut microflora of H. armigera in its susceptibility to Bt toxins. The susceptibility of H. armigera to Bt toxin Cry1Ac was assessed using Log-dose-Probit analysis, and the microbial communities were identified by 16S rRNA sequencing. The H. armigera populations from nine locations harbored diverse microbial communities, and had some unique bacteria, suggesting a wide geographical variation in microbial community in the midgut of the pod borer larvae. Phylotypes belonging to 32 genera were identified in the H. armigera midgut in field populations from nine locations. Bacteria belonging to Enterobacteriaceae (Order Bacillales) were present in all the populations, and these may be the common members of the H. armigera larval midgut microflora. Presence and/or absence of certain species were linked to H. armigera susceptibility to Bt toxins, but there were no clear trends across locations. Variation in susceptibility of F1 neonates of H. armigera from different locations to the Bt toxin Cry1Ac was found to be 3.4-fold. These findings support the idea that insect migut microflora may influence the biological activity of Bt toxins.

  9. Purification of Aminopeptidase N Protein and Differences in cDNAs Encoding APN1 Between Susceptible and Resistant Helicoverpa armigera Strains to Bacillus thuringiensis Toxins

    Institute of Scientific and Technical Information of China (English)

    LIANG Ge-mei; WANG Gui-rong; XU Guang; WU Kong-ming; GUO Yu-yuan

    2004-01-01

    The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera were successfully separated, and most of the Aminopeptidase N (APN) activities in BBMV were preserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-l-propane-sulphonate (CHAPS)can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C (PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified using a Mono-Q column. The results of immunoblotting showed that the 120 and 170 kDa proteins in the BBMV could bind CrylAc, and 120kDa APN was a glycosylphosphalidylinositol(GPI)anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after being selected for more than five years in laboratory using Bt insecticides and Bt transgenic cotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1 083.3and 48.7 times that of susceptible strain. The genes encoding APN1 in midgut of susceptible and resistant H.armigera were cloned by PCR and RACE techniques. The inferred amino acid sequences of APN1 possessed the common character of APN family in insects. In comparison with APN1 in susceptible strain, three nucleotide mutations were observed in the APN1 of Bt-M strain and resulted in two amino acid replace in the putative protein sequences, and eight nucleotide mutations were observed in Bt-P strain and resulted in five amino acid replace.

  10. Sorghum seed maturity affects the weight and feeding duration of immature corn earworm, Helicoverpa zea, and fall armyworm, Spodoptera frugiperda, in the laboratory.

    Science.gov (United States)

    Soper, Alysha M; Whitworth, R Jeff; McCornack, Brian P

    2013-01-01

    Corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), and fall armyworm, Spodoptera frugiperda J.E. Smith, are occasional pests in sorghum, Sorghum bicolor L. Moench (Poales: Poaceae), and can be economically damaging when conditions are favorable. Despite the frequent occurrence of mixed-species infestations, the quantitative data necessary for developing yield loss relationships for S. frugiperda are not available. Although these species share similar biological characteristics, it is unknown whether their damage potentials in developing grain sorghum panicles are the same. Using no-choice feeding assays in the laboratory, this study examined larval growth and feeding duration for H. zea and S. frugiperda in the absence of competition. Each species responded positively when exposed to sorghum seed in the soft-dough stage, supporting evidence for the interactions between host-quality and larval growth and development. The results of this study also confirmed the suitability of using laboratory-reared H. zea to develop sorghum yield loss estimates in the field, and provided insights into the biological responses of S. frugiperda feeding on developing sorghum seed.

  11. Trans-generational desensitization and within-generational resensitization of a sucrose-best neuron in the polyphagous herbivore Helicoverpa armigera (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Ma, Ying; Li, Jingjing; Tang, Qingbo; Zhang, Xuening; Zhao, Xincheng; Yan, Fengming; van Loon, Joop J. A.

    2016-01-01

    Dietary exposure of insects to a feeding deterrent substance for hours to days can induce habituation and concomitant desensitization of the response of peripheral gustatory neurons to such a substance. In the present study, larvae of the herbivore Helicoverpa armigera were fed on diets containing either a high, medium or low concentration of sucrose, a major feeding stimulant. The responsiveness of the sucrose-best neuron in the lateral sensilla styloconica on the galea was quantified. Results showed the response of the sucrose-best neuron exposed to high-sucrose diets decreased gradually over successive generations, resulting in complete desensitization in the 5th and subsequent generations. However, the sensitivity was completely restored in the ninth generation after neonate larvae were exposed to low-sucrose diet. These findings demonstrate phenotypic plasticity and exclude inadvertent artificial selection for low sensitivity to sucrose. No significant changes were found in the sensitivity of caterpillars which experienced low- or medium-sucrose diets over the same generations. Such desensitization versus re-sensitization did not generalise to the phagosimulant myo-inositol-sensitive neuron or the feeding deterrent-sensitive neuron. Our results demonstrate that under conditions of high sucrose availability trans-generational desensitization of a neuron sensitive to this feeding stimulant becomes more pronounced whereas re-sensitization occurs within one generation. PMID:27966640

  12. Susceptibility of Helicoverpa zea and Heliothis virescens (Lepidoptera: Noctuidae) to Vip3A insecticidal protein expressed in VipCot™ cotton.

    Science.gov (United States)

    Ali, M I; Luttrell, R G

    2011-10-01

    Susceptibility of laboratory and field colonies of Helicoverpa zea (Boddie) and Heliothis virescens F. to Vip3A insecticidal protein was studied in diet incorporation and diet overlay assays from 2004 to 2008. Responses of field populations were compared to paired responses of University of Arkansas laboratory susceptible H. zea (LabZA) and H. virescens (LabVR) colonies. After 7d of exposure, observations were made on number of dead larvae (M) and the number of larvae alive but remaining as first instars (L1). Regression estimates using M (LC(50)) and M plus L1 (MIC(50)) data were developed for laboratory and field populations. Susceptibility of laboratory and field populations exposed to Vip3A varied among different batches of protein used over the study period. Within the same batch of Vip3A protein, susceptibilities of laboratory colonies of both species (LabZA and LabVR) were similar. Field colonies were significantly more susceptible to Vip3A than the respective reference colonies of both species. Within field populations, susceptibility to Vip3A varied up to 75-fold in H. zea and 132-fold in H. virescens in LC(50) estimates. Variabilities in MIC(50)s were up to 59- and 11-fold for H. zea and H. virescens, respectively.

  13. A bifunctional α-amylase/trypsin inhibitor from pigeonpea seeds: Purification, biochemical characterization and its bio-efficacy against Helicoverpa armigera.

    Science.gov (United States)

    Gadge, Prafull P; Wagh, Sandip K; Shaikh, Faiyaz K; Tak, Rajesh D; Padul, Manohar V; Kachole, Manvendra S

    2015-11-01

    This paper evaluates α-amylase inhibitor (α-AI) mediated defense of pigeonpea against Helicoverpa armigera. A bifunctional α-amylase/trypsin inhibitor was purified from the seeds of pigeonpea by native liquid phase isoelectric focusing (N-LP-IEF), affinity chromatography and preparative electrophoresis. Its in-vivo and in-vitro interaction with midgut amylases of H. armigera was studied along with growth inhibitory activity. One and two dimensional (2D) zymographic analyses revealed that the purified inhibitor is dimeric glycoprotein (60.2kDa and 56kDa) exist in a multi-isomeric form with five pI variants (pI 5.5 to 6.3). It was found to be heat labile with complete inactivation up to 80°C and stable over a wide range of pH (4-11). The slow binding and competitive type of α-amylase inhibition was observed with 0.08μM of dissociation constant (Ki) for the enzyme-inhibitor complex (EI). The internal protein sequence of two subunits obtained by mass spectrometry matched with cereal-type α-AI, a conserved domain from AAI_LTSS superfamily and sialyltransferase-like protein respectively. In-vivo studies indicated up-regulation of total midgut α-amylase activity with negative effect on growth rate of H. armigera suggesting its suitability for pest control.

  14. Bioactivity of a water extract of boldus (Peumus boldus Molina against Spodoptera frugiperda (J.E. Smith and Helicoverpa zea Boddie (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Gonzalo Silva

    2013-06-01

    Full Text Available The insecticidal properties of water-extract of Peumus boldus Molina and its effect on the development cycle and feeding habits of Spodoptera frugiperda J.E. Smith and Helicoverpa zea Boddie were evaluated under laboratory conditions in concentrations of 0.25, 0.5, 1.0, 2.0, 4.0, and 8.0% (w/w. Spodoptera frugiperda was the most susceptible with 75% mortality at 7 d at 8% P. boldus concentration, while H. zea had only 30% mortality. LC50 was 2.31 mL kg-1 for S. frugiperda and 16.05 mL kg¹ for H. zea. When the extract concentration increased in the diet, larval size and weight, percentage of pupation and number of adults decreased, and the time required to reach those states was greater. Neonate larvae fed primarily on the diet with the lower extract concentration and the control was preferred by more than 50% of larvae. Inhibition of feeding, growth, weight gain of 3rd instar larvae as well as new biomass production decreased with concentration of the extract.

  15. No evidence for change in oviposition behaviour of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) after widespread adoption of transgenic insecticidal cotton.

    Science.gov (United States)

    Zalucki, M P; Cunningham, J P; Downes, S; Ward, P; Lange, C; Meissle, M; Schellhorn, N A; Zalucki, J M

    2012-08-01

    Cotton growing landscapes in Australia have been dominated by dual-toxin transgenic Bt varieties since 2004. The cotton crop has thus effectively become a sink for the main target pest, Helicoverpa armigera. Theory predicts that there should be strong selection on female moths to avoid laying on such plants. We assessed oviposition, collected from two cotton-growing regions, by female moths when given a choice of tobacco, cotton and cabbage. Earlier work in the 1980s and 1990s on populations from the same geographic locations indicated these hosts were on average ranked as high, mid and low preference plants, respectively, and that host rankings had a heritable component. In the present study, we found no change in the relative ranking of hosts by females, with most eggs being laid on tobacco, then cotton and least on cabbage. As in earlier work, some females laid most eggs on cotton and aspects of oviposition behaviour had a heritable component. Certainly, cotton is not avoided as a host, and the implications of these finding for managing resistance to Bt cotton are discussed.

  16. Flutuação Populacional e Parasitismo de Ovos de Spodoptera frugiperda e Helicoverpa zea em milho pulverizado com extratos vegetais e Metarhizium anisopliae

    Directory of Open Access Journals (Sweden)

    Jaqueline Ramos de Freitas

    2010-10-01

    Full Text Available We evaluated the effect of plant extracts and Metarhizium anisopliae on population and parasitism of eggs of Spodoptera frugiperda and Helicoverpa zea in corn planted at two spacings. The research was conducted at the Agricultural School "Assis Chateaubriand" in Laguna Seca, PB, and Laborat6rio of Entomology at the Center for Integrated Pest Management / UEPB in Campina Grande-PB. Corn was planted in an area of 500m2, in spacing: (I 0,8 m x 0,4 m, and (II 0,4 m x 0,4 m, with one or two plants per hole, respectively. The treatments consisted of: 1 water as a control, 2 M. anisopliae (100 g 10 L-1 water, 3 Extract of Momordica charantia (50 ml L-1 water, 4 M. anisopliae (10 g L-1 water + water extract of M. charantia (50 ml L-1 water, 5 M. anisopliae (10 g L-1 water + cassava (Manihot esculenta Crantz (50 ml L-1 water. According to the results, no significant difference between treatments to control spacing I S. frugiperda egg, which was due, probably, late spraying, when 100% of the plants were attacked. The treatments also not efficient to control H zea eggs, recommending further studies to determine the concentration and dosage most appropriate for controlling these pests.

  17. Effects of different brush border membrane vesicle isolation protocols on proteomic analysis of Cry1 Ac binding proteins from the midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    Li-Zhen Chen; Ge-Mei Liang; Brian G.Rector; Jie Zhang; Kong-Ming Wu; Yu-Yuan Guo

    2008-01-01

    Brush border membrane vesicles(BBMV)isolated from insect midguts have been widely used to study CrylA binding proteins.Sample preparation is important in two-dimensional electrophoresis(2-DE),so to determine a suitable BBMV preparation method in Helicoverpa armigera for 2-DE,we compared three published BBMV preparation methods mostly used in sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).All mctllods yielded similar types and numbers of binding proteins,but in different quantifies.The Abdul.Rauf and Ellar protocol was the best of the three,but had limitations.Sufficient protein qu antity iS important for research involving limited numbers of insects,such as studies of insect resistance to Bacillus thuringiensis in the field.Consequently,we integrated the three BBMV isolation methods into a single protocol that yielded high quantities of BBMV proteins from H.armigera larval midguts.which proved suitable for 2-DE analysis.

  18. Fitness costs to Helicoverpa armigera after exposure to sub-lethal concentrations of Metarhizium anisopliae sensu lato: Study on F1 generation.

    Science.gov (United States)

    Jarrahi, Azadeh; Safavi, Seyed Ali

    2016-07-01

    The entomopathogenic fungus, Metarhizium anisopliae (Metsch.) Sorokin is a valuable biocontrol agent attacking larval stages of many lepidopteran pests including Helicoverpa armigera (Hübner). Sub-lethal effects of M. anisopliae sensu lato (s.l.) (isolate M14) were investigated on life table parameters of offspring from treated larvae of H. armigera. Duration of different life stages was significantly affected by fungal treatments. Fecundity was decreased in females derived from H. armigera larvae treated with M. anisopliae s.l. Sub-lethal concentrations of the entomopathogen reduced the net reproduction rate (R0) of F1 insects for all treatments compared with the control. Similar reductions were observed for the intrinsic and the finite rates of increase (rm and λ, respectively). The mean generation time (T) and the doubling time (DT) were statistically higher in offspring of individuals exposed to some fungal concentrations than control insects. Our results indicated that there was a significant decrease in the F1 population of H. armigera derived from larvae that were exposed to sub-lethal concentrations of M. anisopliae s.l.

  19. Transgenic plants over-expressing insect-specific microRNA acquire insecticidal activity against Helicoverpa armigera: an alternative to Bt-toxin technology.

    Science.gov (United States)

    Agrawal, Aditi; Rajamani, Vijayalakshmi; Reddy, Vanga Siva; Mukherjee, Sunil Kumar; Bhatnagar, Raj K

    2015-10-01

    The success of Bt transgenics in controlling predation of crops has been tempered by sporadic emergence of resistance in targeted insect larvae. Such emerging threats have prompted the search for novel insecticidal molecules that are specific and could be expressed through plants. We have resorted to small RNA-based technology for an investigative search and focused our attention to an insect-specific miRNA that interferes with the insect molting process resulting in the death of the larvae. In this study, we report the designing of a vector that produces artificial microRNA (amiR), namely amiR-24, which targets the chitinase gene of Helicoverpa armigera. This vector was used as transgene in tobacco. Northern blot and real-time analysis revealed the high level expression of amiR-24 in transgenic tobacco plants. Larvae feeding on the transgenic plants ceased to molt further and eventually died. Our results demonstrate that transgenic tobacco plants can express amiR-24 insectice specific to H. armigera.

  20. Laboratory testing and molecular analysis of the resistance of wild and cultivated soybeans to cotton bollworm, Helicoverpa armigera(Hübner)

    Institute of Scientific and Technical Information of China (English)

    Xiaoyi; Wang; Haifeng; Chen; Aihua; Sha; Rong; Zhou; Zhihui; Shang; Xiaojuan; Zhang; Chanjuan; Zhang; Limiao; Chen; Qingnan; Hao; Zhonglu; Yang; Dezhen; Qiu; Shuilian; Chen; Xinan; Zhou

    2015-01-01

    Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm(Helicoverpa armigera Hübner) is one of the major defoliators of soybean(Glycine max [L.] Merr.) worldwide. In this study, we evaluated the effect of H. armigera larvae on ED059, a wild soybean(Glycine soja Sieb. et Zucc.), and three cultivated soybean varieties: Tianlong 2, PI 535807, and PI 533604, in choice and no-choice assays. The percentage of ED059 leaflets consumed by H. armigera was lower than that of the three cultivated soybeans. Larvae that fed on ED059 exhibited low weight gain and high mortality rate.Waldbauer nutritional indices suggested that ED059 reduced the growth, consumption, and frass production of H. armigera larvae. Larvae that fed on ED059 showed lower efficiency of conversion of ingested and of digested food than those that fed on Tianlong 2 and PI 533604.However, they showed statistically similar consumption index and approximate digestibility compared with those fed on the three cultivated soybeans. Quantitative real-time PCR analysis revealed that 24 h after insect attack, ED059 had higher transcript levels of Kunitz trypsin inhibitor 3, Cysteine proteinase inhibitor 2, and Nerolidol synthase 1 but a lower transcript level of Pathogenesis-related protein 1 than Tianlong 2. The gene expression results were consistent with the presence of higher levels of jasmonic acid(JA) and transcript levels of the JA biosynthesis enzyme allene oxide cyclase 3 in ED059 than in Tianlong 2. Our findings indicate that ED059 is a superior soybean line with strong insect resistance that may be mediated via the JA pathway.

  1. The Impact of Inter-Kernel Movement in the Evolution of Resistance to Dual-Toxin Bt-Corn Varieties in Helicoverpa zea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Caprio, Michael A; Martinez, Jeannette C; Porter, Patrick A; Bynum, Ed

    2016-02-01

    Seeds or kernels on hybrid plants are primarily F(2) tissue and will segregate for heterozygous alleles present in the parental F(1) hybrids. In the case of plants expressing Bt-toxins, the F(2) tissue in the kernels will express toxins as they would segregate in any F(2) tissue. In the case of plants expressing two unlinked toxins, the kernels on a Bt plant fertilized by another Bt plant would express anywhere from 0 to 2 toxins. Larvae of corn earworm [Helicoverpa zea (Boddie)] feed on a number of kernels during development and would therefore be exposed to local habitats (kernels) that varied in their toxin expression. Three models were developed for plants expressing two Bt-toxins, one where the traits are unlinked, a second where the traits were linked and a third model assuming that maternal traits were expressed in all kernels as well as paternally inherited traits. Results suggest that increasing larval movement rates off of expressing kernels tended to increase durability while increasing movement rates off of nonexpressing kernels always decreased durability. An ideal block refuge (no pollen flow between blocks and refuges) was more durable than a seed blend because the refuge expressed no toxins, while pollen contamination from plants expressing toxins in a seed blend reduced durability. A linked-trait model in an ideal refuge model predicted the longest durability. The results suggest that using a seed-blend strategy for a kernel feeding insect on a hybrid crop could dramatically reduce durability through the loss of refuge due to extensive cross-pollination.

  2. The movement and distribution of Helicoverpa armigera (Hübner) larvae on pea plants is affected by egg placement and flowering.

    Science.gov (United States)

    Perkins, L E; Cribb, B W; Hanan, J; Zalucki, M P

    2010-10-01

    The distribution and movement of 1st instar Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae on whole garden pea (Pisum sativum L.) plants were determined in glasshouse trials. This economically-important herbivore attacks a wide variety of agricultural, horticultural and indigenous plants. To investigate the mechanisms underlying larval intra-plant movement, we used early-flowering and wild-type plant genotypes and placed eggs at different vertical heights within the plants, one egg per plant. Leaf water and nitrogen content and cuticle hardness were measured at the different plant heights. Of 92 individual larvae, 41% did not move from the node of eclosion, 49% moved upwards and 10% moved downwards with the distance moved being between zero and ten plant nodes. Larvae from eggs placed on the lower third of the plant left the natal leaf more often and moved further than larvae from eggs placed in the middle or upper thirds. The low nutritive value of leaves was the most likely explanation for more movement away from lower plant regions. Although larvae on flowering plants did not move further up or down than larvae on non-flowering plants, they more often departed the leaflet (within a leaf) where they eclosed. The final distribution of larvae was affected by plant genotype, with larvae on flowering plants found less often on leaflets and more often on stipules, tendrils and reproductive structures. Understanding intra-plant movement by herbivorous insects under natural conditions is important because such movement determines the value of economic loss to host crops. Knowing the behaviour underlying the spatial distribution of herbivores on plants will assist us to interpret field data and should lead to better informed pest management decisions.

  3. Utilization of metarhizium anisopliae and vegetable extract for control of the spodoptera frugiperda and helicoverpa zea (lepidoptera: noctuidae in the corn

    Directory of Open Access Journals (Sweden)

    Eduardo Barbosa Beserra

    2008-05-01

    Full Text Available The potential use of the vegetable extracts and Metarhizium anisopliae about the population and damage of the Spodoptera frugiperda and Helicoverpa zea in corn, it was evaluated when planted in two spacings. The experiment was installed in the culture of corn, in the city of Lagoa Seca/PB, in two areas of 500 m2, in the spacings 0,8 x 0,4 and 0,4 x 0,4 m, with two and one plant for hole. The basis was constituited of: 1 Water as witness; 2 Metarhizium anisopliae; 3 Extracts of Mormodica charantia; 4 Metarhizium anisopliae + extracts of M. charantia; 5 M. anisopliae + manipueira. The results showed some statistical difference between the two spacings, with a larger number of collected caterpillars, 5,84, and a larger damage to the plant, 3,24, in the spacing 0,4 x 0,4 m, in relation to the spacing 0,8 x 0,4 m, within as average of 4,13 caterpillars and danificated of 2,71. There was not any significant interaction between the spacings and the products used for the control of S. frugiperda. However, there was a significant difference among the treatments, with a smaller number of caterpillars, 4,17, and a smaller medium damage to the plant, 2,81, when was used, M. anisopliae + extract of M. charantia. Considering to the control of the plaque the percentage of damage ears of corn by H. zea, weight and length of the ear of corn in corn, there wasn’t neither significant difference with regard to the spacing, neither with regard to the used treatments.

  4. Cloning and Tissue-Specific Expression of a Chitin Deacetylase Gene from Helicoverpa armigera (Lepidoptera: Noctuidae) and Its Response to Bacillus thuringiensis

    Science.gov (United States)

    Han, Guoying; Li, Xiumin; Zhang, Ting; Zhu, Xiaoting

    2015-01-01

    Chitin deacetylases (CDAs) convert chitin into chitosan, the N-deacetylated form of chitin, which influences the mechanical and permeability properties of structures such as the cuticle and peritrophic matrices. In this article, a new CDA encoding gene, Hacda2, was cloned by reverse transcription-polymerase chain reaction method in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), with an open reading frame of 1,611 bp. The deduced protein composed of 536 amino acid residues with a signal peptide, a chitin-binding domain, a low-density lipoprotein receptor class A domain, and a polysaccharide deacetylase-like catalytic domain. The highest expression level of Hacda2 was detected in fat body among tissues tested in the fifth-instar larvae using real-time quantitative polymerase chain reaction method. Feeding of Bacillus thuringiensis (Bt) (Bacillales: Bacillaceae) diet changed the expression level of Hacda1, Hacda2, Hacda5a, and Hacda5b significantly and differentially in the third-instar larvae. Hacda5a and Hacda5b expression were initially down-regulated and then up-regulated, whereas, the expression level of Hacda1 and Hacda2 was suppressed constantly postfeeding on Bt diet. These results suggested that HaCDAs may be involved in the response of H. armigera larvae to Bt and may be helpful to elucidate the roles of HaCDAs in the action of Bt cry toxin. The potential of HaCDAs to be used as synergists of Bt insecticidal protein needs to be further tested. PMID:26163665

  5. High Susceptibility to Cry1Ac and Low Resistance Allele Frequency Reduce the Risk of Resistance of Helicoverpa armigera to Bt Soybean in Brazil

    Science.gov (United States)

    Bacalhau, Fabiana B.; Amado, Douglas; Carvalho, Renato A.; Martinelli, Samuel; Head, Graham P.; Omoto, Celso

    2016-01-01

    The Old World bollworm, Helicoverpa armigera (Hübner), was recently introduced into Brazil, where it has caused extensive damage to cotton and soybean crops. MON 87701 × MON 89788 soybean, which expresses the Bt protein Cry1Ac, was recently deployed in Brazil, providing high levels of control against H. armigera. To assess the risk of resistance to the Cry1Ac protein expressed by MON 87701 × MON 89788 soybean in Brazil, we conducted studies to evaluate the baseline susceptibility of H. armigera to Cry1Ac, in planta efficacy including the assessment of the high-dose criterion, and the initial resistance allele frequency based on an F2 screen. The mean Cry1Ac lethal concentration (LC50) ranged from 0.11 to 1.82 μg·mL−1 of diet among all H. armigera field populations collected from crop seasons 2013/14 to 2014/15, which indicated about 16.5-fold variation. MON 87701 × MON 89788 soybean exhibited a high level of efficacy against H. armigera and most likely met the high dose criterion against this target species in leaf tissue dilution bioassays up to 50 times. A total of 212 F2 family lines of H. armigera were established from field collections sampled from seven locations across Brazil and were screened for the presence of MON 87701 × MON 89788 soybean resistance alleles. None of the 212 families survived on MON 87701 × MON 89788 soybean leaf tissue (estimated allele frequency = 0.0011). The responses of H. armigera to Cry1Ac protein, high susceptibility to MON 87701 × MON 89788 soybean, and low frequency of resistance alleles across the main soybean-producing regions support the assumptions of a high-dose/refuge strategy. However, maintenance of reasonable compliance with the refuge recommendation will be essential to delay the evolution of resistance in H. armigera to MON 87701 × MON 89788 soybean in Brazil. PMID:27532632

  6. Cloning and expression of the cDNA encoding the FXPRL family of peptides and a functional analysis of their effect on breaking pupal diapause in Helicoverpa armigera.

    Science.gov (United States)

    Zhang, Tian-Yi; Sun, Jiu-Song; Zhang, Liu-Bin; Shen, Jin-Liang; Xu, Wei-Hua

    2004-01-01

    Diapause hormone (DH) and pheromone biosynthesis activating neuropeptide (PBAN) are encoded by a single mRNA in the suboesophegeal ganglion (SG) and are responsible for induction of embryonic diapause in Bombyx mori and sex pheromone biosynthesis in lepidopteran insects. PBAN cDNA analyses revealed that the DH-like peptide is present in several species that have a pupal diapause. However, the function of the DH-like peptide remains unknown. In the present study, we cloned the cDNA encoding DH-PBAN in Helicoverpa armigera utilizing the rapid amplification of the cDNA ends method. The nucleotide se quence analysis revealed that the longest open reading frame of this cDNA encodes a 194-amino acid precursor protein that con tains a 33-aa PBAN, a 24-aa DH-like peptide, and three other neuropeptides, all of which have a common C-terminal pentapeptide motif FXPR/KL ( X=G, T, S). A homology search showed that H. armigera DH-like and PBAN are highly homologous to those from other insects. Northern blot analysis demonstrated a single message RNA corresponding to the size of Har-DH-PBAN cDNA from pupal SG with significantly higher expression in the SG of nondiapause pupae than diapausing pupae. Western blot analysis showed DH-like peptide expression from SG of both males and females. When DH-like peptide was injected into nondiapause larvae and pupae, it did not induce diapause, but rather efficiently broke pupal diapause in H. armigera. The ED(50) of DH to terminate pupal diapause is 20 pmol/pupae. The other four FXPRLamide neuropeptides from the DH-PBAN polyprotein precursor have cross activity for diapause termination. These observations therefore suggest a potential role for these FXPRL family peptides in promoting continuous development in several noctuid species. The high expression of this gene in pharate adults and adults indicates that the FXPRL family peptides may have multiple physiological functions.

  7. A cDNA encoding diazepam-binding inhibitor/acyl-CoA-binding protein in Helicoverpa armigera: molecular characterization and expression analysis associated with pupal diapause.

    Science.gov (United States)

    Liu, Ming; Zhang, Tian-Yi; Xu, Wei-Hua

    2005-06-01

    The diazepam binding inhibitor (DBI) or the acyl-CoA-binding protein (ACBP) is a 9-10 kDa highly conserved multifunctional protein that plays important roles in GABA(A) receptor activity regulation, lipid absorption and steroidogenesis in various organisms. To study the functions of DBI/ACBP in insect development or diapause, we cloned the cDNA from Helicoverpa armigera (Har) utilizing rapid amplification of cDNA ends (RACE). By homology search, Har-DBI/ACBP is conserved with the DBI/ACBPs known from other insects. Northern blot analysis showed that DBI/ACBP gene expressed in nonneural and neural tissues. RT-PCR combined Southern blot analysis revealed that DBI/ACBP mRNA in the brain of nondiapause individual was much higher than that in the brain of diapausing insects. At early and middle stages of 6th instar larvae, the level of DBI/ACBP mRNA was higher in the midgut of diapause type than that in nondiapause type and low at late 6th instar larval stage and early pupal stage in both types. In the prothoracic gland (PG), DBI/ACBP expression appeared at a high level at middle and late stages of 6th larval instar in both nondiapause and diapause types, and declined after pupation. In vitro experiments revealed that DBI/ACBP mRNA in PG could be stimulated by synthetic H. armigera diapause hormone (Har-DH), suggesting that Har-DH may stimulate the PG to produce ecdysteroids by the DBI/ACBP signal pathway. By in vitro assay, we also found that FGIN-1-27, which has similar functions to DBI/ACBP in ecdysteroidogenesis, could induce PG ecdysteroidogenesis effectively, suggesting that DBI/ACBP regulates biosynthesis of ecdysteroids in PG. Thus, DBI/ACBP indeed plays a key role in metabolism and development in H. armigera.

  8. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  9. Presence of snow coverage and its thickness affected the mortality of overwintering pupae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Huang, Jian

    2016-10-01

    Helicoverpa armigera causes serious damage to most crops around the world. However, the impacts of snow thickness on the H. armigera overwintering pupae are little known. A field experiment was employed in 2012-2015 at Urumqi, China. At soil depths of 5, 10, and 15 cm, overwintering pupae were embedded with four treatments: no snow cover (NSC), snow cover (SC), increasing snow thickness to 1.5 times the thickness of SC (ISSC-1), and to two times the thickness of SC (ISSC-2). Results suggested that snow cover and increasing snow thickness both significantly increased soil temperatures, which helped to decrease the mortality of overwintering pupae (MOP) of H. armigera. However, the MOP did not always decrease with increases in snow thickness. The MOPs in NSC and ISSC-1 were the highest and the lowest, respectively, though ISSC-2 had much thicker snow thickness than ISSC-1. A maximum snow thickness of 60 cm might lead to the lowest MOP. The longer the snow cover duration (SCD) at a soil depth of 10 cm in March and April was, the higher the MOP was. A thicker snow cover layer led to a higher soil moisture content (SMC) and a lower diurnal soil temperature range (DSTR). The highest and the lowest MOP were at a depth of 15 and 10 cm, respectively. The SMC at the depths of 10 and 15 cm had significant effects on MOP. A lower accumulated temperature (≤0 °C) led to a higher MOP. The DSTR in March of approximately 4.5 °C might cause the lowest MOP. The largest influence factor for the MOPs at depths of 5 and 10 cm and the combined data were the SCDs during the whole experimental period, and for the MOPs at a depth of 15 cm was the soil temperature in November.

  10. Purification and Partial Characterization of Trypsin-Specific Proteinase Inhibitors from Pigeonpea Wild Relative Cajanus platycarpus L.(Fabaceae active against Gut Proteases of Lepidopteran pest Helicoverpa armigera

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    Marri Swathi

    2016-09-01

    Full Text Available AbstractProteinase inhibitors (PIs are natural defense proteins of plants found to be active against gut proteases of various insects. A pigeonpea wild relative Cajanus platycarpus was identified as a source of resistance against Helicoverpa armigera, a most devastating pest of several crops including pigeonpea. In the light of earlier studies, trypsin-specific PIs (CpPI 63 were purified from mature dry seeds of C. platycarpus (ICPW-63 and characterized their biochemical properties in contributing to H. armigera resistance. CpPI 63 possessed significant H. armigera gut trypsin-like proteinase inhibitor (HGPI activity than trypsin inhibitor (TI activity. Analysis of CpPI 63 using two-dimensional (2-D electrophoresis and matrix assisted laser desorption ionization time-of-flight (MALDI-TOF mass spectrometry revealed that it contained several isoinhibitors and small oligomers with masses ranging between 6-58 kDa. The gelatin activity staining studies suggest that these isoinhibitors and oligomers possessed strong inhibitory activity against H. armigera gut trypsin-like proteases (HGPs. The N-terminal sequence of the isoinhibitors (pI 6.6 and pI 5.6 of CpPI 63 exhibited 80% homology with several Kunitz trypsin inhibitors (KTIs as well as miraculin-like proteins (MLPs. Further, modification of lysine residue(s lead to 80% loss in both TI and HGPI activities of CpPI 63. In contrast, the TI and HGPI activities of CpPI 63 were stable over a wide range of temperature and pH conditions. The reported results provide a biochemical basis for pod borer resistance in C. platycarpus.

  11. Response of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls, under elevated CO2

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.

  12. Laboratory testing and molecular analysis of the resistance of wild and cultivated soybeans to cotton bollworm, Helicoverpa armigera (Hübner

    Directory of Open Access Journals (Sweden)

    Xiaoyi Wang

    2015-02-01

    Full Text Available Identifying a superior soybean variety with high defoliator resistance is important to avoid yield loss. Cotton bollworm (Helicoverpa armigera Hübner is one of the major defoliators of soybean (Glycine max [L.] Merr. worldwide. In this study, we evaluated the effect of H. armigera larvae on ED059, a wild soybean (Glycine soja Sieb. et Zucc., and three cultivated soybean varieties: Tianlong 2, PI 535807, and PI 533604, in choice and no-choice assays. The percentage of ED059 leaflets consumed by H. armigera was lower than that of the three cultivated soybeans. Larvae that fed on ED059 exhibited low weight gain and high mortality rate. Waldbauer nutritional indices suggested that ED059 reduced the growth, consumption, and frass production of H. armigera larvae. Larvae that fed on ED059 showed lower efficiency of conversion of ingested and of digested food than those that fed on Tianlong 2 and PI 533604. However, they showed statistically similar consumption index and approximate digestibility compared with those fed on the three cultivated soybeans. Quantitative real-time PCR analysis revealed that 24 h after insect attack, ED059 had higher transcript levels of Kunitz trypsin inhibitor 3, Cysteine proteinase inhibitor 2, and Nerolidol synthase 1 but a lower transcript level of Pathogenesis-related protein 1 than Tianlong 2. The gene expression results were consistent with the presence of higher levels of jasmonic acid (JA and transcript levels of the JA biosynthesis enzyme allene oxide cyclase 3 in ED059 than in Tianlong 2. Our findings indicate that ED059 is a superior soybean line with strong insect resistance that may be mediated via the JA pathway.

  13. Novel Vip3A Bacillus thuringiensis (Bt) maize approaches high-dose efficacy against Helicoverpa zea (Lepidoptera: Noctuidae) under field conditions: Implications for resistance management.

    Science.gov (United States)

    Burkness, Eric C; Dively, Galen; Patton, Terry; Morey, Amy C; Hutchison, William D

    2010-01-01

    Sweet corn, Zea mays L., transformed to express a novel vegetative insecticidal protein, Vip3A (event MIR162, Syngenta Seeds, Inc..), produced by the bacterium, Bacillus thuringiensis (Bt), was evaluated over four field seasons in Maryland and two field seasons in Minnesota for efficacy against the corn earworm, Helicoverpa zea (Boddie). Hybrids expressing the Vip3A protein and pyramided in hybrids also expressing the Cry1Ab Bt protein (event Bt11, ATTRIBUTE(®), Syngenta Seeds, Inc.) were compared to hybrids expressing only Cry1Ab or to genetically similar non-Bt hybrids each year. In addition to H. zea efficacy, results for Ostrinia nubilalis (Hübner) and Spodoptera frugiperda (J.E. Smith) are presented. Over all years and locations, the non-Bt hybrids, without insecticide protection, averaged between 43 and 100% ears infested with a range of 0.24 to 1.74 H. zea larvae per ear. By comparison, in the pyramided Vip3A x Cry1Ab hybrids, no larvae were found and only minimal kernel damage (likely due to other insect pests) was recorded. Hybrids expressing only Cry1Ab incurred a moderate level of H. zea feeding damage, with surviving larvae mostly limited to the first or second instar as a result of previously documented growth inhibition from Cry1Ab. These results suggest that the Vip3A protein, pyramided with Cry1Ab, appears to provide the first "high-dose" under field conditions and will be valuable for ongoing resistance management.

  14. Characterization and functional analysis ofβ-1,3-galactosyltransferase involved in Cry1Ac resistance from Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; CAO Guang-chun; GUO Yu-yuan

    2015-01-01

    Carbohydrate chains are the principal antigens by which Bacil us thuringiensis (Bt) identify receptor proteins. The interaction between the antigen and Bt causes a pore in the membrane of midgut epithelial cel s of insects. Receptor proteins, such as aminopeptidase N and alkaline phosphatase, are glycoproteins. Cadherin is another cel surface receptor protein which has potential glycosylation sites. Glycosyltransferase is very important for the synthesis and modiifcation of receptor proteins. It can indirectly inlfuence the function of Bt. The 1 950 bp ful-length cDNA encodingβ-1,3-galactosyltransferase was cloned from the the midgut of Helicoverpa armigera by degenerative PCR combined with RACE techniques (GAL-Harm, GenBank accession no.:GQ904195.1) with two potential N-glycosylation sites (157NNTI160 and 272NKTL275). Protein sequence alignments revealed that H. armigeraβ-1,3-galactosyltransferase shared high identity withβ-1,3-galactosyltransferase in other insect species. The expression level of theβ-1,3-galactosyltransferase gene in Cry1Ac-resistant H. armigera larvae was 9.2-fold higher than that in susceptible strain. The function ofβ-1,3-galactosyltransferase was investigated using RNAi technique. The result showed Cry1Ac enhanced the toxicity against the siRNA-treated larvae compared with non-siRNA-treated ones, which indicatedβ-1,3-galactosyltransferase played an important role for the insecticidal toxicity of Cry1Ac in H. armigera.

  15. An independent occurrence of the chimeric P450 enzyme CYP337B3 of Helicoverpa armigera confers cypermethrin resistance in Pakistan.

    Science.gov (United States)

    Rasool, Akhtar; Joußen, Nicole; Lorenz, Sybille; Ellinger, Renate; Schneider, Bernd; Khan, Sher Afzal; Ashfaq, Muhammad; Heckel, David G

    2014-10-01

    The increasing resistance level of insect pest species is a major concern to agriculture worldwide. The cotton bollworm, Helicoverpa armigera, is one of the most important pest species due to being highly polyphagous, geographically widespread, and resistant towards many chemical classes of insecticides. We previously described the mechanism of fenvalerate resistance in Australian populations conferred by the chimeric cytochrome P450 monooxygenase CYP337B3, which arose by unequal crossing-over between CYP337B1 and CYP337B2. Here, we show that this mechanism is also present in the cypermethrin-resistant FSD strain from Pakistan. The Pakistani and the Australian CYP337B3 alleles differ by 18 synonymous and three nonsynonymous SNPs and additionally in the length and sequence of the intron. Nevertheless, the activity of both CYP337B3 proteins is comparable. We demonstrate that CYP337B3 is capable of metabolizing cypermethrin (trans- and especially cis-isomers) to the main metabolite 4'-hydroxycypermethrin, which exhibits no intrinsic toxicity towards susceptible larvae. In a bioassay, CYP337B3 confers a 7-fold resistance towards cypermethrin in FSD larvae compared to susceptible larvae from the Australian TWB strain lacking CYP337B3. Linkage analysis shows that presence of CYP337B3 accounts for most of the cypermethrin resistance in the FSD strain; up-regulation of other P450s in FSD plays no detectable role in resistance. The presence or absence of CYP337B3 can be easily detected by a simple PCR screen, providing a powerful tool to rapidly distinguish resistant from susceptible individuals in the field and to determine the geographical distribution of this resistance gene. Our results suggest that CYP337B3 evolved twice independently by unequal crossing-over between CYP337B2 and two different CYP337B1 alleles.

  16. Molecular analysis of CYP321A1, a novel cytochrome P450 involved in metabolism of plant allelochemicals (furanocoumarins) and insecticides (cypermethrin) in Helicoverpa zea.

    Science.gov (United States)

    Sasabe, Masataka; Wen, Zhimou; Berenbaum, May R; Schuler, Mary A

    2004-09-01

    Cytochrome P450 monooxygenases play a significant role in the detoxification of hostplant allelochemicals and synthetic insecticides in Lepidoptera. In the corn earworm Helicoverpa zea, a noctuid of considerable economic importance, metabolisms of xanthotoxin, a toxic furanocoumarin, and alpha-cypermethrin, an insecticide, are mediated by at least one P450 with a catalytic site capable of accepting both substrates. To further the characterization of P450s in this species, we have cloned three full-length cDNAs encoding two CYP4M subfamily members and a novel CYP321A subfamily member. RNA analyses have demonstrated that the CYP321A1 gene is highly induced (51-fold) in larval midguts in response to xanthotoxin but not cypermethrin. Both CYP4M genes are expressed at negligible levels that are not increased by xanthotoxin or cypermethrin. Baculovirus-mediated expression of the full-length CYP321A1 cDNA has demonstrated that the CYP321A1 protein metabolizes xanthotoxin and angelicin, like the CYP6B1 protein in the furanocoumarin specialist Papilio polyxenes, and alpha-cypermethrin, like the CYP6B8 protein previously characterized in H. zea. In contrast, the CYP4M7 protein does not metabolize xanthotoxin at any detectable level. We conclude that at least two xanthotoxin-inducible P450s from highly divergent subfamilies (CYP6B and CYP321A) contribute to the resistance of H. zea larvae to toxic furanocoumarins and insecticides. Genomic PCR analysis indicates that the CYP321A1 gene has evolved independently from the CYP6B genes known to be present in this insect.

  17. Helicoverpa zea CYP6B8 and CYP321A1: different molecular solutions to the problem of metabolizing plant toxins and insecticides.

    Science.gov (United States)

    Rupasinghe, Sanjeewa G; Wen, Zhimou; Chiu, Ting-Lan; Schuler, Mary A

    2007-12-01

    Under continual exposure to naturally occurring plant toxins and synthetic insecticides, insects have evolved cytochrome P450 monooxygenases (P450s) capable of metabolizing a wide range of structurally different compounds. Two such P450s, CYP6B8 and CYP321A1, expressed in Helicoverpa zea (a lepidopteran) in response to plant allelochemicals and plant signaling molecules metabolize these compounds with varying efficiencies. While sequence alignments of these proteins indicate highly divergent substrate recognition sites (SRSs), homology models developed for them indicate that the two active site cavities have essentially the same volume with distinct shapes dictated by side-chain differences in SRS1 and SRS5. CYP6B8 has a narrower active site cavity extending from substrate access channel pw2a with a very narrow access to the ferryl oxygen atom. This predicted shape suggests that bulkier molecules bind further from the ferryl oxygen at positions that are not as effectively metabolized. In contrast, CYP321A1 is predicted to have a more spacious cavity allowing larger molecules to access the heme-bound oxygen. The metabolic profiles for several plant toxins (xanthotoxin, angelicin) and insecticides (cypermethrin, aldrin and diazinon) correlate well with these predictive models. The absence of Thr in the I helix of CYP321A1 and hydroxyl groups on many of its substrates suggests that this insect P450 mediates oxygen activation by a mechanism different from that employed by CYP107A1 and CYP158A1, which are two bacterial P450s also lacking Thr in their I helix, and most other P450s that contain Thr in their I helix.

