Insecticide susceptibility status of human biting mosquitoes in ...

African Journals Online (AJOL)

Background: There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This situation presents a challenge to chemicals that are currently used to control mosquitoes in sub-Saharan African. Furthermore, there is limited information on insecticide ...

Antagonism at combined effects of chemical fertilizers and carbamate insecticides on the rice-field N2-fixing cyanobacterium Cylindrospermum sp. in vitro

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Padhy Rabindra N.

2014-03-01

Full Text Available Effects of chemical fertilizers (urea, super phosphate and potash on toxicities of two carbamate insecticides, carbaryl and carbofuran, individually to the N2-fixing cyanobacterium, Cylindrospermum sp. were studied in vitro at partially lethal levels (below highest permissive concentrations of each insecticide. The average number of vegetative cells between two polar heterocysts was 16.3 in control cultures, while the mean value of filament length increased in the presence of chemical fertilizers, individually. Urea at the 10 ppm level was growth stimulatory and at the 50 ppm level it was growth inhibitory in control cultures, while at 100 ppm it was antagonistic, i.e. toxicity-enhancing along with carbaryl, individually to the cyanobacterium, antagonism was recorded. Urea at 50 ppm had toxicity reducing effect with carbaryl or carbofuran. At 100 and 250 ppm carbofuran levels, 50 ppm urea only had a progressive growth enhancing effect, which was marked well at 250 ppm carbofuran level, a situation of synergism. Super phosphate at the 10 ppm level only was growth promoting in control cultures, but it was antagonistic at its higher levels (50 and 100 ppm along with both insecticides, individually. Potash (100, 200, 300 and 400 ppm reduced toxicity due to carbaryl 20 and carbofuran 250 ppm levels, but potash was antagonistic at the other insecticide levels. The data clearly showed that the chemical fertilizers used were antagonistic with both the insecticides during toxicity to Cylindrospermum sp.

Antagonism at combined effects of chemical fertilizers and carbamate insecticides on the rice-field N2-fixing cyanobacterium Cylindrospermum sp. in vitro

Science.gov (United States)

Nayak, Nabakishore; Rath, Shakti

2014-01-01

Effects of chemical fertilizers (urea, super phosphate and potash) on toxicities of two carbamate insecticides, carbaryl and carbofuran, individually to the N2-fixing cyanobacterium, Cylindrospermum sp. were studied in vitro at partially lethal levels (below highest permissive concentrations) of each insecticide. The average number of vegetative cells between two polar heterocysts was 16.3 in control cultures, while the mean value of filament length increased in the presence of chemical fertilizers, individually. Urea at the 10 ppm level was growth stimulatory and at the 50 ppm level it was growth inhibitory in control cultures, while at 100 ppm it was antagonistic, i.e. toxicity-enhancing along with carbaryl, individually to the cyanobacterium, antagonism was recorded. Urea at 50 ppm had toxicity reducing effect with carbaryl or carbofuran. At 100 and 250 ppm carbofuran levels, 50 ppm urea only had a progressive growth enhancing effect, which was marked well at 250 ppm carbofuran level, a situation of synergism. Super phosphate at the 10 ppm level only was growth promoting in control cultures, but it was antagonistic at its higher levels (50 and 100 ppm) along with both insecticides, individually. Potash (100, 200, 300 and 400 ppm) reduced toxicity due to carbaryl 20 and carbofuran 250 ppm levels, but potash was antagonistic at the other insecticide levels. The data clearly showed that the chemical fertilizers used were antagonistic with both the insecticides during toxicity to Cylindrospermum sp. PMID:26038669

Digestive enzyme as benchmark for insecticide resistance development in Culex pipiens larvae to chemical and bacteriologic insecticides.

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Kamel, Nashwa H; Bahgat, Iman M; El Kady, Gamal A

2013-04-01

This work monitored changes in some digestive enzymes (trypsin and aminopeptidase) associated with the building up of resistance in Cx. pipiens larvae to two chemical insecticides (methomyl and/or malathion) and one biological insecticide (Bacillus thuringiensis-H14 or B.t H 14). The LC50 value of methomyl for both field- and the 12th generation (F12) of the selected strain was 1.789 ppm and 8.925 ppm respectively. The LC50 value of malathion for both field and the F12 of the selected strain was 0.082 ppm and 0.156 ppm respectively, and those of B.t H14 of field strain and the F12 was 2.550ppm & 2.395ppm respectively. The specific activity of trypsin enzyme in control susceptible colony was 20.806 +/- 0.452micromol/min/mg protein; but at F4 and F8 for malathion and methomyl treated larvae were 10.810 +/- 0.860 & 15.616+/-0.408 micromol/min/mg protein, respectively. Trypsin activity of F12 in treated larvae with B.t.H14 was 2.097 +/- 0.587 microiol/min/mg protein. Aminopeptidase specific activity for susceptible control larvae was 173.05 +/- 1.3111 micromol/min/mg protein. This activity decreased to 145.15 +/- 4.12, 152.497 +/- 6.775 & 102.04 +/- 3.58a micromol/min/mg protein after larval (F 12) treatment with methomyl, malathion and B.t H 14 respectively.