  18. Determinant Factors in the Production of a Co-Occluded Binary Mixture of Helicoverpa armigera Alphabaculovirus (HearNPV) Genotypes with Desirable Insecticidal Characteristics

    Science.gov (United States)

    Arrizubieta, Maite; Simón, Oihane; Williams, Trevor; Caballero, Primitivo

    2016-01-01

    A co-occluded binary mixture of Helicoverpa armigera nucleopolyhedrovirus genotypes HearSP1B and HearLB6 at a 1:1 ratio (HearSP1B+HearLB6) was selected for the development of a virus-based biological insecticide, which requires an efficient large-scale production system. In vivo production systems require optimization studies in each host-virus pathosystem. In the present study, the effects of larval instar, rearing density, timing of inoculation, inoculum concentration and temperature on the production of HearSP1B+HearLB6 in its homologous host were evaluated. The high prevalence of cannibalism in infected larvae (40–87%) indicated that insects require individual rearing to avoid major losses in OB production. The OB production of recently molted fifth instars (7.0 x 109 OBs/larva), combined with a high prevalence of mortality (85.7%), resulted in the highest overall OB yield (6.0 x 1011 OBs/100 inoculated larvae), compared to those of third or fourth instars. However, as inoculum concentration did not influence final OB yield, the lowest concentration, LC80 (5.5 x 106 OBs/ml), was selected. Incubation temperature did not significantly influence OB yield, although larvae maintained at 30°C died 13 and 34 hours earlier than those incubated at 26°C and 23°C, respectively. We conclude that the efficient production of HearSP1B+HearLB6 OBs involves inoculation of recently molted fifth instars with a LC80 concentration of OBs followed by individual rearing at 30°C. PMID:27732657

  19. Push-pull Strategy with Trap Crops, Neem and Nuclear Polyhedrosis Virus for Insecticide Resistance Management in Helicoverpa armigera (Hubner in Cotton

    Directory of Open Access Journals (Sweden)

    P. Duraimurugan

    2005-01-01

    Full Text Available Insecticide resistance in Helicoverpa armigera (Hubner is a major threat to cotton production in India. The virus infection was found to increase the susceptibility of H. armigera to the insecticides. But, use of Nuclear Polyhedrosis Virus (NPV on a larger scale and on cotton due to leaf alkalinity poses certain practical problems. Hence, studies were carried out to assess the effects of push-pull strategy with trap crops, neem and NPV in cotton for the management of insecticide resistant H. armigera. Field experiments were conducted on cotton (MCU5 with trap crops (okra and pigeonpea and neem was used to diversify the pests to trap crops whereby the control of these pests was assessed with the application of NPV. The preference of H. armigera was towards okra and pigeonpea as a trap crop compared to cotton. Application of NSKE on cotton diversified the H. armigera towards untreated okra and pigeonpea. Push-pull strategy with the conjunctive use of trap crops, restricted application of NSKE on cotton leaving trap crops and restricted application of NPV on trap crops was highly effective in reducing the incidence of H. armigera and damage to fruiting bodies, boll, locule and inter locule basis over cotton sole crop (untreated check. The percent recovery of NPV infected larvae varied from 37.5-47.5, 32.8-39.2 and 14.2-20.2% on okra, pigeon pea and cotton respectively. The synthetic pyrethroids resistance in field survived H. armigera at the end of the season was reduced from 87.5-93.1% to 76.4-84.3%.

  20. Inhibition of Helicoverpa zea (Lepidoptera: Noctuidae) Growth by Transgenic Corn Expressing Bt Toxins and Development of Resistance to Cry1Ab.

    Science.gov (United States)

    Reisig, Dominic D; Reay-Jones, Francis P F

    2015-08-01

    Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.105 × Cry2Ab2 × Cry3Bb1, Cry1A.105 × Cry2Ab2, and Vip3Aa20 × Cry1Ab × mCry3A were planted in both 2012 and 2013 inNorth and South Carolina with paired non-Bt hybrids from the same genetic background. H. zea larvae were sampled on three time periods from ears and the following factors were measured: kernel area injured (cm(2)) by H. zea larvae, larval number per ear, larval weight, larval length, and larval head width. Pupae were sampled on a single time period and the following factors recorded: number per ear, weight, time to eclosion, and the number that eclosed. There was no reduction in larval weight, number of insect entering the pupal stadium, pupal weight, time to eclosion, and number of pupae able to successfully eclose to adulthood in the hybrid expressing Cry1Ab compared with a non-Bt paired hybrid. As Cry1Ab affected these in 1996, H. zea may be developing resistance to Cry1Ab in corn, although these results are not comprehensive, given the limited sampling period, size, and geography. We also found that the negative impacts on larval growth and development were greater in corn hybrids with pyramided traits compared with single traits.

  1. Insecticidal Efficacy of Azadirachta indica, Nucleopolyhedrovirus and Chlorantraniliprole Singly or Combined against Field Populations fo Helicoverpa armigera Hübner (Lepidoptera: Noctuidae Eficacia Insecticida de Azadirachta indica, Nucleopolihedrovirus y Clorantraniliprol solo y sus Aplicaciones Integradas contra Poblaciones de Campo de Helicoverpa armigera Hübner (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Waqas Wakil

    2012-03-01

    Full Text Available The development of resistance in cosmopolitan insect Helicoverpa armigera Hubner (Lepidoptera: Noctuidae forced the researchers for alternative control measures. In the present study, insecticidal efficacy of formulations of Azadirachta indica, a Nucleopolyhedrovirus (NPV, and new anthranilic diamide insecticide (chlorantraniliprole formulations was determined against 2nd, through 5th larval instars of H. armigera collected from diverse geographical locations in the Punjab province, Pakistan. Azadirachta indica was applied at 5 μL L-1; NPV at 2.1 x 10(5 polyhedral occlusion bodies (POB mL4 and chlorantraniliprole at 0.01 μL L-1, either alone or in combinations with each other. The bioassays were conducted at 27 ± 1 °C and 65 ± 5% relative humidity. The mortality varied greatly among treatments, larval instars, and locations. The combinations of NPV with A. indica and chlorantraniliprole caused higher mortality, pupation and produced an additive effect compared to their application singly in all the tested populations. The population from Rawalpindi was always susceptible while the Gujranwala was the resistant. The results herein suggest that the effectiveness of NPV and A. indica can be improved by the presence of chlorantraniliprole against the larvae of H. armigera.Se determinó la eficacia insecticida de formulaciones de Azadirachta indica, Nucleopolihedrovirus (VPN y el nuevo insecticida diamida antranílico (clorantraniliprol en contra de segundo, tercero, cuarto y quinto estadios larvales de Helicoverpa armigera Hubner (Lepidoptera: Noctuidae recogidos de diversas ubicaciones geográficas de la provincia de Punjab, Pakistán. Azadirachta indica se aplicó en dosis de 5 μL L-1; VPN en dosis 2.1 x 10(5 POB mL-1 y clorantraniliprol fue 0,01 μL L-1 ya sea solos o en combinaciones. Los bioensayos se realizaron a 27 ± 1 °C y 65 ± 5% de humedad relativa. La mortalidad fue notablemente variada entre los tratamientos, estadios larvales y

  2. Induction of nicotine in tobacco by herbivory and its relation to glucose oxidase activity in the labial gland of three noctuid caterpillars

    Institute of Scientific and Technical Information of China (English)

    ZONG Na; WANG Chenzhu

    2004-01-01

    Tobacco Nicotiana tabacum L. Is a host plant of Helicoverpa armigera (Hüibner), Helicoverpa assulta Guenée and Spodoptera litura (Fabricius) (Lepidoptera, Noctuidae).The difference in leaf nicotine response to the feeding by these three larvae and the mechanical simulation of their feeding was examined by HPLC. Results indicated that nicotine induction was suppressed by H. Armigera and H. Assulta larvae feeding or by simulated damage treated with their labial glands extracts. The production of nicotine was also suppressed by the glucose oxidase from Aspergillus niger when it was treated on mechanically wounded leaf area. On the contrary, the nicotine production was stimulated by S.litura larva feeding or by simulated damage treated with its labial gland extract. Heat denature can not counteract the stimulation effect of the S. Litura labial gland extracts to tobacco nicotine production. The glucose oxidase activity was detected in labial gland extracts of both H. Arrnigera and H.assulta, but the activity in H. Armigera was significantly higher than that in H. Assulta. No glucose oxidase activity was detected in labial gland extracts of S. Litura. It is shown that the glucose oxidase activity in labial glands of caterpillars plays an important role in the nicotine response to herbivory. The glucose oxidase was mainly contained in the labial gland of H. Armigera larva, and had the highest activity at pH 7.0. D-Glucose was the optimal substrate of the glucose oxidase. Labial gland glucose oxidase activities varied daily during larval development with high activities found when larvae were actively feeding.

  3. Development of a novel‐type transgenic cotton plant for control of cotton bollworm

    OpenAIRE

    2016-01-01

    Summary The transgenic Bt cotton plant has been widely planted throughout the world for the control of cotton budworm Helicoverpa armigera (Hubner). However, a shift towards insect tolerance of Bt cotton is now apparent. In this study, the gene encoding neuropeptide F (NPF) was cloned from cotton budworm H. armigera, an important agricultural pest. The npf gene produces two splicing mRNA variants—npf1 and npf2 (with a 120‐bp segment inserted into the npf1 sequence). These are predicted to for...

  4. Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions.

    Science.gov (United States)

    Cui, Jinjie; Luo, Junyu; Van Der Werf, Wopke; Ma, Yan; Xia, Jingyuan

    2011-04-01

    Transgenic cotton (Cossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects, the CrylAc gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in conferring resistance to cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was studied in laboratory and field experiments. In each experiment, performance of Bt+CpTI cotton was compared with Bt cotton and to a conventional nontransgenic variety. Larval survival was lower on both types of transgenic variety, compared with the conventional cotton. Survival of first-, second-, and third-stage larvae was lower on Bt+CpTI cotton than on Bt cotton. Plant structures differed in level of resistance, and these differences were similar on Bt and Bt + CpTI cotton. Likewise, seasonal trends in level of resistance in different plant structures were similar in Bt and Bt+CpTI cotton. Both types of transgenic cotton interfered with development of sixth-stage larvae to adults, and no offspring was produced by H. armigera that fed on Bt or Bt+CpTI cotton from the sixth stage onward. First-, second-, and third-stage larvae spent significantly less time feeding on transgenic cotton than on conventional cotton, and the reduction in feeding time was significantly greater on Bt+CpTI cotton than on Bt cotton. Food conversion efficiency was lower on transgenic varieties than on conventional cotton, but there was no significant difference between Bt and Bt+CpTI cotton. In 3-yr field experimentation, bollworm densities were greatly suppressed on transgenic as compared with conventional cotton, but no significant differences between Bt and Bt+CpTI cotton were found. Overall, the results from laboratory work indicate that introduction of the CpTI gene in Bt cotton raises some components of resistance in cotton against H. armigera, but enhanced control of H. armigera under field

  5. Pertussis toxin modulation of sodium channels in the central neurons of cyhalothrin-resistant and cyhalothrin-susceptible cotton bollworm, Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    QIANG ZHAO; DE-LING KONG; BING-JUN HE; YAN-QIANG LIU; XIAN-LIN FAN; AN-XI LIU

    2007-01-01

    Pertussis toxin (PTX) inhibits the activation of the α-subunit of the inhibitory heterotrimeric G-proteins (Gαi/o) and modulates voltage-gated sodium channels, which may be one of the primary targets of pyrethroids. To investigate the potential mechanisms of agricultural pests resistance to pyrethroid insecticides, we examined the modulations by PTX on sodium channels in the central neurons of the 3rd-4th instar larvae of cyhalothrin-resistant (Cy-R) and cyhalothrin-susceptible (Cy-S) Helicoverpa armigera by the whole-cell patch-clamp technique.The isolated neurons were cultured for 12-16 h in an improved L15 insect culture medium with or without PTX (400 ng/mL). The results showed that both the Cy-R and Cy-S sodium channels exhibited fast kinetics and tetrodotoxin (TTX) sensitivity. The Cy-R sodium channels exhibited not only altered gating properties, including a 8.88-mV right shift in voltage-dependent activation (V0.5act) and a 6.54-mV right shift in voltage-dependent inactivation (V0.5inact), but also a reduced peak in sodium channel density (Idensity) (55.2% of that in Cy-S neurons). Cy-R sodium channels also showed low excitability, as evidenced by right shift of activation potential (Vacti) by 5-10 mV and peak potential (Vpeak) by 20 mV. PTX exerted significant effects on Cy-S sodium channels,reducing sodium channel density by 70.04%, right shifting V0.5act by 14.41 mV and V0.5inact by 9.38 mV. It did not cause any significant changes of the parameters mentioned above in the Cy-R sodium channels. The activation time (Tpeak) from latency to peak at peak voltage and the fast inactivation time constant (τinact) in both Cy-S and Cy-R neurons were not affected. The results suggest that cotton bollworm resistant to pyrethroid insecticides involves not only mutations and allosteric alterations of voltage-gated sodium channels, but also might implicate perturbation of PTX-sensitive Gαi/o-coupled signaling transduction pathways.

  6. LABORATORY AND FIELD EVALUATION OF ESSENTIAL OILS FROM Cymbopogon nardus AS OVIPOSITION DETERRENT AND OVICIDAL ACTIVITIES AGAINST Helicoverpa armigera Hubner ON CHILI PEPPER

    Directory of Open Access Journals (Sweden)

    Wiwin Setiawati

    2011-04-01

    Full Text Available The fruit borer (Helicoverpa armigera Hubner is one of the key pests of chili pepper in Indonesia. Yield loss due to this insect pest may reach up to 60%. Chemical treatment for con-trolling this insect pest is ineffective and eventually leads to environmental pollution. More environmentally safe insecticides are developed based on natural plant ingredients as their active compound such as essential oils. This study aimed to assess the potential of citronella oil for managing H. armigera on chili pepper. The experiments were conducted at the Indonesian Vegetables Research Institute from April 2009 to March 2010 and in Cirebon, West Java from November 2009 to March 2010. A field experiment was designed in a randomized complete block design with five treatments and replicated five times. Citronella oil was extracted by steam distillation from Cymbo-pogon  nardus. The oil was then chemically characterized by using GC-MS and its efficacy (ovicidal and feeding deterrent against H. armigera was tested both in laboratory and field conditions. The GC-MS result showed that major chemical compounds of the citronella oil used were citronella (35.97%, nerol (17.28%, citronellol (10.03%, geranyle acetate (4.44%, elemol (4.38%, limonene (3.98%, and citronnellyle acetate (3.51%. The laboratory experiment revealed that the highest concentration (4,000 ppm of citronella oil reduced egg laying by 53-66%. Ovicidal activity was concentration dependent, and egg hatchability decreased by 15-95% compared to control. The field experiment showed that treatment of citronella oil at 2.0 mL L-1 significantly reduced fruit damage by H. armigera similar to the plots treated with spinosad at the recommended dose (60 g ai ha-1. Application of citronella oil significantly reduced fruit damage by 72% and increased quality of the chili pepper. Because oviposition and feeding deterrent properties are key factors in controlling the pest, therefore this study revealed that

  7. The Binding Characterization of Cry Insecticidal Proteins to the Brush Border Membrane Vesicles of Helicoverpa armigera, Spodoptera exigua, Spodoptera litura and Agrotis ipsilon

    Institute of Scientific and Technical Information of China (English)

    LU Qiong; CAO Guang-chun; ZHANG Li-li; LIANG Ge-mei; GAO Xi-wu; ZHANG Yong-jun; GUO Yu-yuan

    2013-01-01

    Cry toxins produced by Bacillus thuringiensis (Bt) are effective biological insecticides against certain insect species. However, there are potential risks of the evolved resistance of insects to Cry toxin owing to decreased binding of toxins to target sites in the brush border membranes of the larva midgut. The Cry toxins with different binding sites in the larval midgut have been considered to be a good combination to deploy in delaying resistance evolution. Bioassay results demonstrated that the toxicity of different Cry toxins ranked differently for each species. The toxicity ranking was Cry1Ac>Cry1Ab>Cry2Ab for Helicoverpa armigera, Cry1B>Cry1C>Cry2Ab for Spodoptera exigua, and Cry2Ab>Cry1B>Cry1C for S. litura. Only Cry2Ab was toxic to Agrotis ipsilon. Binding experiments were performed with 125I-Cry1Ab, 125I-Cry1Ac, 125I-Cry1B, 125I-Cry1C, 125I-Cry2Ab and the brush border membranes vesicles (BBMV) from H. armigera, S. exigua, S. litura and A. ipsilon. The binding of Cry1Ab and Cry1Ac was shown to be saturable by incubating with increasing concentrations of H. armigera BBMV (Kd=(45.00±2.01) nmol L-1 and (12.80±0.18) nmol L-1, respectively;Bmax=(54.95±1.79) ng and (55.44±0.91) ng, separately). The binding of Cry1B was shown to be saturable by incubating with increasing concentrations of S. exigua BBMV (Kd=(23.26±1.66) nmol L-1;Bmax=(65.37±1.87) ng). The binding of 125I-Cry toxins was shown to be non-saturable by incubating with increasing concentrations of S. litura and A. ipsilon BBMV. In contrast, Cry1B and Cry1C showed some combination with the BBMV of S. litura, and a certain amount of Cry2Ab could bind to the BBMV of A. ipsilon. These observations suggest that a future strategy could be devised for the focused combination of specific cry genes in transgenic crops to control target pests, widen the spectrum of insecticide effectiveness and postpone insect resistance evolution.

  8. 转基因抗虫棉田棉铃虫庇护所的建立和评价%Establishment and Evaluation of Refuge for Helicoverpa Armigera Hübner of Bt Cotton Fields

    Institute of Scientific and Technical Information of China (English)

    吴莉莉; 王登元; 吕昭智; 马睿

    2011-01-01

    [目的]对转基因棉田棉铃虫庇护所的植物进行选择.[方法]通过采取随机区组排列方式在转基因抗虫棉田种植庇护所植物,种植植物为:鹰嘴豆、木豆、玉米、胡麻、高粱、棉花等6种植物,并进行定期、定点、定株调查,比较分析不同植物种类棉铃虫卵和幼虫的数量差异.[结果]鹰嘴豆作为庇护所植物最好,其次是木豆、玉米、胡麻、高粱效果较差.鹰嘴豆的引诱效果与其他5种植物有极显著差异.几种诱集植物能够蓄养大量的草岭、瓢虫、蜘蛛等天敌昆虫.[结论]鹰嘴豆、木豆、玉米作为转基因棉田棉铃虫庇护所植物较好.%[Objective]This study was conducted to select the plants of refuge on Bt cotton fields’ Helicoverpa armigera (H(u)bner) .[Method]Planting refuge in the Bt cotton fields by the way of a random block arrangement, plants are: chickpea’( Cicer arietinum Linn. ) , pigeonpea ( Cajannus cajan L. Mill,) , com ( Zea mays L.), benne( Linseed), grain sorghum( Sorghum vulgare Pers.), cotton( Gossypium spp.) 6 species of plants, whose fixed date,fixed point and fixed plants were surveyed, compare and analyse the quantity difference of Helicoverpa armigera eggs and larvae in different plant were comparatively analyzed . [ Resultr]The results showed tlat chickpea were best as refuge plant; pigeonpea and com followed . benne, grain sorghum leas than other plant.The analysis of variance showed that chickpea had a significant difference with other five plants . These host plants can provide a lot of natural enemies : lacewing, ladybird beetle, spider, etc. [ Conclusion] Chickpea, Pigeonpea, Com can be some better host plant for refuge of Helicoverpa armigera (Hubner) on Bt Cotton Fields.

  9. Tarsi of Male Heliothine Moths Contain Aldehydes and Butyrate Esters as Potential Pheromone Components.

    Science.gov (United States)

    Choi, Man-Yeon; Ahn, Seung-Joon; Park, Kye-Chung; Meer, Robert Vander; Cardé, Ring T; Jurenka, Russell

    2016-05-01

    The Noctuidae are one of the most speciose moth families and include the genera Helicoverpa and Heliothis. Females use (Z)-11-hexadecenal as the major component of their sex pheromones except for Helicoverpa assulta and Helicoverpa gelotopoeon, both of which utilize (Z)-9-hexadecenal. The minor compounds found in heliothine sex pheromone glands vary with species, but hexadecanal has been found in the pheromone gland of almost all heliothine females so far investigated. In this study, we found a large amount (0.5-1.5 μg) of hexadecanal and octadecanal on the legs of males of four heliothine species, Helicoverpa zea, Helicoverpa armigera, H. assulta, and Heliothis virescens. The hexadecanal was found on and released from the tarsi, and was in much lower levels or not detected on the remaining parts of the leg (tibia, femur, trochanter, and coxa). Lower amounts (0.05-0.5 μg) of hexadecanal were found on female tarsi. This is the first known sex pheromone compound to be identified from the legs of nocturnal moths. Large amounts of butyrate esters (about 16 μg) also were found on tarsi of males with lower amounts on female tarsi. Males deposited the butyrate esters while walking on a glass surface. Decapitation did not reduce the levels of hexadecanal on the tarsi of H. zea males, indicating that hexadecanal production is not under the same neuroendocrine regulation system as the production of female sex pheromone. Based on electroantennogram studies, female antennae had a relatively high response to hexadecanal compared to male antennae. We consider the possible role of aldehydes and butyrate esters as courtship signals in heliothine moths.

  10. Identification of an E-box DNA binding protein, activated protein 4, and its function in regulating the expression of the gene encoding diapause hormone and pheromone biosynthesis-activating neuropeptide in Helicoverpa armigera.

    Science.gov (United States)

    Hu, C-H; Hong, B; Xu, W-H

    2010-04-01

    Activated protein 4 (AP-4), an E-box DNA-binding protein, was cloned from the cotton bollworm, Helicoverpa armigera (Har). The expression of Har-AP-4 mRNA and the protein that it encodes are significantly higher in nondiapause pupae than in diapause pupae. In vitro-translated Har-AP-4 can bind specifically to the E-box motif on the promoter of the diapause hormone and pheromone biosynthesis-activating neuropeptide (DH-PBAN). Har-AP-4, fused with the green fluorescent protein (GFP), is localized to the nucleus, and overexpression of Har-AP-4 can significantly activate the promoter of the DH-PBAN gene that is involved in nondiapause pupal development in H. armigera. These results suggest that Har-AP-4, which binds to the promoter of DH-PBAN, may play a role in regulating pupal development in H. armigera.

  11. 光因子对棉铃虫(Helicoverpa armigera)雌蛾性信息素产生及其求偶行为的影响%Effects of light factors on sex pheromone produce and femal's calling behavior of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    刘云国; 许少甫; 杜家纬

    2001-01-01

    The effects of light factors on the calling behavior, sex pheromone titer and the activity of brain suboesophageal ganglia(Br-SOG) of female cotton bollworm, Helicoverpa aramigera, were investigated. Unusual photoperiod, exposure to light during scotophase and red, orange, yellow, green, blue, black, violet and white color light were used to treat female cotton bollworms. The results showed that on these factors, the calling peak value decreased, calling rhythm was disrupted, sex pheromone titer decreased, the activity of Br-SOG was inhibition. These results are useful to explore a new ecological approach for controlling insect pests not relying on or little relying on pesticides.%分为3部分:第1部分为光因子对棉铃虫雌蛾求偶行为的影响;第2部分为光因子对棉铃虫雌蛾性信息素(Z-11-16:Ald)含量的影响;第3部分为光因子对棉铃虫雌蛾脑因子活性的影响。研究结果表明:用非正常光周期、间隔光照、不同光质处理棉铃虫雌蛾后,求偶峰值下降,求偶节律混乱,性信息素含量下降,脑因子活性受到抑制。主要研究目的是探讨一种不使用或少使用农药的新型生态防治方法。

  12. Frequency of alleles conferring resistance to the Bacillus thuringiensis toxins Cry1Ac and Cry2Ab in Australian populations of Helicoverpa punctigera (Lepidoptera: Noctuidae) from 2002 to 2006.

    Science.gov (United States)

    Downes, S; Parker, T L; Mahon, R J

    2009-04-01

    Helicoverpa punctigera and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) are important pests of field and horticultural crops in Australia. The former is endemic to the continent, whereas the latter is also distributed in Africa and Asia. Although H. armigera rapidly developed resistance to virtually every group of insecticide used against it, there is only one report of resistance to an insecticide in H. punctigera. In 1996 the Australian cotton industry adopted Ingard, which expresses the Bacillus thuringiensis (Bt) toxin gene cry1Ac. In 2004/2005, Bollgard II (which expresses Cry1Ac and Cry2Ab) replaced Ingard and has subsequently been grown on 80% of the area planted to cotton, Gossypium hirsutum L. From 2002/2003 to 2006/2007, F2 screens were used to detect resistance to Cry1Ac or Cry2Ab. We detected no alleles conferring resistance to Cry1Ac; the frequency was < 0.0005 (n = 2,180 alleles), with a 95% credibility interval between 0 and 0.0014. However, during the same period, we detected alleles that confer resistance to Cry2Ab at a frequency of 0.0018 (n = 2,192 alleles), with a 95% credibility interval between 0.0005 and 0.0040. For both toxins, the experiment-wise detection probability was 94%, i.e., if there actually was a resistance allele in any tested lines, we would have detected it 94% of the time. The first isolation of Cry2Ab resistance in H. punctigera was before the widespread deployment of Bollgard II. This finding supports our published notion for H. armigera that alleles conferring resistance to Cry2Ab may be present at detectable frequencies in populations before selection by transgenic crops.

  13. Réponse des stades larvaires de Helicoverpa armigera (Hübner (Lepidoptera : Noctuidae à l'application de champignons entomopathogènes Metarhizium anisopliae et Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    Tamò, M.

    2012-01-01

    Full Text Available Response of the nymphs of Helicoverpa armigera (Hübner (Lepidoptera: Noctuidae to entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana. Two experiments on dose/mortality response between the instars of Helicoverpa armigera and two strains of entomopathogenic fungi, Metarhizium anisopliae (Met 31 and Beauveria bassiana (Bb 11 were carried out in laboratory conditions. In the first experiment, M. anisopliae Met 31 was tested on the third instar of H. armigera, while in the second experiment, both Met 31 and Bb 11 were tested on the fourth instar. In all the experiments, the following different doses of conidia per insect were used: 104, 105, 106, 107. The following parameters were measured: mortality and sporulation rates, the number of pupae formed and the number of adults that emerged. Abbott's formula was used to correct the treatment mortality rates. LD50 was determined using Cox-regression. For the third instar in experiment one, no significant difference was observed between high doses (106 and 107 conidia per insect. For instar L4, only the dose of 107 conidia per insect showed high mortality rates (74%. For the strain Bb 11, in spite of the variation observed between the mortality rates induced by high doses (106 and 107 conidia per insect, no significant difference was recorded at the 5% level. No mycosis was observed from cadavers resulting from lower doses when tested on L4. The control recorded the highest numbers of pupae and adults. These two parameters were related to the level of dosage: the higher the dose, the lower the numbers of pupae and adults that emerged. For all the strains of fungi used, whatever the larval stage of H. armigera, the dose/mortality response was significant.

  14. Evaluación y selección de un protocolo vía Agrobacterium para la incorporación de resistencia al cogollero en la variedad de tomate Unapal-Arreboles Evaluation and selection of a protocol for Agrobacterium-mediated genetic transformation of tomato variety Unapal-Arreboles for resistance to budworm

    Directory of Open Access Journals (Sweden)

    Hernando Ramírez

    2009-04-01

    Full Text Available Se evaluó y seleccionó una metodología para la transformación genética de la variedad de tomate UNAPAL-Arreboles con el gen cry1Ab para la incorporación de resistencia al cogollero (Tuta absoluta, utilizando el sistema de Agrobacterium. Se regeneraron 59 plantas transgénicas a partir de 3.200 explantes (1.84%. La integración estable, expresión y herencia de los genes nptII y gus-intrón, se demostraron mediante análisis histoquímico y molecular en los clones To28, To33 y To47 y en la correspondiente generación T1. Sin embargo, los análisis molecular e inmunológico indicaron ausencia del gen cry1Ab sugiriendo que la secuencia de este gen se puede haber modificado.A plant transformation methodology was selected and evaluated to incorporate the cry1Ab gene by Agrobacterium-mediate genetic transformation into tomato variety UNAPAL-Arreboles for resistance to budworm (Tuta absoluta. A total of 59 transgenic plants were regenerated from 3.200 explants (1.84%. Histochemical gus assay and molecular analysis of three independent events To28, To33 and To47 and corresponding T1 derived generations, demonstrate the stable integration, expression and inheritance of the nptII and gus-intron genes. However, the molecular and immunological analysis of these same clones, indicate that the cry1Ab gene is not present in the transformed plants, suggesting that the sequence of this gene may be modified as result of possible recombinant events.

  15. Vip3A, a novel Bacillus thuringiensis vegetative insecticidal protein with a wide spectrum of activities against lepidopteran insects.

    OpenAIRE

    Estruch, J J; Warren, G W; Mullins, M A; Nye, G J; Craig, J. A.; Koziel, M G

    1996-01-01

    A novel vegetative insecticidal gene, vip3A(a), whose gene product shows activity against lepidopteran insect larvae including black cutworm (Agrotis ipsilon), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), tobacco budworm (Heliothis virescens), and corn earworm (Helicoverpa zea) has been isolated from Bacillus thuringiensis strain AB88. VIP3-insecticidal gene homologues have been detected in approximately 15% of Bacillus strains analyzed. The sequence of the vip3A(...

  16. Sound-sensitive neurons innervate the ventro-lateral protocerebrum of the heliothine moth brain

    DEFF Research Database (Denmark)

    Pfuhl, Gerit; Zhao, Xin Cheng; Ian, Elena

    2014-01-01

    -sensitive neurons in the moth brain. During intracellular recordings from the lateral protocerebrum in the brain of three noctuid moth species, Heliothis virescens, Helicoverpa armigera and Helicoverpa assulta, we found an assembly of neurons responding to transient sound pulses of broad bandwidth. The majority...... of the auditory neurons ascended from the ventral cord and ramified densely within the anterior region of the ventro-lateral protocerebrum. The physiological and morphological characteristics of these auditory neurons were similar. We detected one additional sound-sensitive neuron, a brain interneuron with its...... soma positioned near the calyces of mushroom bodies and with numerous neuronal processes in the ventro-lateral protocerebrum. Mass-staining of ventral-cord neurons supported the assumption that the ventro-lateral region of the moth brain was the main target for the auditory projections ascending from...

  17. 金银花尺蠖及棉铃虫的一种病原真菌鉴定%Identification of Entomopathogenic Fungi from Heterolocha jinyinhuaphaga and Helicoverpa armigera Damaging Lonicera japonica Thunb

    Institute of Scientific and Technical Information of China (English)

    马维思; 徐常青; 张金良; 董杰; 乔海莉; 郭昆; 徐荣; 陈君; 张大勇

    2015-01-01

    目的:明确金银花上的棉铃虫、金银花尺蠖2种害虫的病原真菌的分类地位,为寻找对药材鳞翅目害虫有高毒力的病原真菌提供材料。方法:通过分生孢子分离、培养,从受真菌侵染死亡的金银花鳞翅目害虫体表分离获得昆虫病原真菌,依据真菌的形态特征和 ITS 序列特征对其进行鉴定。结果:从12份受真菌感染死亡的幼虫体表分离到12株形态特征一致的真菌,依据形态特征和 ITS 序列特征将其鉴定为莱氏野村菌 Nomurea rileyi。结论:莱氏野村菌为金银花尺蠖及棉铃虫两种金银花鳞翅目害虫的一种病原真菌,因其能够在某些鳞翅目害虫间形成流行病,对防治药材害虫具有应用潜力。%Objective: To identify the entomopathogenic fungi which killing Heterolocha jinyinhuaphaga and Helicoverpa armigera damaging Lonicera japonica Thunb.Methods:Eleven samples of Heterolocha jinyinhuaphaga and one sample of Helicoverpa armigera lepidoptera larvae infected by entomopathogenic fungi were collected from Lonicera japonica Thunb,twelve entomopathogenic fungi strains were isolated by culturing spores washing from dead larvae,these fungi were identified with morphological characteristic and rDNA ITS sequence.Results:All strains of fungi were identified as Nomurea rileyi.Conclusion:Nomurea rileyi is one kind of entomopathogenic fungus that could kill some kind of lepidoptera larvae on the medicinal plant of Lonicera japonica Thunb,it will be useful research materials for study to control insects of Lonicera japonica Thunb and other medicinal plants.

  18. Effects of nuclear polyhedrosis virus on cannibalism in Helicoverpa armigera%核型多角体病毒感染对棉铃虫幼虫同类相残行为的影响

    Institute of Scientific and Technical Information of China (English)

    李静雯; 褚艳娜; 王琼; 刘小侠; 张青文

    2012-01-01

    The effects of nuclear polyhedrosis virus infection on cannibalism in Helicoverpa armigera ( H(u)bner) was evaluated under laborratory conditions. The number of infected larvae preyed on by healthy larvae increased with the progress of the disease. There was no significant difference in the percentage of dead infected larvae, frozen infected larvae and frozen healthy larvae that were preyed on by healthy larvae. This suggests that infected larvae and dead infected larvae are more likely to be cannibalized simply because they become less vigorous and less capable of defending themselves than healthy larvae. There was no significant difference in the frequency of cannibalism of frozen infected larvae by healthy larvae and infected larvae. This suggests that the tendency towards cannibalism is not altered by infection. Cannibalism is potentially costly. The pupation and eclosion rate of healthy larvae that ate infected larvae was lower than that of those that had not cannibalized infected larvae.%在室内研究核型多角体病毒(HaSNPV)感染对棉铃虫Helicoverpa armigera(Hübner)幼虫同类相残行为的影响.结果显示:感病棉铃虫随感病程度的加重,越容易被健康棉铃虫残食,而自然死亡的感病棉铃虫、冻死的感病棉铃虫和冻死的健康棉铃虫三者被健康棉铃虫残食的百分率无显著差异.表明感病棉铃虫和病虫尸体更易于被健康棉铃虫残食,是由于棉铃虫体力减弱而失去反击能力,不是由于病毒本身的影响.以健康棉铃虫、感病棉铃虫为残食者,冻死的病虫为被残食者,相残率无显著差异,表明病毒并未改变棉铃虫残食同类的天性.残食病虫的健康棉铃虫的化蛹率和羽化率均低于正常的健康棉铃虫,残食者为相残行为付出了很高的代价.

  19. SEQUENCE OF THE 18S RIBOSOMAL RNA GENE OF COTTON BOLLWORM (HELICOVERPA ARMIGERA) AND MOLECULAR SYSTEMATICS ANALYSIS%棉铃虫18S核糖体RNA基因的序列分析及其分子系统学

    Institute of Scientific and Technical Information of China (English)

    王瑛; 陈晓峰; 刘伟; 周红章; 赵珩

    1999-01-01

    克隆并分析了鳞翅目棉铃虫Helicoverpa armigera (Hbner)18S核糖体RNA基因(18S rDNA)的全序列,将该序列与鞘翅目、膜翅目、同翅目、双翅目、捻翅目和弹尾目各一种昆虫的同源保守区进行了比较.序列分析结果显示:鳞翅目和双翅目昆虫在18S rDNA结构上彼此较为相似,捻翅目昆虫的18S rDNA分子结构表现出与其它目昆虫有较大的差异,但相对与弹尾目昆虫的18S rDNA较为接近.该结果支持了有关捻翅目属于一个独立的目级分类阶元的论点.

  20. 棉铃虫组织蛋白酶B组织分布与合成部位的研究%Distribution and Biosynthesis Sites of Cathepsin B in Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    徐夏莲; 赵小凡; 王金星

    2001-01-01

    The distribution and biosynthesis sites of cathepsin B in Helicoverpa armigera through the developing stages were studied by means of Immunoblot and Northern Blot.The results of Immunoblot showed that cathepsin B existed in ovary,female and male adult fat body.The mRNA in larval fat body,female pupal fat body,male adult fat body,female adult fat body and ovary were detected using Northern Blot.This indicated that cathepsin B mRNA could be transcribed in these tissues.However there was no cathepsin B mRNA in larval epidermis and larval mid-gut as also no distribution of this proteinase.Furthermore,we detected mRNA transcription in larval fat body,female pupal fat body using Northern Blot,but there were no cathepsin B distributed in these two issues accordingly in Immunoblot.This indicated that the mRNA in these two tissues could not be translated into cathepsin B,and there might be some kind of regulation in translation level.

  1. Prevalence of cry2-type genes in Bacillus thuringiensis isolates recovered from diverse habitats in India and isolation of a novel cry2Af2 gene toxic to Helicoverpa armigera (cotton boll worm).

    Science.gov (United States)

    Katara, Jawahar Lal; Kaur, Sarvjeet; Kumari, Gouthami Krishna; Singh, Nagendra Kumar

    2016-12-01

    Insecticidal cry and vip genes from Bacillus thuringiensis (Bt) have been used for control of lepidopteran insects in transgenic crops. However, novel genes are required for gene pyramiding to delay evolution of resistance to the currently deployed genes. Two PCR-based techniques were employed for screening of cry2-type genes in 129 Bt isolates from diverse habitats in India and 27 known Bt strains. cry2Ab-type genes were more prevalent than cry2Aa- and cry2Ac-type genes. Correlation between source of isolates and abundance of cry2-type genes was not observed. Full-length cry2A-type genes were amplified by PCR from 9 Bt isolates and 4 Bt strains. The genes from Bt isolates SK-758 from Sorghum grain dust and SK-793 from Chilli seeds warehouse, Andhra Pradesh, were cloned and sequenced. The gene from SK-758 (NCBI GenBank accession No. GQ866915) was novel, while that from SK-793 (NCBI GenBank accession No. GQ866914) was identical to the cry2Ab1 gene. The Bacillus thuringiensis Nomenclature Committee ( http://www.lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/toxins2.html ) named these genes cry2Af2 and cry2Ab16, respectively. The cry2Af2 gene was expressed in Escherichia coli and found to be toxic towards Helicoverpa armigera. The cry2Af2 gene will be useful for pyramiding in transgenic crops.

  2. Identificação morfológica e molecular de Helicoverpa armigera (Lepidoptera: Noctuidae e ampliação de seu registro de ocorrência no Brasil

    Directory of Open Access Journals (Sweden)

    Alexandre Specht

    2013-06-01

    Full Text Available O objetivo deste trabalho foi descrever métodos para a caracterização morfológica e molecular de Helicoverpa armigera e ampliar o registro de ocorrência da praga no Brasil. As mariposas foram obtidas de lagartas coletadas nas culturas de algodão, milho e soja, com uso de armadilhas luminosas. As coletas foram realizadas na Bahia, no Distrito Federal, no Mato Grosso e no Paraná. A identificação foi baseada na genitália masculina e nas análises das sequências dos genes mitocondriais do citocromo B e da região cox1-tRNALeu-cox2. A genitália masculina foi comparada com as descrições morfológicas na literatura, e as sequências de genes, com as depositadas no GenBank. Ambas as análises confirmaram a presença de H. armigera nos locais de coleta. Ampliou-se o registro de ocorrência da praga para a região Sul do país.

  3. The pathogenicity of Beauveria bassiana to Helicoverpa armigera under different temperatures and humidities%不同温、湿度下白僵菌对棉铃虫幼虫的致病力

    Institute of Scientific and Technical Information of China (English)

    孙鲁娟; 吴孔明; 郭予元

    2001-01-01

    测试了不同温、湿度下白僵菌Beauveria bassiana对棉铃虫Helicoverpa armigera幼虫的致病力.实验设置了10、15、20、25、30℃5个温度水平,用高浓度(1×108孢子/mL)、中浓度(1×107孢子/mL)、低浓度(1×106孢子/mL)的白僵菌孢子液分别感染1~4龄的棉铃虫.结果表明:三个浓度处理的棉铃虫在温度为25℃时的致死中时(LT50)最短,死亡速度最快,死亡率最高;高于或低于此温度时,棉铃虫的LT50延长,死亡速度减慢.相对湿度发生变化时,感病棉铃虫死亡速度和死亡率明显不同.相对湿度为95%左右时,棉铃虫死亡速度最快,死亡率最高;相对湿度低于70%时,棉铃虫死亡率显著降低.

  4. 不同光源和暗适应时间对棉铃虫蛾趋光行为的影响%Effects of different light source and dark-adapted time on phototactic behavior of cotton bollworms (Helicoverpa armigera )

    Institute of Scientific and Technical Information of China (English)

    靖湘峰; 罗峰; 朱芬; 黄求应; 雷朝亮

    2005-01-01

    In this paper, the phototactic behaviors of different emergence period Helicoverpa armigera were studied in a phototactic box. The results showed that under the five test wavelength lights, different emergence period female and male moths had no significant difference in their phototactic behaviors. The phototactic rate differed significantly when the dark-adapted time was between 15 and 30 min, but had no significant difference among 30, 45 and 60 min. No significant difference was also found in phototactic rate between dark-adapted time 0 and 15 min under test wavelength lights except green one (500~565 nm).

  5. cDNA library construction and EST analysis of larval salivary glands of Helicoverpa armigera ( Lepidoptera: Noctuidae)%棉铃虫幼虫唾液腺cDNA文库的构建及EST分析

    Institute of Scientific and Technical Information of China (English)

    张帅; 崔金杰; 王春义; 雒珺瑜; 吕丽敏

    2012-01-01

    Helicoverpa armigera ( Hiibner) saliva play important roles in insect-host plant interactions. In this study we constructed a cDNA library of salivary glands of H. armigera larvae where saliva is secreted. We randomly sequenced 1 501 expressed sequence tags (ESTs) , and clustering resulted in a total of 821 unigenes. Blast2 GO program was used to do BLASTx, functional annotation and metabolism analysis. Finally, we classified mRNAs in salivary glands of H. armigera larvae. By annotation of these ESTs, genes encoding 17 enzymes for digestion of fat, 5 enzymes for digestion of carbohydrates, and 20 serine proteases (of which 16 are newly reported) were identified, suggesting that the function of salivary glands is secreting saliva for predigestion. The cuticle protein, odorant-binding protein and chemosensory protein genes were identified in salivary glands of H. armigera larvae for the first time. The results will lay a foundation for studying predigestion system in H. armigera.%棉铃虫Helicoverpa armigera(Hübner)幼虫唾液中的各种酶类及各种生化组分在棉铃虫与植物相瓦作用及协同进化中起到重要作用;唾液腺是棉铃虫唾液成分的合成器官.本研究通过构建棉铃虫幼虫唾液腺全长cDNA文库,测序得到1502条EST序列,聚类分析后获得821个unigenes,为筛选棉铃虫与寄主互作信号因子提供基因信息资源.使用Blast2 GO软件对821个unigenes进行了比对和功能注释,初步获得棉铃虫幼虫唾液腺中Mrna的构成特征.结果显示,在棉铃虫唾液腺ESTs文库中,鉴定得到脂类相关消化酶基因17个,糖类相关消化酶基因5个,半胱氨酸蛋白酶基因1个,丝氨酸蛋白酶基因20个(其中16个为新发现),提示唾液腺的主要功能是分泌消化酶进行预消化;还发现在棉铃虫幼虫唾液腺中存在表皮蛋白、气味结合蛋白和化学感受蛋白基因.结果为研究棉铃虫预消化系统打下基础.

  6. Coexpression of the silent cry2Ab27 together with cry1 genes in Bacillus thuringiensis subsp. aizawai SP41 leads to formation of amorphous crystal toxin and enhanced toxicity against Helicoverpa armigera.

    Science.gov (United States)

    Somwatcharajit, Rasapirose; Tiantad, Itsares; Panbangred, Watanalai

    2014-02-01

    The unexpressed cry2Ab27 gene of Bacillus thuringiensis subsp. aizawai SP41 (SP41) consists of a single open reading frame (ORF) of 1902bp encoding for 634 amino acid residues. The cry2Ab27 gene appears to be silent due to the lack of promoter and terminator sequences. In this study we fused the cry2Ab27 ORF with the cry1Ab promoter (500bp) and the terminator (300bp) in vector pHT304-18Z in order to drive the expression of cry2Ab27 in both SP41 and an acrystaliferous, B. thuringiensis subsp. thuringiensis 407 (407). A protein with a molecular mass of 65kDa, consistent with the Cry2Ab protein, was detected in both transformants using SDS-PAGE and Western blot analysis. Bipyramidal crystals were observed in SP41 and its transformant containing the pHT304-18Z vector (SPHT) in contrast, cells expressing cry2Ab27 (SPC2) exhibited crystal proteins with irregular shapes. No inclusion protein was detected in the 407 transformant expressing the cry2Ab27 gene. Cry2Ab27 was found in the purified crystal toxin from strain SPC2. The solubilized crystal toxin proteins from SPC2 were 6.9-fold more toxic toward the larvae of Helicoverpa armigera compared to toxin proteins from SPHT. However SPC2 crystal toxin displayed only slightly higher toxicity against the larvae of Spodoptera litura and S. exigua compared to SPHT produced toxin. Our data support the use of Cry2Ab in combination with the Cry1 toxin for enhanced control of heliothine insect pests.

  7. Preparation of Polyclonal Antibody of Helicoverpa armigera Single-nucleopolyhedrovirus orf80%棉铃虫核型多角体病毒orf80多克隆抗体的制备

    Institute of Scientific and Technical Information of China (English)

    徐利; 吕婷婷; 甘恩宇; 高秋荣; 王敦

    2012-01-01

    从HearNPV G4株基因组中克隆得到orf80基因的全序列,将该基因构建于pMAL-c4E载体并在TB1中融合表达,orf80融合表达蛋白分子质量为73.3 ku,与预测的蛋白一致,Western blot验证正确.纯化融合蛋白后制备抗原并注射新西兰大白兔从而得到orf80的多克隆抗体,经ELISA检测其效价达到2.56×105,表明该抗体具有较高的免疫原性,可用于orf80编码蛋白的检测及蛋白互作等相关研究.%The HearNPV ori80 was cloned from Helicoverpa armigera Single-nucleopolyhedrovirus (HearNPV) G4 genome by PCR and the prokaryotic expression vector pMAL-c4E-Ha80 was constructed. The recombinant plasmid was transformed into the Escherichi coli TB1 to express the MBP-Ha80 fushion protein. Purified MBP-Ha80 protein was injected into rabbits as antigen to prepare the polyclonal antibodies of orf80. The titer of anti-HearNPV orf80 polyclonal antibodies was 2. 56 X 105 detected by ELISA. The prepared antibodies can be used to determine orf80 coding protein in the research of protein detection and protein interaction.

  8. The transmission of sperm in the female reproduction tract of cotton bollworm,Helicoverpa armigera%棉铃虫精子在雌蛾生殖道内的转移动态

    Institute of Scientific and Technical Information of China (English)

    刘绪生; 李国清; 陈长琨

    2001-01-01

    The transmission and distribution of sperm in the reproduction tract of mated female Helicoverpa armigera,were studied with Feulgen smear and microscope count methods.The results were summarized as follows:(1)Both eupyrene and apyrene sperms started their transmission from the spermatophore to spermatheca at 1.5 h after copulation,and finished this process in half hour.Thereafter,the number of sperms in spermatheca decreased gradually;(2)After transferred to spermatheca,the sperms stored in the utriculus in the form of sperm mass.No sperm was found in lagena;(3)Transportation of sperm to the spermatheca was achieved by means of rhythmic muscular contraction of the female reproduction tract.The active apyrene sperm was also believed to assist in the transmission of the eupyrene sperm.%通过显微镜观察、孚尔根涂片法和显微镜计数法研究了棉铃虫精子在雌蛾生殖道内的转移、分布及转移的动力。结果表明:(1)交配结束后1.5 h,雌蛾精包内的真核精子和无核精子开始向受精囊转移,2 h时近2/3的精子已转入受精囊,其后受精囊内精子的数量逐渐下降;(2)精子转移至受精囊后只分布于主囊,成团聚集,副囊中没有精子;(3)雌虫生殖道肌肉的节律性收缩推动精子转移,同时无核精子的运动也有助于真核精子的移动。

  9. 棉铃虫Polycalin基因的克隆及其表达分析%Cloning and expression analysis of the polycalin gene in the cotton bollworm Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    王亚楠; 钟丰; 魏纪珍; 谢丙堂; 张万娜; 陈利珍; 梁革梅

    2015-01-01

    Objetives] To further define the role of Polycalin in the Cry1Ac resistance mechanism of Helicoverpa armigera in and thereby develop a feasible resistance management strategy for this pest. [Methods] The full-lengthsequence of the polycalin coding gene was obtained using RT-PCR (reverse transcription-polymerase chain reaction) and RACE (rapid amplification of cDNA ends) technology. The expression levels of polycalin in different development stages and different tissues of the larval digestive tract were analyzed using real-time quantitative PCR. Changes in the expression of polycalin in the larval midgut in 4th instar larvae fed on an artificial diet containing the Bt insecticide protein Cry1Ac were also compared. [Results] The results indicate that the full-length of the polycalin from H. armigera coding gene was 2 955 bp (GenBank accession number KP100652), the open reading frame was 2 781 bp in length, encoding 926 amino acid residues. The predicted molecular weight was 101.68 ku and the isoelectric point was 4.95. The putative protein sequence contained a N-terminal signal peptide of 20 amino acids, three N-linked and eight O-linked glycosylation sites, and a GPI anchor signal peptide with 2 amino acids at the C-terminus. Polycalin was expressed in all growth stages of H. armigera, and expression in larvae was higher than that in other stages, especially in 1st-3rd instar larvae. The lowest expression levels occurred in eggs, adults and pupae. The expression of the polycalin gene was dramatically suppressed after larvae were fed on food containing the Cry1Ac toxin. [Conclusion] These results provide a basis for further clarifying the function of polycalin with respect to the Bt toxin.%【目的】通过对棉铃虫 Polycalin 基因的克隆及其表达谱分析,进一步明确 Polycalin 基因在抗性中发挥的作用,为棉铃虫Helicoverpa armigera的抗性治理提供理论依据。【方法】通过RACE结合PCR技术克隆获得了棉铃虫Polycalin

  10. Vip3Aa及Cry1Ac对棉铃虫幼虫多种酶活力的影响%Effects of Vip3Aa and Cry1Ac on enzyme activity in cotton bollworm Helicoverpa armigera larvae

    Institute of Scientific and Technical Information of China (English)

    张彦; 梁革梅; 高珍

    2012-01-01

    In order to clarify the activity of Vip3Aa and provide a theoretical basis for its application in the " New toxin strategy", the effects of Vip3Aa and CrylAc on protease, detoxification enzymes were and aminopeptidase N ( APN ) activity in larvae of the cotton bollworm Helicoverpa armigera (H(ll)bner) were compared and the impacts of Cryl Ac + Vip3Aa on these enzymes were investigated. The lethality of Vip3Aa was lower than that of CrylAc, but Vip3Aa had an obvious inhibitory effect on larval development. Total protease and trypsin-like enzyme activity quickly increased in H. armigera fed an artificial diet containing either CrylAc or Vip3Aa or CrylAc + Vip3Aa. However, compared to the control, there was no significant difference in the activity of these two enzymes after 12 h of feeding on the Cryl Ac diet. While the period during which the activity of these two enzymes increased was clearly prolonged in larvae fed on diets containing Vip3Aa, that of the chymotrypsin-like enzyme was also higher than in the control. This indicates that the degradation rate of CrylAc was faster than that of Vip3Aa, and that the enzyme systems involved in degradation could be different. Meanwhile, the diet containing Cryl Ac and Vip3Aa together extended the degradation time. The activities of glutathione-5-transferase and a-naphthalene acetate esterase increased in H. armigera fed on a diet containing either Cryl Ac or Vip3Aa or CrylAc + Vip3Aa. This indicates that these enzymes may be involved in the detoxification of Vip3Aa and CrylAc. However, Vip3Aa and CrylAc had little effect on aminopeptidase N activities, suggesting that the toxieity of the latter has no relationship to APN enzyme activity.%为了明确Vip3Aa的作用机制,为其作为新毒素策略重要蛋白的应用提供理论依据,本文比较了Vip3Aa、Cry1Ac对棉铃虫Helicoverpa armigera(Hübner)主要蛋白酶、解毒酶、APN活性的影响,并研究了Vip3Aa和Cry1Ac共同使用对几种酶活力的作

  11. 黄帚橐吾乙醇提取物对棉铃虫的生物活性%Bioactivity of ethanol extracts of Ligularia virgaurea against Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    刘锦霞; 李晶; 李娜; 杜文静; 丁品; 柳军玺; 张建军; 武建荣

    2015-01-01

    棉铃虫食性杂,寄主广,为害严重又对现有农药易产生抗药性,为有效防控其对作物的为害,本文通过室内毒力测定研究了甘南草原有毒植物黄帚橐吾(Ligularia virgaurea )乙醇提取物对棉铃虫幼虫的农药生物活性,结果表明:黄帚橐吾乙醇提取物对棉铃虫2~3龄幼虫有很强的拒食活性,拒食中浓度(AFC50)为2.59 mg/mL。当提取物浓度为10.00 mg/mL 时,拒食率可达95%以上;触杀和胃毒活性也较强,致死中浓度(LC50)在3.00 mg/mL 左右,浓度为10.00 mg/mL 时,校正死亡率均可达80%以上,而且3种作用的活性强度随浓度增大而增强。杀卵和熏蒸活性相对较弱,但浓度大于10.00 mg/mL 时也有比较明显的杀灭活性。本研究结果证明黄帚橐吾乙醇提取物可以有效防控棉铃虫幼虫的危害,为黄帚橐吾类农药的开发和棉铃虫的有效防治提供了依据和有效途径。%Helicoverpa armigera Hübner is a major Lepidoptera pest on various crops in China,and it can develop easily pesticide resistance.Ligularia virgaurea (Maxim.)Mattf.is a kind of poisonous plant growing in the grass-land of Gannan Tibetan autonomous prefecture.In order to prevent and control H .armigera effectively,the bio-activity of the ethanol extracts of L .virgaurea against H .armigera was investigated in laboratory.The results showed that the extracts of L .virgaurea had strong antifeedant activity against the 2nd-3rd instars of H .armig-era with the AFC50 value of 2.59 mg/mL.Once the concentration of the extracts increased to 10.00 mg/mL,the antifeedant rate could reach to more than 95%.The extracts also demonstrated good contact toxicity and stomach toxicity activity,with LC50 value of all above 3.00 mg/mL.The corrected mortality was above 80% when the concentration of the extracts was 10.00 mg/mL.The higher the concentration,the stronger the activity.The ex-tracts had only weak

  12. 棉铃虫幼虫中栓锥感器对肌醇和糖类的电生理反应%Responses of medial sensillum of Helicoverpa armigera (Hiibner) (Lepidoptera:Noctuidae) larvae to inositol and sugars

    Institute of Scientific and Technical Information of China (English)

    张雪凝; 汤清波; 蒋金炜; 马英; 胡锡敏; 闫凤鸣

    2011-01-01

    The gustatory electrophysiological responses of medial sensillum of the polyphagous caterpillar, Helicoverpa armigera, to 7 kinds of sugars, inositol and their mixtures were measured by top recording technology. The responding cells in medial sensillum corresponding different stimulus and the interactions of different compounds in mixtures during the process of electrophysiological responses were analyzed. The results showed that: (1) the electrophysiological responses of medial sensillum to D-inositol, D-fructose, xylose, D-arabinose, D-glucose, maltose, D-trehalose and L-rhamnose were obvious, but the responding patterns between sugars and innositol were different trom a concentration-dependent responses in inositol and non-concentration-dependent responseses in sugars; (2) the differences of responding patterns between the pure sugar compounds and the mixture of fructose, arabinose and trehalose were not significant, indicating the same cell responding the 3 kinds of sugars; (3) Responses of the mixtures of fructose and inositol indicated that inositol-sensitive cell responded to fructose. The firing rate of mixture of fructose and inositol were higher than that of the two pure compounds, suggesting the synergistic interaction of responses of the two stimulus. All the results suggested that the inisitol-sensitive cell in medial sensillum of the polyphagous species of H. armigera may be one of “broad-spectrum” taste cells.%利用电生理学技术,以多食性的棉铃虫为研究对象,测定幼虫下颚中栓锥感器对7种糖和肌醇及其混合物的味觉电生理反应,分析不同物质诱导中栓锥感器内对应的味觉感受细胞及不同物质之间诱导昆虫电生理反应的交互作用.结果表明:(1)棉铃虫幼虫下颚中栓锥感器对肌醇、果糖、木糖、阿拉伯糖,葡萄糖、麦芽糖、海藻糖和鼠李糖的单一物质都有明显的电生理反应,但是对肌醇和糖类的反应模式不同,肌醇诱导的反

  13. Effects of ultraviolet light stress on juvenile hormone in Helicoverpa armigera adults%紫外胁迫对棉铃虫成虫保幼激素的影响

    Institute of Scientific and Technical Information of China (English)

    张长禹; 孟建玉; 周丽君; 桑文; 雷朝亮

    2012-01-01

    采用高效液相色谱法,测定了紫外(Ultraviolet,UV)胁迫对棉铃虫体内保幼激素JHⅠ、JHⅡ和JHⅢ的影响.结果表明:棉铃虫体内JHⅠ、JHⅡ和JHⅢ的滴度均随着日龄的变化发生了显著的改变,与1日龄相比,CK、1 h/d、5 h/d组在2、3、4日龄时的JHⅠ、JHⅡ和JHⅢ滴度均升高,其中1 h/d和5 h/d组的JHⅠ、JHⅡ和JHⅢ滴度在2日龄时达到最高值,且达到显著水平,然后均随着日龄的增大逐渐下降,9 h/d组JHⅠ、JHⅡ和JHⅢ滴度则随着日龄的增大显著降低;棉铃虫体内JHⅠ、JHⅡ和JHⅢ的滴度随着UV照射时间的延长均发生了显著的变化,当照射时间为5 h/d和9 h/d时,2~5日龄棉铃虫体内的JHⅠ、JHⅡ和JHⅢ滴度显著低于对照水平,不同日龄虫体内的JHⅠ、JHⅡ和JHⅢ滴度均在9 h/d时达到最低;此外,日龄与UV照射的交互作用均达到显著水平.%The effects of ultraviolet (UV) light stress on juvenile hormone in Helicoverpa armigera adults were studied by HPLC. The results showed that JHⅠ, JHⅡ and JHⅢ titres in adults changed significantly with the age. Compared with adults at 1 day of age, JHⅠ, JHⅡ and JHⅢ titres increased in adults at 2 to 4 days of age in the groups of control, 1 h/day and 5 h/day treatments. And the titres reached maximum in adults at 2 days of age with significant differences after exposure for 1 and 5 h/day, and then decreased gradually with the age. When a-dults were exposed to UV for 9 h/day, JHⅠ, JHⅡ and JHⅢ titres decreased significantly with age. JHⅠ, JHⅡ and JHⅢ titres changed significantly with increasing exposure time. Compared to the control, exposure to UV light for 5 h/day and 9 h/day resulted in a significant decline in JHⅠ, JHⅡ and JHⅢ titres in adults at 2 to 5 days of age. JHⅠ, JHⅡ and JHⅢ titres in adults reached the minimum after exposure for 9 h/day. The results also showed that the interaction between the age and the exposure time was

  14. 紫外线照射对棉铃虫成虫几种同工酶的影响%Effects of ultraviolet light irradiation on several isozymes in Helicoverpa armigera (Hiiber) adults

    Institute of Scientific and Technical Information of China (English)

    孟建玉; 张长禹; 雷朝亮

    2012-01-01

    The effects of ultraviolet (UV) light stress on esterase, peroxidases (POX) , and catalase (CAT) isozymes in Helicoverpa armigera (Hüber) adults were studied by isozyme electrophoresis. When exposed to UV light irradiation, zymogram of esterase isozyme changed mainly in number and activity of isozyme. After 30 min and 60 min exposure, the intensity of isozyme bands E4,E9 and E10 were enhanced, E2 and E8 were weakened. The bands E1, E5, E7 and El 1 disappeared after UV light irradiation, while E3 and E6 newly emerged. At the longest exposure time (90 min), the intensity of isozyme bands E4 and E9 was enhanced, while the intensity of E2 and E8 was weakened. The bands El, E5 and E7 disappeared after UV light irradiation, whereas E3 and E6 newly emerged. The intensity of POX band P5 was enhanced in adults following the exposure to UV light for 30,60,90 minutes. The intensity of CAT band Cl was enhanced in adults following the exposure to UV light for 30,60,90 minutes, but that of band C2 was weakened after 30 min and 90 min exposure in comparison with the control.%采用同工酶电泳的方法,研究了紫外(ultraviolet,UV)胁迫条件下对棉铃虫体内酯酶、过氧化物酶(peroxidase,POX)及过氧化氢酶(catalase,CAT)等同工酶的影响.结果表明:与对照相比,紫外线照射处理组酯酶同工酶谱带发生了质和量的变化,照射时间为30 min和60 min时,谱带E4、E9、E10增强,谱带E2、E8减弱,谱带E1、F5、E7、E11消失,新增了谱带E3、E6;照射时间延长至90 min时,谱带F4、E9增强,谱带E2、E8减弱,谱带E1、E5、E7消失,新增了谱带E3、E6.紫外线照射处理下,棉铃虫POX同工酶谱带P5有所增强,CAT同工酶谱带的变化因照射时间不同而有所差异.与对照相比,紫外线照射处理组的C1谱带增强,但C2谱带在30 min时减弱,60 min时恢复到对照水平,90 min时与对照相比又有所减弱.

  15. 甲氨蝶呤和紫杉醇对棉铃虫繁育能力的影响%Effects of Methotrexate and Paclitaxel on the Ability of Breeding of Cotton Bollworm, Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    马天文; 王俊刚; 何泽敏; 江海澜; 邓小霞; 彭俊

    2012-01-01

    [目的]研究药剂对棉铃虫繁育能力的影响,为安全有效的控制棉铃虫危害奠定理论基础.[方法]采用饲喂法处理棉铃虫成虫,对其产卵量、卵孵化率、实验前后成虫体重差、成虫寿命进行测定.[结果]甲氨蝶呤抑制棉铃虫产卵量效果优于紫杉醇,0.02%甲氨蝶呤处理的棉铃虫单雌产卵量(104粒)最低,比对照降低了72.48%;紫杉醇抑制卵孵化效果好于甲氨蝶呤,0.5%紫杉醇处理的卵孵化率为11.43%,平均校正不育卵率(89.19%)达到最高.甲氨蝶呤处理对雌虫的寿命比对照缩短l~2d.紫杉醇对棉铃虫雄虫有增重作用,而甲氨蝶呤对棉铃虫雌虫有减重作用.[结论]甲氨蝶呤和紫杉醇对棉铃虫繁育能力均有弱化作用,0.02%甲氨蝶呤弱化棉铃虫单雌产卵量效果最好,0.5%紫杉醇抑制卵孵化效果最佳.%[Objective] The purpose of this study was to investigate the effects of agenda on the ability of breeding of cotton bollworm, Helicoverpa armigera (Hübner) in order to lay foundation of controlling the harm of cotton bollworm safely and effectively. [ Method ] Feeding treatment with Methotrexate and Paclitaxel was used to determine the number of eggs laid by per female moth, hatching rate, body weight and lifetime of the adult. [ Result ] The inhibition effect of Methotrexate for laying eggs of cotton bollworm was better than Paclitaxel indoor environment. The number (104 head) of eggs laid by per female moth was the lowest after the treatment using 0.02% Methotrexate, 72.48% reduced than CK, while the inhibition effect of Paclitaxel for hatching rate of eggs was better than Methotrexate. The rate of hatching rate of eggs was 11.43% treated by using 0.5% Paclitaxel,and the revised sterility eggs rates(89. 19%) was the highest. Lifetime of adult moth was reduced by 1 to 2 days in female moths with Methotrexate treatment. Paclitaxel had the function of increasing weight of the male, but Methotrexate

  16. 胡椒碱和山椒醇经历对棉铃虫幼虫取食的影响%Effect of Piperine-and Sanshool-Experiences on Larval Feeding of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    李为争; 胡晶晶; 李慧玲; 郭线茹; 闫凤鸣; 原国辉

    2015-01-01

    [Objective]Feeding deterrents or anti-feedants are a broad range of chemicals regulating the feeding behaviour via altering the palatability of crops to herbivores. The idea of pest ecological control using feeding deterrents is an alternative strategy to overcome the negative effect of chemical control. However, almost all insect pests can develop experience-dependent adaptivity to various feeding deterrents, especially gustatory habituation, which limited the practical use of these substances. The objective of this study is to elucidate the sensory organs involved in the feeding deterrence of two amides against a generalist herbivore, Helicoverpa armigera (Hübner), and the effect of prior feeding experience of piperine and sanshool on subsequent feeding behaviour of the larvae, providing a scientific basis for large-scale application.[Method]The olfactory approaching response under dual-choice condition with piperine-and sanshool-treated with tobacco leaf discs was tested, respectively, paired with the control leaf disc, and the feeding duration of the larvae after first encounter with the piperine-or sanshool-treated tobacco leaf discs under non-choice condition was measured. Then the effect of larval feeding experience to piperine and sanshool on their subsequent choice feeding behaviour was tested based on the concentrations at 50%feeding deterrence against the fourth instar larvae.[Result]Piperine and sanshool did not exhibit any repellent effect, and the feeding durations of the larvae after first encounter with piperine-and sanshool-treated tobacco leaf discs were approximately 30 s, significantly shorter than that of the control (longer than 100 s). This feeding duration time was in accordance with the typical post-ingestive response time of a model insect species, Manduca sexta. The concentrations at 50%feeding deterrence to the fourth instar larvae of piperine and sanshool were 0.2259 and 0.4003 mg per tobacco leaf disc (1.5 cm ID), respectively. The

  17. 基于均匀设计与支持向量回归的棉铃虫幼虫全纯人工饲料配方优化%Optimization of chemically defined diet for larvae of the cotton bollworm (Helicoverpa armigera)based on uniform design and support vector regression

    Institute of Scientific and Technical Information of China (English)

    周世豪; 李俊; 姚润贤; 张星; 袁哲明

    2012-01-01

    昆虫全纯人工饲料配方是精细研究昆虫营养生理的前提.本研究以棉铃虫Helicoverpa armigera幼虫为供试对象,以本研究室前期发展的多因素多水平配方优化实验设计与分析方法UD-SVR为指导,以略加修改的苹浅褐卷蛾Epiphyas postvittana幼虫全纯人工饲料为初始配方,先优化20种天然氨基酸,再优化蔗糖等其他8种非氨基酸营养组分,经4轮97个处理组合,获得一个棉铃虫幼虫全纯人工饲料满意配方,平均蛹重、化蛹率分别由初始配方的0.160 g和10.4%高效增至满意配方的0.255 g和97.9%.该全纯人工饲料满意配方的获得,不但再次证实了 UD-SVR方法的有效性,同时为进一步深入研究棉铃虫营养需求与营养代谢奠定了基础.%In order to get a satisfying formula of the chemically artificial diet for larvae of the cotton bollworm, Helicoverpa armigera, we used UD-SVR, an experimental design and analysis method reported by our preliminary studies, for formula optimization. Based on the benchmark diet of a chemically artificial diet for the larvae of the light brown apple moth, Epiphyas postvittana, the contents of 20 natural amino acids were optimized first, and the contents of 8 non-amino acid nutrients including sucrose were optimized then. After 4 rounds of optimization with total 97 schemes, an optimal formula of the chemically artificial diet for the cotton bollworm larvae was obtained. When the H. Armigera larvae fed on this diet, their mean pupal weight and the pupation rate were 0. 255 g and 97. 9% , respectively; when the larvae fed on the benchmark diet, however, the above two indices were only 0. 160 g and 10. 4% ,respectively. The results reconfirmed the effectiveness of UD-SVR in the complex prescription optimization. More importantly, the optimized chemically artificial diet for the cotton bollworm provides the basis for further research on the requirement and metabolism of nutrition compounds in the moth.

  18. 棉铃虫酯酶突变体的构建、表达及酶促动力学特性%Construction, expression and activities of mutant carboxylesterases from Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    李永强; 吴美玲; 马志卿; 冯俊涛; 张兴

    2014-01-01

    The cotton bollworm , Helicoverpa armigera ( Hübner),is a major pest of many agricultural crops around the world , and many of the classes of chemical insecticides are widely used for its control such as organophosphates ( OPs) , synthetic pyrethroids ( SPs) , and so on . Currently H .armigera has developed serious resistance to OPs and SPs all over the world . Carboxylesterases ( CarEs) are a multi-gene family of enzymes that hydrolyze a diverse range of carboxylesters and are frequently implicated in the resistance of insects . Gene mutations of CarEs are a major mechanism of insects for the development of resistance to OPs in the OP-resistant Diptera pests like Musca domestica and Lucilia cuprina . It involves the substitution of a single amino acid within the active site of the esterase which convert it to an OP hydrolyase . However , no resembled mutation in nature was reported in the Lepidopterapestslikecottonbollworm,H.armigeratodate.Hence,followingourpreviousstudiestheaimofthe current work was to elucidate the effects of specific point mutations of the carboxylesterases from H . armigera on the kinetic properties of the enzymes . Two CarEs , 001F and 001G from H . armigera , were induced to mutate at positions 127 ( A → D) or 238 (F → L) using a site-directed mutagenesis technique . They were then expressed with the baculovirus expression vector system (BEVS) . The kinetic assays with α-naphthyl acetate ( α-NA) and para-nitrophenyl acetate ( p-NA) were carried out for all mutants using a spectrophotometer . The results showed that the A127D mutations had dramatically reduced the hydrolytic activities of the CarEs toward the two substrates . The mutants all showed lower affinities to the substrates as the Km values were at least 1.6-fold higher than those of the wild type enzymes , and the kcat values (6.5 52.1 s- 1 ) were decreased obviously , which were between 4- and 20-fold lower than those of the wild type enzymes . What’s more , the rate

  19. 棉铃虫幼虫取食Vip3Aa蛋白后的中肠组织病理变化%Pathological changes in midgut tissues of larvae of the cotton bollworm,Helicoverpa armigera ( Lepidoptera: Noctuidae ), after feeding Vip3Aa protein

    Institute of Scientific and Technical Information of China (English)

    张彦; 梁革梅; 张丽丽; 魏纪珍

    2012-01-01

    The pathological changes in midgut tissues of larvae of the cotton bollworm, Helicoverpa armigera (H(u)bner) , fed on artificial diet containing Vip3Aa protein were observed using transmission electron microscope, and the changes induced by Cry1Ac were also investigated in order to ascertain the action mechanism of Vip3Aa. The results showed that the goblet cells changed gradually after H. armigera larvae fed on artificial diet containing Vip3Aa protein, and the major symptoms included: microvilli swelled and dropped off, the boundaries of karyotheca in cell nucleus blurred and the chromatins unevenly distributed, the numbers of mitochondria and endoplasmic reticulum reduced, the inner cristae of mitochondria blurred, and the endoplasmic reticulum mixed disorderly. The pathological changes of goblet cells in the midgut of H. armigera larvae induced by Vip3Aa were slower than that by CrylAc. The obvious pathological changes were detected at 12 h after feeding Vip3Aa, and the pathological changes became more and more evident with extension of feeding time. The obvious pathological changes of H. armigera induced by CrylAc, however, appeared at 2 h after CrylAc treatment. This study may enrich the theoretical basis for better using Vip3Aa as new toxin strategy in IPM of the cotton bollworm.%为了进一步明确Vip3Aa的作用机制,利用透射电镜观察了棉铃虫4龄幼虫取食含Vip3Aa蛋白饲料后中肠杯状细胞的病理变化,并比较了其病变与取食含Cry1Ac饲料后棉铃虫组织病变的差异.取食含Vip3Aa饲料后,棉铃虫幼虫的中肠杯状细胞逐渐发生病变,主要表现为:微绒毛肿胀、脱落;细胞核核膜界限不清晰,染色质分布不均匀;线粒体变形、数量减少,内脊不清晰;内质网杂乱不规则、数量减少.与取食Cry1 Ac的棉铃虫相比,取食Vip3Aa的棉铃虫中肠杯状细胞发生病变较为缓慢,在取食12 h后才发现明显病变,随着取食时间的增加病变

  20. 棉铃虫中肠氨肽酶 APN4与 Cry1Ac、Cry2Aa 结合能力的比较%Comparison of the binding affinity of the APN4 receptor in Helicoverpa armigera (Hübner) to the Cry1Ac and Cry2Aa insecticidal proteins

    Institute of Scientific and Technical Information of China (English)

    袁向东; 葛朝虹; 肖玉涛; 梁革梅

    2015-01-01

    Objectives] Bt (Bacillus thuringiensis) insecticidal proteins have been widely adopted to control agricultural pests because of their high target specificity. The binding of a Bt insecticidal protein to its specific receptor in the insect midgut plays a key role in the insecticidal action process. Aminopeptidase N (APN) is one of the major Bt protein receptors. To better characterize the molecular mechanism underlying the insecticidal activity of different Bt insecitcidal proteins, and lay the foundation for Bt resistance management and novel Bt insecticidal protein development, we analyzed the binding affinity of aminopeptidase N4 (APN4) to the Cry1Ac and Cry2Aa insecitcidal proteins in Helicoverpa armigera. [Methods] The binding affinity of aminopeptidase N4 (APN4) was assessed using ligand blot analysis and an ELISA binding assay, respectively. [Results] The results show that recombinant APN4 could bind to both Cry1Ac and Cry2A; their respective dissociation constants were 46.7 nmol/L and 26.5 nmol/L. [Conclusion] The results suggest that there was no significant difference in the binding affinity of APN4 to Cry1Ac and Cry2Aa in H. armigera.%【目的】 Bt 杀虫蛋白(Bacillus thuringiensis)具有高度的靶标特异性,已经被广泛用于农业害虫防治。Bt 杀虫蛋白要发挥杀虫活性,必须首先与其受体蛋白结合,氨肽酶 N(Aminopeptidase N)是一类重要的 Bt 受体蛋白。因此,分析该受体与 Bt 杀虫蛋白的结合能力,可为进一步明确不同 Bt 的分子作用机制、Bt 的抗性治理以及新 Bt 的开发应用等提供借鉴。【方法】本文利用 Ligand blot 和 Elisa 方法比较了棉铃虫 Helicoverpa armigera 中肠 APN4(Aminopeptidase N4,APN4)与 Cry1Ac、Cry2Aa 的结合能力。【结果】原核表达的 APN4片段与活化的 Cry1Ac、Cry2Aa 都可以结合,解离常数(Kd)分别是48.59 nmol/L和21.73 nmol/L。【结论】 APN4片段与 Cry1Ac、Cry2Aa 的结合能力

  1. AcMNPV chiA基因表达产物对棉铃虫围食膜的破坏及对Bt和NPV的增效作用%AcMNPV ChiA Disrupts the Peritrophic Membrane of Helicoverpa armigera and Enhances Activity to Bt and NPV

    Institute of Scientific and Technical Information of China (English)

    刘文霞; 郑桂玲; 梁革梅; 李长友; 李国勋

    2008-01-01

    采用PCR方法扩增出苜蓿银纹夜蛾(Autographa califomica)核型多角体病毒(AcMNPV)几丁质酶基因(chiA)编码区1.6 kb全长片段,并将该片段分别克隆至原核表达载体pET30a和杆状病毒Bac to Bac表达系统转移载体pFastBac中,分别在大肠杆菌(Escherichia coli)BL21(DE3)和草地贪夜蛾(Spodoptera frugiperda)细胞系Sf-9中进行了表达.SDS-PAGE分析表明,在大肠杆菌和昆虫细胞中均有效表达了60kD的蛋白.将表达产物饲喂5龄棉铃虫(Helicoverpa armigera)幼虫后取其围食膜,扫描电镜结果显示,围食膜结构遭到破坏形成大量孔洞.生物测定结果表明,以上两种表达产物对苏云金芽孢杆菌(Bt)和核型多角体病毒(NPV)均具有增效作用.以AcMNPV ChiA在大肠杆菌和细胞系Sf-9中的表达产物分别与Bt Cry2Ac蛋白混合饲喂棉铃虫初孵幼虫,增效率分别为33.4%和54.5%,其LT50较对照处理分别缩短了17.8和20.6 h;当AcMNPV ChiA在大肠杆菌和细胞系Sf-9中的表达产物分别与甘蓝夜蛾(Mamestra brassica)核型多角体病毒(MbNPv)混合处理棉铃虫初孵幼虫时,其LT50与对照比较分别缩短了16.6和22.4 h.

  2. Transgenic Tobacco Plants With Efficient Insect Resistance

    Institute of Scientific and Technical Information of China (English)

    李太元; 田颖川; 秦晓峰; 莽克强; 李文谷; 何永刚; 沈蕾

    1994-01-01

    Insecticidal protein gene CryIA(c)from Bacillus thuringiensis HD-1(B.t.toxin gene)with 5’-end modified and 3’-end deleted to 4 different lengths were inserted downstream of 35S promoterwith double enhancer and"Ω’"fragment of TMV-RNA cDNA in the binary vector pBin438 to constructthe chimeric expression vector of B.t.toxin gene.Leave stripes of tobacco plant var.NC89 widelygrown in China were transformed with A.tumefaciens LBA4404 harbouring the above expression vectorsrespectively,and kanamycin resistant tobacco plants were regenerated.Insect test with tobacco budwormH.assulta showed that insect-resistant transform.ants could be obtained from the regenerated plantstransformed with B.t.genes of different lengths though highest percentage(~50%)of plants with ahigh morality(90%-100%)to the testing insects is among those transformed with 1.8-kb toxin gene.Genetic,molecular and biological analyses of T1 and T2 progenies of plants with high efficient insect re-sistance showed that B.t.toxin gene and the character of insect resistance have been inherited in the pro-genies.Insect-resistant homozygotes D8-14 and D19-8 have been selected for small-scale field tests.

  3. Effects of thermoperiod on larval development and pupal diapause in different geographic populations of Helicoverpa armigera (Hiibner) ( Lepidoptera: Noctuidae)%温周期对不同地理种群棉铃虫幼虫发育及蛹滞育的影响

    Institute of Scientific and Technical Information of China (English)

    陈元生; 陈超; 涂小云; 匡先钜; 薛芳森

    2011-01-01

    To understand the thermoperiodic response of the cotton bollworm, Helicoverpa armigera (Hübner) , the effects of thermoperiod on larval development and pupal diapause in 4 different geographic populations (Guangzhou population, 23.08°N, 113. 14°E; Yongxiu population, 29. 04°N, 115.82°E; Tai'an population, 36. 15°N, 116. 59°E; and Kazuo population, 41.34°N, 120. 27°E) were systematically investigated under the photoperiod of L12: D12. The results showed that at the same photophase temperature there were no significant differences in the larval duration (P > 0. 05 ) between 20T ( thermophase, 20℃) : 5C (cryophase, 5℃) ( 12 h photophase temperature : 12h scotophase temperature) (the rest in the same analogy) and 20T:9C, 22T:5C and 22T:9C, 25T:5C and 25T:9C, and 28T:5C and 28T:9C, respectively, in 4 different populations. However, at the same or near average temperature, the larval duration at 20T:9C (an average temperature of 14. 5℃ ) was significantly higher than that at 22T: 5C (an average temperature of 13. 5℃ ) ( P 0.05 ) at the same photophase temperature between 20T:5C and 20T:9C, 22T:5C and 22T:9C, 25T:5C and 25T:9C, and 28T:5G and 28T:9C, respectively, suggesting that the diapause induction is influenced strongly by the photophase temperature. At the same thermoperiod, the larval duration and diapause rate were significantly different among different geographic populations. The larval duration and diapause rate were positively correlated with latitude of habitat, suggesting that sensitivity to temperature is gradually enhanced with a decrease in latitude of habitat.%为了探明不同地理种群棉铃虫Helicoverpa armigera (Hiibner)对温周期的反应,本研究系统调查了棉铃虫广东广州种群(23.08°N,113.14°E)、江西水修种群(29.04°N,115.82°E)、山东泰安种群(36.15°N,116.59°E)和辽宁喀佐种群(41.34°N,120.27°E)在滞育诱导的光周期(L12∶D12)条件下,温周期(光期高温20~ 28℃,暗期低温5和9

  4. 霍乱毒素对三氟氯氰菊酯抗性及敏感棉铃虫神经细胞L型钙通道的调节作用%Modulations by CTX of the L-type Ca2+ channels in the central neurons of the cyhalothrin-resistant and cyhalothrin-susceptible cotton bollworm, Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    赵强; 李杰; 刘燕强; 范贤林; 季青; 刘安西

    2006-01-01

    霍乱毒素(CTX)可激活兴奋性异三聚体G蛋白(Gαs)的α-亚基和刺激电压门控L-型钙通道,而昆虫的L-型钙通道可能是拟除虫菊酯类杀虫剂的作用靶点.为进一步探讨农业害虫对拟除虫菊酯类杀虫剂产生抗药性的作用机理,我们检测了CTX对三氟氯氰菊酯抗性及敏感棉铃虫Helicoverpa armigera中枢神经细胞电压门控L-型钙通道的调节作用.分别急性分离三氟氯氰菊酯抗性及敏感的3~4龄棉铃虫幼虫胸腹神经节细胞,并在改良的L15培养基(加入或未加入700 ng/mL的CTX)中培养12~16 h.钡离子为载流子,应用全细胞膜片钳技术记录电压门控L-型钙通道电流.结果显示,CTX可使敏感组棉铃虫神经细胞L-型钙通道的峰值电流密度增大36%、峰值电压左移5 mV,但对抗性组棉铃虫神经细胞L-型钙通道无上述作用.并且,CTX对敏感组及抗性组棉铃虫神经细胞L-型钙通道的激活电位、翻转电位、激活曲线和失活曲线等其他一些参数的影响也不明显.在无CTX作用时,所检测到的抗性组与敏感组棉铃虫神经细胞L-型钙通道的上述参数值间差异不显著.结果提示,棉铃虫神经细胞内存在Gs-腺苷酸环化酶(AC)-cAMP-蛋白激酶A (PKA)-L-型钙通道信号调节系统;与敏感棉铃虫神经细胞L-型钙通道相比,三氟氯氰菊酯抗性棉铃虫神经细胞L-型钙通道的活性相对不易受到CTX调节,这可能与昆虫对拟除虫菊酯产生抗药性的机理有关.%Cholera toxin (CTX) activates the α-subunit of stimulatory heterotrimeric G-proteins (Gαs) and stimulates voltage-gated L-type (Ca2+(L)) channels, which may be primary targets of pyrethroids. To investigate the potential mechanisms underlying the resistance to pyrethroids in agriculturally important insect pests, we examined the modulations by CTX of Ca2+(L) channels in the central neurons of the cyhalothrin-resistant (Cy-R) and cyhalothrin-susceptible (Cy-S) cotton

  5. Expression of Two Carboxylesterase Genes (001f and 001g) from Helicoverpa armigera Using Baculovirus Expression Vector System(BEVS)and Analysis of Their Enzymatic Activity%两个棉铃虫酯酶基因(001f和001g)在杆状病毒表达载体系统(BEVS)中的表达及酶活分析

    Institute of Scientific and Technical Information of China (English)

    李永强; 袁国瑞; 张兴

    2012-01-01

    Metabolic detoxification of carboxylesterases (CarEs) is a major mechanism for the development of resistance in insects to organophosphates (Ops), synthetic pyrethroids (SPs) and carbamates (CBs). In order to elucidate the role of CarE genes from Helicoverpa armigera in metabolic resistance, two CarE genes, Oolf and 001g,were successfully expressed in the Sf9 insect cell lines using the Baculovirus Expression Vector System (BEVS). Both of the expressed CarEs were subjected to native PAGE and stained with artificial substrate a-naphthyl acetate (a-NA), and showed high activity against cx-NA according to the darker stained bands. The resulting stained bands (closely together) indicated that the relative mobility (Rm) of CarEs fell in two zones (0.27 ~0.36 and 0.37 -0.48). The kinetic assays with a-NA and para-nitrophyl acetate (p-NA) using a spectrophotometer showed the two CarEs had high affinity to the former substrate (Xm=(3.9±0.6) and (3.3±0.4) |xmol/L, respectively). They also produced a considerably high rate constant (kcat/Km= (26.5+1.9) and (95±9.3) |xmol"1*s"1*L, respectively) agianst a-NA, but a relatively lower rate constant against p-NA (&cai/X77i=(4.47±0.33) and (12.8±0.10) (imol"1*s"1*L, respectively) compared with that of a-NA. It's showed that the two CarEs had high hydrolytic activity against the artificial substrates. Thus, 00IF and 001G esterases are probabaly associated with metabolic resistance of insecticides, and may have relatively high detoxification activity against some traditional chemical insecticdes such as Ops, SPs and CBs.%昆虫羧酸酯酶(carboxylesterases,CarEs)对有机磷、拟除虫菊酯、氨基甲酸酯等三大类化学杀虫剂的代谢解毒作用是昆虫代谢抗性产生的一种重要机制.为明确棉铃虫(Helicoverpa armigera)两个酯酶基因001f和001g在代谢抗性中的作用,本研究基于杆状病毒表达载体系统(BEVS)在草地夜蛾(Spodoptera frugiperda)Sf9细胞系

  6. 棉铃虫硫氧还蛋白类似基因HaTrx-like的分子鉴定和抗逆特征%Molecular identification of a thioredoxin-like gene in Helicoverpa armigera and its expression following different kinds of stress

    Institute of Scientific and Technical Information of China (English)

    张松斗; 张博宇; 申忠健; 刘彦君; 李贞; 张青文; 刘小侠

    2015-01-01

    【目的】克隆棉铃虫Helicoverpa armigera硫氧还蛋白类似基因(HaTrx-like)的cDNA全长并进行序列分析,研究HaTrx-like基因的时间和空间表达模式以及参与抵抗机械损伤、紫外线照射和极端温度等逆境的特征。【方法】利用RT-PCR的方法扩增得到HaTrx-like基因的全长cDNA并通过测序进行验证,运用几种生物信息学软件对基因和氨基酸序列进行分析,利用荧光定量 PCR 检测 HaTrx-like 基因的时间和空间分布以及4种逆境条件处理后的表达模式。【结果】棉铃虫 HaTrx-like 基因的 cDNA 全长为526 bp,其中开放阅读框长度为381 bp,编码126个氨基酸,含有一个保守的氧化还原活性位点CXXC,其氨基酸序列和帝王斑蝶Danaus plexippus以及家蚕Bombyx mori同源物的序列一致性为72%和71%。HaTrx-like基因在幼虫5龄0 h和5龄96 h,蛹期第1天和第5天,以及成虫第1天的表达量相对较高,在幼虫的中肠、马氏管和成虫的肌肉中的表达量相对较高。在机械损伤、紫外线照射、极端低温和高温处理后,该基因的表达均显著地升高。【讨论】获得了棉铃虫HaTrx-like基因的cDNA全长,并初步鉴定该基因为硫氧还蛋白家族成员,其表达水平受到机械损伤、紫外线照射和极端温度的上调,为进一步深入研究昆虫中硫氧还蛋白家族基因的各种生理功能提供理论基础。%[Objectives] To clone the full-length cDNA of a thioredoxin-like (HaTrx-like) gene in Helicoverpa armigera, to analyze its spatio-temporal distribution in different developmental stages and different tissues, and to determine its expression patterns following mechanical injury, exposure to UV radiation and extreme temperatures. [Methods] The full-length cDNA of HaTrx-like gene was amplified using the RT-PCR method and further validated by sequencing. The gene and protein sequences of HaTrx-like were analyzed with several kinds of

  7. Modes of action of fraxinellone against the tobacco budworm,Heliothis virescens

    Institute of Scientific and Technical Information of China (English)

    Zhi Long Liu; Shuit Hung Ho; Swee Hock Goh

    2009-01-01

    Fraxinellone significantly reduced the relative growth rate, food consumption rate as well as the efficiency of conversion of ingested food into biomass of Heliothis virescens when incorporated into artificial diets at concentrations of 4.31 × 10-5 mol/L and above. After being fed with fraxinellone-treated diets for 24 h, the larval midguts of H. virescens possess significantly lower activities of a-amylase and non-specific proteases and higher activities ofcytochrome P450s. In vitro, the compound did not inhibit the activities of α-amylase and non-specific proteases extracted from the larval midguts. Clear evidence of post-ingestive toxicity of fraxinellone to midgut cells was observed under an electron microscope. The modes of action of the compound against insects were discussed.