Trifluoromethylphenyl amides as novel insecticides and fungicides

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Because of increased resistance to insecticides in arthropods, it is necessary to identify new chemicals that may have novel modes of action. Following an extensive literature search for compounds with insecticidal and mosquito repellent activity, we have designed and synthesized a set of 20 trifluo...

Dynamic plant uptake model applied for drip irrigation of an insecticide to pepper fruit plants.

Science.gov (United States)

Legind, Charlotte N; Kennedy, Coleen M; Rein, Arno; Snyder, Nathan; Trapp, Stefan

2011-05-01

Drip application of insecticides is an effective way to deliver the chemical to the plant that avoids off-site movement via spray drift and minimizes applicator exposure. The aim of this paper is to present a cascade model for the uptake of pesticide into plants following drip irrigation, its application for a soil-applied insecticide and a sensitivity analysis of the model parameters. The model predicted the measured increase and decline of residues following two soil applications of an insecticide to peppers, with an absolute error between model and measurement ranging from 0.002 to 0.034 mg kg fw(-1). Maximum measured concentrations in pepper fruit were approximately 0.22 mg kg fw(-1). Temperature was the most sensitive component for predicting the peak and final concentration in pepper fruit, through its influence on soil and plant degradation rates. Repeated simulations of pulse inputs with the cascade model adequately describe soil pesticide applications to an actual cropped system and reasonably mimic it. The model has the potential to be used for the optimization of practical features, such as application rates and waiting times between applications and before harvest, through the integrated accounting of soil, plant and environmental influences. Copyright © 2011 Society of Chemical Industry.

Insecticide-induced hormesis and arthropod pest management.

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Guedes, Raul Narciso C; Cutler, G Christopher

2014-05-01

Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide-induced hormesis within entomology and acarology. Hormesis describes a biphasic dose-response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide-induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide-induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas. © 2013 Society of Chemical Industry.

A renaissance for botanical insecticides?

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Isman, Murray B

2015-12-01

Botanical insecticides continue to be a subject of keen interest among the international research community, reflected in the steady growth in scientific publications devoted to the subject. Until very recently though, the translation of that theory to practice, i.e. the commercialisation and adoption of new botanical insecticides in the marketplace, has seriously lagged behind. Strict regulatory regimes, long the bane of small pesticide producers, are beginning to relax some of the data requirements for 'low-risk' pesticide products, facilitating movement of more botanicals into the commercial arena. In this paper I discuss some of the jurisdictions where botanicals are increasingly finding favour, some of the newer botanical insecticides in the plant and animal health arsenal and some of the specific sectors where botanicals are most likely to compete effectively with other types of insecticidal product. © 2015 Society of Chemical Industry.

Prospects for managing turfgrass pests with reduced chemical inputs.

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Held, David W; Potter, Daniel A

2012-01-01

Turfgrass culture, a multibillion dollar industry in the United States, poses unique challenges for integrated pest management. Why insect control on lawns, golf courses, and sport fields remains insecticide-driven, and how entomological research and extension can best support nascent initiatives in environmental golf and sustainable lawn care are explored. High standards for aesthetics and playability, prevailing business models, risk management-driven control decisions, and difficulty in predicting pest outbreaks fuel present reliance on preventive insecticides. New insights into pest biology, sampling methodology, microbial insecticides, plant resistance, and conservation biological control are reviewed. Those gains, and innovations in reduced-risk insecticides, should make it possible to begin constructing holistic management plans for key turfgrass pests. Nurturing the public's interest in wildlife habitat preservation, including beneficial insects, may be one means to change aesthetic perceptions and gain leeway for implementing integrated pest management practices that lend stability to turfgrass settings. Copyright © 2012 by Annual Reviews. All rights reserved.

An Operational Framework for Insecticide Resistance Management Planning.