  8. Effects of antiserums of cadherin, aminopeptidase N and alkaline phosphatase on the toxicities of Cry1Ac and Cry2Aa in Helicoverpa armigera (Lepidoptera: Noctuidae)%棉铃虫中肠钙粘蛋白、氨肽酶N及碱性磷酸酯酶的抗血清对Cry1Ac和Cry2Aa毒力的影响

    Institute of Scientific and Technical Information of China (English)

    王冰洁; 袁向东; 赵曼; 刘臣; 陈琳; 梁革梅

    2016-01-01

    [Aim] Cry1A and Cry2A toxins play insecticidal roles by specifically binding with receptor proteins on insect midgut,and are widely used in Bt transgenic crops now.This study aims to further understand the action mechanisms of Cry2A and the roles of the functional receptor proteins of Cry1 A in the toxicity of Cry2A.[Methods] We firstly extracted brush border membrane vesicles (BBMV) of midgut,prepared antibody and antiserums of cadherin (CAD),aminopeptidase N (APN),and alkaline phosphatase (ALP) in Helicoverpa armigera.Then,after detecting the antiserums of these three receptor proteins in BBMV by Western blot,we compared the effects of antiserums of these three receptor proteins on the toxicities of Cry1Ac and Cry2Aa in the susceptible and Cry1Ac-resistant H.armigera (BtR) by the antibody blocking technology.[Results] For the susceptible H.armigera,the antiserums of these three receptor proteins not only significantly reduced the toxicity of Cry1 Ac,but also remarkably reduced the toxicity of Cry2Aa.Among them,anti-APN antiserum had the biggest impact on the toxicity of Cry1Ac,causing the mortality of H.armigera larvae to be reduced by 84.44%,and anti-ALP antiserum had the greatest effect on the toxicity of Cry2Aa,causing the larval mortality to be reduced by 71.04% compared with the control (without treatment by antiserum).The toxicity of Cry1Ac to Cry1Ac-resistant H.armigera (BtR) was obviously reduced and the toxicity of Cry2Aa also became less to these resistant larvae.The influences of the antiserums of these three receptors on the toxicity of Cry1Ac to the Cry1Acresistant strain of H.armigera (BtR) were smaller than those to the susceptible strain.Especially,the inhibition percentage of anti-CAD and-APN antiserums to the toxicity of Cry1 Ac decreased significantly.The effects of anti-CAD and-ALP antiserums on the toxicity of Cry2Aa to the Cry1Ac-resistant strain (BtR) and the susceptible strain were not significantly different,but the anti-APN antiserum

  9. Peripheral genetic structure of Helicoverpa zea indicates asymmetrical panmixia

    Science.gov (United States)

    Seasonal climatic shifts create peripheral habitats that alternate between habitable and uninhabitable for migratory species. Such dynamic peripheral habitats are potential sites where migratory species could evolve high genetic diversity resulting from convergence of immigrants from multiple region...

  10. Development of a novel-type transgenic cotton plant for control of cotton bollworm.

    Science.gov (United States)

    Yue, Zhen; Liu, Xiaoguang; Zhou, Zijing; Hou, Guangming; Hua, Jinping; Zhao, Zhangwu

    2016-08-01

    The transgenic Bt cotton plant has been widely planted throughout the world for the control of cotton budworm Helicoverpa armigera (Hubner). However, a shift towards insect tolerance of Bt cotton is now apparent. In this study, the gene encoding neuropeptide F (NPF) was cloned from cotton budworm H. armigera, an important agricultural pest. The npf gene produces two splicing mRNA variants-npf1 and npf2 (with a 120-bp segment inserted into the npf1 sequence). These are predicted to form the mature NPF1 and NPF2 peptides, and they were found to regulate feeding behaviour. Knock down of larval npf with dsNPF in vitro resulted in decreases of food consumption and body weight, and dsNPF also caused a decrease of glycogen and an increase of trehalose. Moreover, we produced transgenic tobacco plants transiently expressing dsNPF and transgenic cotton plants with stably expressed dsNPF. Results showed that H. armigera larvae fed on these transgenic plants or leaves had lower food consumption, body size and body weight compared to controls. These results indicate that NPF is important in the control of feeding of H. armigera and valuable for production of potential transgenic cotton.

  11. Electrophysiological responses of differently diet-experienced Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae to sugars and inositol%不同取食经历的棉铃虫幼虫对糖和肌醇的味觉电生理反应

    Institute of Scientific and Technical Information of China (English)

    曹欢; 汤清波; 马英; 詹欢; 赵新成; 闫凤鸣

    2013-01-01

    利用单感受器记录技术测定了不同取食经历的棉铃虫幼虫对糖和肌醇的电生理反应,以分析昆虫味觉细胞的可塑性.研究结果表明,(1)连续多代取食含量约39 mmol.L-1蔗糖的标准人工饲料的棉铃虫幼虫下颚中栓锥感器和侧栓锥感器对阿拉伯糖、海藻糖、麦芽糖、葡萄糖和蔗糖均产生明显的脉冲反应,但中栓锥感器对海藻糖和葡萄糖的反应频率显著高于侧栓锥感器,表明中栓锥感器内存在海藻糖和葡萄糖敏感细胞.(2)直接从田间采集的野生棉铃虫幼虫中栓锥感器对阿拉伯糖、麦芽糖、葡萄糖、蔗糖和肌醇脉冲反应的反应频率显著高于室内种群的反应频率,但2种群对海藻糖的反应频率没有显著差异,表明幼虫对海藻糖的反应机制不同于对蔗糖、肌醇和其他糖的反应机制.(3)连续多代取食标准人工饲料的棉铃虫幼虫中栓椎感器对阿拉伯糖、麦芽糖、葡萄糖、蔗糖和肌醇的电生理反应被抑制,但是当下一代幼虫取食不含蔗糖的人工饲料后,幼虫对这4种糖的反应频率恢复到野生种群的水平,而对肌醇的反应强度继续被抑制,表明幼虫对肌醇的反应机制不同于对阿拉伯糖、麦芽糖、葡萄糖和蔗糖的反应机制.这些结果表明幼虫前期取食经历能够显著影响后代对不同糖及肌醇的电生理反应,但是不同糖之间、糖与肌醇之间的反应机制存在差异.%The diet-induced plasticities of gustatory cells of larvae were investigated using single sensillum recording technology (SSR) by recording the gustatory electrophysiological responses to 5 sugars and inositol in Helicoverpa armigera with differently dietary experiences.The results showed as follows:(1) frequencies of electrophysiological responses to sucrose,D-(+)-glucose,maltose,(D-(+)-trehalose dehydrate,D-arabinose and inositol in both styloconic sensilla of larvae with sucrose-feed experiences for

  12. Effects of infestation by Helicoverpa armigera together with Fusarium verticillioides on the severity of maize ear rot and the contamination level of fumonisin in kernels%棉铃虫为害与拟轮生镰孢侵染对玉米穗腐病发生及玉米籽粒中伏马毒素污染水平的影响

    Institute of Scientific and Technical Information of China (English)

    李人杰; 魏铁松; 郭聪聪; 庞民好; 刘颖超; 董金皋

    2015-01-01

    The effects of co-infestation by Helicoverpa armigera and Fusarium verticillioides on the severity of maize ear rot and the contamination level of fumonisins in kernels were investigated.The maize variety ‘Xundan 20’was used,and the maize ears were inoculated with H .armigera ,F .verticillioides ,and H .armigera together with F .verticillioides ,respectively.The results of 2011 and 2012 showed that the co-inoculation of H .armigera and F .verticillioides significantly increased the severity of maize ear rot and the content of fumonisins in kernels. Average disease levels of maize ear rot in the treatment with both H .armigera and F .verticillioides were 0.68± 0.05 and 1.08±0.19 for 2011 and 2012,respectively,while the average disease levels of maize ear rot were 0.31 ±0.05 and 0.71±0.06 for the treatment with H .armigera only,and 0.24±0.03 and 1.05±0.29 for the treat-ment with F .verticillioides only.Meanwhile,the content of fumonisins in kernels treated with both H .armigera and F .verticillioides were (0.85±0.56)mg/kg and (2.36±0.98)mg/kg for 2011 and 2012,respectively.For the treatment with H .armigera only,it was (0.17±0.12)mg/kg and (0.01±0.002)mg/kg,respectively,and (0.10 ±0.03)mg/kg and (1.14±0.62)mg/kg after treated with F .verticillioides only,respectively.Under the same treatment conditions,the climatic conditions of high rainfall and high relative humidity were in favor of the sever-ity of maize ear rot and the accumulation of fumonisins in kernels.%本研究以‘浚单20’为供试玉米品种,以棉铃虫为供试昆虫,以拟轮生镰孢为供试病原菌,分别进行单独及复合处理,以明确棉铃虫和拟轮生镰孢单独处理和复合处理对玉米穗腐病发病程度及籽粒中伏马毒素污染水平的影响。结果表明,2011年和2012年均以棉铃虫与拟轮生镰孢侵染复合处理对穗腐病发病程度及籽粒中伏马毒素污染水平的影响最大,穗腐病平均病级分别为0.68±0

  13. 棉铃虫酯酶两个位点突变对三种杀虫剂代谢活性的影响%Effects of two points mutations of esterases from Helicoverpa armigera on metabolic activities of three kinds of insecticides

    Institute of Scientific and Technical Information of China (English)

    李永强; 安凤秋; 苏立德; 冯俊涛; 张兴

    2012-01-01

    为研究棉铃虫酯酶对有机磷和拟除虫菊酯类杀虫剂的代谢活性,在前期对酯酶001F和001G酶活性研究的基础上,进一步采用荧光法和高效液相色谱法测定了酯酶及其突变体(A127位和F238位突变)对二甲基-4甲基伞形酮磷酸酯(dMUP)、二乙基-7羟基香豆素磷酸酯(dECP)及顺式氰戊菊酯(2.s,d5)的酶促代谢活性。酯酶001F和001G对有机磷的酶促反应常数(kcat值)在2.0×10^-3/min~5.2×10^-3/min之间,后者对顺式氰戊菊酯的代谢活性为10.19μmol·min-1·μmol-1;001F的突变提高了对有机磷的代谢活性,其中001FA127D和001F238L对dMUP的kcat值至少是突变前的2倍;001G的突变却降低了对dECP的代谢活性,但001GF238L对dMUP的活性有所提高。此外,突变体中001F舢。阳对顺式氰戊菊酯的活性与突变前接近,而001G心蹦。则降低到突变前的1/2,其它突变体未检测到活性。结果表明,酯酶001F和001G对杀虫剂有代谢活性,A127位和F238位的突变对酶活性有显著影响。%In order to understand the metabolic activities of esterases in Helicoverpa armigera toward organophosphorus (OPs) and pyrethroid insecticides, the catalytic activities of two esterases (001F and O01G) and their mutants (mutated at positions A127 and F238) toward three kinds of insecticides (i. e., dimethyl- and diethyl- phosphates (dMUP and dECP) and esfenvalerate (2S, aS) ) were measured with iluorometric and HPLC assays. The results showed the enzymatic constants (kcat) of 001F and 001 G for OPs were between 2.0 × 10-3/min and 5.2 ×10-3/min, and 001G also had some metabolic activities toward esfenvalerate (10.19 μmol · min -μmol-1). The mutants of 001 F showed enhanced activities for OPs, the kcat values of both O01FA127D and O01Fr23sL for dMUP (4.5 ×10-3/min and 6.1 ×10 -3/min respectively) were at least 2-fold higher than that of the wild

  14. Cry1Ac抗、感棉铃虫碱性磷酸酯酶(ALP1)的表达量比较%The Expression Level of Alkaline Phosphatase (ALP1) in Cry1Ac-Resistant and Susceptible Cotton Bollworm Helicoverpa armigera Hübner

    Institute of Scientific and Technical Information of China (English)

    张涛; 张丽丽; 魏纪珍; 肖玉涛; 梁革梅; 周瑞阳

    2013-01-01

    [目的]通过比较Cry1Ac抗、感棉铃虫昆虫中肠碱性磷酸酶(ALP1)表达量的差异及抗性棉铃虫取食Cry1Ac蛋白对ALP1表达量的影响,分析ALP1表达量变化与抗性的关系,为进一步明确Bt抗性机制、制定抗性治理策略提供理论依据.[方法]利用实时荧光定量PCR技术,比较敏感棉铃虫、Cry1Ac抗性棉铃虫取食含Cry1Ac蛋白的饲料和正常饲料后ALP1表达量的差异.[结果]ALP1在棉铃虫整个发育期都表达,幼虫的表达量最高,蛹期表达量最低,在成虫体内也有较高的表达;ALP1在幼虫中肠表达量最高,其次是后肠、前肠、马氏管,表皮中的表达量最低;与敏感品系相比,对Cry1Ac具有中等水平抗性的棉铃虫ALP1表达量明显增加,尤其是取食含Cry1Ac蛋白饲料的抗性棉铃虫幼虫的ALP1的表达量显著升高,但抗性棉铃虫取食正常饲料后,2、3龄幼虫的ALP1的表达量与敏感棉铃虫差异不显著;所有的抗性品系4龄棉铃虫幼虫中肠ALP1的表达量都显著高于敏感品系,而且随着棉铃虫抗性倍数的升高,ALP1的表达量呈逐渐降低的趋势.[结论]抗性棉铃虫中肠ALP1表达量的改变可能与Cry1Ac抗性、Cry1Ac代谢有一定的关系.%[Objective] The objective of this study is to provide a theoretical basis for further clarifying Cry1Ac resistance mechanism and constituting reasonable resistance management strategy,the difference of ALP1 expression level between Cry1Ac-resistant and susceptible Helicoverpa armigera,the effect of Cry1Ac toxin on ALP1 expression level in Cry1Ac-resistant larvae and the relationship between ALP 1 and Cry 1 Ac-resistant strains were analyzed.[Method] The expression levels of ALP1 in susceptible and Cry1Ac-resistant H.armigera larvae feeding on artificial diet containing Cry1Ac and no-Cry1Ac were compared using real-time quantitative PCR analysis.[Result] The ALP1 could express in whole development period ofH.armigera,the highest expression level

  15. 一株粘质沙雷氏菌对蔬菜常见害虫毒力的研究%Study on the Toxicity of Serratia marcesens to the Common Vegetable Insects

    Institute of Scientific and Technical Information of China (English)

    陈秀为; 范寰; 周可; 兰洪霞; 孙伯芝

    2005-01-01

    从棉田中自然死亡的棉铃虫体上分离得到一株昆虫致病菌,经鉴定为肠杆菌科沙雷氏菌属粘质沙雷氏菌(Serratia marcescens).实验证明该菌对烟青虫(Heliothis assulta)、菜青虫(Pieris rapae)、棉铃虫(Helicoverpa armigera)、小菜蛾(Plutella xylostella)等蔬菜上常见的鳞翅目害虫具有一定的毒力作用.该昆虫致病菌对目标昆虫的毒力主要表现在造成昆虫停食、行动迟缓、对刺激反应迟钝、幼虫生长期缩短、提前化蛹、不能正常羽化等方面.

  16. Ace2, rather than ace1, is the major acetylcholinesterase in the silkworm, Bombyx moil

    Institute of Scientific and Technical Information of China (English)

    Hui-Juan Chen; Zhen Liao; Xiao-Ming Hui; Guo-Qing Li; Fei Li; Zhao-Jun Han

    2009-01-01

    Two acetylcholinesterase (ace) genes have been reported in many insect species. In pests such as Helicoverpa assulta and Plutella xylostellas, acel gene encodes the predominant synaptic enzyme that is the main target of organophosphorus (OP) and carbamate pesticides. It has been reported that pesticide selection has an impact on the ace gene evolution. The domesticated silkworm, Bombyx mori, also has two ace genes. We studied ace gene expression and enzyme activities in silkworm as this has not faced pesticide selection over the past decades. The expression levels of two ace genes, Bm-acel and Bin-ace2, were estimated by quantitative real-time polymerase chain reaction. Bm-ace2 was expressed more highly than Bm-acel in all tested samples of different developmental stages or tissues, suggesting ace2, rather than ace 1, is the major type of acetylcholinesterase (ACHE) in Bombyx mori. This is inconsistent with the aforementioned lepidopterons agricultural pests, partly be due to the widespread use of pesticides that may induce high expression of the acel gene in these pests. Besides high expression in the head, Bm-acel also expresses highly in the silk glands and Bm-ace2 is abundant in the germline, implying both ace genes may have potential non-hydrolytic roles in development. Furthermore, we found that the m_RNA levels of two ace genes and their ratios (ace2/ace1) change day to day in the first and third instars. This challenges the conventional method of estimating enzymatic activity using crude extract as an enzyme solution, as it is a mixture of ACHE1 and ACHE2. An efficient and simple method for separating different ACHEs is necessary for reliable toxicological analyses.

  17. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth

    Directory of Open Access Journals (Sweden)

    Xin-Cheng eZhao

    2014-10-01

    Full Text Available In the primary olfactory centre of the moth brain, for example, a few enlarged glomeruli situated dorsally, at the entrance of the antennal nerve, are devoted to information about female-produced substances whereas a set of more numerous ordinary glomeruli receives input about general odorants. Heliothine moths are particularly suitable for studying central chemosensory mechanisms not only because of their anatomically separated systems for plant odours and pheromones but also due to their use of female-produced substances in communication across the species. Thus, the male-specific system of heliothine moths includes two sub arrangements, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecifics, and the other reproductive isolation via signal information emitted from heterospecifics. Based on previous tracing experiments, a general chemotopic organization of the male-specific glomeruli has been demonstrated in a number of heliothine species. As compared to the well explored organization of the moth antennal lobe, demonstrating a non-overlapping representation of the biologically relevant stimuli, less is known about the neural arrangement residing at the following synaptic level, i.e. the mushroom body calyces and the lateral horn. In the study presented here, we have labelled physiologically characterized antennal-lobe projection neurons in males of the two heliothine species, Heliothis virescens and Helicoverpa assulta, for the purpose of mapping their target regions in the protocerebrum. In order to compare the representation of plant odours, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models of distinct uniglomerular projection neuron types into the relevant atlas.

  18. Examination of the biological effects of high anionic peroxidase production in tobacco plants grown under field conditions. I. Insect pest damage.

    Science.gov (United States)

    Dowd, Patrick F; Lagrimini, L Mark

    2006-04-01

    At least 25 wild type and high peroxidase tobacco Nicotiana tabacum L. plants were examined semiweekly over several weeks for pest insect distribution and damage in a 2 year field study. Incidence and/or severity of naturally occurring caterpillar damage (dingy cutworm (Feltia ducens Walker), black cutworm (Agrotis ipsilon (Hufnagel), tobacco hornworm (Manduca sexta L.), and false tobacco budworm (= corn earworm Helicoverpa zea (Boddie)) was significantly reduced at several sample dates for high peroxidase vs. wild type plants. These results parallel those of prior laboratory studies with caterpillars. The number of adult whiteflies (Trialeurodes vaporariorum (Westwood) per plant was significantly reduced on high peroxidase compared to wild type plants on most sample dates in both years. The number of plants with leaves containing >100 aphids (primarily Myzus persicae Sulzer) per leaf on high peroxidase plants was significantly lower that on wild type plants after an equivalent invasion period in both years. A significantly higher proportion of aphids were found dead on leaf five of high peroxidase compared to wild type plants at most sample dates in both years. These results indicate that high peroxidase plants have resistance to a wide range of insects, implicating this enzyme as a broad range resistance mechanism.

  19. Vip3A, a novel Bacillus thuringiensis vegetative insecticidal protein with a wide spectrum of activities against lepidopteran insects.

    Science.gov (United States)

    Estruch, J J; Warren, G W; Mullins, M A; Nye, G J; Craig, J A; Koziel, M G

    1996-05-28

    A novel vegetative insecticidal gene, vip3A(a), whose gene product shows activity against lepidopteran insect larvae including black cutworm (Agrotis ipsilon), fall armyworm (Spodoptera frugiperda), beet armyworm (Spodoptera exigua), tobacco budworm (Heliothis virescens), and corn earworm (Helicoverpa zea) has been isolated from Bacillus thuringiensis strain AB88. VIP3-insecticidal gene homologues have been detected in approximately 15% of Bacillus strains analyzed. The sequence of the vip3A(b) gene, a homologue of vip3A(a) isolated from B. thuringiensis strain AB424 is also reported. Vip3A(a) and (b) proteins confer upon Escherichia coli insecticidal activity against the lepidopteran insect larvae mentioned above. The sequence of the gene predicts a 791-amino acid (88.5 kDa) protein that contains no homology with known proteins. Vip3A insecticidal proteins are secreted without N-terminal processing. Unlike the B. thuringiensis 5-endotoxins, whose expression is restricted to sporulation, Vip3A insecticidal proteins are expressed in the vegetative stage of growth starting at mid-log phase as well as during sporulation. Vip3A represents a novel class of proteins insecticidal to lepidopteran insect larvae.

  20. Insect resistance management for Syngenta's VipCot transgenic cotton.

    Science.gov (United States)

    Kurtz, Ryan W; McCaffery, Alan; O'Reilly, David

    2007-07-01

    Syngenta is seeking commercial registration for VipCot cotton, a pyramided transgenic cotton trait that expresses two insecticidal proteins derived from Bacillus thuringiensis Vip3A and Cry1Ab. Both proteins are highly effective against two key cotton pests, Helicoverpa zea cotton bollworm; and Heliothis virescens, tobacco budworm. To investigate the role of VipCot cotton in delaying the development of resistance in these pests to transgenic Bt traits, Syngenta has performed studies to determine the dose of proteins expressed in VipCot and evaluate the potential for cross-resistance between the component proteins. Following United States Environmental Protection Agency (US EPA) high dose methods 1 and 4, VipCot was shown to express a high dose of proteins for H. zea and H. virescens. VipCot was also confirmed to express a high dose of proteins for H. zea through US EPA Method 5. Additionally, all the data collected to date verify a lack of cross-resistance between Vip3A and Cry proteins. These two key pieces of information indicate that VipCot cotton should be very durable under the currently mandated high dose plus refuge insect resistance management strategy.

  1. Discovery of an unusual biosynthetic origin for circular proteins in legumes.

    Science.gov (United States)

    Poth, Aaron G; Colgrave, Michelle L; Lyons, Russell E; Daly, Norelle L; Craik, David J

    2011-06-21

    Cyclotides are plant-derived proteins that have a unique cyclic cystine knot topology and are remarkably stable. Their natural function is host defense, but they have a diverse range of pharmaceutically important activities, including uterotonic activity and anti-HIV activity, and have also attracted recent interest as templates in drug design. Here we report an unusual biosynthetic origin of a precursor protein of a cyclotide from the butterfly pea, Clitoria ternatea, a representative member of the Fabaceae plant family. Unlike all previously reported cyclotides, the domain corresponding to the mature cyclotide from this Fabaceae plant is embedded within an albumin precursor protein. We confirmed the expression and correct processing of the cyclotide encoded by the Cter M precursor gene transcript following extraction from C. ternatea leaf and sequencing by tandem mass spectrometry. The sequence was verified by direct chemical synthesis and the peptide was found to adopt a classic knotted cyclotide fold as determined by NMR spectroscopy. Seven additional cyclotide sequences were also identified from C. ternatea leaf and flower, five of which were unique. Cter M displayed insecticidal activity against the cotton budworm Helicoverpa armigera and bound to phospholipid membranes, suggesting its activity is modulated by membrane disruption. The Fabaceae is the third largest family of flowering plants and many Fabaceous plants are of huge significance for human nutrition. Knowledge of Fabaceae cyclotide gene transcripts should enable the production of modified cyclotides in crop plants for a variety of agricultural or pharmaceutical applications, including plant-produced designer peptide drugs.

  2. A seed mixture increases dominance of resistance to Bt cotton in Helicoverpa zea

    OpenAIRE

    2015-01-01

    Widely grown transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) can benefit agriculture, but adaptation by pests threatens their continued success. Refuges of host plants that do not make Bt toxins can promote survival of susceptible insects and delay evolution of resistance, particularly if resistance is inherited as a recessive trait. However, data have been lacking to compare the dominance of resistance when Bt and non-Bt seeds are planted in random mixtures ...

  3. Function, oligomerization and N-linked glycosylation of the Helicoverpa armigera single nucleopolyhedrovirus envelope fusion protein

    NARCIS (Netherlands)

    Long, G.; Westenberg, M.; Wang, H.; Vlak, J.M.; Hu, Z.

    2006-01-01

    In the family Baculoviridae, two distinct envelope fusion proteins are identified in budded virions (BVs). GP64 is the major envelope fusion protein of group I nucleopolyhedrovirus (NPV) BVs. An unrelated type of envelope fusion protein, named F, is encoded by group II NPVs. The genome of Helicoverp

  4. The effect of Gossypolone on the growth and development of Helicoverpa zea (Boddie)

    Science.gov (United States)

    The pigment glands of the cotton plant (Gossypium) produce a group of structurally related terpenoid aldehydes that protect the plant from herbivorous insects. Of these terpenoids, the most extensively studied is gossypol. Gossypolone, a compound closely related to gossypol, has been reported in t...

  5. Effect of gossypolone on the growth and development of helicoverpa zea

    Science.gov (United States)

    The pigment glands of the cotton plant (Gossypium) produce terpenoid aldehydes that protect the plant from herbivorous insects. Of these terpenoids, the most extensively studied is gossypol. Gossypolone, a compound closely related to gossypol, has been reported in these pigment glands but its activ...

  6. Histopathological Effects of the Protein Toxin from Xenorhabdus nematophila on the Midgut of Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    NANGONG Zi-yan; WANG Qin-ying; SONG Ping; YANG Jun; MAO Wen-jie

    2006-01-01

    Xenorhabdus nematophila HB310, which is highly virulent for many insects, is symbiotic with Steinernema carpocapsae HB310. Toxin Ⅱ was obtained using methods such as salting out and native-PAGE from the cells of X. Nematophila HB310. The histopathology of toxin Ⅱ on H. Armigera larvae was studied by dissecting an olefin slice of the midgut. The symptoms showed that the histopathology of the H. Armigera midgut was similar to that of other novel midgut-active toxins such as the δ-endotoxins from Bacillus thuringiensis, as well as Tca from Photorhabdus luminescens W14. The midgut tissues of H. Armigera fourth-instar larvae began to transform after the oral intake of the toxin Ⅱ over 6 h. First, the anterior region of the peritrophic membrane (PM) began to degrade followed by the elongation of the columnar cells.The epithelium decomposed gradually, and the midgut tissues were either loose or disordered. The PM disappeared after 12 h but reappeared after 72 h following transient or sublethal exposure to the toxin Ⅱ. Toxin Ⅱ also directly destroyed in vitro PMs of H. Armigera.

  7. Identification of genes differentially expressed during larval molting and metamorphosis of Helicoverpa armigera

    Directory of Open Access Journals (Sweden)

    Jiang Xiao-Juan

    2007-06-01

    Full Text Available Abstract Background Larval molting and metamorphosis are important physiological processes in the life cycle of the holometabolous insect. We used suppression subtractive hybridization (SSH to identify genes differentially expressed during larval molting and metamorphosis. Results We performed SSH between tissues from a variety of developmental stages, including molting 5th and feeding 6th instar larvae, metamorphically committed and feeding 5th instar larvae, and feeding 5th instar and metamorphically committed larvae. One hundred expressed sequence tags (ESTs were identified and included 73 putative genes with similarity to known genes, and 27 unknown ESTs. SSH results were further characterized by dot blot, Northern blot, and RT-PCR. The expression levels of eleven genes were found to change during larval molting or metamorphosis, suggesting a functional role during these processes. Conclusion These results provide a new set of genes expressed specifically during larval molt or metamorphosis that are candidates for further studies into the regulatory mechanisms of those stage-specific genes during larval molt and metamorphosis

  8. Sustainable Control of Helicoverpa armigera%棉铃虫的可持续治理

    Institute of Scientific and Technical Information of China (English)

    李明福; 马呈瑞; 高汉红; 廖少龙; 张琴; 郭少波

    2005-01-01

    根据湖北棉区的生态环境条件和棉铃虫发生特点,提出了现阶段棉铃虫可持续控制策略为:立足当前、放眼长远,以促进生态平衡为根本点,从农业和栽培措施入手,控制棉铃虫种群数量,实施有效的综合防治措施,控制棉铃虫危害.

  9. Interaction of proteinase inhibitors with Cry1Ac toxicity and presence of fifteen chymotrypsin cDNAs in midgut of the tobacco budworm Heliothis virescens (F.) (Lepidoptera: noctuidae)

    Science.gov (United States)

    Extensive adoption of Bt cotton places heavy selection pressure on lepidopteran insects. The potential development of Bt resistance is a major risk in the durability of Bt plant technology. Another concern is the surging of non-lepidopteran pests not controlled by Bt toxins. Intensive cloning and se...

  10. Cloning eleven midgut trypsin cDNAs and evaluating the interaction of proteinase inhibitors with Cry1Ac against the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Midgut trypsins are associated with Bt protoxin activation and toxin degradation. Proteinase inhibitors have potential insecticidal toxicity against a wide range of insect species. Proactive action to examine trypsin gene profiles and proteinase inhibitors for interaction with Bt toxin is necessary ...

  11. Comparative insecticidal properties of two nucleopolyhedrovirus vectors encoding a similar toxin gene chimer.

    Science.gov (United States)

    Treacy, M F; Rensner, P E; All, J N

    2000-08-01

    Laboratory, greenhouse and field studies were conducted to characterize the insecticidal properties of genetically altered forms of Autographa californica (Speyer) nucleopolyhedrovirus (AcNPV) and Helicoverpa zea (Boddie) NPV (HzNPV) against selected heliothine species. The altered viruses each contained a chimeric 0.8-kb fragment encoding the insect-specific, sodium channel neurotoxin from the Algerian scorpion Androctonus australis Hector (AaIT, hence recombinant viruses designated Ac-AaIT and Hz-AaIT). Based on LD50 values, results from diet-overlay bioassays showed Ac-AaIT and Hz-AaIT to be equally virulent against larval tobacco budworm, Heliothis virescens (F.), but Hz-AaIT averaged 1,335-fold greater bioactivity than Ac-AaIT against larval cotton bollworm, Helicoverpa zea (Boddie). Hz-AaIT killed larvae of both heliothine species at rates significantly faster than those imparted by HzNPV (viral LT50 values averaged 2.5 and 5.6 d, respectively). In greenhouse studies, foliar sprays of Ac-AaIT and Hz-AaIT were equally effective in controlling H. virescens on cotton; however, Hz-AaIT provided control of H. zea on cotton at a level superior to that of Ac-AaIT. For example, after three weekly sessions of foliar application and H. zea artificial infestation, cotton treated with Ac-AaIT or Hz-AaIT at 10 x 10(11) occulsion bodies (OB)/ha averaged 2.5 and 16.2 nondamaged flower buds per plant, respectively. Another greenhouse study conducted against heliothine species on cotton showed that the quicker killing speed exhibited by Hz-AaIT led to improved plant protection versus HzNPV. Finally, results from three field trials demonstrated that Hz-AaIT at 5-12 x 10(11) OB/ha provided control of the heliothine complex in cotton at levels slightly better than Bacillus thuringiensis, equal to the macrolide, spinosad, and only slightly less than that of selected pyrethroid and carbamate insecticides. Overall, results from these studies indicate that, because of host range

  12. Pinellia ternata agglutinin expression in chloroplasts confers broad spectrum resistance against aphid, whitefly, Lepidopteran insects, bacterial and viral pathogens.

    Science.gov (United States)

    Jin, Shuangxia; Zhang, Xianlong; Daniell, Henry

    2012-04-01

    Broad spectrum protection against different insects and pathogens requires multigene engineering. However, such broad spectrum protection against biotic stress is provided by a single protein in some medicinal plants. Therefore, tobacco chloroplasts were transformed with the agglutinin gene from Pinellia ternata (pta), a widely cultivated Chinese medicinal herb. Pinellia ternata agglutinin (PTA) was expressed up to 9.2% of total soluble protein in mature leaves. Purified PTA showed similar hemagglutination activity as snowdrop lectin. Artificial diet with purified PTA from transplastomic plants showed marked and broad insecticidal activity. In planta bioassays conducted with T0 or T1 generation PTA lines showed that the growth of aphid Myzus persicae (Sulzer) was reduced by 89%-92% when compared with untransformed (UT) plants. Similarly, the larval survival and total population of whitefly (Bemisia tabaci) on transplastomic lines were reduced by 91%-93% when compared with UT plants. This is indeed the first report of lectin controlling whitefly infestation. When transplastomic PTA leaves were fed to corn earworm (Helicoverpa zea), tobacco budworm (Heliothis virescens) or the beet armyworm (spodoptera exigua), 100% mortality was observed against all these three insects. In planta bioassays revealed Erwinia population to be 10,000-fold higher in control than in PTA lines. Similar results were observed with tobacco mosaic virus (TMV) challenge. Therefore, broad spectrum resistance to homopteran (sap-sucking), Lepidopteran insects as well as anti-bacterial or anti-viral activity observed in PTA lines provides a new option to engineer protection against biotic stress by hyper-expression of an unique protein that is naturally present in a medicinal plant.

  13. Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

    Science.gov (United States)

    Griffin, T W; Zapata, S D

    2016-08-01

    The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the

  14. RNA Interference of the PBAN/Pyrokinin Gene: Impact on Ant, Solenopsis invicta, and Moth, Helicoverpa zea, Development

    Science.gov (United States)

    Recently, an emerging RNA interference (RNAi) technology has shown high potential for development of novel biologically-based control agents as alternatives to insecticides. This represents a paradigm shift that will avoid many problems associated with conventional insecticides. Insect neuropeptide ...

  15. Field test of 22% Lambda -cyhalothrin & Thiamethoxam CS on controlling Heliothis assulta and Myzus persicae%22%高效氯氟氰菊酯·噻虫嗪微囊悬浮剂防治烟草烟青虫和蚜虫田间药效试验

    Institute of Scientific and Technical Information of China (English)

    陶开泉

    2013-01-01

    田间小区试验结果表明,22%高效氯氟氰菊酯·噻虫嗪微囊悬浮剂666.7m2用8.42~ 11.23 g的处理,对烟草烟青虫的防效为88.74%~94.59%,对烟草蚜虫的防效为89.54%~94.55%,能较好控制两种害虫的危害.

  16. Preliminary study on the prevention effect of five insecti cides on tobacco budworm%5种杀虫剂的烟青虫防治效果研究

    Institute of Scientific and Technical Information of China (English)

    王少丽; 杨明国; 王忠田; 张素方

    2000-01-01

    5种杀虫剂对烟青虫的毒力试验表明:质量分数为80%~83% 的高效氯氰菊酯和86.7%的氰戊菊酯分别稀释2 000和1 000倍对烟青虫的防治效果较好,LC 50 分别为0.032 2 μg·头-1和0.058 2 μg·头-1,久效磷和乙酰甲胺磷稀释1 000倍的效果次之,吡虫啉效果最差.

  17. Ocorrência da lagarta-da-maçã-do-algodoeiro em frutos de tomateiro no estado do Espírito Santo Occurrence of tobacco budworm in tomato fruits in the Espírito Santo State, Brazil

    Directory of Open Access Journals (Sweden)

    Dirceu Pratissoli

    2006-06-01

    Full Text Available Ovos e lagartas de Heliothis virescens (Fabricius (Lepidoptera: Noctuidae foram encontrados em frutos de tomateiro da cultivar Santa Clara, em um plantio localizado em área experimental, em Alegre-ES. Essa infestação proporcionou dano de cerca de 10%, caracterizado por perfurações de tamanhos variados na polpa de frutos com diâmetros superiores a 2 cm, variando de acordo com o estádio de desenvolvimento das lagartas. Ovos foram coletados e levados ao laboratório, onde foram mantidos à temperatura de 25±3ºC e 70±10% de umidade relativa até a eclosão. As lagartas recém-eclodidas foram individualizadas em caixa gerbox e alimentadas em fatias de frutos de tomate, onde permaneceram até a fase de pupa para sua identificação. Este é o primeiro relato da ocorrência de Heliothis virescens em frutos de tomate no Brasil.Eggs and caterpillars of the Heliothis virescens (Fabricius, 1781 (Lepidoptera: Noctuidae were found in tomato fruits of cv. Santa Clara, in a plantation located in Alegre, Espirito Santo State, Brazil. The attack caused damage in 10% of fruits characterized by different perforation sizes in the pulp of the fruits with diameters of two or more centimeters, depending on the state of development of the caterpillars. Eggs were collected, taken to the laboratory, and kept at 25±3ºC and 70±10% of relative humidity until the larval phase. The caterpillars were individually kept in gerboxes and fed with tomato slices until the pupa phase for identification. This is the first report of the occurrence of Heliothis virescens in tomato fruits in Brazil.

  18. Purification of Vip3Aa from Bacillus thuringiensis HD-1 and its contribution to toxicity of HD-1 to spruce budworm (Choristoneura fumiferana) and gypsy moth (Lymantria dispar) (Lepidoptera).

    Science.gov (United States)

    Milne, Ross; Liu, Yuehong; Gauthier, Debbie; van Frankenhuyzen, Kees

    2008-10-01

    We developed a protocol for obtaining high yields (10-15 mg per 1100 ml of culture supernatant) of highly purified (up to 95%) Vip3Aa protein from HD-1 cultures. The protocol is based on acetone precipitation of supernatant protein, followed by HPLC fractionation (DEAE-5PW column) and several concentration steps. Our protocol resulted in higher yields and purity of Vip3Aa than a previously published method [Estruch, J.J., Warren, G.W., Mullins, M.A., Nye, G.J., Craig, J.A., Koziel, M.G., 1996. Vip3A, a 353 novel Bacillus thuringiensis vegetative insecticidal protein with a wide spectrum of 354 activities against lepidopteran insects. Proc. Nat. Acad. Sci. USA 93, 5389-5394.]. This was achieved by using acetone rather than ammonium sulfate for precipitation of proteins from culture supernatants, and a shallow rather than a steep NaCl gradient for elution of the toxin, and by conducting all the purification steps at low temperature to prevent toxin degradation. In bioassays of the purified protein, Choristoneura fumiferana and Lymantria dispar larvae were less susceptible than Spodopteraexigua (10- and approximately 100-fold, respectively). A B. thuringiensis var. kurstaki strain HD-1 from which the vip3Aa gene had been deleted (EG12414) showed reduced toxicity to S. exigua relative to the unmodified parental strain (EG2001), but not to L. dispar or C. fumiferana. We interpret these results as indicating that the Vip3Aa toxin does not contribute measurably to pathogenicity of HD-1 in these species.

  19. Highlights of forest pest conditions in the maritimes at the end of July, 1993. Technical note No. 286. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.E.

    1993-01-01

    This note describes forest pest conditions in the Maritimes at the end of July, 1993. It discusses diseases and pests found including forest tent caterpiller, gypsy moth, fall webworm, spruce budworm, and wind damage. Others include eastern blackheaded budworm, elm leafroller, alder flea beetle, birch leafminers, oak olethreutid leafroller, yellowheaded spruce sawfly, and spruce spider mite.

  20. Tissue-specific expression of glutathione S-transferases induced by 2-tridecanone or quercetin in cotton bollworms, Helicoverpa armigera (Hübner)

    Institute of Scientific and Technical Information of China (English)

    TANG Fang; LIANG Pei; GAO Xiwu

    2005-01-01

    The tissue-specific expression of glutathione S-transferases (GSTs) in the cotton bollworm and the expression level induced by 2-tridecanone and quercetin were examined using the methods of biochemistry and the quantitative PCR. The relative expression level of GST mRNA was unanimous with the GSTs activity conjugaging with 1-chloro-2, 4-dimitro-benzene (CDNB) in fat bodies,midguts, heads and integuments of cotton bollworms. The GSTs activity in fat bodies was the highest, then midguts, heads and integuments in turn, which was in consistent with the relative expression level of GST mRNA. The specific activity of GSTs and the relative expression level of GST mRNA could be significantly induced by 2-tridecanone and quercetin, and after the induction the order of the GSTs activity and the relative expression level of GST mRNA in the above four tissues in cotton bollworms was not different from the control.The induction of GSTs by 2-tridecanone was stronger than by quercetin in all four tissues, which was in accordance with the relative expression level of GST mRNA. It suggested that the increase of GSTs activity induced by plant allelochemicals was associated with the elevated expression of GST mRNA in cotton bollworms.

  1. Response of the digestive system of Helicoverpa zea to ingestion of potato carboxypeptidase inhibitor and characterization of an uninhibited carboxypepidase B

    NARCIS (Netherlands)

    Bayes, A.; Rodrigues de la Vega, M.; Vendrell, J.; Aviles, F.X.; Jongsma, M.A.; Beekwilder, M.J.

    2006-01-01

    Carboxypeptidase activity participates in the protein digestion process in the gut of lepidopteran insects, supplying free amino-acids to developing larvae. To study the role of different carboxypeptidases in lepidopteran protein digestion, the effect of potato carboxypeptidase inhibitor (PCI) on th

  2. Increased Helicoverpa zea (Boddie) larval feeding on a RNAi construct CYP82D109 that blocks gossypol-related terpenoid synthesis in cotton plants

    Science.gov (United States)

    Glandled cotton plants, Gossypium hirsutum L., have long been known to be more resistant to insect pests compared to their glandless counterparts. This resistance has been mainly attributed to the presence of terpenoid aldehydes such as gossypol, hemigossypolone, and heliocides in the glands. We p...

  3. Effect of pyramiding Bt and CpTI genes on resistance of cotton to Helicoverpa armigera (Lepidoptera: Noctuidae) under laboratory and field conditions

    NARCIS (Netherlands)

    Cui, J.J.; Luo, J.Y.; Werf, van der W.; Ma, Y.; Xia, J.Y.

    2011-01-01

    Transgenic cotton (Gossypium hirsutum L.) varieties, adapted to China, have been bred that express two genes for resistance to insects. the Cry1Ac gene from Bacillus thuringiensis (Berliner) (Bt), and a trypsin inhibitor gene from cowpea (CpTI). Effectiveness of the double gene modification in confe

  4. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding

    OpenAIRE

    Maissa Chakroun; Núria Banyuls; Tom Walsh; Sharon Downes; Bill James; Juan Ferré

    2016-01-01

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past...

  5. Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding.

    Science.gov (United States)

    Chakroun, Maissa; Banyuls, Núria; Walsh, Tom; Downes, Sharon; James, Bill; Ferré, Juan

    2016-04-20

    Crops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relatively frequent. Vip3Aa-resistance does not confer cross-resistance to Cry1Ac or Cry2Ab. Vip3Aa was labeled with (125)I and used to show specific binding to H. armigera brush-border membrane vesicles (BBMV). Binding was of high affinity (Kd = 25 and 19 nM for susceptible and resistant insects, respectively) and the concentration of binding sites was high (Rt = 140 pmol/mg for both). Despite the narrow-spectrum resistance, binding of (125)I-labeled Vip3Aa to BBMV of resistant and susceptible insects was not significantly different. Proteolytic conversion of Vip3Aa protoxin into the activated toxin rendered the same products, though it was significantly slower in resistant insects.

  6. Specific binding  of Bacillus thuringiensis Cry2A insecticidal proteins to a common site in the midgut of Helicoverpa species

    OpenAIRE

    Hernández Rodríguez, Carmen Sara; van Vliet, A.; Bautsoens, Nadine; Van Rie, Jeroen; Ferré Manzanero, Juan

    2008-01-01

    For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with 125 I-labeled Cry2Ab. Saturation assays showed tha...

  7. Maize silk antibiotic polyphenol compounds and molecular genetic improvement of resistance to corn earworm (Helicoverpa zea Boddie in sh2 sweet corn

    Directory of Open Access Journals (Sweden)

    Baozhu Guo

    2010-01-01

    Full Text Available The flavor of sh2 super-sweet corn is preferred by consumers. Unfortunately, sh2 sweet corn has little genetic variation for insect resistance. In this paper we review the functions of two loci, p1 and a1. The P1 allele has a major role in sh2 sweet corn resistance to corn earworm, an allele that was lost in historical selection because of its pleiotropic effect on undesirable cob color and silk browning. The P1 allele has significant effects on biosyntheses of silk antibiotic compounds, maysin, apimaysin, methoxymaysin, and chlorogenic acid. The effect of a1 shows gene action for lowered maysin and significant epistatic action with p1. The dominant functional allele A1 causes anthocyanin pigments in aleurone, plant, and pericarp tissues; the recessive a1 allele causes absence of pigment in these tissues. If silk browning and cob color are critical factors for maysin production but lack the customer’s preference, then separating red cob and browning silk, which are controlled by the P1 allele, may be difficult if not impossible. One high silk maysin sh2 sweet corn germ­plasm, shrunken Zapalote Chico, has been released. There is some field corn germplasm with p1-wwr alleles, but the amount of antibiotic flavones and their potential as a donor need further investigation.

  8. 76 FR 55268 - Chromobacterium subtsugae Strain PRAA4-1T

    Science.gov (United States)

    2011-09-07

    ... exigua), cabbage looper (Trichoplusia ni), tobacco budworm (Heliothis virescens), diamondback moth... eventual human consumption (e.g., through spray drift or runoff) and directed to wastewater treatment... about consumption patterns among infants and children, special susceptibility of infants and children...

  9. 7 CFR 319.56-49 - Eggplant from Israel.

    Science.gov (United States)

    2010-01-01

    ... introduction of the following quarantine pests: Ceratitis capitata, Eutetranychus orientalis, Helicoverpa..., Ceratitis capitata) is required both inside and outside the pest-exclusionary structures. Trapping...

  10. Response of last instar Helicoverpa armigera larvae to Bt toxin ingestion: changes in the development and in the CYP6AE14, CYP6B2 and CYP9A12 gene expression.

    Directory of Open Access Journals (Sweden)

    Pilar Muñoz

    Full Text Available Bt crops are able to produce Cry proteins, which were originally present in Bacillus thuringiensis bacteria. Although Bt maize is very efficient against corn borers, Spanish crops are also attacked by the earworm H. armigera, which is less susceptible to Bt maize. Many mechanisms could be involved in this low susceptibility to the toxin, including the insect's metabolic resistance to toxins due to cytochrome P450 monooxygenases. This paper examines the response of last instar H. armigera larvae to feeding on a diet with Bt and non-Bt maize leaves in larval development and in the gene expression of three P450 cytochromes: CYP6AE14, CYP6B2 and CYP9A12. Larvae fed on sublethal amounts of the Bt toxin showed reduced food ingestion and reduced growth and weight, preventing most of them from achieving the critical weight and pupating; additionally, after feeding for one day on the Bt diet the larvae showed a slight increase in juvenile hormone II in the hemolymp. Larvae fed on the non-Bt diet showed the highest CYP6AE14, CYP6B2 and CYP9A12 expression one day after feeding on the non-Bt diet, and just two days later the expression decreased abruptly, a finding probably related to the developmental programme of the last instar. Moreover, although the response of P450 genes to plant allelochemicals and xenobiotics has been related in general to overexpression in the resistant insect, or induction of the genes when feeding takes place, the expression of the three genes studied was suppressed in the larvae feeding on the Bt toxin. The unexpected inhibitory effect of the Cry1Ab toxin in the P450 genes of H. armigera larvae should be thoroughly studied to determine whether this response is somehow related to the low susceptibility of the species to the Bt toxin.

  11. Preliminary survey on the pesticide resistance of Chinese cotton  29 to helicoverpa armigera Hümber%中棉29对棉铃虫的抗性初步观察

    Institute of Scientific and Technical Information of China (English)

    王宣山

    2001-01-01

    通过用中棉29、苏棉15室内饲养2~4代棉铃虫,观察其发育状况,结合田间调查,初步明确了中棉29在苏北沿海棉区抗虫表现及棉田天敌消长动态,据此提出了综合治理对策.

  12. 华北地区棉铃虫对Bt杀虫蛋白的抗性监测%Resistance Monitoring of Helicoverpa armigera (Hübner) to Bacillus thuringiensis Insecticidal Proteins in North China

    Institute of Scientific and Technical Information of China (English)

    卢美光; 赵建周; 范贤林; 芮昌辉; 魏岑; 梁桂梅

    2000-01-01

    采用Bt可湿性粉剂标样和含单一Bt杀虫蛋白Cry Ⅰ A(c)的MVPⅡ水剂,研究改进了棉铃虫对Bt杀虫蛋白的抗性测定方法.1996~1998年进行华北地区棉铃虫对Bt制剂的抗性监测,结果表明,河北省邱县、冀州市、山东省高密市、河南省西华县棉铃虫与敏感种群相比的抗性指数(RR)为1.3~5.3倍;用诊断剂量法测定,只在1998年检测到山东高密棉铃虫的抗性个体频率为0.9%,其余均为0.1998年测定棉铃虫对Cry Ⅰ A(c)敏感性,与室内种群相比,河北邱县、冀州和山东高密棉铃虫种群对Cry Ⅰ A(c)的相对RR值分别为4.9、3.9和3.8倍,对Bt粉剂的相对抗性指数(RR)分别为1.1、1.4和1.6倍;用转Bt基因棉叶直接测定,田间棉铃虫的死亡率降低,表明用Cry Ⅰ A(c)进行测定与用转Bt基因棉叶直接测定结果相关性较大.

  13. 三种转基因抗虫工程菌对棉铃虫的药效研究%Pesticide Effects of Three Bt-transgenic Bacteria on Helicoverpa armiqera ( Hubner )

    Institute of Scientific and Technical Information of China (English)

    冉隆珣

    2003-01-01

    通过对由中国农业大学提供的PT45,PT61,WH-1这3种转基因抗虫工程菌发酵液对棉铃虫的药效研究,结果表明:PT45,PT61,WH-1三种菌种对棉铃虫幼虫具有较好的毒杀和忌避作用.其中PT45杀虫效果较好,WH-1的杀虫效果较差.3种菌对棉铃虫幼虫的生长发育都有明显的抑制作用.

  14. 几种药剂对新疆南疆地区棉花棉铃虫的防效%Control Effect of Different Pesticides Against Helicoverpa armigera In Cotton in Southern Xinjiang

    Institute of Scientific and Technical Information of China (English)

    王剑; 王锁牢; 李号宾; 李广阔; 姚举; 王伟

    2010-01-01

    [目的]自20世纪90年代中期以来棉铃虫在新疆南疆棉区严重发生,给新疆棉花生产造成了一定的损失.生产上滥用农药现象严重,造成防治效果不稳定,棉铃虫抗药性增强.为了有效控制棉铃虫为害,降低棉铃虫产生抗药性的速度.[方法]试验选择几种类型、作用方式不同的化学药剂,于2007、2008年在新疆莎车县进行了防治棉铃虫的田间药效试验.试验采用随机区组排列,在棉田二代棉铃虫卵高峰期至低龄幼虫期采用棉田自然虫口基数的基础上接虫进行田间试验.[结果]45%丙溴磷·高效氯氰菊酯EC 540~675 g a.i./hm2、40%丙溴磷EC 540~600 g a.i./hm2、5%氟铃脲EC 75 g a.i./hm2、40%毒死蜱EC 720 g a.i./hm2和1.8%阿维菌素EC 18.9 g a.i./hm2等药剂在试验浓度下对棉花安全,优于35%硫丹EC和2.5%高效氯氟氰菊酯EW 2对照药剂的防效或与其效果相当.[结论]防治棉铃虫,可采用以上几种化学农药及用量在当地替代常用药剂或与其交替使用进行防治.

  15. 棉铃虫中肠Bt毒素受体蛋白(APN)的分离与纯化%Isolation and Purification of Aminopeptidase N (APNs), the Main Receptor Proteins for Bacillus thuringiensis toxin in Midgut of Helicoverpa armigera Larva

    Institute of Scientific and Technical Information of China (English)

    梁革梅; 徐广; 王桂荣; 吴孔明; 郭予元

    2005-01-01

    利用Mg/EGTA方法,以不同的速度进行离心,成功地分离了棉铃虫(Bacillus thuringiensis)中肠刷状缘膜囊泡(BBMV0,BBMV中保留了大部分氨肽酶N(aminopeptidase N,APN)活性,BBMV中APN的特异活性较粗匀浆液相比提高了3.29倍;CHAPS3-[(3-chlor-amidopropyl)dimethylammonio]-1-propane sulphonate可以增加BBMV的溶解,加入1%(CHAPS)之后APN特异活性增加至5.21倍;利用磷酸酰肌醇特异性的磷脂酶(PI-PLC)能将APN从膜上解离下来,BBMV经PI-PLC处理后,SDS-PAGE电泳结果仅有120 kD的1条带;Mono-Q和FPLC结合的方法可以纯化部分APN,SDS-PAGE电泳结果显示,经Mono-Q柱处理后的BBMV中分子量约100 kD的蛋白条带加粗;棉铃虫3个抗性品系与敏感品系相比,APN特异活性差异不显著,说明棉铃虫对Bt产生抗性与APN活性的变化无关,抗性的产生可能与Bt毒素和APN结合能力的改变有关.

  16. Influence of the Ingestion of Cry1Ac Toxin on Trypsin-Like Protease in Helicoverpa Armigera Midgut%喂食Cry1Ac毒素对棉铃虫中肠类胰蛋白酶的影响

    Institute of Scientific and Technical Information of China (English)

    袁灿; 夏立秋; 丁学知; 田野; 尹佳

    2009-01-01

    苏云金芽胞杆菌(Bacillus thuringiensis,Bt)在芽胞形成过程中产生的原毒素被敏感昆虫吞食进入消化道后,在中肠蛋白酶的作用下经历一系列酶的剪切活化过程,形成具有杀虫活性的毒性肽.类胰蛋白酶因其在昆虫中肠内蛋白质水解和Bt毒素活化中起着重要作用而受到广泛研究.本研究提取了棉铃虫4龄幼虫的中肠BBMV蛋白,利用SDS-PAGE分析鉴定到喂食Cry1Ac毒素24 h后,棉铃虫幼虫中肠类胰蛋白酶的表达量呈明显下降趋势.该下降趋势很有可能是作为一种昆虫对Bt毒素作用的早期反应,通过影响Bt毒素在中肠中的酶解活化过程,从而为昆虫提供即时保护.

  17. 一种新颖的棉铃虫单粒包埋核多角体病毒表达系统%A Novel Expression System of Helicoverpa armigera single-nucleocapsid nucleopolydrovirus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    将含有低拷贝数的mini-F replicon、一个卡那霉素抗性基因和一个lacZα基因8.6kb的DNA片段经同源重组置换到棉铃虫核型多角体病毒基因组中的多角体蛋白基因内,构建了既能在E.coli内复制又可在昆虫细胞内复制形成完整的病毒粒子棉铃虫核型多角体病毒Bacmid(HaBacmid-HZ8).另外将HaSNPV的多角体蛋白基因和P10启动子序列取代pFastBacDual质粒上的AcMNPV的多角体启动子序列和P10启动子序列,构建插入HaSNPV多角体蛋白基因和 P10启动子序列的HapFastBacPhP10供体质粒.利用HapFastBacPhP10供体质粒将eGFP基因转位至HZ8的Tn7附着位点上,随后将含有eGFP基因的重组HaBacmid DNA转染至HZAm1细胞内.转染5d后,细胞核内能形成典型的多角体,在萤光显微镜下观察到细胞内显示出强烈的绿色萤光.结果证明我们构建的HaBac to Bcac 表达系统能有效的表达外源基因.

  18. Forecasting of the occurring quantities of the fourth generation of Helicoverpa armigera in cotton fields in Jianghan plain%江汉平原棉区第四代棉铃虫发生量的预测

    Institute of Scientific and Technical Information of China (English)

    周柏龄

    2004-01-01

    运用相关分析,挑选与棉铃虫四代发生量相关性好、超前性好的4项前期气象、苗情因子,采用列联表方法,建立了江汉平原棉区第四代棉铃虫发生量的长期预测模型,经对38 a历史发生情况回测,准确率达89.5%,通过5 a试用,预报结果与实际相符.

  19. Preliminary Study on Insecticidal Activity of Transgenic Corn Expressing Bt Insecticidal Protein Gene to Helicoverpa armigera Hübner%转Bt基因抗虫玉米对棉铃虫杀虫活性的初步评价

    Institute of Scientific and Technical Information of China (English)

    芮昌辉; 范贤林; 孟香清; 董丰收

    2000-01-01

    @@ 国内外在转Bt基因抗虫作物的研究和应用上已取得重大进展,其中Bt抗虫棉已在美国、澳大利亚、中国等进入商品化应用阶段,近年来种植面积增长很快,并取得了显著的经济、生态 和社会效益.

  20. Can a fake fir tell the truth about Swiss needle cast?

    Science.gov (United States)

    A key question in dendrochronology to reconstruct forest disturbance history is how to distinguish between the effects of Swiss needle cast (SNC) and other forest disturbance agents (e.g., Douglas-fir beetle, tussock moth, western spruce budworm, laminated root rot, Armillaria ro...

  1. Dicty_cDB: VSD413 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available nit 5, partial cds, isolate:Locality No.6, Andrate, Torino, Piemonte, Italy. 46 0.13 1 AB047198 |AB047198.1 ..., Val Sesia, Varallo, Piemonte, Italy. 46 0.13 1 L17343 |L17343.1 Budworm mitocho

  2. Losing Chlordimeform Use in Cotton Production. Its Effects on the Economy and Pest Resistance. Agricultural Economic Report Number 587.

    Science.gov (United States)

    Osteen, Craig; Suguiyama, Luis

    This report examines the economic implications of losing chlordimeform use on cotton and considers chlordimeform's role in managing the resistance of bollworms and tobacco budworms to synthetic pyrethroids. It estimates changes in prices, production, acreage, consumer expenditures, aggregate producer returns, regional crop effects, and returns to…

  3. Insecticidal Activity of a Basement Membrane-Degrading Protease against Heliothis virescens (Fabricius) and Acyrthosiphon pisum (Harris)

    Science.gov (United States)

    ScathL is a cathepsin L-like cysteine protease derived from the flesh fly Sarcophaga peregrina that functions in basement membrane (BM) remodeling during insect development. A recombinant baculovirus expressing ScathL (AcMLF9.ScathL) kills larvae of the tobacco budworm, Heliothis virescens, signific...

  4. Lack of detrimental effects of Bacillus thuringiensis Cry toxins on the insect predator Chrysoperla carnea: a toxicological, histopathological, and biochemical analysis

    NARCIS (Netherlands)

    Rodrigo-Simón, A.; Maagd, de R.A.; Avilla, C.; Bakker, P.L.; Molthoff, J.W.; González-Zamora, J.; Ferré, J.

    2006-01-01

    The effect of Cry proteins of Bacillus thuringiensis on the green lacewing (Chrysoperla carnea) was studied by using a holistic approach which consisted of independent, complementary experimental strategies. Tritrophic experiments were performed, in which lacewing larvae were fed Helicoverpa armiger

  5. Fight plant pests using RNA interference

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ CAS plant physiologists have recently invented a plant-mediated RNA interference (RNAi) technique to effectively and specifically control the gene expression of the cotton bollworm (Helicoverpa armigera) and stunt its growth.

  6. 78 FR 25623 - Importation of Fresh Beans, Shelled or in Pods, From Jordan Into the Continental United States

    Science.gov (United States)

    2013-05-02

    ... risk Type Organism Taxonomy potential Arthropods Chrysodeixis chalcites (Esper). Lepidoptera: Noctuidae......... High Helicoverpa armigera Lepidoptera: Noctuidae......... High (H bner). Liriomyza huidobrensis Diptera... littoralis Lepidoptera: Noctuidae......... High (Boisduval). Lampides boeticus Linnaeus........

  7. Differential activity of multiple saponins against omnivorous insects with varying feeding preferences

    Science.gov (United States)

    A variety of saponin glycosides and aglycones from seven different plant families (Aquifoliaceae, Asparagaceae, Caryophyllaceae, Dioscoreaceae, Leguminosae, Rosaceae, Sapindaceae) were tested against the corn earworm, Helicoverpa zea, and the fall armyworm, Spodoptera frugiperda. The corn earworm fe...

  8. Holocene occurrence of Lophodermium piceae, a black spruce needle endophyte and possible paleoindicator of boreal forest health

    Science.gov (United States)

    Jasinski, J. P. Paul; Payette, Serge

    2007-01-01

    Holocene occurrences of conifer needle endophytes have not previously been reported. We report the fossil remains of Lophodermium piceae (Fckl.) Hoehn., a fungal endophyte of black spruce ( Picea mariana (Mill.) B.S.P.) needles, in macrofossils dating back to 8000 cal yr BP. Spruce budworm head capsules and L. piceae remains were found preceding charcoal layers delineating the transformation of four spruce-moss forest sites to spruce-lichen woodland. As L. piceae is found solely on senescent needles, its increased presence during these transformation periods likely indicates that the forests were in decline due to the spruce budworm ( Choristoneura fumiferana (Clem.)) when they burned. Future paleoecological studies incorporating needle fungi observations could be used to investigate the historical occurrence of tree disease and the role of fungi in forest health and decline.

  9. Forest insect- and disease-caused impacts to timber resources of west-central Canada, 1988-92. Information report No. -X-341

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, J.P.

    1995-12-31

    Describes the impacts caused by major forest insects (defoliators and bark beetles) and diseases (excluding those caused by fungi) to the timber resources of the Prairie Provinces and Northwest Territories in terms of wood volume losses due to tree mortality and growth reduction for the 1988-92 period. Most impacts were calculated using an automated system based on defoliation or infestation maps produced by geographic information systems and related inventory data. Results are presented for losses due to the following: Spruce budworm (Choristoneura fumiferana), jack pine budworm (C. pinus pinus), forest tent caterpillar (Malacosoma disstria), large aspen tortrix (C. conflictana), bruce spanworm (Operophtera bruceata), mountain pine beetle (Dendroctonus ponderosae), spruce beetle (D. rufipennis), Douglas-fir beetle (D. pseudotsugae), Lodgepole pine dwarf mistletoe (Arceuthobium americanum), and wood decay.

  10. Larval host types for the 3rd Helicoverpa armigera in Bt cotton field from North China determined by δ13C%应用稳定同位素技术分析华北部分地区第三代棉铃虫虫源性质

    Institute of Scientific and Technical Information of China (English)

    叶乐夫; 付雪; 谢宝瑜; 戈峰

    2011-01-01

    玉米等C4植物被认为是华北Bt棉种植区内第三代棉铃虫最重要的天然庇护所,但尚缺乏直接证据.连续2a(2006~2007年)利用杨树把诱集棉铃虫成虫,进行碳稳定同位素比值的测定,并结合棉铃虫成虫捕获时间、虫源的数量比例等,评估C4植物在华北第三代棉铃虫期间的庇护所功能.结果表明,第三代棉铃虫成虫来源于C4植物(玉米)的为40.5%-56·8%,与C3来源的数鼍上大体相当.但C4来源的成虫羽化时间比C3来源的个体明显滞后,呈现出先少后多的特点.结果提示,C4植物确实是华北第三代棉铃虫重要的庇护所,但存在着时间上与C3来源的成虫交配不同步而失效的风险;结果建议玉米等天然庇护所作物的种植不仅在面积上要足够,而且播种时间上要充分考虑C4植物(玉米)来源的敏感棉铃虫个体的发育与C3植物寄主来源个体的同步性.

  11. 苏云金芽孢杆菌Cry1Ac原毒素、毒素制备及其对棉铃虫的毒力测定%Preparation of Bacillus thuringiensis Cry1Ac protoxin, toxin and their toxicity to Helicoverpa armigera

    Institute of Scientific and Technical Information of China (English)

    余杰; 韦宏伟; 李香香; 畅红; 苏建亚

    2008-01-01

    对提取苏云金芽孢杆菌Cry1Ac原毒素与活化毒素的制备方法进行了改进,经牛胰蛋白酶作用后用等电点沉淀法和纯化法获得毒素.对样品进行SDS-PAGE分析,并测定其对棉铃虫初孵幼虫的毒力.结果表明制备的Cry1Ac原毒素和毒素降解较少,杀虫活性高.

  12. 玉米田四代棉铃虫老熟幼虫空间分布型应用%Spatial Distribution Pattern Application of Fourth-Generation Mature Larvae of Cotton Bollworm (Helicoverpa armigera Hübner) in Maize Field

    Institute of Scientific and Technical Information of China (English)

    李贺年; 齐巧丽; 李德新; 姚克荣

    2011-01-01

    [ Objective ] The paper was to study the spatial distribution pattern of fourth-generation mature larvae of cotton bollworm in maize field. [ Method] The plots with different occurrence densities of fourth-generation cotton bollworm were investigated during August to September in 2009. Six groups of sampling data were obtained, and seven indicators were used to determined its spatial distribution pattern. including aggregation index method, lwao method and Taylor method, etc. [ Result] Aggregation index test showed that in all plots, Moore I < 0,Lloyod m*/m < 1, Kuno Ca <0, diffusion coefficient C < 1, diffusion index Iδ < 1, negative binomial distribution K <0, indicating that mature larvae of cotton bollworm showed uniform distribution in summer maize. Iwao regression equation of fourth-generation mature larvae of cotton bollworm in summer maize was m * =0. 090 6 +0. 766 9m, r =0.986 3, indicating that the basic components of cotton bollworm distribution was single individual, and mature larvae of cotton bollworm in summer maize showed uniform distribution. The optimal sampling number of fourth-generation mature larvae of cotton bollwonn in maize under different population densities could be calculated using formula N1 =( 1. 090 6/m - 0. 233 1 )/D2. [ Conclusion ] The result provided basis for accurate evaluation of population quantities and variation law of cotton bollworm, as well as prediction and control of the pest.%[目的]研究玉米田四代棉铃虫老熟幼虫空间分布型.[方法]于2009年8~9月,对第4代棉铃虫不同发生密度地块进行调查,取得了6组样本资料,应用聚集度指标法、Iwao法和Taylor法等7种指标分析,对其空间分布型进行检验.[结果]聚集度指标的检验结果表明:所有样地Moore I<0,Lloyod m*/m<1,Kuno Ca<0,扩散系数C<1,扩散型指数 Iδ<1,负二项分布,K<0,表明棉铃虫老熟幼虫在夏玉米上均呈均匀分布.棉铃虫第4代老熟幼虫在夏玉米上的Iwao回归方程为m*=0.090 6+0.766 9m,r=0.986 3;说明棉铃虫分布的基本成分为单个个体,老熟幼虫在夏玉米上呈均匀分布.利用公式N1 =(1.090 6/m-0.233 1)/D2即可求出棉铃虫第4代老熟幼虫在玉米上不同密度下的最适抽样数.[结论]研究结果为准确佑值棉铃虫种群数量及变动规律,为预测及防治棉铃虫提供依据.

  13. Response of GST in the Cotton Bollworm (Helicoverpa armigera)to the Flavones Extracts and Terpenes Extracted from Artemisia rupestris%棉铃虫中肠谷胱甘肽S-转移酶(GST)对新疆一枝蒿黄酮提取物和萜类提取物的响应

    Institute of Scientific and Technical Information of China (English)

    何海; 朱燕; 刘宁; 晁群芳; 刘小宁

    2012-01-01

    [目的]研究新疆一枝蒿提取物黄酮及萜类提取物对棉铃虫解毒酶谷胱甘肽S-转移酶(GST)的影响,探明外源有毒物质对该解毒酶表达规律的影响,阐明棉铃虫与植物次生物质相互作用的机制,为发展新型无公害植物源农药提供理论依据.[方法]从新疆一枝蒿中分离提纯黄酮与萜类提取物,以室内饲养棉铃虫(3龄幼虫)为对象,利用生物测定、实时荧光定量PCR及酶联免疫吸附测定法,分别测定新疆一枝蒿中黄酮与萜类提取物对棉铃虫的毒杀效果及其在mRNA水平和蛋白水平上对GST表达的影响.[结果]黄酮和萜类提取物对棉铃虫3龄幼虫在24 h时的半致死浓度LC50分别是21.4和4.1 mg/100 g,在48 h时的半致死浓度LC50分别是19.3和3.1 mg/100 g;实时荧光定量PCR结果表明GST在mRNA水平的表达量受到诱导,时间效应为当黄酮和萜类提取物浓度分别为20和2 mg/100 g时,GST在12 h时能够被两种物质显著诱导表达,而在24 h时表达受到抑制;浓度效应为在18h时,黄酮和萜类提取物浓度分别为20和2 mg/100 g时显著诱导GST的表达,而在40和4 mg/100 g时抑制GST的表达;酶联免疫吸附测定结果表明,萜类和黄酮在时间和浓度效应上都能显著诱导GST蛋白表达,并且蛋白水平在时间与浓度效应中的表达趋势与mRNA水平相类似.[结论]GST对外源物质新疆一枝蒿的黄酮提取物和萜类提取物存在积极响应,低浓度或短时间内黄酮和萜类均能诱导GST的过表达,从而化解外源毒性,而浓度过高或时间过长则抑制其表达.%[Objective] In order to elucidate the roles of detoxification enzyme glutathion S - transferase ( GST) between cotton bollworm and biochemicals, we investigated the expression patterns of GST in the mid-gut from the cotton bollworm induced by flavones and terpenes extract from Artemisia rupestris, which will provide a clue to develop a new pollution - free botanical insecticide. [ Method] The toxicity of the flavones ex- tracts and terpenes extracts from A. rupestris to the third larvae of cotton bollworm were assayed by bioassay. The GST expression patterns at mRNA level and protein level were detected by real - time quantitative PCR (qPCR) and ELISA, respectively. [Result]1. The LC50 at 24 h of flavones extracts and terpenes extracts to bollworm were 20.41 and 4.1 mg/100 g, respectively; the LC50 at 48 h were 19. 3 and 3. 1 mg/100 g; respectively. 2. qPCR results showed that the GST mRNA levels in the midgut of the larvae were induced by these two extracts. For the time effect, when the larvae were exposed to 20 mg/100 g flavones extracts and 2 mg/100 g terpenes extracts respectively for 12 h the relative expression level of GST mRNA in the midgut was over - expressed, while at 24 h the expression was inhibited; For the concentration effect, when the larvae were treated with these two exyracts for 18 h respectively, the relative expression level of GST mRNA was over - expressed by 20 mg/100 g flavones and 2 mg/100 g terpenes extracts, respectively, while the expression was inhibited by 40 mg/100 g flavones and 4 mg/100 g terpenes extrcts in the diet, respectively; 3. ELISA results showed similar trends in the GST expression at the protein level to the mRNA. [Conclusion] The GST adopted an active response to the flavones and terpenes extracts from Artemisiar upestris:GST was induced to over - express when the cotton bollworm third larvae were treated with flavones extracts or terpenes extracts from A. upestris either at low concentrations or for short time, but was inhibited at high concentrations or for long time.

  14. Results of three years of experimental aerial application of Bacillus thuringiensis at 2. 0 l/ha against choristoneura fumiferana c. Information report No. LAU-X-89B

    Energy Technology Data Exchange (ETDEWEB)

    Valero, J.R.

    1989-01-01

    Research into the potential of using Bacillus thuringiensis 3a3b for control of the spruce budworm led to the development of a concentrated, effective and economical suspension of B.t. called Futura. This report gives the results of spraying Futura in the Saguenay/Lac St.-Jean and Lower St. Lawrence regions of Quebec in 1985, 1986 and 1987. Eight blocks of mature forest dominated by fir and white spruce were treated using two different strengths.

  15. Highlights of forest pest conditions in the maritimes at the end of June, 1993. Technical note No. 285. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, J.E.

    1993-01-01

    This note describes forest pest conditions in the Maritimes at the end of June, 1993. It discusses diseases and pests found including forest tent caterpiller, gypsy moth, red shoots of balsam fir, aspen leafroller, spruce budworm, poplar serpentine leafminer, maple leafroller, and spruce spider mite. Others include elm leafminer, leafroller of birch, satin moth, cherry blight, aspen twoleaf, fall cankerworm, winter moth, and leaf and twig blight of aspen.

  16. Molecular research and genetic engineering of resistance to Verticillium wilt in cotton: A review

    Science.gov (United States)

    Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing the crop’s production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became e...

  17. 78 FR 25620 - Importation of Female Squash Flowers From Israel Into the Continental United States

    Science.gov (United States)

    2013-05-02

    ... through the importation of immature fruit attached to female squash flowers. These are Ceratitis capitata... are designed to prevent the introduction of the following quarantine pests: Ceratitis capitata, Dacus... inspected and found free of Ceratitis capitata, Dacus ciliatus, Helicoverpa armigera, and...

  18. Efficacy of silk channel injections with insecticides for management of Lepidopteran pests of sweet corn

    Science.gov (United States)

    The primary Lepidopteran pests of sweet corn in Georgia are the corn earworm, Helicoverpa zea (Boddie), and the fall armyworm, Spodoptera frugiperda (J.E. Smith). Control of these pests typically requires multiple insecticide applications from first silking until harvest, with commercial growers fre...

  19. Effect of eastern gamagrass on fall armyworm and corn earworm development

    Science.gov (United States)

    The fall armyworm, Spodoptera frugiperda (J.E. Smith) and the corn earworm, Helicoverpa zea (Boddie) are two important corn pests in the southern U.S. states. Effect of the leaves from the corn relative, the Eastern gamagrass (Tripsacum dactyloides L.) on fall armyworm and corn earworm development ...

  20. Dicty_cDB: Contig-U02910-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available J237693_1( AJ237693 |pid:none) Ajuga reptans mRNA for galactinol ... 55 8e-06 AY1...77 |pid:none) Helicoverpa armigera granulovirus... 35 8.1 AJ237694_1( AJ237694 |pid:none) Ajuga reptans mRNA

  1. A selective CAP2b neuropeptide antagonist for an expressed receptor from the red flour beetle, Tribolium castaneum

    Science.gov (United States)

    Diapause hormone (DH) is an insect neuropeptide that is highly effective in terminating the overwintering pupal diapause in members of the Helicoverpa/Heliothis complex of agricultural pests, thus DH and related compounds have promise as tools for pest management. To augment our development of effec...

  2. A New Strategy of Insect Pest Control:Down-regulating Cotton Boliworm Gene Expression by Engineering Plant Double Stranded RNA

    Institute of Scientific and Technical Information of China (English)

    MAO Ying-bo; XUE Xue-yi; WANG Ling-jiang; CHEN Xiao-ya

    2008-01-01

    @@ Cotton bollworm (Helicoverpa armigera ) is an important agricultural pest that causes severeyield loss to crops,particularly to cotton.Transgenic Bt crops have been successful in protectingplants,however,Bt proteins are toxic to all lepidopteran insects but have little effects to sucking pests,such as aphids.Furthermore,the continuous use of Bt crops increases insect resistance.

  3. Effects of elevated peroxidase levels and corn earworm feeding on gene expression in tomato

    Science.gov (United States)

    Tomato gene arrays were used to investigate how high levels of transgenic peroxidase expression and feeding by the corn earworm, Helicoverpa zea, affected expression of defensive and other genes. High peroxidase activity significantly upregulated proteinase inhibitors and a few other defensive gene...

  4. Integration of biological control and transgenic insect protection for mitigation of mycotoxins in corn

    Science.gov (United States)

    Biological control is known to be effective in reducing aflatoxin contamination of corn and some transgenic corn hybrids incur greatly reduced damage from corn earworm (Helicoverpa zea). We conducted seven field trials over two years to test the hypothesis that transgenic insect protection and biol...

  5. Results of forest insect and disease surveys in the Eastern Region of Ontario, 1987. Miscellaneous report No. 81. Annual publication

    Energy Technology Data Exchange (ETDEWEB)

    Keizer, A.

    1988-01-01

    Report for 1987 summarizing forest damage by insects, diseases and abiotic agents in the Eastern Region of Ontario. Included are summaries of forest decline and dieback evaluations as well as special surveys, infestation forecasts and miscellaneous pests in the forest districts of Napanee, Tweed, Carleton Place, Cornwall and Brockville. Textual descriptions of pests are accompanied by maps and statistical tables. Pests covered include birch leafminers, spruce budworm, gypsy moths, tent caterpillars, canker, needle rust, bark diseases, and leaf spot. Abiotic damage described in this report covers drought, frost injury, and snow and ice damage. Forest health reports and special surveys are also described.

  6. Do Offspring of Insects Feeding on Defoliation-Resistant Trees Have Better Biological Performance When Exposed to Nutritionally-Imbalanced Food?

    Science.gov (United States)

    Quezada-Garcia, Roberto; Fuentealba, Alvaro; Nguyen, Ngoc; Bauce, Éric

    2015-01-12

    White spruce (Picea glauca (Moench) Voss) trees that are resistant or susceptible to spruce budworm (Choristoneura fumiferana (Clem.)) attack were identified in a southern Quebec plantation. Due to high mortality-induced selective pressures imposed by resistant trees on spruce budworm larvae, insects that survive on resistant trees exhibited greater biological performance than those on susceptible trees. We tested the hypothesis that this better biological performance is maintained across generations when progeny were subjected to nutritional stress. We collected pupae from resistant and susceptible trees (phenotype). Adults were reared under controlled laboratory conditions. Progeny were subsequently reared on two types of artificial diet (high vs. low quality). Low quality diet simulated food quality deterioration during outbreak conditions. Results confirmed that surviving insects collected from resistant trees have better performance than those from susceptible trees. Offspring performance (pupal mass, developmental time) was affected only by diet quality. These results suggest that adaptive advantages that would be acquired from parents fed on resistant trees are lost when progeny are exposed to nutritionally-imbalanced food, but the effects persist when larvae are fed a balanced diet. Offspring mortality, fecundity and fertility were positively influenced by parental origin (tree phenotype).

  7. Starch industry wastewater for production of biopesticides--ramifications of solids concentrations.

    Science.gov (United States)

    Vu, Khanh Dang; Tyagi, R D; Brar, S K; Valéro, J R; Surampalli, R Y

    2009-04-01

    Total solids (TS) concentrations ranging from 15 to 66 g L(-1) of starch industry wastewater (SIW) were tested as raw material for the production of Bacillus thuringiensis var. kurstaki HD-1 (Btk) biopesticide in shake flasks and a 15 L bench-scale fermenter. Shake flask studies revealed a higher delta-endotoxin concentration of Btk at 30 g L(-1) TS concentration and 2.5% (v v(-1)) volume of pre-culture. The fermenter experiments conducted using SIW at 30 g L(-1) TS concentration under controlled conditions of temperature, pH and dissolved oxygen showed higher spore count, enzyme production (protease and amylase) and delta-endotoxin concentration as compared with those of SIW at 15 g L(-1) TS concentration. The entomotoxicity, at the end of fermentation, with SIW at 30 g L(-1) solids concentration (17.8 x 10(9) SBU L(-1), measured against spruce budworm) was considerably higher as compared with entomotoxicity at 15 g L(-1) solids concentration (15.3 x 10(9) SBU L(-1)) and semi-synthetic medium (11.7 x 10(9) SBU L(-1)). The pellet, comprising spores and delta-endotoxin complex obtained after centrifugation and followed by resuspension (in supernatant) in one-tenth of the original volume, of SIW at 30 g L(-1) solids concentration media registered the highest potential for application (to protect forests against spruce budworm) than other media in term of entomotoxicity.

  8. Defoliation of interior Douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks.

    Science.gov (United States)

    Song, Yuan Yuan; Simard, Suzanne W; Carroll, Allan; Mohn, William W; Zeng, Ren Sen

    2015-02-16

    Extensive regions of interior Douglas-fir (Pseudotsuga menziesii var. glauca, IDF) forests in North America are being damaged by drought and western spruce budworm (Choristoneura occidentalis). This damage is resulting from warmer and drier summers associated with climate change. To test whether defoliated IDF can directly transfer resources to ponderosa pine (Pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme response. We grew pairs of ectomycorrhizal IDF 'donor' and ponderosa pine 'receiver' seedlings in pots and isolated transfer pathways by comparing 35 μm, 0.5 μm and no mesh treatments; we then stressed IDF donors either through manual defoliation or infestation by the budworm. We found that manual defoliation of IDF donors led to transfer of photosynthetic carbon to neighboring receivers through mycorrhizal networks, but not through soil or root pathways. Both manual and insect defoliation of donors led to increased activity of peroxidase, polyphenol oxidase and superoxide dismutase in the ponderosa pine receivers, via a mechanism primarily dependent on the mycorrhizal network. These findings indicate that IDF can transfer resources and stress signals to interspecific neighbors, suggesting ectomycorrhizal networks can serve as agents of interspecific communication facilitating recovery and succession of forests after disturbance.

  9. Degeneration of host prothoracic glands caused by Campoletis chlorideae polydnavirus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cong; YAN Yunhua; WANG Chenzhu

    2003-01-01

    The development of last instar Helicoverpa armigera prothoracic glands was investigated first; then the effects on the prothoracic glands of Helicoverpa armigera was studied by injection with calyx fluid and polydnavirus (PDV) from the endoparasitoid Campoletis chlorideae. Results showed that 3 female equivalents of calyx fluid or 4 female equivalents of PDV induced degeneration of host prothoracic glands. 24 h after calyx fluid or PDV injection the ultrastructure of the gland cells showed a significant decrease in intercellular channel system, while an increase in the number of round mitochondria, lysosomes and whorled figures, the organelle of some cells has degenerated and only organelle debris remained in the cells. These results suggest that calyx fluid or PDV cause the inactivation and degeneration of host prothoracic glands.

  10. History and current status of development and use of viral insecticides in China.

    Science.gov (United States)

    Sun, Xiulian

    2015-01-20

    The use of insect viruses as biological control agents started in the early 1960s in China. To date, more than 32 viruses have been used to control insect pests in agriculture, forestry, pastures, and domestic gardens in China. In 2014, 57 products from 11 viruses were authorized as commercial viral insecticides by the Ministry of Agriculture of China. Approximately 1600 tons of viral insecticidal formulations have been produced annually in recent years, accounting for about 0.2% of the total insecticide output of China. The development and use of Helicoverpa armigera nucleopolyhedrovirus, Mamestra brassicae nucleopolyhedrovirus, Spodoptera litura nucleopolyhedrovirus, and Periplaneta fuliginosa densovirus are discussed as case studies. Additionally, some baculoviruses have been genetically modified to improve their killing rate, infectivity, and ultraviolet resistance. In this context, the biosafety assessment of a genetically modified Helicoverpa armigera nucleopolyhedrovirus is discussed.

  11. History and Current Status of Development and Use of Viral Insecticides in China

    Directory of Open Access Journals (Sweden)

    Xiulian Sun

    2015-01-01

    Full Text Available The use of insect viruses as biological control agents started in the early 1960s in China. To date, more than 32 viruses have been used to control insect pests in agriculture, forestry, pastures, and domestic gardens in China. In 2014, 57 products from 11 viruses were authorized as commercial viral insecticides by the Ministry of Agriculture of China. Approximately 1600 tons of viral insecticidal formulations have been produced annually in recent years, accounting for about 0.2% of the total insecticide output of China. The development and use of Helicoverpa armigera nucleopolyhedrovirus, Mamestra brassicae nucleopolyhedrovirus, Spodoptera litura nucleopolyhedrovirus, and Periplaneta fuliginosa densovirus are discussed as case studies. Additionally, some baculoviruses have been genetically modified to improve their killing rate, infectivity, and ultraviolet resistance. In this context, the biosafety assessment of a genetically modified Helicoverpa armigera nucleopolyhedrovirus is discussed.

  12. MATCHING COTTON GROWERS’ PERCEPTIONS OF THE VALUE OF INGARD™ COTTON WITH ECONOMIC ANALYSIS BASED ON SAME FARM PAIRED COMPARISONS OF PERFORMANCE

    OpenAIRE

    Hancock, Wayne M.; Harrison, Jennifer L.; O'Brian, Dennis T.

    1999-01-01

    The genetically modified INGARD™ cotton seed was released in Australia in 1996 and was greeted with high expectations and enthusiasm within the cotton industry. INGARD™ cotton seed contains the Cry1A(c) gene from the soil bacteria Bacillus thuringiensis var kurstaki for the biological control of Helicoverpa armigera and H. punctigera moth larvae in cotton. These are the most serious insect pests of cotton and account for the majority of insecticides applied to cotton in Australia. Significant...

  13. Disruption of insect diapause using agonists and an antagonist of diapause hormone

    OpenAIRE

    Zhang, Qirui; Nachman, Ronald J.; Kaczmarek, Krzysztof; Zabrocki, Janusz; Denlinger, David L.

    2011-01-01

    The dormant state known as diapause is widely exploited by insects to circumvent winter and other adverse seasons. For an insect to survive, feed, and reproduce at the appropriate time of year requires fine coordination of the timing of entry into and exit from diapause. One of the hormones that regulates diapause in moths is the 24-aa neuropeptide, diapause hormone (DH). Among members of the Helicoverpa/Heliothis complex of agricultural pests, DH prompts the termination of pupal diapause. Ba...

  14. Streptomyces avermitilis from marine

    Institute of Scientific and Technical Information of China (English)

    XIONG Li-xia; LI Jian-zhong; WANG Hui-li

    2005-01-01

    The insecticidal strain 173 was isolated from marine source and its activity was explored by the bioassay of brine shrimp and Helicoverpa armigera. Based on morphological, physiological and molecular properties, the insecticidal strain 173 was identified as Streptonycetes avermitilis, which is the best insecticidal microorganism found in the terrestrial environment. The taxonomy of the strain173, insecticidal spectrum and properties of the corresponding insecticidal antibiotics are reported.

  15. Recent Advances in Biological Control of Pest Insects by Using Viruses in China

    Institute of Scientific and Technical Information of China (English)

    Xiu-lian SUN; Hui-yin PENG

    2007-01-01

    Insect viruses are attractive as biological control agents and could be a feasible alternative to chemical insecticides in the management of insect infestations. This review describes recent advances in the development of wild-type and genetically modified viruses as insecticides. A new strategy of application of insect viruses in China is reviewed. Also, the assessment of biosafety of genetically modified Helicoverpa armigera Nucleopolyhedovirus (HearNPV) is emphasized as a case-study.

  16. Genome‐wide transcriptomic and proteomic analyses of bollworm‐infested developing cotton bolls revealed the genes and pathways involved in the insect pest defence mechanism

    OpenAIRE

    Kumar, Saravanan; Kanakachari, Mogilicherla; Gurusamy, Dhandapani; Kumar, Krishan; Narayanasamy, Prabhakaran; Kethireddy Venkata, Padmalatha; Solanke, Amolkumar; Gamanagatti, Savita; Hiremath, Vamadevaiah; Katageri, Ishwarappa S.; Leelavathi, Sadhu; Kumar, Polumetla Ananda; Reddy, Vanga Siva

    2016-01-01

    Summary Cotton bollworm, Helicoverpa armigera, is a major insect pest that feeds on cotton bolls causing extensive damage leading to crop and productivity loss. In spite of such a major impact, cotton plant response to bollworm infection is yet to be witnessed. In this context, we have studied the genome‐wide response of cotton bolls infested with bollworm using transcriptomic and proteomic approaches. Further, we have validated this data using semi‐quantitative real‐time PCR. Comparative ana...

  17. Japodic Acid, A Novel Aliphatic Acid from Jatropha podagrica Hook

    OpenAIRE

    Aiyelaagbe, Olapeju O.; Gloer, James B.