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Chanda, Emmanuel; Thomsen, Edward K; Musapa, Mulenga; Kamuliwo, Mulakwa; Brogdon, William G; Norris, Douglas E; Masaninga, Freddie; Wirtz, Robert; Sikaala, Chadwick H; Muleba, Mbanga; Craig, Allen; Govere, John M; Ranson, Hilary; Hemingway, Janet; Seyoum, Aklilu; Macdonald, Michael B; Coleman, Michael

2016-05-01

Arthropod vectors transmit organisms that cause many emerging and reemerging diseases, and their control is reliant mainly on the use of chemical insecticides. Only a few classes of insecticides are available for public health use, and the increased spread of insecticide resistance is a major threat to sustainable disease control. The primary strategy for mitigating the detrimental effects of insecticide resistance is the development of an insecticide resistance management plan. However, few examples exist to show how to implement such plans programmatically. We describe the formulation and implementation of a resistance management plan for mosquito vectors of human disease in Zambia. We also discuss challenges, steps taken to address the challenges, and directions for the future.

Decaleside: a new class of natural insecticide targeting tarsal gustatory sites

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Rajashekar, Yallappa; Rao, Lingamallu J. M.; Shivanandappa, Thimmappa

2012-10-01

Natural sources for novel insecticide molecules hold promise in view of their eco-friendly nature, selectivity, and mammalian safety. Recent progress in understanding the biology of insect olfaction and taste offers new strategies for developing selective pest control agents. We have isolated two natural insecticidal molecules from edible roots of Decalepis hamiltonii named Decalesides I and II, which are novel trisaccharides, highly toxic to household insect pests and stored-product insects. We have experimentally shown that insecticidal activity requires contact with tarsi on the legs but is not toxic orally. The insecticidal activity of molecules is lost by hydrolysis, and various sugars modify toxic response, showing that the insecticidal activity is via gustatory sites on the tarsi. Selective toxicity to insects by virtue of their gustatory site of action and the mammalian safety of the new insecticides is inherent in their chemical structure with 1-4 or 1-1 α linkage that is easily hydrolyzed by digestive enzymes of mammals. Decalesides represent a new chemical class of natural insecticides with a unique mode of action targeting tarsal chemosensory/gustatory system of insects.

Chemical Quality of Water in Anopheles stephensi Habitats and its susceptibility to different insecticides in South Eastern of Iran

International Nuclear Information System (INIS)

Davari, B.; Vatandoost, H.

2009-01-01

Using of insecticides depends on the knowledge of the susceptibility levels of malaria vectors to these chemical. In this study, the chemical quality of water in the larval breeding habitats and the susceptibility levels of Anopheles stephensi to DDT 4% dieldrin 0.4% permethrin 0.75, cyfluthrin 0.15 deltamethrin 0.05% and lambdacyhalothrin 0.05% were investigated according to WHO method in south eastern of Iran. (Author)

Low-input, low-cost IPM program helps manage potato psyllid

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Sean M. Prager

2016-04-01

Full Text Available Potato psyllid is a pest of solanaceous plants throughout much of the western United States, including California, where it has increased and is now overwintering. The psyllid affects its plant hosts from direct feeding and by transmitting a plant pathogenic bacterium, Lso. Millions of dollars of damages have occurred in the U.S. potato industry, and a large acreage of crops is susceptible in California. Control is complicated because different crops have different pest complexes and susceptibilities to Lso; currently most growers use multiple pesticide applications, including broad-spectrum insecticides. Results of our field trials at South Coast Research and Extension Center indicate that the use of broad-spectrum insecticides actually increases psyllid numbers in both peppers and potatoes. We have developed a low-input IPM program, which in field trials produced encouraging results in peppers, potatoes and tomatoes compared to broad-spectrum insecticides. Economic analysis showed the low-input IPM approach was more cost effective than a standard insecticide program in tomatoes.

Does multigenerational exposure to hormetic concentrations of imidacloprid precondition aphids for increased insecticide tolerance?

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Rix, Rachel R; Cutler, G Christopher

2018-02-01

Hormetic preconditioning, whereby exposure to mild stress primes an organism to better tolerate subsequent stress, is well documented. It is unknown if exposure to hormetic concentrations of insecticide can trans-generationally prime insects to better tolerate insecticide exposure, or whether exposure to hormetic concentrations of insecticide can induce mutations in genes responsible for insecticide resistance. Using the aphid Myzus persicae (Sulzer) and the insecticide imidacloprid as a model, we examined if exposure to mildly toxic and hormetic concentrations of imidacloprid reduced aphid susceptibility to insecticides across four generations, and whether such exposures induced mutations in the imidacloprid binding site in post-synaptic nicotinic acetylcholine receptors. Chronic, multigenerational exposure of aphids to hormetic concentrations of imidacloprid primed offspring to better survive exposure to certain concentrations of imidacloprid, but not exposure to spirotetramat, an insecticide with a different mode of action. Exposure to hormetic and mildly toxic concentrations of imidacloprid did not result in mutations in any of the examined nicotinic acetylcholine receptor subunits. Our findings demonstrate that exposure to hormetic concentrations of insecticide can prime insects to better withstand subsequent chemical stress, but this is dependent upon the insecticide exposure scenario, and may be subtle over generations. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Greenhouse Gases Emission and Global Warming Potential as Affected by Chemical Inputs for Main Cultivated Crops in Kerman Province: - Horticultural Crops