    2008-01-01

    A new aliphatic acid named japodic acid (1) with a gem-dimethyl cyclopropane ring has been isolated from the roots of Jatropha podagrica. Its structure was established by 1D and 2D NMR and mass spectrometric data. Two other known compounds, erythrinasinate (2) and fraxidin (3) were also isolated from this plant for the first time. Japodic acid showed mild insect growth inhibition activity against Helicoverpa zea (37% growth reduction at 100 ppm). Fraxidin and erythrinasinate exhibited antibac...

  18. Scenario of Entomological Research in Legume Crops in Nepal

    Directory of Open Access Journals (Sweden)

    Bishnu Prasad Neupane

    2015-09-01

    Full Text Available This review paper highlights scenario of entomological research in grain legumes in Nepal into headings of the monitoring, survey and surveillance, insect pest management, existing problem and future strategies. A survey study on yield loss assessment of chickpea due to Helicoverpa pod borer under field condition has been recorded up to 75% in the year 1996-1998 at Banke and Bardiya district. While monitored Helicoverpa armigera through pheromone trap, during the 2nd week of March, peak catches of 91 male moths were recorded at Rampur, while it was the maximum (42 male moths during the 3rd week of March. Synthetic pyrethroids, deltamethrin, fenvalerate and cypermethrin used at 0.01% concentration (a.i., were effective in controlling the chickpea pod borer, Helicoverpa armigera Hubner. Genotypes NCH-18, NCH -31, NCH-138 and ICC 3075 WR were found resistant. Ripcord 10%@0.05% was found to be superior and effective chemical insecticides to control stem fly and soybean hairy caterpillar. The late sowing date December, 10 showed significantly higher percentage of chickpea pod borer damage with lower grain yield. Inter crops combinations of Chickpea +wheat (2:1 ratio was found effective against Helicoverpa armigera damage (1.2% followed by chickpea+barley (2.36% and Chickpea+linseed (2:1 ratio (3.7%. Bakaino (Melia azederach L. was identified as the best indigenous pesticides to check the normal growth of hairy caterpillar (Spilarctia casigneta kollar under laboratory condition. Metarhizium anisopliae was found effective for the management of Helicoverpa armigera that caused maximum mortality (94.67%, infection (45.33% within 7.49 days (LT50. Similarly, Beauveria bassiana caused maximum mortality (98.67%, infection (80.00% with the least LT50 value (5 days. Crop sprayed with HaNPV had the lowest pod damage (0.3% and the highest in Racer (2.2%. This review work provided a lot of information to conduct entomological research activity conducted in grain

  19. 白僵菌对烟蚜的致病性研究%Study on Pathogenicity of Beauveria bassiana on Tobacco Aphid

    Institute of Scientific and Technical Information of China (English)

    黄刚; 徐明勇; 钱凤英; 张西仲

    2011-01-01

    [Objective] The aim was to explore the pathogenicity of Beauveria bassiana on tobacco aphid. [ Method] The pathogenicity of four Beauveria bassiana (B-l ,B-2,B-3 and B-4)strains on the tobacco budworm was studied. [ Result] Different tested Beauveria bassiana strains had different levels of insecticidal effect on tobacco aphids. The corrected mortality of tobacco budworm treated by B-3 was more than 95% ; the mortality rates of conidia of B-l and B-2 strains against tobacco aphid were over 80% , and their hyphae also caused higher morbidity a-gainst tobacco aphid; metabolites of different strains of had a strong contact action against tobacco budworm, and all the mortality rates of metabolites of different strains against tobacco aphid were over 85% after 48 h treatment. [Conclusion] The research provides reference for further study on microbial control of tobacco aphid.%[目的]探讨白僵菌(Beauveria bassiana)对烟蚜的致病性.[方法]以4株球孢白僵菌(B-1、B-2、B-3和B-4)为供试菌株,测定其对烟草蚜虫的致病性.[结果]受测的4株白僵菌菌株对烟草蚜虫均有不同程度的杀虫效果.其中,B-3处理烟草蚜虫的校正死亡率达到95%以上,B-1、B-2菌株的分生孢子处理烟草蚜虫的校正死亡率超过80%,其菌丝对蚜虫也有较高的致病率;4株菌株的代谢产物对烟草蚜虫均有较强的触杀作用,施用48 h后其烟草蚜虫的校正死亡率均超过85%.[结论]为烟草蚜虫的微生物防治研究提供了参考.

  20. An insert in the Hpy region of hscp in Heliothis virescens (Lepidoptera: Noctuidae) reveals a possible CORE-SINE of insects

    Institute of Scientific and Technical Information of China (English)

    Sujin Park; Thomas M.Brown; Sam-Kyu Kim; Chunkeun Lim; Jang Hyun Hur; Yong Chul Park; Saeyoull Cho

    2009-01-01

    A new putative transposon was identified in the tobacco budworm, Hellothis virescens. This transposon was characterized as a full length CORE-SINE (65 bp of "CORE" core specific nuclootide short interspersed elements) that resembled sequences from three other lcpidopterans and humans. In particular, the A-box and B-box regions of this sequence most closely conformed to the signature of CORE-SINEs from widely divergent species. This CORE-SINE was present as a polymorphism in a hypcrvariable region of the gene hscp, which is the target ofpyrethroid insecticides and other xenobiotics in the nerve axon. We described this new putative transposon as Noct-1 due to its presence in a noctuid moth. This is the first description of a full-length CORE-SINE with the A-box, B-box, target site duplication, and candidate core domain from an insect.

  1. Secondary metabolites from anti-insect extracts of endophytic fungi isolated from Picea rubens.

    Science.gov (United States)

    Sumarah, Mark W; Puniani, Eva; Sørensen, Dan; Blackwell, Barbara A; Miller, J David

    2010-05-01

    The extracts of a selection of 150 foliar fungal endophytes isolated from Picea rubens (red spruce) needles were screened by LC-MS and assayed for toxicity. Three of these strains that were toxic to the forest pest Choristoneura fumiferana (eastern spruce budworm) in dietary bioassays were selected for further study. Their culture extracts were analyzed by LC-NMR spectroscopy, and the major metabolites were isolated by LC-MS-SPE or PTLC/column chromatography and characterized. The structures were elucidated by spectroscopic analyses including 2D NMR, HRMS and by comparison to literature data. Compounds 1 and 5-7 are hitherto unknown whereas compounds 2 and 3 are natural products described for the first time. Compound 4 is reported for the first time as a fungal metabolite and 8-9 were identified as known fungal metabolites in genera.

  2. Mid-Holocene Hemlock Decline in Eastern North America Linked with Phytophagous Insect Activity

    Science.gov (United States)

    Bhiry, Najat; Filion, Louise

    1996-05-01

    Macrofossil evidence indicates that the mid-Holocene hemlock [ Tsuga canadensisL. (Carr.)] decline that occurred over a wide area in eastern North America was associated with phytophagous insect activity. In situhemlock macrofossils and insect remains found in a paludified dunefield at the northern limit of hemlock testify that two defoliation events occurred at 4910 ± 90 and 4200 ± 100 yr B.P., respectively. The sharp coincidence of remains from hemlock needles with chewing damage typical of hemlock looper feeding, head capsules from the hemlock looper ( Lambdina fiscellaria) and the spruce budworm ( Choristoneura fumiferana), absence of hemlock fruiting remains, and tree-ring anomalies in fossil hemlocks that died prematurely (caused mass mortality. Our findings indicate that defoliation can affect ecosystems for centuries, especially when long-lived tree species are involved.

  3. Climatic change and indigenous and non-indigenous ravagers : a new reality?; Changements climatiques et les ravageurs indigenes et exotiques : une nouvelle realite?

    Energy Technology Data Exchange (ETDEWEB)

    Regniere, J.; Cooke, B.; Logan, J.A.; Carroll, A.; Safranyik, L. [Natural Resources Canada, Ottawa, ON (Canada). Canadian Forest Service

    2005-07-01

    The impact that climate change may have on ecological diversity was discussed with particular reference to the movement of indigenous and non-indigenous insects that are harmful to trees. Insects in particular, are more likely to evolve rapidly and adapt to ecological change. Those with a high rate of reproduction and which can move long distances will colonize new habitats and survive a wide range of bio-physical conditions. This PowerPoint presentation included a series of graphs, tables and charts to illustrate the increased presence of various harmful insects in northern forests, including the balsam twig aphid, balsam gall midge, gypsy moth, hemlock looper, western spruce budworm, and forest tent caterpillar. It was shown that large changes in ecosystems are expected to occur at northern latitudes and higher altitudes. tabs., figs.

  4. A Three-Year Field Validation Study to Improve the Integrated Pest Management of Hot Pepper

    Directory of Open Access Journals (Sweden)

    Ji-Hoon Kim

    2013-09-01

    Full Text Available To improve the integrated pest management (IPM of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control. The number of annual pesticide applications for the IPM treatment ranged from six to eight, whereas the plots subjected to the periodic treatment received pesticide 11 or 12 times annually for three years. Compared to the former strategy, our improved IPM strategy features more intense pest management, with frequent spraying for anthracnose and mixed spraying for tobacco budworm or Phytophthora blight. The incidences for no pesticide control in 2010, 2011, and 2012 were 91, 97.6, and 41.4%, respectively. Conversely, the incidences for the IPM treatment for those years were 7.6, 62.6, and 2%, and the yields from IPM-treated plots were 48.6 kg, 12.1 kg, and 48.8 kg. The incidence and yield in the IPM-treated plots were almost the same as those of the periodic treatment except in 2011, in which no unnecessary sprays were given, meaning that the IPM control was quite successful. From reviewing eight years of field work, sophisticated forecasts that optimize pesticide spray timing reveal that reliance on pesticides can be reduced without compromising yield. Eco-friendly strategies can be implemented in the pest management of hot pepper.

  5. A three-year field validation study to improve the integrated pest management of hot pepper.

    Science.gov (United States)

    Kim, Ji-Hoon; Yun, Sung-Chul

    2013-09-01

    To improve the integrated pest management (IPM) of hot pepper, field study was conducted in Hwasung from 2010 to 2012 and an IPM system was developed to help growers decide when to apply pesticides to control anthracnose, tobacco budworm, Phytophthora blight, bacterial wilt, and bacterial leaf spot. The three field treatments consisted of IPM sprays following the forecast model advisory, a periodic spray at 7-to-10-day intervals, and no spray (control). The number of annual pesticide applications for the IPM treatment ranged from six to eight, whereas the plots subjected to the periodic treatment received pesticide 11 or 12 times annually for three years. Compared to the former strategy, our improved IPM strategy features more intense pest management, with frequent spraying for anthracnose and mixed spraying for tobacco budworm or Phytophthora blight. The incidences for no pesticide control in 2010, 2011, and 2012 were 91, 97.6, and 41.4%, respectively. Conversely, the incidences for the IPM treatment for those years were 7.6, 62.6, and 2%, and the yields from IPM-treated plots were 48.6 kg, 12.1 kg, and 48.8 kg. The incidence and yield in the IPM-treated plots were almost the same as those of the periodic treatment except in 2011, in which no unnecessary sprays were given, meaning that the IPM control was quite successful. From reviewing eight years of field work, sophisticated forecasts that optimize pesticide spray timing reveal that reliance on pesticides can be reduced without compromising yield. Eco-friendly strategies can be implemented in the pest management of hot pepper.

  6. Target and nontarget effects of novel "triple-stacked" Bt-transgenic cotton 1: canopy arthropod communities.

    Science.gov (United States)

    Whitehouse, M E A; Wilson, L J; Davies, A P; Cross, D; Goldsmith, P; Thompson, A; Harden, S; Baker, G

    2014-02-01

    Transgenic cotton varieties (Bollgard II) expressing two proteins (Cry1Ac and Cry2Ab) from Bacillus thuringiensis (Bt) have been widely adopted in Australia to control larvae of Helicoverpa. A triple-stacked Bt-transgenic cotton producing Cry1Ac, Cry2Ab, and Vip3A proteins (Genuity Bollgard III) is being developed to reduce the chance that Helicoverpa will develop resistance to the Bt proteins. Before its introduction, nontarget effects on the agro-ecosystem need to be evaluated under field conditions. By using beatsheet and suction sampling methods, we compared the invertebrate communities of unsprayed non-Bt-cotton, Bollgard II, and Bollgard III in five experiments across three sites in Australia. We found significant differences between invertebrate communities of non-Bt and Bt (Bollgard II and Bollgard III) cotton only in experiments where lepidopteran larval abundance was high. In beatsheet samples where lepidopterans were absent (Bt crops), organisms associated with flowers and bolls in Bt-cotton were more abundant. In suction samples, where Lepidoptera were present (i.e., in non-Bt-cotton), organisms associated with damaged plant tissue and frass were more common. Hence in our study, Bt- and non-Bt-cotton communities only differed when sufficient lepidopteran larvae were present to exert both direct and indirect effects on species assemblages. There was no overall significant difference between Bollgard II and III communities, despite the addition of the Vip gene in Bollgard III. Consequently, the use of Bollgard III in Australian cotton provides additional protection against the development of resistance by Helicoverpa to Bt toxins, while having no additional effect on cotton invertebrate communities.

  7. Herbivory: Caterpillar saliva beats plant defences

    Science.gov (United States)

    Musser, Richard O.; Hum-Musser, Sue M.; Eichenseer, Herb; Peiffer, Michelle; Ervin, Gary; Murphy, J. Brad; Felton, Gary W.

    2002-04-01

    Blood-feeding arthropods secrete special salivary proteins that suppress the defensive reaction they induce in their hosts. This is in contrast to herbivores, which are thought to be helpless victims of plant defences elicited by their oral secretions. On the basis of the finding that caterpillar regurgitant can reduce the amount of toxic nicotine released by the tobacco plant Nicotiana tabacum, we investigate here whether specific salivary components from the caterpillar Helicoverpa zea might be responsible for this suppression. We find that the enzyme glucose oxidase counteracts the production of nicotine induced by the caterpillar feeding on the plant.

  8. Lepidoptera (Insecta associated with soybean in Argentina, Brazil, Chile and Uruguay

    Directory of Open Access Journals (Sweden)

    Aline Carraro Formentini

    2015-12-01

    Full Text Available ABSTRACT: The present research updates the systematic position and nomenclature of Lepidoptera associated with soybean crops in Argentina, Brazil, Chile and Uruguay. Scientific literature lists 69 species of Lepidoptera feeding on soybean plants. These species are representatives of the Superfamilies Noctuoidea (31, Pyraloidea (13, Hesperioidea (12, Tortricoidea (5, Geometroidea (5, and Bombycoidea (3. Diversity of Lepidoptera associated to crop, injury in different parts of the plant, and changes in species composition are discussed considering the changes in plant disease management, introduction of plants expressing Bt proteins, and the recent introduction of Helicoverpa armigera (Hübner as a new crop pest.

  9. Introgression of Bt Genes in Novel Germplasm and Contribution to Indian Cotton Economy

    Institute of Scientific and Technical Information of China (English)

    VIDYASAGAR Parchuri

    2008-01-01

    @@ Emergence of transgenic Bt-cotton technology has opened up a new chapter in Indian cotton production in 21st century.The crylAc gene of Monsanto derived from American Upland Coker-312 background was not directly suitable for varied cotton growing situations in India.Delivery of Bt-gene technology to Indian farming systems should be superimposed on hybrid technology,fiber quality,and superior agronomic adaptation.Protection offered by this alien Bt-gene against major serious pest Helicoverpa armigera,by preventing annual losses ranging from 15~35 percent,automaticaly contributed to higher yield.

  10. Cloning and characterization of an insecticidal crystal protein gene from Bacillus thuringiensis subspecies kenyae

    Indian Academy of Sciences (India)

    Hari S. Misra; Nivedita P. Khairnar; Manjula Mathur; N. Vijayalakshmi; Remesh S. Hire; T. K. Dongre; S. K. Mahajan

    2002-04-01

    A sporulating culture of Bacillus thuringiensis subsp. kenyae strain HD549 is toxic to larvae of lepidopteran insect species such as Spodoptera litura, Helicoverpa armigera and Phthorimaea operculella, and a dipteran insect, Culex fatigans. A 1.9-kb DNA fragment, PCR-amplified from HD549 using cryII-gene-specific primers, was cloned and expressed in E. coli. The recombinant protein produced 92% mortality in first-instar larvae of Spodoptera litura and 86% inhibition of adult emergence in Phthorimaea operculella, but showed very low toxicity against Helicoverpa armigera, and lower mortality against third-instar larvae of dipteran insects Culex fatigans, Anopheles stephensi and Aedes aegypti. The sequence of the cloned crystal protein gene showed almost complete homology with a mosquitocidal toxin gene from Bacillus thuringiensis var. kurstaki, with only five mutations scattered in different regions. Amino acid alignment with different insecticidal crystal proteins using the MUTALIN program suggested presence of the conserved block 3 region in the sequence of this protein. A mutation in codon 409 of this gene that changes a highly conserved phenylalanine residue to serine lies in this block.

  11. Effects of transgenic Cry1A+CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae (Hymenoptera:Ichneumonidae)

    Institute of Scientific and Technical Information of China (English)

    XIAO-XIALIU; CHANG-GUISUN; QING-WENZHANG

    2005-01-01

    The effect oftransgenic double genes, Cry1A + CpTlcotton and Cry1Ac toxin on the parasitoid, Carnpoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first,second and third instar could not survive if fed on transgenic cotton leaves. Consequently,C. chlorideae larvae could not complete their development if parasitizing on such hosts.After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12-48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12-48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.

  12. Phytopesticidal effects of Spilanthes acmella (L.) Murr. leaves on three economically important lepidopteran insect pests

    Institute of Scientific and Technical Information of China (English)

    Manickam Pavunraj; Kathirvelu Baskar; Sundaram Janarthanan; Munusamy Arumugam

    2014-01-01

    Objective: To evaluate the antifeedant and larvicidal activities of dichloromethane (DCM), acetone, dimethylsulfoxide (DMSO) and aqueous extracts of Spilanthes acmella (S. acmella) leaves against Earias vitella, Helicoverpa armigera and Spodoptera litura.Methods:DCM, acetone, DMSO and aqueous extracts were studied using fruit and leaf discs no-choice method at 0.625%, 1.25%, 2.5% and 5% concentration. Results: All the extracts showed antifeedant and larvicidal activities against all the tested insects. However, maximum antifeedant activity was detected in DCM extract of S. acmella against all tested pest, followed by acetone, DMSO and aqueous extracts at 5% concentration. The leaves extract of S. acmella also showed larvicidal activity; maximum larval mortality was observed in DCM extract against Helicoverpa armigera (48.88%), Spodoptera litura (44.88%) and Earias vitella (75.11%) followed by acetone, DMSO and aqueous extracts at 5% concentration.Conclusions:DCM extract of S. acmella could be further purified to develop a formulation for eco-friendly pest control agent.

  13. In-silico determination of insecticidal potential of Vip3Aa-Cry1Ac fusion protein against Lepidopteran targets using molecular docking

    Directory of Open Access Journals (Sweden)

    Aftab eAhmad

    2015-12-01

    Full Text Available Study and research of Bt (Bacillus thuringiensis transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac insecticidal protein and vegetative insecticidal protein (Vip3Aa have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua and Spodoptera litura revealed that the Ser290, Ser293, Leu337, Thr340 and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein.

  14. Bio-potency of a 21 kDa Kunitz-type trypsin inhibitor from Tamarindus indica seeds on the developmental physiology of H. armigera.

    Science.gov (United States)

    Pandey, Prabhash K; Jamal, Farrukh

    2014-11-01

    A trypsin inhibitor purified from the seeds of Tamarindus indica by Sephadex G-75, DEAE-Sepharose and Trypsin-Sepharose CL-4B columns was studied for its antifeedant, larvicidal, pupicidal and growth inhibitory activities against Helicoverpa armigera larvae. Tamarindus trypsin inhibitor (TTI) exhibited inhibitory activity towards total gut proteolytic enzymes of H. armigera (~87%) and bovine trypsin (~84%). Lethal doses which caused mortality and weight reduction by 50% were 1% w/w and 0.50% w/w, respectively. IC50 of TTI against Helicoverpa midgut proteases and bovine trypsin were ~2.10 µg/ml and 1.68 µg/ml respectively. In larval feeding studies the 21 kDa Kunitz-type protein was found to retard growth and development, prolonged the larval-pupal development durations along with adversely affecting the fertility and fecundity of H. armigera. In artificial diet at 0.5% w/w TTI, the efficiency of conversion of ingested food as well as of digested food, relative growth rate, growth index declined whereas approximate digestibility, metabolic cost, relative consumption rate, consumption index and total developmental period enhanced for H. armigera larvae. These results suggest that TTI has toxic and adverse effect on the developmental physiology of H. armigera and could be useful in controlling the pest H. armigera.

  15. Characterization of insecticidal peptides from venom Australian funnel-web spiders

    Directory of Open Access Journals (Sweden)

    E. J. Vonorax

    2006-04-01

    Full Text Available Australian funnel-web spiders are relatively large primitive hunting spiders. Male Atrax robustus spiders have been responsible for a number of human deaths. Venom was collected from the species Hadronyche infensa (Hickman [female], H. formidabilis [male and female], H. versuta [female], and A. robustus (Cambridge [male] and was fractionated by high performance liquid chromatography. This resulted in the isolation and purification of a homologous series of 7 insecticidal peptides of relatively low molecular mass (approximately 4kDa. The amino acid sequences of these toxins consisted of 36 or 37 amino acids and were named atracotoxins. For the major bioassay of these toxins, we used the cotton bollworm, Helicoverpa armigera (Hubner, due to the great damage it causes to crops worldwide. These toxins, when injected subcutaneously into fifth or sixth instar larvae of Helicoverpa armigera,were lethal or caused an apparently irreversible writhing. The toxin from H. versuta venom showed no significant toxicity when subcutaneously injected into newborn mice. One of the toxins was found to have a free acid carboxyl terminus. These toxins have great potential as lead compounds for insecticide design or for incorporation in recombinant baculovirus insecticides.

  16. Binding sites for Bacillus thuringiensis Cry2Ae toxin on heliothine brush border membrane vesicles are not shared with Cry1A, Cry1F, or Vip3A toxin.

    Science.gov (United States)

    Gouffon, C; Van Vliet, A; Van Rie, J; Jansens, S; Jurat-Fuentes, J L

    2011-05-01

    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance.

  17. Binding Sites for Bacillus thuringiensis Cry2Ae Toxin on Heliothine Brush Border Membrane Vesicles Are Not Shared with Cry1A, Cry1F, or Vip3A Toxin ▿

    Science.gov (United States)

    Gouffon, C.; Van Vliet, A.; Van Rie, J.; Jansens, S.; Jurat-Fuentes, J. L.

    2011-01-01

    The use of combinations of Bacillus thuringiensis (Bt) toxins with diverse modes of action for insect pest control has been proposed as the most efficient strategy to increase target range and delay the onset of insect resistance. Considering that most cases of cross-resistance to Bt toxins in laboratory-selected insect colonies are due to alteration of common toxin binding sites, independent modes of action can be defined as toxins sharing limited or no binding sites in brush border membrane vesicles (BBMV) prepared from the target insect larvae. In this paper, we report on the specific binding of Cry2Ae toxin to binding sites on BBMV from larvae of the three most commercially relevant heliothine species, Heliothis virescens, Helicoverpa zea, and Helicoverpa armigera. Using chromatographic purification under reducing conditions before labeling, we detected specific binding of radiolabeled Cry2Ae, which allowed us to perform competition assays using Cry1Ab, Cry1Ac, Cry1Fa, Vip3A, Cry2Ae, and Cry2Ab toxins as competitors. In these assays, Cry2Ae binding sites were shared with Cry2Ab but not with the tested Cry1 or Vip3A toxins. Our data support the use of Cry2Ae toxin in combination with Cry1 or Vip3A toxins in strategies to increase target range and delay the onset of heliothine resistance. PMID:21441333

  18. In-Silico Determination of Insecticidal Potential of Vip3Aa-Cry1Ac Fusion Protein Against Lepidopteran Targets Using Molecular Docking.

    Science.gov (United States)

    Ahmad, Aftab; Javed, Muhammad R; Rao, Abdul Q; Khan, Muhammad A U; Ahad, Ammara; Din, Salah Ud; Shahid, Ahmad A; Husnain, Tayyab

    2015-01-01

    Study and research of Bt (Bacillus thuringiensis) transgenic plants have opened new ways to combat insect pests. Over the decades, however, insect pests, especially the Lepidopteran, have developed tolerance against Bt delta-endotoxins. Such issues can be addressed through the development of novel toxins with greater toxicity and affinity against a broad range of insect receptors. In this computational study, functional domains of Bacillus thuringiensis crystal delta-endotoxin (Cry1Ac) insecticidal protein and vegetative insecticidal protein (Vip3Aa) have been fused to develop a broad-range Vip3Aa-Cry1Ac fusion protein. Cry1Ac and Vip3Aa are non-homologous insecticidal proteins possessing receptors against different targets within the midgut of insects. The insecticidal proteins were fused to broaden the insecticidal activity. Molecular docking analysis of the fusion protein against aminopeptidase-N (APN) and cadherin receptors of five Lepidopteran insects (Agrotis ipsilon, Helicoverpa armigera, Pectinophora gossypiella, Spodoptera exigua, and Spodoptera litura) revealed that the Ser290, Ser293, Leu337, Thr340, and Arg437 residues of the fusion protein are involved in the interaction with insect receptors. The Helicoverpa armigera cadherin receptor, however, showed no interaction, which might be due to either loss or burial of interactive residues inside the fusion protein. These findings revealed that the Vip3Aa-Cry1Ac fusion protein has a strong affinity against Lepidopteran insect receptors and hence has a potential to be an efficient broad-range insecticidal protein.

  19. Nucleopolyhedrovirus Introduction in Australia

    Institute of Scientific and Technical Information of China (English)

    Patrick Buerger; Caroline Hauxwell; David Murray

    2007-01-01

    Nucleopolyhedrovirus (NPV) has become an integral part of integrated pest management (IPM) in many Australian agricultural and horticultural crops. This is the culmination of years of work conducted by researchers at the Queensland Department of Primary Industries and Fisheries (QDPI&F) and Ag Biotech Australia Pty Ltd. In the early 1970's researchers at QDPI&F identified and isolated a virus in Helicoverpa armigera populations in the field. This NPV was extensively studied and shown to be highly specific to Helicoverpa and Heliothis species. Further work showed that when used appropriately the virus could be used effectively to manage these insects in crops such as sorghum, cotton, chickpea and sweet corn. A similar virus was first commercially produced in the USA in the 1970's. This product, Elcar(R), was introduced into Australia in the late 1970's by Shell Chemicals with limited success. A major factor contributing to the poor adoption of Elcar was the concurrent enormous success of the synthetic pyrethroids. The importance of integrated pest management was probably also not widely accepted at that time. Gradual development of insect resistance to synthetic pyrethroids and other synthetic insecticides in Australia and the increased awareness of the importance of IPM meant that researchers once again turned their attentions to environmentally friendly pest management tools such NPV and beneficial insects. In the 1990's a company called Rhone-Poulenc registered an NPV for use in Australian sorghum, chickpea and cotton. This product, Gemstar(R), was imported from the USA. In 2000 Ag Biotech Australia established an in-vivo production facility in Australia to produce commercial volumes of a product similar to the imported product. This product was branded, ViVUS(R), and was first registered and sold commercially in Australia in 2003. The initial production of ViVUS used a virus identical to the American product but replicating it in an Australian Helicoverpa

  20. 频振式杀虫灯在烟草害虫防治中的应用研究%The Application Research of Frequency Trembler Lamp in Control of Tobacco Insect Pest

    Institute of Scientific and Technical Information of China (English)

    孔凡全; 朱列书

    2012-01-01

    为了探索云南烟叶生产中害虫防治的有效方法,在火木龙现代烟草示范区利用频振式杀虫灯开展了烟草主要害虫防治示范试验,结果表明:该杀虫灯把杀虫工作日常化,能有效防止爆发大面积虫害;对蚜茧蜂、食蚜、蝇草蛉等天敌有一定的保护作用,对烟青虫、斜纹夜蛾、金龟子等害虫防效显著;投入成本低,控制面积大,操作简便;通过物理方法诱杀害虫,大大减少农药用量,同时不会使害虫产生抗药性,降低了烟叶农药残留,提高烟叶品质,减少对环境的污染,避免人畜中毒事件发生.这说明频振式杀虫灯具有较好的经济效益、社会效益和生态效益,可在烟草害虫防治中大面积推广使用.%In order to find effective method for controlling insect pests during production of tobacco leaves, a demonstrating experiment for controlling insect pests of tobacco by using frequency trembler lamp were conducted in Huomulong modern tobacco test area. The results showed that this frequency trembler lamp makes the killing insect pests to be routinized, and it can prevent the occurrence of large scale insect pests efficiently. The lamp has certain protection effect for the natural enemy of tobacco insect pests, such as Aphid, Syrphidae and Chrysopidae; meanwhile, it has significant control effect on tobacco insect pests, such as Heliothis assulta Guenee, Prodenia litura and Cheirotonus. The lamp has lots of good characteristics, such as low input and cost, large controlling area, easy use, etc. Using this frequency trembler lamp is a physical way to trapping and killing insect pests, so it will help to reduce pesticide consumption and pesticide residue greatly, and the insects would not have drug resistance, therefore, it can improve tobacco quality, reduce contamination on environment, and avoid poisoning of human and livestock. Therefore, the frequency trembler lamp can be popularized in a large scale for it has good

  1. Development of a bipartite ecdysone-responsive gene switch for the oomycete Phytophthora infestans and its use to manipulate transcription during axenic culture and plant infection.

    Science.gov (United States)

    Gamboa-Meléndez, Heber; Judelson, Howard S

    2015-01-01

    Conditional expression systems have been proven to be useful tools for the elucidation of gene function in many taxa. Here, we report the development of the first useful inducible promoter system for an oomycete, based on an ecdysone receptor (EcR) and the ecdysone analogue methoxyfenozide. In Phytophthora infestans, the potato late blight pathogen, a monopartite transactivator containing the VP16 activation domain from herpes simplex virus, the GAL4 DNA-binding domain from yeast and the EcR receptor domain from the spruce budworm enabled high levels of expression of a β-glucuronidase (GUS) reporter gene, but unacceptable basal activity in the absence of the methoxyfenozide inducer. Greatly improved performance was obtained using a bipartite system in which transcription is activated by a heterodimer between a chimera of VP16 and the migratory locust retinoid X receptor, and a separate EcR-DNA-binding domain chimera. Transformants were obtained that exhibited >100-fold activation of the reporter by methoxyfenozide, with low basal levels of expression and induced activity approaching that of the strong ham34 promoter. Performance varied between transformants, probably as a result of position effects. The addition of methoxyfenozide enabled strong induction during hyphal growth, zoosporogenesis and colonization of tomato. No significant effects of the inducer or transactivators on growth, development or pathogenicity were observed. The technology should therefore be a useful addition to the arsenal of methods for the study of oomycete plant pathogens.

  2. Insect radiosensitivity: dose curves and dose-fractionation studies of dominant lethal mutations in the mature sperm of 4 insect species

    Energy Technology Data Exchange (ETDEWEB)

    LaChance, L.E.; Graham, C.K. (Department of Agriculture, Fargo, ND (USA))

    1984-06-01

    Males of 4 species of insects: Musca domestica L. (housefly) (Diptera), Oncopeltus fasciatus (Dallas) (milkweed bug) (Hemiptera), Anagasta kuhniella (Zeller) (mealmoth) (Lepidoptera) and Heliothis virescens (Fab.) (tobacco budworm) (Lepidoptera) were irradiated as adults. Dose-response curves for the induction of dominant lethal mutations in the mature sperm were constructed. The curves were analyzed mathematically and compared with theoretical computer simulated curves requiring 1, 2, 4, 8 and 16 'hits' for the induction of a dominant lethal mutation. The 4 species belonging to 3 different orders of insects showed a wide range in radiation sensitivity and vastly different dose-response curves. When the data were analyzed by several mathematical models the authors found that a logistic response curve gave reasonably good fit with vastly different parameters for the 4 species. Dose-fractionation experiments showed no reduction in the frequency of lethal mutations induced in any species when an acute dose was fractionated into 2 equal exposures separated by an 8-h period.

  3. Growth Response of Northern White-Cedar (Thuja occidentalis to Natural Disturbances and Partial Cuts in Mixedwood Stands of Quebec, Canada

    Directory of Open Access Journals (Sweden)

    Jean-Claude Ruel

    2014-05-01

    Full Text Available Northern white-cedar (Thuja occidentalis is a species of high commercial and ecological value, the abundance of which has been declining since the middle of the 19th century. Very little information regarding its silviculture in mixedwood stands is currently available, even though a significant portion of wood resources comes from these stands. The present study is a retrospective analysis of white-cedar growth in partially harvested mixedwood stands of western Quebec, Canada. Eight stands distributed across two regions were analyzed. Dendrochronological approaches examined long-term diameter growth for sample white-cedar trees and stems of associated species. These approaches were used to reconstruct stand characteristics at the time of harvesting, together with local harvesting intensity. The study demonstrated white-cedar’s capacity to maintain good growth for long periods of time and at large tree sizes. Accession to the upper canopy positions occurs through repeated episodes of suppression/release, most of which seem to be associated with spruce budworm (Choristoneura fumiferana outbreaks. White-cedar response to partial harvesting varies with tree size, residual basal area and species composition. Growth response was generally stronger for small trees, even though large trees still maintained the best diameter growth. Growth of white-cedar was negatively affected by an increase in softwood proportion in basal area. Growth responses to harvesting could be sustained for a period of 20 years.

  4. Systemic Imidacloprid Affects Intraguild Parasitoids Differently.

    Directory of Open Access Journals (Sweden)

    Sally V Taylor

    Full Text Available Toxoneuron nigriceps (Viereck (Hymenoptera, Braconidae and Campoletis sonorensis (Cameron (Hymenoptera, Ichneumonidae are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius (Lepidoptera, Noctuidae. They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011-2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches.

  5. DIETARY SILVER NANOPARTICLES REDUCE FITNESS IN A BENEFICIAL, BUT NOT PEST, INSECT SPECIES.

    Science.gov (United States)

    Afrasiabi, Zahra; Popham, Holly J R; Stanley, David; Suresh, Dhananjay; Finley, Kristen; Campbell, Jonelle; Kannan, Raghuraman; Upendran, Anandhi

    2016-12-01

    Silver nanoparticles (AgNPs) have antimicrobial and insecticidal properties and they have been considered for their potential use as insecticides. While they do, indeed, kill some insects, two broader issues have not been considered in a critical way. First, reports of insect-lethal AgNPs are often based on simplistic methods that yield nanoparticles of nonuniform shapes and sizes, leaving questions about the precise treatments test insects experienced. Second, we do not know how AgNPs influence beneficial insects. This work addresses these issues. We assessed the influence of AgNPs on life history parameters of two agricultural pest insect species, Heliothis virescens (tobacco budworm) and Trichoplusia ni (cabbage looper) and a beneficial predatory insect species, Podisus maculiventris (spined soldier bug), all of which act in agroecosystems. Rearing the two pest species on standard media amended with AgNPs led to negligible influence on developmental times, pupal weights, and adult emergence, however, they led to retarded development, reductions in adult weight and fecundity, and increased mortality in the predator. These negative effects on the beneficial species, if also true for other beneficial insect species, would have substantial negative implications for continued development of AgNPs for insect pest management programs.

  6. Molecular basis for antifreeze activity difference of two insect antifreeze protein isoforms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The insect spruce budworm(Choristoneura fumiferana) produces antifreeze protein(AFP) to assist in the protection of the over-wintering larval stage and contains multiple isoforms. Structures for two isoforms,known as CfAFP-501 and CfAFP-337,show that both possess similar left-handed β-helical structure,although thermal hysteresis activity of the longer isoform CfAFP-501 is three times that of CfAFP-337. The markedly enhanced activity of CfAFP-501 is not proportional to,and cannot be simply accounted for,by the increased ice-binding site resulting from the two extra coils in CfAFP-501. In or-der to investigate the molecular basis for the activity difference and gain better understanding of AFPs in general,we have employed several different computational methods to systematically study the structural properties and ice interactions of the AFPs and their deletion models. In the context of intact AFPs,a majority of the coils in CfAFP-501 has better ice interaction and causes stronger ice lattice disruption than CfAFP-337,strongly suggesting a cooperative or synergistic effect among β-helical coils. The synergistic effect would play a critical role and make significant contributions to the anti-freeze activity β-helical antifreeze proteins. This is the first time that synergistic effect and its implica-tion for antifreeze activity are reported for β-helical antifreeze proteins.

  7. Molecular basis for antifreeze activity difference of two insect antifreeze protein isoforms

    Institute of Scientific and Technical Information of China (English)

    ZHOU YanXia; TAN HongWei; YANG ZuoYin; JIA ZongChao; LIU RuoZhuang; CHEN GuangJu

    2007-01-01

    The insect spruce budworm (Choristoneura fumiferana) produces antifreeze protein (AFP) to assist in the protection of the over-wintering larval stage and contains multiple isoforms. Structures for two isoforms, known as CfAFP-501 and CfAFP-337, show that both possess similar left-handed β-helical structure, although thermal hysteresis activity of the longer isoform CfAFP-501 is three times that of CfAFP-337. The markedly enhanced activity of CfAFP-501 is not proportional to, and cannot be simply accounted for, by the increased ice-binding site resulting from the two extra coils in CfAFP-501. In order to investigate the molecular basis for the activity difference and gain better understanding of AFPs in general, we have employed several different computational methods to systematically study the structural properties and ice interactions of the AFPs and their deletion models. In the context of intact AFPs, a majority of the coils in CfAFP-501 has better ice interaction and causes stronger ice lattice disruption than CfAFP-337, strongly suggesting a cooperative or synergistic effect among β-helical coils. The synergistic effect would play a critical role and make significant contributions to the antifreeze activity β-helical antifreeze proteins. This is the first time that synergistic effect and its implication for antifreeze activity are reported for β-helical antifreeze proteins.

  8. Insect-induced tree mortality of boreal forests in eastern Canada under a changing climate.

    Science.gov (United States)

    Zhang, Xiongqing; Lei, Yuancai; Ma, Zhihai; Kneeshaw, Dan; Peng, Changhui

    2014-06-01

    Forest insects are major disturbances that induce tree mortality in eastern coniferous (or fir-spruce) forests in eastern North America. The spruce budworm (SBW) (Choristoneura fumiferana [Clemens]) is the most devastating insect causing tree mortality. However, the relative importance of insect-caused mortality versus tree mortality caused by other agents and how this relationship will change with climate change is not known. Based on permanent sample plots across eastern Canada, we combined a logistic model with a negative model to estimate tree mortality. The results showed that tree mortality increased mainly due to forest insects. The mean difference in annual tree mortality between plots disturbed by insects and those without insect disturbance was 0.0680 per year (P climate moisture index (CMI) and decreased significantly with annual minimum temperature (T min), annual mean temperature (T mean) and the number of degree days below 0°C (DD0), which was inconsistent with previous studies (Adams et al. 2009; van Mantgem et al. 2009; Allen et al. 2010). Furthermore, the results for the trends in the magnitude of forest insect outbreaks were consistent with those of climate factors for annual tree mortality. Our results demonstrate that forest insects are the dominant cause of the tree mortality in eastern Canada but that tree mortality induced by insect outbreaks will decrease in eastern Canada under warming climate.

  9. Reduced stability and intracellular transport of dsRNA contribute to poor RNAi response in lepidopteran insects.

    Science.gov (United States)

    Shukla, Jayendra Nath; Kalsi, Megha; Sethi, Amit; Narva, Kenneth E; Fishilevich, Elane; Singh, Satnam; Mogilicherla, Kanakachari; Palli, Subba Reddy

    2016-07-02

    RNA interference (RNAi) has become a widely used reverse genetic tool to study gene function in eukaryotic organisms and is being developed as a technology for insect pest management. The efficiency of RNAi varies among organisms. Insects from different orders also display differential efficiency of RNAi, ranging from highly efficient (coleopterans) to very low efficient (lepidopterans). We investigated the reasons for varying RNAi efficiency between lepidopteran and coleopteran cell lines and also between the Colorado potato beetle, Leptinotarsa decemlineata and tobacco budworm, Heliothis virescens. The dsRNA either injected or fed was degraded faster in H. virescens than in L. decemlineata. Both lepidopteran and coleopteran cell lines and tissues efficiently took up the dsRNA. Interestingly, the dsRNA administered to coleopteran cell lines and tissues was taken up and processed to siRNA whereas the dsRNA was taken up by lepidopteran cell lines and tissues but no siRNA was detected in the total RNA isolated from these cell lines and tissues. The data included in this paper showed that the degradation and intracellular transport of dsRNA are the major factors responsible for reduced RNAi efficiency in lepidopteran insects.

  10. Molecular characterization of prothoracicotropic hormone and diapause hormone in Heliothis virescens during diapause, and a new role for diapause hormone.

    Science.gov (United States)

    Xu, W-H; Denlinger, D L

    2003-10-01

    cDNAs encoding prothoracicotropic hormone (PTTH) and diapause hormone (DH) were isolated from the tobacco budworm, Heliothis virescens (Hvi). Hvi-PTTH cDNA reveals key structural features known from other PTTHs, yet there is a > 30% amino acid difference between the PTTH sequences found in this noctuid when compared with the PTTHs known from Bombycoidea. Hvi-DH-PBAN cDNA encodes a precursor protein including a DH-like peptide, pheromone biosynthesis-activating neuropeptide (PBAN) and three additional neuropeptides with an FXPRL sequence at the C terminus. PTTH and DH-PBAN transcripts are most highly expressed in the brain and subesophageal ganglion (SG), respectively. Expression of both the PTTH and the DH-PBAN transcripts is high in larvae and remains high in nondiapausing pupae, but in larvae programmed for pupal diapause, expression declines sharply at the onset of larval wandering behaviour and remains low during pupal diapause. This pattern implies that both of these genes are shut down during diapause. These results are not consistent with a role for DH in promoting the entry into diapause as noted in Bombyx mori. Instead, the higher expression of DH in nondiapausing pupae suggests a possible role for DH in promoting continuous development. The injection of DH into diapausing pupae did indeed successfully terminate diapause, thus suggesting a possible new role for this neuropeptide.

  11. Systemic Imidacloprid Affects Intraguild Parasitoids Differently.

    Science.gov (United States)

    Taylor, Sally V; Burrack, Hannah J; Roe, R Michael; Bacheler, Jack S; Sorenson, Clyde E

    2015-01-01

    Toxoneuron nigriceps (Viereck) (Hymenoptera, Braconidae) and Campoletis sonorensis (Cameron) (Hymenoptera, Ichneumonidae) are solitary endoparasitoids of the tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera, Noctuidae). They provide biological control of H. virescens populations in Southeastern US agricultural production systems. Field and greenhouse experiments conducted from 2011-2014 compared parasitism rates of parasitoids that developed inside H. virescens larvae fed on tobacco plants treated with and without imidacloprid. The parasitoids in our study did not have a similar response. Toxoneuron nigriceps had reduced parasitism rates, but parasitism rates of C. sonorensis were unaffected. Preliminary data indicate that adult female lifespans of T. nigriceps are also reduced. ELISA was used to measure concentrations of neonicotinoids, imidacloprid and imidacloprid metabolites in H. virescens larvae that fed on imidacloprid-treated plants and in the parasitoids that fed on these larvae. Concentrations were detectable in the whole bodies of parasitized H. virescens larvae, T. nigriceps larvae and T. nigriceps adults, but not in C. sonorensis larvae and adults. These findings suggest that there are effects of imidacloprid on multiple trophic levels, and that insecticide use may differentially affect natural enemies with similar feeding niches.

  12. The nicotinic acetylcholine receptor gene family of the malaria mosquito, Anopheles gambiae.

    Science.gov (United States)

    Jones, Andrew K; Grauso, Marta; Sattelle, David B

    2005-02-01

    Nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission in the insect nervous system and are targets of widely selling insecticides. We have identified the nAChR gene family from the genome of the malaria mosquito vector, Anopheles gambiae, to be the second complete insect nAChR gene family described following that of Drosophila melanogaster. Like Drosophila, Anopheles possesses 10 nAChR subunits with orthologous relationships evident between the two insects. Interestingly, the Anopheles orthologues of Dbeta2 and Dbeta3 possess the vicinal cysteines that define alpha subunits. As with Dalpha4 and Dalpha6, the Anopheles orthologues are alternatively spliced at equivalent exons. Reverse transcription-polymerase chain reaction analysis shows that RNA A-to-I editing sites conserved between Dalpha6 of Drosophila and alpha7-2 of the tobacco budworm, Heliothis virescens, are not shared with the equivalent nAChR subunit of Anopheles. Indeed, RNA-editing sites identified in functionally significant regions of Dbeta1, Dalpha5, and Dalpha6 are not conserved in the mosquito orthologues, indicating considerable divergence of RNA molecules targeted for editing within the insect order Diptera. These findings shed further light on the diversity of nAChR subunits and may present a useful basis for the development of improved malaria control agents by enhancing our understanding of a validated mosquito insecticide target.

  13. Impact of different pH control agents on biopesticidal activity of Bacillus thuringiensis during the fermentation of starch industry wastewater.

    Science.gov (United States)

    Vu, Khanh Dang; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2009-06-01

    Different pH control agents (NaOH/H(2)SO(4)--SodSulp, NaOH/CH(3)COOH--SodAcet, NH(4)OH/CH(3)COOH--AmmoAcet and NH(4)OH/H(2)SO(4)--AmmoSulp) were used to investigate their effects on growth, enzyme production (alkaline protease and amylase), and entomotoxicity of Bacillus thuringiensis var. kurstaki HD-1 (Btk) against eastern spruce budworm larvae (Choristoneura fumiferana) using starch industry wastewater (SIW) as a raw material in a 15-l fermentor. AmmoSulp and SodSulp were found to be the best pH control agents for alkaline protease and amylase production, respectively; whereas, the fermented broth obtained by using SodAcet as pH control agents recorded the highest delta-endotoxin production of 1043.0 mg/l and entomotoxicity value 18.4 x 10(9) SBU/l. Entomotoxicity of re-suspended centrifuged pellet in one-tenth of original volume in case of SodAcet as pH control agents was 26.7 x 10(9) SBU/l and was the highest value compared to three other pH control agents.

  14. Wastewater treatment sludge as a raw material for the production of Bacillus thuringiensis based biopesticides.

    Science.gov (United States)

    Montiel, M D; Tyagi, R D; Valero, J R

    2001-11-01

    Seven wastewater sludges of different origins and types were used as an alternate culture medium for producing Bacillus thuringiensis variety kurstaki HD-1. The sludge samples were used under three different preparations: without pre-treatment, with acid treatment (hydrolysed sludge) and the supernatant obtained after centrifugation of the hydrolysed sludge. The sludge composition varied widely with origin and the type of sludge. Growth and sporulation were evaluated by the total viable cell count and spore count of the preparations. Growth, sporulation and endotoxin production were affected by the sludge origin. Hydrolysed sludge gave the highest viable cell and spore counts while the liquid phase (supernatant) gave the lowest. Non-hydrolysed primary sludge from Valcartier was unable to sustain bacterial growth because of its low pH. Bioassays were conducted against larvae of spruce budworm to evaluate entomotoxic potential of the preparations obtained. In general, sludge hydrolysis increased the entomotoxicity yields. Similar entomotoxicity was observed in Black Lake secondary sludge (4100 IU/microL) as that obtained in the reference soya medium (3800 IU/microL). The use of the sludge supernatant (liquid phase) was not recommended due to the low entomotoxic potential obtained.

  15. Effect of temperature on the fitness of a Vip3A resistant population of Heliothis virescens (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Gulzar, Asim; Pickett, Brian; Sayyed, Ali H; Wright, Denis J

    2012-06-01

    Microbial insecticides derived from the soil bacterium Bacillus thuringiensis (Bt) have become increasingly important for pest management. In addition to crystal (Cry) insecticidal protein toxins formed during sporulation, vegetative insecticidal protein (Vip) toxins can be produced during the vegetative phase. Resistance to Cry toxins has been reported in laboratory- and field-selected populations of various Lepidoptera species and several studies have identified fitness costs associated with Cry toxin resistance. Here, fitness costs are examined in the first insect population to be reported with resistance to a Vip toxin, a laboratory-selected Vip3A-resistant subpopulation of the tobacco budworm, Heliothis virescens (L.) (Vip-Sel). The Vip-Sel population showed reduced survival to adult eclosion compared with an unselected subpopulation at all test temperatures, including the culture temperature (25 degrees C). Vip3A resistance was also associated with reduced egg viability and mating success and a lower intrinsic rate of population increase (r(m)) at temperatures below (20 degrees C) and above (30 degrees C) the optimal laboratory culture temperature. The latter findings agree with previous studies, that fitness costs associated with resistance are usually greater under stressful conditions. Such data can help predict the impact of fitness costs on the rate of development of resistance in the field and in the development of resistance management strategies that more fully exploit fitness costs.

  16. A single gene (yes controls pigmentation of eyes and scales in Heliothis virescens

    Directory of Open Access Journals (Sweden)

    Thomas M. Brown

    2001-02-01

    Full Text Available A yellow-eyed mutant was discovered in a strain of Heliothis virescens, the tobacco budworm, that already exhibited a mutation for yellow scale, y. We investigated the inheritance of these visible mutations as candidate markers for transgenesis. Yellow eye was controlled by a single, recessive, autosomal factor, the same type of inheritance previously known for y. Presence of the recombinant mutants with yellow scales with wild type eyes in test crosses indicated independent segregation of genes for these traits. The recombinant class with wild type scales and yellow eyes was completely absent and there was a corresponding increase of the double mutant parental class having yellow scales and yellow eyes. These results indicated that a single factor for yellow eye also controls yellow scales independently of y. This gene was named yes, for yellow eye and scale. We hypothesize that yes controls both eye and scale color through a deficiency in transport of pigment precursors in both the ommochrome and melanin pathways. The unlinked gene y likely controls an enzyme affecting the melanin pathway only. Both y and yes segregated independently of AceIn, acetylcholinesterase insensitivity, and sodium channel hscp, which are genes related to insecticide resistance.

  17. The role of analytical science in natural resource decision making

    Science.gov (United States)

    Miller, Alan

    1993-09-01

    There is a continuing debate about the proper role of analytical (positivist) science in natural resource decision making. Two diametrically opposed views are evident, arguing for and against a more extended role for scientific information. The debate takes on a different complexion if one recognizes that certain kinds of problem, referred to here as “wicked” or “trans-science” problems, may not be amenable to the analytical process. Indeed, the mistaken application of analytical methods to trans-science problems may not only be a waste of time and money but also serve to hinder policy development. Since many environmental issues are trans-science in nature, then it follows that alternatives to analytical science need to be developed. In this article, the issues involved in the debate are clarified by examining the impact of the use of analytical methods in a particular case, the spruce budworm controversy in New Brunswick. The article ends with some suggestions about a “holistic” approach to the problem.

  18. Wood formation in Abies balsamea seedlings subjected to artificial defoliation.

    Science.gov (United States)

    Rossi, Sergio; Simard, Sonia; Deslauriers, Annie; Morin, Hubert

    2009-04-01

    We determined the cambial sensitivity and quantified the anatomical differences in xylem of Abies balsamea (L.) Mill. seedlings subjected to artificial defoliation to simulate spruce budworm feeding. Defoliation was performed by removing two-thirds of needles of all current-year shoots for up to four consecutive growth cycles to account for inter- and intra-annual xylem formation. In Experiment 1, xylem development was studied from May to October 2005 in seedlings defoliated at the end of June. In Experiment 2, anatomical features of the xylem were measured along the tree rings formed in 2005 and 2006 during the four cycles of growth and defoliation. Control and defoliated seedlings showed similar patterns of cambial activity and timing of xylem differentiation, although fewer enlarging cells were observed in August to September in defoliated seedlings. Tree-ring widths were similar in control and defoliated seedlings, with thinner rings produced in the greenhouse in winter. No effect of defoliation on cell lumen area was observed, and effects on radial cell diameter and wall thickness were found only occasionally. The results indicate that the A. balsamea seedlings produced all the resources required to maintain stem growth during the four cycles of defoliation.

  19. RNA-Seq Study of Microbially Induced Hemocyte Transcripts from Larval Heliothis virescens (Lepidoptera: Noctuidae

    Directory of Open Access Journals (Sweden)

    Kent S. Shelby

    2012-08-01

    Full Text Available Larvae of the tobacco budworm are major polyphagous pests throughout the Americas. Development of effective microbial biopesticides for this and related noctuid pests has been stymied by the natural resistance mediated innate immune response. Hemocytes play an early and central role in activating and coordinating immune responses to entomopathogens. To approach this problem we completed RNA-seq expression profiling of hemocytes collected from larvae following an in vivo challenge with bacterial and fungal cell wall components to elicit an immune response. A de novo exome assembly was constructed by combination of sequence tags from all treatments. Sequence tags from each treatment were aligned separately with the assembly to measure expression. The resulting table of differential expression had > 22,000 assemblies each with a distinct combination of annotation and expression. Within these assemblies > 1,400 were upregulated and > 1,500 downregulated by immune activation with bacteria or fungi. Orthologs to innate immune components of other insects were identified including pattern recognition, signal transduction pathways, antimicrobial peptides and enzymes, melanization and coagulation. Additionally orthologs of components regulating hemocytic functions such as autophagy, apoptosis, phagocytosis and nodulation were identified. Associated cellular oxidative defenses and detoxification responses were identified providing a comprehensive snapshot of the early response to elicitation.

  20. Caractérisation du savoir paysan sur les insectes nuisibles du pois d'Angole (Cajanus Cajan (L. Millsp. dans le Nord de l'Ouganda

    Directory of Open Access Journals (Sweden)

    Velay F.

    2001-01-01

    Full Text Available Characterization of indigenous traditional knowledge on insect pests of pigeonpea (Cajanus cajan (L. Millsp. in Northern Uganda. In order to assess the perception of the main insect pests of pigeonpea (Cajanus cajan (L. Millsp. by small farmers and to inventoriate methods traditionally used to control these insects, a survey was conducted in 41 households of Northern Uganda (Lira and Apac districts. Virtually all small farmers (95/ considered blister beetle (Mylabris sp., which is the most conspicious insect damaging pigeonpea at the flowering stage, as the main pest of the crop. This is conflicting with field observations made earlier in Northern Uganda which pointed out pod borers (Helicoverpa armigera Huebner and Maruca vitrata Geyer and pod sucking bugs (mainly Clavigralla sp. as the most damaging pests for pigeonpea production. A new pest of pigeonpea, Luprops baldius Mueller, was identified during this survey. Its adults and larvae are damaging to mature pods in case of late harvest.

  1. Preliminary studies on differential defense responses induced during plant communication

    Institute of Scientific and Technical Information of China (English)

    Jin Ying PENG; Zhong Hai LI; Hui XIANG; Jian Hua HUANG; Shi Hai JIA; Xue Xia MIAO; Yong Ping HUANG

    2005-01-01

    We compared the expression patterns of three representative genes in undamaged tomato and tobacco plants in response to exposure to either tomato or tobacco fed on by Helicoverpa armigera (cotton bollworm). When tomato and tobacco, two species of one family, were incubated in the chambers with the tomato plants damaged by the cotton bollworm, the expression of the PR1, BGL2, and PAL genes was up-regulated in leaves of both plants. However, the levels of gene expression were significantly higher in the tomato than that in the tobacco. In addition, the activities of enzymes, peroxidase, polyphenol oxidase, and lipoxygenase were found to be higher in the tomato than those in the tobacco. Similar results were obtained when the damaged plants were replaced by the tobacco.

  2. Biological characteristics of Bacillus thuringiensis strain Btll and identification of its cry-type genes

    Institute of Scientific and Technical Information of China (English)

    Tinghui LIU; Wei GUO; Weiming SUN; Yongxiang SUN

    2009-01-01

    A novel strain of Bacillus thuringiensis Bt11, isolated from soil samples in China, was classified and characterized in terms of its crystal proteins, cry genes content. The Bt11 strain showed high toxicity against Spodoptera exigua and Helicoverpa armigera neonates. Btll strain shares morphological and biochemical characteristics with the previously described Bacillus thuringiensis subsp. kurstaki. SDS-polyacrylamide gel electrophoresis revealed that crystals were composed of several polypeptides ranging from 20 to 130 kDa, of which the 35, 80, and 130 kDa proteins were the major components. PCR-RFLP with total DNA from strain Btll and specific primers for cryl, cry2, cry3, cry4/10, cry7, cry8, cry9, and cryll genes revealed that crylAa, crylAb, crylla, and cry9Ea genes were present.

  3. Enhancement of Bacillus thuringiensis insecticidal activity by combining Cry1Ac and bi-functional toxin HWTX-XI from spider.

    Science.gov (United States)

    Sun, Yunjun; Fu, Zujiao; He, Xiaohong; Yuan, Chunhua; Ding, Xuezhi; Xia, Liqiu

    2016-03-01

    In order to assess the potency of bi-functional HWTX-XI toxin from spider Ornithoctonus huwena in improving the insecticidal activity of Bacillus thuringiensis, a fusion gene of cry1Ac and hwtx-XI was constructed and expressed in an acrystalliferous B. thuringiensis strain Cry(-)B. Western blot analysis and microscopic observation revealed that the recombinant strain could express 140-kDa Cry1Ac-HWTX-XI fusion protein and produce parasporal inclusions during sporulation. Bioassay using the larvae of Helicoverpa armigera and Spodoptera exigua showed that the Cry1Ac-HWTX-XI fusion was more toxic than the control Cry1Ac protoxin, as revealed by 95% lethal concentration. Our study indicated that the HWTX-XI from spider might be a candidate for enhancing the toxicity of B. thuringiensis products.

  4. Safety assessment and detection method of genetically modified Chinese Kale (Brassica oleracea cv. alboglabra ).

    Science.gov (United States)

    Lin, Chih-Hui; Lu, Chien-Te; Lin, Hsin-Tang; Pan, Tzu-Ming

    2009-03-11

    Sporamins are tuberous storage proteins and account for 80% of soluble protein in sweet potato tubers with trypsin-inhibitory activity. The expression of sporamin protein in transgenic Chinese kale (line BoA 3-1) conferred insecticidal activity toward corn earworm [ Helicoverpa armigera (Hubner)] in a previous report. In this study, we present a preliminary safety assessment of transgenic Chinese kale BoA 3-1. Bioinformatic and simulated gastric fluid (SGF) analyses were performed to evaluate the allergenicity of sporamin protein. The substantial equivalence between transgenic Chinese kale and its wild-type host has been demonstrated by the comparison of important constituents. A reliable real-time polymerase chain reaction (PCR) detection method was also developed to control sample quality. Despite the results of most evaluations in this study being negative, the safety of sporamin in transgenic Chinese kale BoA 3-1 was uncluded because of the allergenic risk revealed by bioinformatic analysis.

  5. Interactions Between Exogenous Bt Insecticidal Protein and Cotton Terpenoid Aldehydes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong-jun; GUO Yu-yuan; WU Kong-ming; WANG Wu-gang

    2002-01-01

    The contents of terpenoid aldehydes in Bt transgenic cotton and their non-Bt parental varieties were analyzed by the HPLC method. Statistical analysis of variance showed that Bt insecticidal protein Bt-ICP expression has no negative effect on the synthesis of gossypol, total heliocides and total resistant terpenoids.The results of the combined dosage test of Bt-ICP and gossypoi in vitro showed that there is no interaction between gossypol and Bt-ICP on the mortality of cotton boilworm larvae Helicoverpa armigera (Hubnner). It is indicated that the actions of Bt-ICP and gossypol on cotton bollworm are additive. Therefore, it is advantageous to combine Bt-ICP with cotton terpenoid aldehydes in controlling cotton bollworm.

  6. The recent disciplinal progresses of agricultural entomology in China

    Institute of Scientific and Technical Information of China (English)

    Guo Yuyuan; Liang Gemei

    2009-01-01

    In this paper, four recent advances and achievements of China in agricultural insect research, namely, on the genome of silkworm (Bombyx mori Linnaeus), on the geographical differentiation and regional migration of cotton boll-worm (Helicoverpa armigera (Htthner)) , on the standardized monitoring techniques for safety of honey bee (Apis mel-lifera Linnaeus) products, and on the virus transmission property of small brown planthopper (Laodelphax striatellus (Fallén)) as well as the interactions between vector and rice stripe virus (RSV), were reported. All of these resear-ches are very important for controlling agricultural insect pests and the diseases they transmit, accelerating the molecular biological research of silkworm, and promoting the international trade of honey bee products. Most of these achievements mentioned above have got the national, provincial, ministerial or municipal awards on science and technology.

  7. An intracellular toxic protein (Xin) isolated from Xenorhabdus nematophilus strain BJ

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An intracellular toxic protein, designated Xin and with remarkable inhibitory effect on growth of Helicoverpa armigera, was isolated from X. Nematophilus strain BJ by ion exchange chromatography and hydrophobic interaction chromatography. After placing neonates on the artificial diet containing Xin at concentration of 0 or 3.48μg/g for 7 days, the average weight of insects was 23.50mg and 0.55mg, respectively. The activity of Xin was lost by heating, freeze-drying, digestion with proteases or urea. The Xin molecular weight, over kD, was determined by gel filtration on Superose 12, and there were six component proteins analyzed by SDS-PAGE. The results show that Xin is a high molecular protein complex inhibiting growth of insect pest.

  8. Spatial and Temporal Distributions of the Fourth Generation Cotton Bollworm Eggs on Summer Corn Seeded at Different Times in North China

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-ying; HE Kang-lai; WEN Li-ping; ZHANG Guang-yi; ZHENG Li

    2002-01-01

    The spatial and temporal distributions of the cotton bollworm (Helicoverpa armigera Hübner) eggs on summer corn seeded at early-, middle- and late-times were studied in 1998 - 1999 in Hengshui, Hebei Province in North China. There were several egg peaks during the period from the middle to late August, which were coincided with the pollen-shedding or blister stage of summer corn depending on the change of bollworm occurrence. The eggs were mainly deposited on silks of ears, and leaves and sheaths above the ears.The number of eggs laid on middle- and late-seeded summer corn were higher than that on the early-planted one, resulting in more heavy damage the on late-seeded corn.

  9. Unusually high frequency of genes encoding vegetative insecticidal proteins in an Australian Bacillus thuringiensis collection.

    Science.gov (United States)

    Beard, Cheryl E; Court, Leon; Boets, Annemie; Mourant, Roslyn; Van Rie, Jeroen; Akhurst, Raymond J

    2008-09-01

    Of 188 Australian Bacillus thuringiensis strains screened for genes encoding soluble insecticidal proteins by polymerase chain reaction/restriction-length fragment polymorphism (RFLP) analysis, 87% showed the presence of such genes. Although 135 isolates (72%) produced an RFLP pattern identical to that expected for vip3A genes, 29 isolates possessed a novel vip-like gene. The novel vip-like gene was cloned from B. thuringiensis isolate C81, and sequence analysis demonstrated that it was 94% identical to the vip3Ba1 gene. The new gene was designated vip3Bb2. Cell-free supernatants from both the B. thuringiensis strain C81 and from Escherichia coli expressing the Vip3Bb2 protein were toxic for the cotton bollworm, Helicoverpa armigera.

  10. The natural refuge policy for Bt cotton (Gossypium L. in Pakistan – a situation analysis

    Directory of Open Access Journals (Sweden)

    Muhammad Sajjad Ali

    2013-07-01

    Full Text Available Bt cotton (event Cry1Ac was formally commercialized in Pakistan in 2010. However, there has been an increasing trend of planting unauthorized Bt cotton germplasm in farmers' fields since 2003 with a high rate of adoption in the core cotton areas especially in the province Punjab. The transgenic cotton technology has provided the growers with substantial economic benefits and has reduced their dependence on pesticides for pest control, especially against Helicoverpa armigera (Hubner. However, keeping in view the capacity of this insect to develop resistance against novel chemical formulations, it is easily speculated that Bt toxin, too, is no exception. Refuge crop policy for mono transgenic crop events has helped in delaying the rate of resistance evolution in the target pests. Thus, in Pakistan, where planting of structured refuge crops along Bt cotton fields is not mandatory, the effectiveness and durability of Bt cotton technology may decrease due to a number of factors which are discussed in this review.

  11. Supplemental control of lepidopterous pests on Bt transgenic sweet corn with biologically-based spray treatments.

    Science.gov (United States)

    Farrar, Robert R; Shepard, B Merle; Shapiro, Martin; Hassell, Richard L; Schaffer, Mark L; Smith, Chad M

    2009-01-01

    Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn.

  12. Baculovirus per os Infectivity Factors Are Involved in HearNPV ODVs Infection of HzAM1 Cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Ting JIANG; Xiang LI; Jian-hua SONG; Chang-yong LIANG; Xin-wen CHEN

    2008-01-01

    Baculoviruses produce two viral phenotypes, the budded virus (BV) and the occlusion-derived virus (ODV). ODVs are released from occlusion bodies in the midgut where they initiate a primary infection. Due to the lack of an in vitro system, the molecular mechanism of ODV infection is still unclear. Here we present data demonstrating that Helicoverpa armigera nucleopolyhedrovirus (HearNPV) ODV infected cultured Hz-AM1 cells in a pH dependent manner. The optimal pH for ODV infection was 8.5, which is same to that in the microvilli of midgut epithelial cells, the ODV native infection sites. Antibodies neutralization analysis indicated that four HearNPV oral infection essential genes p74, pif-1, pif-2 and pif-3 are also essential for HearNPV ODV infection in vitro. Thus, HearNPV-HzAM1 system can be used to analyze the mechanism of ODV entry.

  13. Struktur Komunitas Hama Pemakan Daun Kubis dan Investigasi Musuh Alaminya

    Directory of Open Access Journals (Sweden)

    KETUT AYU YULIADHI

    2014-01-01

    Full Text Available The data concerning the community of pests that eat and destroy cabbage leaves in Bali has notbeen available yet. However, it is required for the pest control purposes. The aim of the research wasto investigate the structure of pest community that eat and destroy cabbage leaves and to find out theirnatural enemies for controlling the pests. Samples of the pest were collected from the cabbage plantsthat were treated with insecticide and without insecticide (control. The results show that the phytophageinsects that found on both treatments of growing cabbages were Plutella xylostella, Crocidolomiapavonana, Spodoptera litura, Helicoverpa armigera, Chrysodiexis orichalcea, and Aphis brassicae.Natural enemies that found on that area were parasitoid larva Plutella Diadegma semiclausum andpredator Crocidolomia pavonana, Sycanus dichotomus pdf (secured.

  14. Characterization of a novel chitinase, DkChi, from Dendrolimus kikuchii nucleopolyhedrovirus.

    Science.gov (United States)

    Wang, Qinghua; Qu, Liangjian; Zhang, Zhilin; Wang, Yuzhu; Zhang, Yongan

    2013-12-01

    Dendrolimus kikuchii Matsumura nucleopolyhedrovirus (DkNPV) is a novel nucleopolyhedrovirus strain that has exhibited high potential as biological control agent against D. kikuchii. In this work, a 1755-bp DkChi gene with sequence homology to a chitinase gene was cloned from the genomic DNA of DkNPV using a DNA fragment library. The DkChi gene, encoding 558 residues protein with a predicted mass of 61.6 kDa, was expressed at high levels in Escherichia coli and purified by affinity chromatography. We confirmed that the prepared protein was the DkChi protein by mass spectrometry analysis. Enzyme activity analysis showed that DkChi had both endo- and exo-chitinase activities. Interestingly, the DkChi protein displayed a strong insecticidal activity against Spodoptera exigua, Hyphantria cunea, Helicoverpa armigera and Lymantria dispar. The results suggest that DkChi is a good candidate protein for significantly contributing to pest control.

  15. Design, synthesis, and insecticidal activity of some novel diacylhydrazine and acylhydrazone derivatives.

    Science.gov (United States)

    Sun, Jialong; Zhou, Yuanming

    2015-03-30

    In this study a series of diacylhydrazine and acylhydrazone derivatives were designed and synthesized according to the method of active group combination and the principles of aromatic group bioisosterism. The structures of the novel derivatives were determined on the basis on 1H-NMR, IR and ESI-MS spectral data. All of the compounds were evaluated for their in vivo insecticidal activity against the third instar larvae of Spodoptera exigua Hiibner, Helicoverpa armigera Hubner, Plutella xyllostella Linnaeus and Pieris rapae Linne, respectively, at a concentration of 10 mg/L. The results showed that all of the derivatives displayed high insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, metaflumizone and tolfenpyrad, and approximately identical insecticidal activity against H. armigera, P. xyllostella and P. rapae as the references metaflumizone and tolfenpyrad.

  16. Design, Synthesis and Insecticidal Activity of Novel Phenylurea Derivatives

    Directory of Open Access Journals (Sweden)

    Jialong Sun

    2015-03-01

    Full Text Available A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and 1H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity.

  17. Novel hydrazone derivatives containing pyridine amide moiety: Design, synthesis, and insecticidal activity.

    Science.gov (United States)

    Yang, Zai-Bo; Hu, De-Yu; Zeng, Song; Song, Bao-An

    2016-02-15

    A series of novel hydrazone derivatives containing pyridine amide moiety were designed, synthesized, and evaluated for their insecticidal activity. Bioassays indicated that some of the target compounds exhibited good insecticidal activities against Nilaparvata lugens (N. lugens), Plutella xylostella (P. xylostella), Mythimna separata (M. separata), Helicoverpa armigera (H. armigera), Pyrausta nubilalis (P. nubilalis), and Culex pipiens pallens (C. pipiens pallens). In particular, compound 5j revealed excellent insecticidal activity against C. pipiens pallens, with the 50% lethal concentration (LC50) and the 95% lethal concentration (LC95) values of 2.44 and 5.76 mg/L, respectively, which were similar to those of chlorpyrifos (3.26 and 6.98 mg/L, respectively), tebufenozide (1.22 and 2.49 mg/L, respectively), and RH-5849 (2.61 and 6.37 mg/L, respectively). These results indicated that hydrazone derivatives containing pyridine amide moiety could be developed as novel and promising insecticides.

  18. Design, synthesis and insecticidal activity of novel phenylurea derivatives.

    Science.gov (United States)

    Sun, Jialong; Zhou, Yuanming

    2015-03-19

    A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and 1H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity.

  19. Investigation and control on diseases and insect pests of‘No. 5 Weiyu’potato under different planting densities%不同种植密度下‘威芋5号’病虫害种类调查及防治

    Institute of Scientific and Technical Information of China (English)

    李杨; 陈祖瑶; 郑元红; 牟东岭

    2014-01-01

    in this investigation 10 types of diseases and insect pests were found, such as Henosepilachna vigintioctomaculata Motschulsky, Polyphagotarsonemus latus Banks, Acyrthosiphon solani (Kaltenbach), Chrysomelidae Latreille, Helicoverpa armigera Hubner, Streptomyces scabies (Thaxter) Waks.et Henvici, PVY, Phytophthora infestans Mont, Erwinia carotovora subsp and Alternaria solani Sorauer. Incidence rates of diseases and pests increased with plant density. To realize the high yield and good quality cultivation of the‘No. 5 Weiyu’potato cultivars, it was very important to identify the diseases and insect pests correctly and to adopt the integrated control technology.%本次调查总共发现马铃薯病、虫害共10种。分别是马铃薯28星瓢虫(Henosepilachna vigintioctomaculata Motschulsky)、茶黄螨(Polyphagotarsonemus latus Banks)、茄无网蚜(Acyrthosiphon solani Kaltenbach)、叶甲(Chrysomelidae Latreil e)、金针虫(Helicoverpa armigera Hubner)、马铃薯疮痂病(Streptomyces scabies (Thaxter) Waks.et Henvici),马铃薯病毒病(PVY)、马铃薯晚疫病(Phytophthora infestans Mont)、马铃薯软腐病(Erwinia carotovora subsp)和马铃薯早疫病(Alternaria solani Sorauer),病虫害的发生率随着种植密度增大而增加。为保证‘威芋5号’的高产、优产,准确识别病虫害的种类,采用综合防治技术是关键。

  20. Influence of Crop Management and Environmental Factors on Wolf Spider Assemblages (Araneae: Lycosidae) in an Australian Cotton Cropping System.

    Science.gov (United States)

    Rendon, Dalila; Whitehouse, Mary E A; Hulugalle, Nilantha R; Taylor, Phillip W

    2015-02-01

    Wolf spiders (Lycosidae) are the most abundant ground-hunting spiders in the Australian cotton (Gossypium hirsutum L.) agroecosystems. These spiders have potential in controlling pest bollworms, Helicoverpa spp. (Lepidoptera: Noctuidae) in minimum-tilled fields. A study was carried out during a wet growing season (2011-2012) in Narrabri, New South Wales, Australia, to determine how different crop rotations and tillage affect wolf spider assemblages in cotton fields. Spider abundance and species richness did not differ significantly between simple plots (no winter crop) and complex plots (cotton-wheat Triticum aestivum L.-vetch Vicia benghalensis L. rotation). However, the wolf spider biodiversity, as expressed by the Shannon-Weaver and Simpson's indices, was significantly higher in complex plots. Higher biodiversity reflected a more even distribution of the most dominant species (Venatrix konei Berland, Hogna crispipes Koch, and Tasmanicosa leuckartii Thorell) and the presence of more rare species in complex plots. T. leuckartii was more abundant in complex plots and appears to be sensitive to farming disturbances, whereas V. konei and H. crispipes were similarly abundant in the two plot types, suggesting higher resilience or recolonizing abilities. The demographic structure of these three species varied through the season, but not between plot types. Environmental variables had a significant effect on spider assemblage, but effects of environment and plot treatment were overshadowed by the seasonal progression of cotton stages. Maintaining a high density and even distribution of wolf spiders that prey on Helicoverpa spp. should be considered as a conservation biological control element when implementing agronomic and pest management strategies.

  1. 邻苯二甲酰胺类化合物的合成及杀虫活性%Synthesis and Insecticidal Activities of Phthalic Diamides

    Institute of Scientific and Technical Information of China (English)

    韦伟; 朱冰春; 邢家华; 孔小林; 谭成侠; 李小年

    2011-01-01

    [Methods]13 Novel phthalic diamides were synthesized from substituted phthalic anhydride, 2-amino-2-methyipropionitrile and heptafluoroisopropyl aniline.[Results]The chemical structures of the target compounds were confirmed by 1H NMR, IR and MS.And the biological activities of the target compounds were tested.The control effect of compounds 6a against Plutella xylostella, Helicoverpa armigera Hubner and Spodoptera frugiperda were 90, 100 and 75% at the concentration of 0.8 mg/L, against Helicoverpa armigera Hubner and Spodoptera frugiperda were 55 and 50% at the concentration of 0.16 mg/L, respectively.[Conclusions]These novel phthalic diamides showed high insecticidal activities against lepidopterous pests.%[方法]以含取代基的邻苯二甲酸酐、2-氨基-2-甲基丙腈和全氟异丙基苯胺为起始原料,合成了13个未见文献报道的新型邻苯二甲酰胺类化合物.[结果]通过1H NMR、IR和MS确定了化合物的结构,并进行了生物活性测试.其中化合物6a在0.8 mg/L质量浓度下对小菜蛾、棉铃虫和草地贪夜蛾的致死率分别为90%、100%和75%;0.16 mg/L质量浓度下对棉铃虫和草地贪夜蛾的致死率分别为55%和50%.[结论]此类新型的邻苯二甲酰胺类化合物对鳞翅目害虫具有较好的杀虫活性.

  2. Examining mechanisms in the final stages of the elimination of boreal tree species on vulnerable sites in boreal Alaska

    Science.gov (United States)

    Juday, G. P.; Jess, R.; Alix, C. M.; Verbyla, D.

    2015-12-01

    The boreal forest of Alaska and western Canada exist in a complex mosaic of environments determined by elevation, aspect of exposure, and longitudinal and latitudinal gradients of change from warm, dry continental to maritime-influenced conditions. This forest region is largely made up of trees with two growth responses to temperature increases. Trees that decrease in growth are termed negative responders, and occupy warm, dry sites at low elevations. Trees that increase in radial growth are termed positive responders, and are largely in western Alaska, and at high elevation of the Brooks and Alaska Ranges. Since the Pacific climate regime shift of the 1970s, mature trees at low elevation sites have experienced increasing climate stress in several quasi-decadal cycles of intensifying drought stress. NDVI trends and tree ring records demonstrating radial growth decline are coherent. Phenological monitoring of spruce height growth also indicates that depletion of spring soil moisture is a critical process driven by the interaction of early warm season temperatures and precipitation. Novel biotic disturbance agents including spruce budworm, outbreaks of which are triggered by warm temperature anomalies related to its biology, and aspen leaf miner are depressing realized growth below climatically predicted levels, suggesting a pathway by which tree death is likely to occur before absolute temperature limits. As a result, insect outbreaks are degrading the otherwise strong long-term climate signal in Alaska boreal trees. However, young tree (> 40 yrs.) regeneration generally does not yet display the symptoms of acute high temperature stress. Overall, on these vulnerable sites, if temperature increases similar to the past 40 years continue, long term survival prospects are questionable because the climate conditions would be outside the limits that have historically defined the species ranges of aspen, Alaska birch, and black and white spruce.

  3. Effect of ecdysteroid UDP-glucosyltransferase gene deletion on efficacy of a baculovirus against Heliothis virescens and Trichoplusia ni (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Treacy, M F; All, J N; Ghidiu, G M

    1997-10-01

    Laboratory, greenhouse, and field studies were conducted to characterize the biological activity of a genetically altered form of Autographa californica (Speyer) nucleopolyhedrosis virus (AcNPV). The altered baculovirus (vEGTDEL) had a deletion in the ecdysteroid UDP-glucosyltransferase gene. Results from bioassays conducted with neonate and 3rd-instar tobacco budworm, Heliothis virescens (F.), as well as with 3rd-instar cabbage looper, Trichoplusia ni (Hübner), showed vEGTDEL caused larval death slightly, but significantly, quicker than AcNPV. Based on supposition (LT50 values were not calculated), it appeared that larval mortality occurred 0.5-1.0 d faster following exposure to vEGTDEL versus AcNPV. Greenhouse studies conducted against H. virescens on cotton showed that hastened virulence exhibited by vEGTDEL led to improved plant protection versus AcNPV. For example, following 5 weekly sessions of foliar application and H. virescens artificial infestation, cotton treated with wettable powder formulations of vEGTDEL or AcNPV at 2.5 x 10(12) OB/ha averaged 25.7 and 61.8% damaged flower buds, respectively. Although vEGTDEL tended to provide more consistent control of T. ni than AcNPV in greenhouse and field trials conducted on leafy vegetables, differences in efficacy between the 2 baculoviruses were marginal and usually not statistically significant. Generally, results from these studies suggest that genetic modification of NPVs to hasten their lethal effect may be a promising strategy for improving the insecticidal properties of the insect-specific pathogens.

  4. Do insect outbreaks reduce the severity of subsequent forest fires?

    Science.gov (United States)

    Meigs, Garrett W.; Zald, Harold S. J.; Campbell, John L.; Keeton, William S.; Kennedy, Robert E.

    2016-04-01

    Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect-fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect-fire events (n = 81 spanning 1987-2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change.

  5. The use of Bacillus thuringiensis on Forest Integrated Pest Management%苏云金杆菌在森林害虫综合治理中的应用

    Institute of Scientific and Technical Information of China (English)

    李贵明; 张响乐; 万鲁全

    2001-01-01

    Bacillus thuringiensis is a major microbial insecticide and a source of genes encoding several proteins toxic to insects. In this paper the authors give a brief summary of Bacillus thuringiensis used on the integrated pest management in forestry. The derivatives of Bt strain HD1 subsp kurstaki have been widely used to control the for-est pests such as the gypsy moth (Lymantria dispar), spruce budworm (Choristoneura fumiferana), the pine proc-essionary moth (Thaumetopoea pityocampa), the European pine shoot moth (Rhyacionia buoliana) and the nun moth (Lymantria monacha). Some progresses of transferring and expressing Bt toxin gene in forest trees are of-fered with a discussion on the limits and future prospects of using Bt products in forestry.%苏云金杆菌是一种重要的微生物杀虫剂,而且能够编码几种昆虫毒蛋白基因。本文概述了苏云金杆菌在森林害虫综合治理中的应用。苏云金杆菌HD1菌株及其衍生物被广泛用于防治各种森林害虫,如Lymantria dispar, Choristoneura fumiferana, Thaumetopoea pityocampa, Rhyacionia buoliana和Lymantria monacha。文章提供了Bt毒蛋白基因在林木中的构建和表达方面的研究进展并对Bt产品在森林害虫综合治理上的应用前景及限制因素进行了初步讨论。

  6. Induced production of chitinase to enhance entomotoxicity of Bacillus thuringiensis employing starch industry wastewater as a substrate.

    Science.gov (United States)

    Vu, Khanh Dang; Yan, S; Tyagi, R D; Valéro, J R; Surampalli, R Y

    2009-11-01

    Induced production of chitinase during bioconversion of starch industry wastewater (SIW) to Bacillus thuringiensis var. kurstaki HD-1 (Btk) based biopesticides was studied in shake flask as well as in computer-controlled fermentors. SIW was fortified with different concentrations (0%; 0.05%; 0.1%; 0.2%; 0.3% w/v) of colloidal chitin and its consequences were ascertained in terms of Btk growth (total cell count and viable spore count), chitinase, protease and amylase activities and entomotoxicity. At optimum concentration of 0.2% w/v colloidal chitin, the entomotoxicity of fermented broth and suspended pellet was enhanced from 12.4x10(9) (without chitin) to 14.4x10(9) SBU/L and from 18.2x10(9) (without chitin) to 25.1x10(9) SBU/L, respectively. Further, experiments were conducted for Btk growth in a computer-controlled 15 L bioreactor using SIW as a raw material with (0.2% w/v chitin, to induce chitinase) and without fortification of colloidal chitin. It was found that the total cell count, spore count, delta-endotoxin concentration (alkaline solubilised insecticidal crystal proteins), amylase and protease activities were reduced whereas the entomotoxicity and chitinase activity was increased with chitin fortification. The chitinase activity attained a maximum value at 24 h (15 mU/ml) and entomotoxicity of suspended pellet reached highest (26.7x10(9) SBU/L) at 36 h of fermentation with chitin supplementation of SIW. In control (without chitin), the highest value of entomotoxicity of suspended pellet (20.5x10(9) SBU/L) reached at 48 h of fermentation. A quantitative synergistic action of delta-endotoxin concentration, spore concentration and chitinase activity on the entomotoxicity against spruce budworm larvae was observed.

  7. A naturally occurring plant cysteine protease possesses remarkable toxicity against insect pests and synergizes Bacillus thuringiensis toxin.

    Science.gov (United States)

    Mohan, Srinidi; Ma, Peter W K; Williams, W Paul; Luthe, Dawn S

    2008-03-12

    When caterpillars feed on maize (Zea maize L.) lines with native resistance to several Lepidopteran pests, a defensive cysteine protease, Mir1-CP, rapidly accumulates at the wound site. Mir1-CP has been shown to inhibit caterpillar growth in vivo by attacking and permeabilizing the insect's peritrophic matrix (PM), a structure that surrounds the food bolus, assists in digestion and protects the midgut from microbes and toxins. PM permeabilization weakens the caterpillar defenses by facilitating the movement of other insecticidal proteins in the diet to the midgut microvilli and thereby enhancing their toxicity. To directly determine the toxicity of Mir1-CP, the purified recombinant enzyme was directly tested against four economically significant Lepidopteran pests in bioassays. Mir1-CP LC(50) values were 1.8, 3.6, 0.6, and 8.0 ppm for corn earworm, tobacco budworm, fall armyworm and southwestern corn borer, respectively. These values were the same order of magnitude as those determined for the Bacillus thuringiensis toxin Bt-CryIIA. In addition to being directly toxic to the larvae, 60 ppb Mir1-CP synergized sublethal concentrations of Bt-CryIIA in all four species. Permeabilization of the PM by Mir1-CP probably provides ready access to Bt-binding sites on the midgut microvilli and increases its activity. Consequently, Mir1-CP could be used for controlling caterpillar pests in maize using non-transgenic approaches and potentially could be used in other crops either singly or in combination with Bt-toxins.

  8. Less pollen-mediated gene flow for more signatures of glacial lineages: congruent evidence from balsam fir cpDNA and mtDNA for multiple refugia in eastern and central North America.

    Directory of Open Access Journals (Sweden)

    Benjamin Cinget

    Full Text Available The phylogeographic structure and postglacial history of balsam fir (Abies balsamea, a transcontinental North American boreal conifer, was inferred using mitochondrial DNA (mtDNA and chloroplast DNA (cpDNA markers. Genetic structure among 107 populations (mtDNA data and 75 populations (cpDNA data was analyzed using Bayesian and genetic distance approaches. Population differentiation was high for mtDNA (dispersed by seeds only, but also for cpDNA (dispersed by seeds and pollen, indicating that pollen gene flow is more restricted in balsam fir than in other boreal conifers. Low cpDNA gene flow in balsam fir may relate to low pollen production due to the inherent biology of the species and populations being decimated by recurrent spruce budworm epidemics, and/or to low dispersal of pollen grains due to their peculiar structural properties. Accordingly, a phylogeographic structure was detected using both mtDNA and cpDNA markers and population structure analyses supported the existence of at least five genetically distinct glacial lineages in central and eastern North America. Four of these would originate from glacial refugia located south of the Laurentide ice sheet, while the last one would have persisted in the northern Labrador region. As expected due to reduced pollen-mediated gene flow, congruence between the geographic distribution of mtDNA and cpDNA lineages was higher than in other North American conifers. However, concordance was not complete, reflecting that restricted but nonetheless detectable cpDNA gene flow among glacial lineages occurred during the Holocene. As a result, new cpDNA and mtDNA genome combinations indicative of cytoplasmic genome capture were observed.

  9. Baseline susceptibility to Cry1Ac insecticidal protein in Heliothis virescens (Lepidoptera: Noctuidae) populations in Brazil.

    Science.gov (United States)

    Albernaz, K C; Merlin, B L; Martinelli, S; Head, G P; Omoto, C

    2013-08-01

    The tobacco budworm, Heliothis virescens (F.), is one of the target pests of genetically modified cotton expressing Cry1Ac insecticidal protein (Bt cotton) derived from Bacillus thuringiensis Berliner. This study was conducted to evaluate the susceptibility of field-collected populations of H. virescens to Cry1Ac to establish a baseline for use in an insect resistance management program for Bt cotton in Brazil. Insects were sampled from the main Brazilian cotton-growing regions (Bahia, Mato Grosso, Mato Grosso do Sul, and Goiás) during the cropping seasons of 2007/08 and 2008/09. Cry1Ac susceptibility was estimated by using diet incorporation bioassays. H. virescens was highly susceptible to Cry1Ac protein. The estimated LC50 values varied from 0.18 to 0.66 microg of Cry1Ac/ml of diet among the 2007-2008 populations (approximately 3.7-fold variation). Similarly, the EC50 values based on growth inhibition ranged from 0.0053 to 0.0161 microg of Cry1Ac/ml of diet for the 2007-2008 populations (approximately 3.0-fold variation). A joint analysis of the mortality data across all tested populations was used to develop and validate the diagnostic concentrations of 3.1 and 5.6 microg of Cry1Ac/ml of diet, the upper bound of the confidence interval and twice the LC99 were selected, for resistance monitoring programs of H. virescens to Cry1Ac protein in Brazil.

  10. A naturally occurring plant cysteine protease possesses remarkable toxicity against insect pests and synergizes Bacillus thuringiensis toxin.

    Directory of Open Access Journals (Sweden)

    Srinidi Mohan

    Full Text Available When caterpillars feed on maize (Zea maize L. lines with native resistance to several Lepidopteran pests, a defensive cysteine protease, Mir1-CP, rapidly accumulates at the wound site. Mir1-CP has been shown to inhibit caterpillar growth in vivo by attacking and permeabilizing the insect's peritrophic matrix (PM, a structure that surrounds the food bolus, assists in digestion and protects the midgut from microbes and toxins. PM permeabilization weakens the caterpillar defenses by facilitating the movement of other insecticidal proteins in the diet to the midgut microvilli and thereby enhancing their toxicity. To directly determine the toxicity of Mir1-CP, the purified recombinant enzyme was directly tested against four economically significant Lepidopteran pests in bioassays. Mir1-CP LC(50 values were 1.8, 3.6, 0.6, and 8.0 ppm for corn earworm, tobacco budworm, fall armyworm and southwestern corn borer, respectively. These values were the same order of magnitude as those determined for the Bacillus thuringiensis toxin Bt-CryIIA. In addition to being directly toxic to the larvae, 60 ppb Mir1-CP synergized sublethal concentrations of Bt-CryIIA in all four species. Permeabilization of the PM by Mir1-CP probably provides ready access to Bt-binding sites on the midgut microvilli and increases its activity. Consequently, Mir1-CP could be used for controlling caterpillar pests in maize using non-transgenic approaches and potentially could be used in other crops either singly or in combination with Bt-toxins.

  11. Snowmelt as a driver of ecosystem response in water limited mountain forests of the Western U.S.

    Science.gov (United States)

    Molotch, N. P.; Trujillo, E.

    2015-12-01

    Recent large-scale changes in snow cover over Western North America associated with climate warming may have widespread impacts on water availability. These changes have potentially varied impacts on water availability as snowmelt influences, soil moisture, streamflow, and evapotranspiration. These changes may significantly alter runoff production and gross primary productivity in mountain forests. Analysis of remotely sensed and in situ soil moisture data indicate strong sensitivities of the timing of peak soil moisture to the timing of snowmelt. Observations of vegetation greenness indicate strong forest and understory growth dependencies associated with snow accumulation, snowmelt, and soil moisture with peak snow water equivalent explaining 40-50% of inter-annual greenness variability in the Rocky Mountains. Examples of these dependencies will be presented based on the 2012 drought in the Southwestern US whereby near record low snow accumulation and record high potential evapotranspiration have resulted in record low forest greening as evident in the 30+ year satellite record. Forest response to aridity in 2012 was exacerbated by forest disturbance with greenness anomalies 90% greater in magnitude in Bark Beetle and Spruce Budworm affected areas versus undisturbed areas and 182% greater in magnitude in areas impacted by fire. Greenness sensitivities to aridity showed seasonal dependencies with record high Normalized Difference Vegetation Index (NDVI) values in April (14% above average) and record low NDVI values in July (7% below average). Gross primary productivity estimates from the Moderate Resolution Imaging Spectroradiometer (MODIS) and from the Niwot Ridge, Colorado Ameriflux tower indicate record high April GPP (30% and 90% above average for MODIS and the tower, respectively) and record low July GPP (19% and 30% below average, respectively). These energy, water, ecosystem relationships indicate that the sensitivity of ecosystems to changes in climate is

  12. Generation of a Transcriptome in a Model Lepidopteran Pest, Heliothis virescens, Using Multiple Sequencing Strategies for Profiling Midgut Gene Expression.

    Directory of Open Access Journals (Sweden)

    Omaththage P Perera

    Full Text Available Heliothine pests such as the tobacco budworm, Heliothis virescens (F., pose a significant threat to production of a variety of crops and ornamental plants and are models for developmental and physiological studies. The efforts to develop new control measures for H. virescens, as well as its use as a relevant biological model, are hampered by a lack of molecular resources. The present work demonstrates the utility of next-generation sequencing technologies for rapid molecular resource generation from this species for which lacks a sequenced genome. In order to amass a de novo transcriptome for this moth, transcript sequences generated from Illumina, Roche 454, and Sanger sequencing platforms were merged into a single de novo transcriptome assembly. This pooling strategy allowed a thorough sampling of transcripts produced under diverse environmental conditions, developmental stages, tissues, and infections with entomopathogens used for biological control, to provide the most complete transcriptome to date for this species. Over 138 million reads from the three platforms were assembled into the final set of 63,648 contigs. Of these, 29,978 had significant BLAST scores indicating orthologous relationships to transcripts of other insect species, with the top-hit species being the monarch butterfly (Danaus plexippus and silkworm (Bombyx mori. Among identified H. virescens orthologs were immune effectors, signal transduction pathways, olfactory receptors, hormone biosynthetic pathways, peptide hormones and their receptors, digestive enzymes, and insecticide resistance enzymes. As an example, we demonstrate the utility of this transcriptomic resource to study gene expression profiling of larval midguts and detect transcripts of putative Bacillus thuringiensis (Bt Cry toxin receptors. The substantial molecular resources described in this study will facilitate development of H. virescens as a relevant biological model for functional genomics and for new

  13. 苏云金芽胞杆菌6618杀虫菌株的分离和鉴定%Isolation and Characterization of an Insecticidal Bacillus thuringiensis Strain 6618

    Institute of Scientific and Technical Information of China (English)

    张晨; 黄菲; 陆秀青; 谢俊雁; 丁学知; 夏立秋; 孙运军

    2015-01-01

    从我国不同地区采集118份土样,利用温度筛选法分离获得一株苏云金芽胞杆菌( Bacillus thuringien-sis,简称Bt)6618,镜检观察发现该菌株能产生典型的菱形晶体,PCR分析表明其含有cry1类杀虫基因。采用SDS-PAGE和质谱分析发现该菌株主要产生130 kD原毒素,其组分由Cry1Ae和Cry1Ac原毒素组成。基因序列分析表明该菌株的cry1 Ac基因为已知的 cry1 Ac1,而 cry1 Ae为新型杀虫基因。毒力生测表明该菌株对棉铃虫( Helicoverpa armigera)幼虫具有显著的杀虫效果。筛选获得的高毒力Bt菌株6618为丰富我国苏云金芽胞杆菌储备和研发新型高效生物杀虫剂提供了菌株资源。%118 soil samples were collected from different parts of our country and a new Bacillus thuringiensis strain 6618 was isolated by temperature screening method. This strain could produce typical bipyramidal crystal under micro-scope observation. PCR analysis showed that it contained cry1-type gene. SDS-PAGE analysis indicated that this strain expressed a major protein band about 130 kD, which was verified by mass spectrometry analysis to be the products of Cry1Ae and Cry1Ac protoxins. Sequence analysis showed that the cry1Ac gene in this strain was identical to the pub-lished cry1Ac1 gene, while the cry1Ae gene was found to be different from the known gene. The crystal-spore mixture of the strain 6618 exhibited high toxicity towards the larvae of Helicoverpa armigera. The isolated Bacillus thuringiensis strain 6618 with high toxicity will not only enrich the reserve of Bacillus thuringiensis strains of our country, but also pro-vide resource for the development of new efficient biological pesticide.

  14. Defensive Sesquiterpenoids from Leaves of Eupatorium adenophorum

    Institute of Scientific and Technical Information of China (English)

    石伟; 骆世洪; 黎胜红

    2012-01-01

    The invasive plant Eupatorium adenophorum Spreng has caused great economic loss in China, and is gravely threatening the native biodiversity and ecosystem. The plant has been phytochemically investigated for the defen- sive chemical substances in its leaves. Three active sesquiterpenoids were isolated and identified, which include a new sesquiterpenoid (1), and two known sesquiterpenoids (2, 3). Their structures were established by spectroscopic studies such as 1D- and 2D-NMR and MS analyses. Meanwhile, the antifeedant activities of these compounds against two generalist plant-feeding insects, Helicoverpa armigera and Spodoptera exigua, were carried out. Com- pound 1 showed significant antifeedant activity against S. exigua with ECs0 = 7.46 μg/cm^2, while compounds 2 and 3 were more active against H. armigera (EC50=2.57 and 3.04 μg/cm^2 respectively). These findings suggest a de- fensive role of sesquiterpenoids in E. adenophorum against herbivores.

  15. Identification and Characterization of Maize salmon silks Genes Involved in Insecticidal Maysin Biosynthesis[OPEN

    Science.gov (United States)

    Falcone-Ferreyra, María Lorena; Rodríguez, Eduardo; Engelmeier, Jacob; Grotewold, Erich

    2016-01-01

    The century-old maize (Zea mays) salmon silks mutation has been linked to the absence of maysin. Maysin is a C-glycosyl flavone that, when present in silks, confers natural resistance to the maize earworm (Helicoverpa zea), which is one of the most damaging pests of maize in America. Previous genetic analyses predicted Pericarp Color1 (P1; R2R3-MYB transcription factor) to be epistatic to the sm mutation. Subsequent studies identified two loci as being capable of conferring salmon silks phenotypes, salmon silks1 (sm1) and sm2. Benefitting from available sm1 and sm2 mapping information and from knowledge of the genes regulated by P1, we describe here the molecular identification of the Sm1 and Sm2 gene products. Sm2 encodes a rhamnosyl transferase (UGT91L1) that uses isoorientin and UDP-rhamnose as substrates and converts them to rhamnosylisoorientin. Sm1 encodes a multidomain UDP-rhamnose synthase (RHS1) that converts UDP-glucose into UDP-l-rhamnose. Here, we demonstrate that RHS1 shows unexpected substrate plasticity in converting the glucose moiety in rhamnosylisoorientin to 4-keto-6-deoxy glucose, resulting in maysin. Both Sm1 and Sm2 are direct targets of P1, as demonstrated by chromatin immunoprecipitation experiments. The molecular characterization of Sm1 and Sm2 described here completes the maysin biosynthetic pathway, providing powerful tools for engineering tolerance to maize earworm in maize and other plants. PMID:27221383

  16. Large-scale test of the natural refuge strategy for delaying insect resistance to transgenic Bt crops.

    Science.gov (United States)

    Jin, Lin; Zhang, Haonan; Lu, Yanhui; Yang, Yihua; Wu, Kongming; Tabashnik, Bruce E; Wu, Yidong

    2015-02-01

    The 'natural refuge strategy" for delaying insect resistance to transgenic cotton that produces insecticidal proteins from Bacillus thuringiensis (Bt) relies on refuges of host plants other than cotton that do not make Bt toxins. We tested this widely adopted strategy by comparing predictions from modeling with data from a four-year field study of cotton bollworm (Helicoverpa armigera) resistance to transgenic cotton producing Bt toxin Cry1Ac in six provinces of northern China. Bioassay data revealed that the percentage of resistant insects increased from 0.93% in 2010 to 5.5% in 2013. Modeling predicted that the percentage of resistant insects would exceed 98% in 2013 without natural refuges, but would increase to only 1.1% if natural refuges were as effective as non-Bt cotton refuges. Therefore, the results imply that natural refuges delayed resistance, but were not as effective as an equivalent area of non-Bt cotton refuges. The percentage of resistant insects with nonrecessive inheritance of resistance increased from 37% in 2010 to 84% in 2013. Switching to Bt cotton producing two or more toxins and integrating other control tactics could slow further increases in resistance.

  17. Transgenic plants expressing the AaIT/GNA fusion protein show increased resistance and toxicity to both chewing and sucking pests.

    Science.gov (United States)

    Liu, Shu-Min; Li, Jie; Zhu, Jin-Qi; Wang, Xiao-Wei; Wang, Cheng-Shu; Liu, Shu-Sheng; Chen, Xue-Xin; Li, Sheng

    2016-04-01

    The adoption of pest-resistant transgenic plants to reduce yield losses and decrease pesticide use has been successful. To achieve the goal of controlling both chewing and sucking pests in a given transgenic plant, we generated transgenic tobacco, Arabidopsis, and rice plants expressing the fusion protein, AaIT/GNA, in which an insecticidal scorpion venom neurotoxin (Androctonus australis toxin, AaIT) is fused to snowdrop lectin (Galanthus nivalis agglutinin, GNA). Compared with transgenic tobacco and Arabidopsis plants expressing AaIT or GNA, transgenic plants expressing AaIT/GNA exhibited increased resistance and toxicity to one chewing pest, the cotton bollworm, Helicoverpa armigera. Transgenic tobacco and rice plants expressing AaIT/GNA showed increased resistance and toxicity to two sucking pests, the whitefly, Bemisia tabaci, and the rice brown planthopper, Nilaparvata lugens, respectively. Moreover, in the field, transgenic rice plants expressing AaIT/GNA exhibited a significant improvement in grain yield when infested with N. lugens. This study shows that expressing the AaIT/GNA fusion protein in transgenic plants can be a useful approach for controlling pests, particularly sucking pests which are not susceptible to the toxin in Bt crops.

  18. Jasmonate response decay and defense metabolite accumulation contributes to age-regulated dynamics of plant insect resistance

    Science.gov (United States)

    Mao, Ying-Bo; Liu, Yao-Qian; Chen, Dian-Yang; Chen, Fang-Yan; Fang, Xin; Hong, Gao-Jie; Wang, Ling-Jian; Wang, Jia-Wei; Chen, Xiao-Ya

    2017-01-01

    Immunity deteriorates with age in animals but comparatively little is known about the temporal regulation of plant resistance to herbivores. The phytohormone jasmonate (JA) is a key regulator of plant insect defense. Here, we show that the JA response decays progressively in Arabidopsis. We show that this decay is regulated by the miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9) group of proteins, which can interact with JA ZIM-domain (JAZ) proteins, including JAZ3. As SPL9 levels gradually increase, JAZ3 accumulates and the JA response is attenuated. We provide evidence that this pathway contributes to insect resistance in young plants. Interestingly however, despite the decay in JA response, older plants are still comparatively more resistant to both the lepidopteran generalist Helicoverpa armigera and the specialist Plutella xylostella, along with increased accumulation of glucosinolates. We propose a model whereby constitutive accumulation of defense compounds plays a role in compensating for age-related JA-response attenuation during plant maturation. PMID:28067238

  19. Cis-mediated down-regulation of a trypsin gene associated with Bt resistance in cotton bollworm.

    Science.gov (United States)

    Liu, Chenxi; Xiao, Yutao; Li, Xianchun; Oppert, Brenda; Tabashnik, Bruce E; Wu, Kongming

    2014-11-27

    Transgenic plants producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) are useful for pest control, but their efficacy is reduced when pests evolve resistance. Here we examined the mechanism of resistance to Bt toxin Cry1Ac in the laboratory-selected LF5 strain of the cotton bollworm, Helicoverpa armigera. This strain had 110-fold resistance to Cry1Ac protoxin and 39-fold resistance to Cry1Ac activated toxin. Evaluation of five trypsin genes revealed 99% reduced transcription of one trypsin gene (HaTryR) was associated with resistance. Silencing of this gene with RNA interference in susceptible larvae increased their survival on diets containing Cry1Ac. Bioassays of progeny from crosses revealed that resistance to Cry1Ac was genetically linked with HaTryR. We identified mutations in the promoter region of HaTryR in the resistant strain. In transfected insect cell lines, transcription was lower when driven by the resistant promoter compared with the susceptible promoter, implicating cis-mediated down-regulation of HaTryR transcription as a mechanism of resistance. The results suggest that H. armigera can adapt to Bt toxin Cry1Ac by decreased expression of trypsin. Because trypsin activation of protoxin is a critical step in toxicity, transgenic plants with activated toxins rather than protoxins might increase the durability of Bt crops.

  20. Cross-resistance and interactions between Bt toxins Cry1Ac and Cry2Ab against the cotton bollworm.

    Science.gov (United States)

    Wei, Jizhen; Guo, Yuyuan; Liang, Gemei; Wu, Kongming; Zhang, Jie; Tabashnik, Bruce E; Li, Xianchun

    2015-01-14

    To delay evolution of pest resistance to transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt), the "pyramid" strategy uses plants that produce two or more toxins that kill the same pest. We conducted laboratory diet experiments with the cotton bollworm, Helicoverpa armigera, to evaluate cross-resistance and interactions between two toxins in pyramided Bt cotton (Cry1Ac and Cry2Ab). Selection with Cry1Ac for 125 generations produced 1000-fold resistance to Cry1Ac and 6.8-fold cross-resistance to Cry2Ab. Selection with Cry2Ab for 29 generations caused 5.6-fold resistance to Cry2Ab and 61-fold cross-resistance to Cry1Ac. Without exposure to Bt toxins, resistance to both toxins decreased. For each of the four resistant strains examined, 67 to 100% of the combinations of Cry1Ac and Cry2Ab tested yielded higher than expected mortality, reflecting synergism between these two toxins. Results showing minor cross-resistance to Cry2Ab caused by selection with Cry1Ac and synergism between these two toxins against resistant insects suggest that plants producing both toxins could prolong the efficacy of Bt cotton against this pest in China. Including toxins against which no cross-resistance occurs and integrating Bt cotton with other control tactics could also increase the sustainability of management strategies.

  1. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Directory of Open Access Journals (Sweden)

    Fei Yang

    Full Text Available To counter the threat of insect resistance, Bacillus thuringiensis (Bt maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag, as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie. Cross-pollination in RIB caused a majority (>90% of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  2. A challenge for the seed mixture refuge strategy in Bt maize: impact of cross-pollination on an ear-feeding pest, corn earworm.

    Science.gov (United States)

    Yang, Fei; Kerns, David L; Head, Graham P; Leonard, B Rogers; Levy, Ronnie; Niu, Ying; Huang, Fangneng

    2014-01-01

    To counter the threat of insect resistance, Bacillus thuringiensis (Bt) maize growers in the U.S. are required to plant structured non-Bt maize refuges. Concerns with refuge compliance led to the introduction of seed mixtures, also called RIB (refuge-in-the-bag), as an alternative approach for implementing refuge for Bt maize products in the U.S. Maize Belt. A major concern in RIB is cross-pollination of maize hybrids that can cause Bt proteins to be present in refuge maize kernels and negatively affect refuge insects. Here we show that a mixed planting of 5% nonBt and 95% Bt maize containing the SmartStax traits expressing Cry1A.105, Cry2Ab2 and Cry1F did not provide an effective refuge for an important above-ground ear-feeding pest, the corn earworm, Helicoverpa zea (Boddie). Cross-pollination in RIB caused a majority (>90%) of refuge kernels to express ≥ one Bt protein. The contamination of Bt proteins in the refuge ears reduced neonate-to-adult survivorship of H. zea to only 4.6%, a reduction of 88.1% relative to larvae feeding on ears of pure non-Bt maize plantings. In addition, the limited survivors on refuge ears had lower pupal mass and took longer to develop to adults.

  3. Small GTPase Rab4b participates in the gene transcription of 20-hydroxyecdysone and insulin pathways to regulate glycogen level and metamorphosis.

    Science.gov (United States)

    Hou, Li; Cai, Mei-Juan; Liu, Wen; Song, Qian; Zhao, Xiao-Fan

    2012-11-01

    The insulin and 20-hydroxyecdysone (20E) pathways coordinately regulate insect growth and metamorphosis. However, the molecular mechanism of the interaction of these two pathways in regulating insect development is not well understood. In the present study, we found that a small GTPase Rab4b from a lepidopteran insect Helicoverpa armigera participates in gene transcription in the two pathways. The results show that RNA interference of Rab4b in larvae results in a decrease in glycogen levels, small pupae, abnormal metamorphic transition, or larval death. The molecular mechanisms are demonstrated that knockdown of Rab4b in the larvae suppresses the transcription of glycogen synthase (GS), as well as the metamorphic-initiating factor (Br) and hormone receptor 3 (HR3), but increases the transcription of Forkhead box class O (FOXO). Further studies in the cell line confirm that Rab4b is necessary for gene transcription in the insulin and 20E pathways. Rab4b locates in the cytoplasm and takes part in regulation on FOXO cytoplasmic location by insulin induction, but travels toward the cell membrane upon 20E induction without affecting the FOXO location. The transcription of Rab4b could be upregulated by insulin injection or glucose feeding to the larvae, but not by 20E or juvenile hormone analogy methoprene. Our data suggest that Rab4b takes part in metamorphosis by regulating gene transcription and glycogen level in the insulin and 20E pathways.

  4. A screening of five Bacillus thuringiensis Vip3A proteins for their activity against lepidopteran pests.

    Science.gov (United States)

    Ruiz de Escudero, Iñigo; Banyuls, Núria; Bel, Yolanda; Maeztu, Mireya; Escriche, Baltasar; Muñoz, Delia; Caballero, Primitivo; Ferré, Juan

    2014-03-01

    Five Bacillus thuringiensis Vip3A proteins (Vip3Aa, Vip3Ab, Vip3Ad, Vip3Ae and Vip3Af) and their corresponding trypsin-activated toxins were tested for their toxicity against eight lepidopteran pests: Agrotis ipsilon, Helicoverpa armigera, Mamestra brassicae, Spodoptera exigua, Spodoptera frugiperda, Spodoptera littoralis, Ostrinia nubilalis and Lobesia botrana. Toxicity was first tested at a high dose at 7 and 10 days. No major differences were found when comparing protoxins vs. trypsin-activated toxins. The proteins that were active against most of the insect species were Vip3Aa, Vip3Ae and Vip3Af, followed by Vip3Ab. Vip3Ad was non-toxic to any of the species tested. Considering the results by insect species, A. ipsilon, S. frugiperda and S. littoralis were susceptible to Vip3Aa, Vip3Ab, Vip3Ae and Vip3Af; S. exigua was susceptible to Vip3Aa and Vip3Ae, and moderately susceptible to Vip3Ab; M. brassicae and L. botrana were susceptible to Vip3Aa, Vip3Ae and Vip3Af; H. armigera was moderately susceptible to Vip3Aa, Vip3Ae and Vip3Af, and O. nubilalis was tolerant to all Vip3 proteins tested, although it showed some susceptibility to Vip3Af. The results obtained will help to design new combinations of insecticidal protein genes in transgenic crops or in recombinant bacteria for the control of insect pests.

  5. [Evaluation of reference genes for quantitative real-time PCR normalization in cotton bollworm, Helicoverna armigera].

    Science.gov (United States)

    Chandra, G Sharath; Asokan, R; Manamohan, M; Kumar, N K K; Sita, T

    2014-01-01

    Reverse-transcription quantitative real-time PCR (RT-qPCR), a sensitive technique is being extensively employed in quantification of gene expression. However this requires normalization with suitable reference gene (RG) which is crucial in minimizing inter sample variations. Information regarding suitable RG is scarce in general and more so in insects, including the cotton bollworm, Helicoverpa armigera, an economically important pest. In management of this pest RNA interference (RNAi), is perceived as a potential tool, which is achieved by double-stranded RNA (dsRNA) delivery. These studies demand accurate quantification of gene silencing. In this study we assessed the suitability of five RGs viz. β-actin (ACTB), 18S rRNA (18S), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), β-tubulin (TUB) and elongation fator-1-alfa (EF1-α) for gene expression studies in dsRNA treatment and across different developmental stages of H. armigera and ranked using geNorm, NormFinder and BestKeeper software programs. Data analysis revealed that best ranked RGs were varied in dsRNA treatment and in developmental stages. Under dsRNA treatment, 18S and GAPDH were more stable whereas, TUB and GAPDH were more stable across developmental stages. We also demonstrate that inappropriate selection of RG led to erroneous estimation of the target gene, chymotrypsin, expression. These results facilitate accurate quantification of gene expression in H. armigera.

  6. Insect damages on structural, morphologic and composition of Bt maize hybrids to silage

    Directory of Open Access Journals (Sweden)

    Geraldo Balieiro Neto

    2013-03-01

    Full Text Available It was aimed to evaluate the effect of insect damage on the morphologic and structural characteristics and chemical composition from maize hybrids DKB 390 and AG 8088 with the Cry1Ab trait versus its nonbiotech counterpart. The GMO did not receive insecticide application and the conventional hybrids received one deltametrina (2.8% application at 42 days. The damages caused bySpodoptera frugiperda and Helicoverpa zea in hybrids with Cry1Ab were smaller than its nonbiotech counterpart. After harvest, 95 days after seedling plants were separated in stalks, ears, leafs, dead leafs and floral pennant. The experimental design was randomized block in factorial arrangement 2 x 2. The height of plant and height of ear, percentage and amount of dead leafs from hybrids with the Cry1Ab were higher than its nonbiotech counterpart. There was higher nutrients transfer from stalks to grain filling and smaller rate stalks:ear on transgenic plant. The quality of the transgenic plants can be better when harvest earlier, by increasing no fiber carbohydrates, but when harvest latter, by increasing stalk percentage and stalk lignin content.

  7. Biorational agents--mechanism and importance in IPM and IRM programs for controlling agricultural pests.

    Science.gov (United States)

    Ishaaya, I; Kontsedalov, S; Mazirov, D; Horowitz, A R

    2001-01-01

    Among the new approaches for controlling agricultural pests is the development of novel compounds affecting specific processes in insects such as chitin synthesis inhibitors, juvenile hormone mimics and ecdysone agonists. In addition, efforts have been made to develop compounds acting selectively on groups of insects by inhibiting or enhancing biochemical sites such as respiration (diafenthiuron), the nicotinyl acetylcholine receptors (imidacloprid and acetamiprid), the GABA receptors (avermectins), the salivary glands of sucking pests (pymetrozine) and others. Among the most recent novel insecticides with selective properties are novaluron, thiamethoxam, emamectin and spinosad. Novaluron (Rimon) is a novel chitin synthesis inhibitor that acts by both ingestion and contact. It is a powerful suppressor of lepidopteran larvae such as Spodoptera littoralis and Helicoverpa armigera (by ingestion) and of whiteflies such as Bemisia tabaci and Trialeurodes vaporariorum (by contact). Thiamethoxam (Actarn), a novel neonicotinoid acts specifically on aphids and whiteflies. Emamectin (Proclaim), an avermectin derivative acts on GABA receptor affecting diversity of insects such as mites, lepidopterans and thrips. Spinosad (Tracer) seems to act on both acetylcholine and GABA receptors affecting diversity of insect species and is considered an important agent for controlling the western flower thrips.

  8. Insect Pest Incidence on Cowpea in the Cameroonian Southwest Forest and Western Derived Savanna Zones, their Contribution to Yield Loss in Foumbot and their Control

    Directory of Open Access Journals (Sweden)

    Parh, LA.

    1999-01-01

    Full Text Available In 1986 and 1987, insect pests sampled on cowpea in the Cameroonian Southwest forest and Western derived savanna ecological 1 zones included Maruca vitrata, Leguminivora (Cydia ptychora, Helicoverpa (Heliothis armigera, Melanagromyza vignalis, Apion disjunctum, Aphis craccivora, heteropteran bugs and bruchids. Under eight different deltamethrin spray schedules evaluated for their control at Foumbot, western derived savanna ecozone, the yield loss they caused ranged from 123.60 kg/ha in plants sprayed twice at the reproductive stage to 362.51 kg/ha in unsprayed plants in 1988 ; 21.86 kg/ha in plants sprayed thrice at the reproductive stage to 90.73 kg/ha in unsprayed plants in 1989 and 91.72 kg/ha in plants sprayed 5 to 6 times at fortnightly intervals, to 184.08 kg/ha in unsprayed plants in 1990. The percentage loss due to Maruca vitrata, Melanagromyza vignalis and heteropteran bugs was high in sprayed and unsprayed plots. In 1989 and 1990, seedyields were significantly increased by spraying deltamethrin either forthnightly or once at 75-100 % flowerbuds and once at 75-100 % podding, or once at 75-100 % flowering and once at 75-100 % podding.

  9. Nutrition affects insect susceptibility to Bt toxins

    Science.gov (United States)

    Deans, Carrie A.; Behmer, Spencer T.; Tessnow, Ashley E.; Tamez-Guerra, Patricia; Pusztai-Carey, Marianne; Sword, Gregory A.

    2017-01-01

    Pesticide resistance represents a major challenge to global food production. The spread of resistance alleles is the primary explanation for observations of reduced pesticide efficacy over time, but the potential for gene-by-environment interactions (plasticity) to mediate susceptibility has largely been overlooked. Here we show that nutrition is an environmental factor that affects susceptibility to Bt toxins. Protein and carbohydrates are two key macronutrients for insect herbivores, and the polyphagous pest Helicoverpa zea self-selects and performs best on diets that are protein-biased relative to carbohydrates. Despite this, most Bt bioassays employ carbohydrate-biased rearing diets. This study explored the effect of diet protein-carbohydrate content on H. zea susceptibility to Cry1Ac, a common Bt endotoxin. We detected a 100-fold increase in LC50 for larvae on optimal versus carbohydrate-biased diets, and significant diet-mediated variation in survival and performance when challenged with Cry1Ac. Our results suggest that Bt resistance bioassays that use ecologically- and physiologically-mismatched diets over-estimate susceptibility and under-estimate resistance. PMID:28045087

  10. Cotton fertilization using PGPR Bacillus amyloliquefaciens FZB42 and compost: Impact on insect density and cotton yield in North Benin, West Africa

    Directory of Open Access Journals (Sweden)

    Thiery B. Charles Alavo

    2015-12-01

    Full Text Available This work has compared the effects of the biofertilizer Bacillus amyloliquefaciens FZB42 with that of compost for cotton production. The population dynamics of pests and predators have been studied in order to check whether the use of both fertilization materials can contribute to pest management in cotton. Three treatments were considered: (i dressing of seeds in rhizobacteria suspension, (ii introduction of rhizobacterial suspension directly in the pocket, same time with the seeds, and (iii fertilization with compost. The study was carried out in northwest Benin (West Africa. Results showed that cotton aphids, Aphis gossypii, pink bollworm, Pectinophora gossypiella, leaf roller, Sylepta derogata, and cotton bugs, Dysdercus sp. are the major insect pests encountered in the experimental plots. Cotton bollworm, Helicoverpa armigera, was present but under the economic threshold. The coccinellid predators, Cheilomenes spp., occurred in the experimental plots and almost suppressed aphid proliferation. Other natural enemies such as chrysopids and ant species also occurred and probably contributed to maintain the cotton bollworm under the economic threshold. The treatment with seeds dressed with the rhizobacteria suspension yielded 39% more cotton compared to the compost fertilization. The use of both fertilization materials without application of chemicals can contribute to pest management in cotton.

  11. Biological Characteristics of Bacillus thuringiensis Isolate GS8 and Identification of its cry-type Genes%苏云金芽胞杆菌GS8菌株的生物学特性及其cry基因型鉴定

    Institute of Scientific and Technical Information of China (English)

    刘廷辉; 郭巍; 申建茹

    2009-01-01

    采用桑叶浸渍法和饲料表面覆盖法测定发现,从土壤中分离的一株苏云金芽胞杆菌菌株GS8对家蚕Bombyx mori、甜菜夜蛾Spodoptera exigrua和棉铃虫Helicoverpa armigera初孵幼虫均表现出较高的杀虫活性,经形态学和生理生化反应鉴定该菌株为东北亚种(Bacillus thuringiensis subsp.tohokuensis).聚丙烯酰胺凝胶电泳(SDS-PAGE)分析结果表明,GS8菌株的杀虫蛋白晶体主要由分子质量为130、81和60 kDa的蛋白组成.聚合酶链反应-限制性片段长度多态性(PCR-RFLP)鉴定结果显示,GS8菌株含有cry1Aa、cry1Ab、cry1Ib、cry2Ab和cry9Ba等基因.

  12. Bioefficacy and mode-of-action of some limonoids of salannin group from Azadirachta indica A. Juss and their role in a multicomponent system against lepidopteran larvae

    Indian Academy of Sciences (India)

    Opender Koul; Gurmeet Singh; Rajwinder Singh; Jasbir Singh; W M Daniewski; Stanislaw Berlozecki

    2004-12-01

    Biological activities of the salannin type of limonoids isolated from Azadirachta indica A. Juss were assessed using the gram pod borer Helicoverpa armigera (Hubner) and the tobacco armyworm Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). Inhibition of larval growth was concomitant with reduced feeding by neonate and third instar larvae. All three compounds exhibited strong antifeedant activity in a choice leaf disc bioassay with 2.0, 2.3 and 2.8 g/cm2 of 3-O-acetyl salannol, salannol and salannin, respectively deterring feeding by 50% in S. litura larvae. In nutritional assays, all three compounds reduced growth and consumption when fed to larvae without any effect on efficiency of conversion of ingested food (ECI), suggesting antifeedant activity alone. No toxicity was observed nor was there any significant affect on nutritional indices following topical application, further suggesting specific action as feeding deterrents. When relative growth rates were plotted against relative consumption rates, growth efficiency of the H. armigera fed diet containing 3-O-acetyl salannol, salannol or salannin did not differ from that of starved control larvae (used as calibration curve), further confirming the specific antifeedant action of salannin type of limonoids. Where the three compounds were co-administered, no enhancement in activity was observed. Non-azadirachtin limonoids having structural similarities and explicitly similar modes of action, like feeding deterrence in the present case, have no potentiating effect in any combination.

  13. Intraear Compensation of Field Corn, Zea mays, from Simulated and Naturally Occurring Injury by Ear-Feeding Larvae.

    Science.gov (United States)

    Steckel, S; Stewart, S D

    2015-06-01

    Ear-feeding larvae, such as corn earworm, Helicoverpa zea Boddie (Lepidoptera: Noctuidae), can be important insect pests of field corn, Zea mays L., by feeding on kernels. Recently introduced, stacked Bacillus thuringiensis (Bt) traits provide improved protection from ear-feeding larvae. Thus, our objective was to evaluate how injury to kernels in the ear tip might affect yield when this injury was inflicted at the blister and milk stages. In 2010, simulated corn earworm injury reduced total kernel weight (i.e., yield) at both the blister and milk stage. In 2011, injury to ear tips at the milk stage affected total kernel weight. No differences in total kernel weight were found in 2013, regardless of when or how much injury was inflicted. Our data suggested that kernels within the same ear could compensate for injury to ear tips by increasing in size, but this increase was not always statistically significant or sufficient to overcome high levels of kernel injury. For naturally occurring injury observed on multiple corn hybrids during 2011 and 2012, our analyses showed either no or a minimal relationship between number of kernels injured by ear-feeding larvae and the total number of kernels per ear, total kernel weight, or the size of individual kernels. The results indicate that intraear compensation for kernel injury to ear tips can occur under at least some conditions.

  14. Cyclic di-GMP contributes to adaption and virulence of Bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein.

    Science.gov (United States)

    Tang, Qing; Yin, Kang; Qian, Hongliang; Zhao, Youwen; Wang, Wen; Chou, Shan-Ho; Fu, Yang; He, Jin

    2016-07-06

    Cyclic di-GMP is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. In Bacillus thuringiensis BMB171, a c-di-GMP riboswitch termed Bc2 RNA resides in the 5'-untranslated region (5'-UTR) of an mRNA that encodes a collagen adhesion protein (Cap). The expression of cap was strongly repressed in parent strain BMB171 because of the presence of Bc2 RNA but was significantly promoted in the Bc2 RNA markerless deletion mutant. Bc2 RNA acts as a genetic "on" switch, which forms an anti-terminator structure to promote cap read-through transcription upon c-di-GMP binding. As a result, cap transcription was de-repressed under high c-di-GMP levels. Therefore, Bc2 RNA regulates cap expression using a repression/de-repression model. Bc2 RNA-regulated Cap was also found to be tightly associated with motility, aggregation, exopolysaccharide secretion, biofilm formation, and virulence of B. thuringiensis BMB171 against its host insect Helicoverpa armigera.

  15. Molecular and Insecticidal Characterization of a Novel Cry-Related Protein from Bacillus Thuringiensis Toxic against Myzus persicae

    Science.gov (United States)

    Palma, Leopoldo; Muñoz, Delia; Berry, Colin; Murillo, Jesús; Ruiz de Escudero, Iñigo; Caballero, Primitivo

    2014-01-01

    This study describes the insecticidal activity of a novel Bacillus thuringiensis Cry-related protein with a deduced 799 amino acid sequence (~89 kDa) and ~19% pairwise identity to the 95-kDa-aphidicidal protein (sequence number 204) from patent US 8318900 and ~40% pairwise identity to the cancer cell killing Cry proteins (parasporins Cry41Ab1 and Cry41Aa1), respectively. This novel Cry-related protein contained the five conserved amino acid blocks and the three conserved domains commonly found in 3-domain Cry proteins. The protein exhibited toxic activity against the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae) with the lowest mean lethal concentration (LC50 = 32.7 μg/mL) reported to date for a given Cry protein and this insect species, whereas it had no lethal toxicity against the Lepidoptera of the family Noctuidae Helicoverpa armigera (Hübner), Mamestra brassicae (L.), Spodoptera exigua (Hübner), S. frugiperda (J.E. Smith) and S. littoralis (Boisduval), at concentrations as high as ~3.5 μg/cm2. This novel Cry-related protein may become a promising environmentally friendly tool for the biological control of M. persicae and possibly also for other sap sucking insect pests. PMID:25384108

  16. Hexokinase is a key regulator of energy metabolism and ROS activity in insect lifespan extension

    Science.gov (United States)

    Lin, Xian-Wu; Xu, Wei-Hua

    2016-01-01

    Developmental arrest (diapause) is a ‘non-aging’ state that is similar to the Caenorhabditis elegans dauer stage and Drosophila lifespan extension. Diapause results in low metabolic activity and a profound extension of insect lifespan. Here, we cloned the Helicoverpa armigera Hexokinase (HK) gene, a gene that is critical for the developmental arrest of this species. HK expression and activity levels were significantly increased in nondiapause-destined pupae compared with those of diapause-destined pupae. Downregulation of HK activity reduced cell viability and delayed pupal development by reducing metabolic activity and increasing ROS activity, which suggests that HK is a key regulator of insect development. We then identified the transcription factors Har-CREB, -c-Myc, and -POU as specifically binding the Har-HK promoter and regulating its activity. Intriguingly, Har-POU and -c-Myc are specific transcription factors for HK expression, whereas Har-CREB is nonspecific. Furthermore, Har-POU and -c-Myc could respond to ecdysone, which is an upstream hormone. Therefore, low ecdysone levels in diapause-destined individuals lead to low Har-POU and -c-Myc expression levels, ultimately repressing Har-HK expression and inducing entry into diapause or lifespan extension. PMID:26852422

  17. Disruption of insect diapause using agonists and an antagonist of diapause hormone.

    Science.gov (United States)

    Zhang, Qirui; Nachman, Ronald J; Kaczmarek, Krzysztof; Zabrocki, Janusz; Denlinger, David L

    2011-10-11

    The dormant state known as diapause is widely exploited by insects to circumvent winter and other adverse seasons. For an insect to survive, feed, and reproduce at the appropriate time of year requires fine coordination of the timing of entry into and exit from diapause. One of the hormones that regulates diapause in moths is the 24-aa neuropeptide, diapause hormone (DH). Among members of the Helicoverpa/Heliothis complex of agricultural pests, DH prompts the termination of pupal diapause. Based on the structure of DH, we designed several agonists that are much more active than DH in breaking diapause. One such agonist that we describe also prevents the entry into pupal diapause when administered to larvae that are environmentally programmed for diapause. In addition, we used the unique antagonist development strategy of incorporating a dihydroimidazole ("Jones") trans-Proline mimetic motif into one of our DH agonists, thereby converting the agonist into a DH antagonist that blocks the termination of diapause. These results suggest potential for using such agents or next-generation derivatives for derailing the success of overwintering in pest species.

  18. Bioprospecting for secondary metabolites in the entomopathogenic bacterium Photorhabdus luminescens subsp. sonorensis.

    Science.gov (United States)

    Orozco, Rousel A; Molnár, István; Bode, Helge; Stock, S Patricia

    2016-11-01

    Crude extracts of in vitro and in vivo cultures of two strains of Photorhabdus l. sonorensis (Enterobacteriaceae) were analyzed by TLC, HPLC-UV and LC-MS. Nine unique compounds with mass/charge ratios (m/z) ranging from 331.3 to 713.5 were found in MS analyses. Bioactivity of extracts was assessed on a selection of plant pathogens/pests and non-target species. Caborca strain extracts showed the highest activity against Helicoverpa zea (Lepidoptera: Noctuidae) neonates at all concentrations tested. Mortality ranged from 11% (at 10μg/ml) to 37% (at 40μg/ml). Strain CH35 extracts showed the highest nematicidal activity on Meloidogyne incognita (Tylenchida: Meloidogynidae) at 40μg/ml. Low to no nematicidal activity was observed against the non-target species Steinernema carpocapsae (Rhabditida: Steinernematidae) and Caenorhabditis elegans (Rhabditida: Rhabditidae). Caborca extracts exhibited a strong antibiotic effect on Pseudomonas syringae (Pseudomonadales: Pseudomonadacedae) at 40μg/ml, while both Caborca and CH35 extracts inhibited the growth of Bacillus subitillis (Bacillales: Bacillaceae) at 40μg/ml. All extracts strongly inhibited the growth of the fungus Fusarium oxysporum (Hypocreales: Nectriceae) but not that of Alternaria alternata (Pleosporales: Pleosporaceae). Contrastingly, a moderate to high inhibitory effect was denoted on the non-target biocontrol fungus Beauveria bassiana (Hypocreales: Clavivipitaceae).

  19. Baculovirus Induced Transcripts in Hemocytes from the Larvae of Heliothis virescens

    Directory of Open Access Journals (Sweden)

    Holly J.R. Popham

    2011-10-01

    Full Text Available Using RNA-seq digital difference expression profiling methods, we have assessed the gene expression profiles of hemocytes harvested from Heliothis virescens that were challenged with Helicoverpa zea single nucleopolyhedrovirus (HzSNPV. A reference transcriptome of hemocyte-expressed transcripts was assembled from 202 million 42-base tags by combining the sequence data of all samples, and the assembled sequences were then subject to BLASTx analysis to determine gene identities. We used the fully sequenced HzSNPV reference genome to align 477,264 Illumina sequence tags from infected hemocytes in order to document expression of HzSNPV genes at early points during infection. A comparison of expression profiles of control insects to those lethally infected with HzSNPV revealed differential expression of key cellular stress response genes and genes involved in lipid metabolism. Transcriptional regulation of specific insect hormones in baculovirus-infected insects was also altered. A number of transcripts bearing homology to retroviral elements that were detected add to a growing body of evidence for extensive invasion of errantiviruses into the insect genome. Using this method, we completed the first and most comprehensive gene expression survey of both baculoviral infection and host immune defense in lepidopteran larvae.

  20. The Characterization of SaPIN2b, a Plant Trichome-Localized Proteinase Inhibitor from Solanum americanum

    Directory of Open Access Journals (Sweden)

    Zeng-Fu Xu

    2012-11-01

    Full Text Available Proteinase inhibitors play an important role in plant resistance of insects and pathogens. In this study, we characterized the serine proteinase inhibitor SaPIN2b, which is constitutively expressed in Solanum americanum trichomes and contains two conserved motifs of the proteinase inhibitor II (PIN2 family. The recombinant SaPIN2b (rSaPIN2b, which was expressed in Escherichia coli, was demonstrated to be a potent proteinase inhibitor against a panel of serine proteinases, including subtilisin A, chymotrypsin and trypsin. Moreover, rSaPIN2b also effectively inhibited the proteinase activities of midgut trypsin-like proteinases that were extracted from the devastating pest Helicoverpa armigera. Furthermore, the overexpression of SaPIN2b in transgenic tobacco plants resulted in enhanced resistance against H. armigera. Taken together, our results demonstrated that SaPIN2b is a potent serine proteinase inhibitor that may act as a protective protein in plant defense against insect attacks.