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Nasibe Pourghasemian

2017-12-01

each GHG changed into CO2using the specific GWP of each gas, which is the warming influence relative to that of carbon dioxide. Results and Discussion The results showed that N and P fertilizers had the highest application share of chemical inputs. Among the studied crops, the highest amount of chemical fertilizers was used in potato. Potato and watermelon were obtained the highest doses of herbicide and pesticide application, respectively. The results demonstrated that in all these three crops, the highest and lowest GHGs emission was related to Jiroft and Rafsanjan, respectively. The amount of annual GHGs emission was related to the regions planting area. The highest share of emission gas in all the three crops and all regions was related to CO2. In potato and onion, herbicide was caused higher CO2 emission compared to insecticide and fungicide. Watermelon cultivation contained no herbicide application. GWP in the studied regions had the same trend with GHGs emission. In all three studied crops, Jiroft and Sirjan were obtained the highest and lowest values of annual GWP, respectively. In all studied crops, N fertilizer led to more GHGs emission in comparison to other inputs. Potato had the highest emission of CO2, N2O and CH4 followed by watermelon, and the lowest amount was gained in onion. Also, annual GWP of potato, watermelon and onion were 6814.2, 6024.2 and 2125 ton CO2 equivalence, respectively. Among all chemical inputs, N (91%, P (6.9% and herbicide (1% were involved the highest share in GWP for studied plants. Conclusion The results showed that in all three studied crops, the highest and lowest GHGs emission was related to Jiroft and Rafsanjan, respectively. Annual GWP in the studied regions had the same trend with GHGs emission. In all three studied crops, Jiroft and Sirjan were obtained the highest and lowest values of annual GWP, respectively. In all studied crops, N fertilizer led to more GHGs emission in comparison to other inputs. Potato had the

Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth

OpenAIRE

David, Jean-Philippe; Ismail, Hanafy Mahmoud; Chandor-Proust, Alexia; Paine, Mark John Ingraham

2013-01-01

The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementat...

Review of insecticide resistance and behavioral avoidance of vectors of human diseases in Thailand

Science.gov (United States)

2013-01-01

Physiological resistance and behavioral responses of mosquito vectors to insecticides are critical aspects of the chemical-based disease control equation. The complex interaction between lethal, sub-lethal and excitation/repellent ('excito-repellent’) properties of chemicals is typically overlooked in vector management and control programs. The development of “physiological” resistance, metabolic and/or target site modifications, to insecticides has been well documented in many insect groups and disease vectors around the world. In Thailand, resistance in many mosquito populations has developed to all three classes of insecticidal active ingredients currently used for vector control with a majority being synthetic-derived pyrethroids. Evidence of low-grade insecticide resistance requires immediate countermeasures to mitigate further intensification and spread of the genetic mechanisms responsible for resistance. This can take the form of rotation of a different class of chemical, addition of a synergist, mixtures of chemicals or concurrent mosaic application of different classes of chemicals. From the gathered evidence, the distribution and degree of physiological resistance has been restricted in specific areas of Thailand in spite of long-term use of chemicals to control insect pests and disease vectors throughout the country. Most surprisingly, there have been no reported cases of pyrethroid resistance in anopheline populations in the country from 2000 to 2011. The precise reasons for this are unclear but we assume that behavioral avoidance to insecticides may play a significant role in reducing the selection pressure and thus occurrence and spread of insecticide resistance. The review herein provides information regarding the status of physiological resistance and behavioral avoidance of the primary mosquito vectors of human diseases to insecticides in Thailand from 2000 to 2011. PMID:24294938

Qualitative evaluation of same insecticides sold in Kinshasa and users behavior survey

International Nuclear Information System (INIS)

Basilua, K.; Essassi El, M.; Himmi, O.; Said Gmouh; Watsenga, T.

2009-01-01

Malaria is a serious public health problem in the tropical countries and particularly into Kinshasa. Anopheles gambiae sl. is the mean vector of this illness. The use of impregnated bednets is the national strategy; the chemical insecticides are used too in figthing the malaria vectors. The survey carried out on 144 households randomly selected in Kinshasa have showed that 61,1% are favourable with using bednets insecticide impregnated and 96,5% of these households use too chemical insecticides, meanly the pyrethroids one (90,5%) and the organophosphates (9,5%). Mass spectrometer analysis revealed that 87,5% of identified insecticides, essentially pyrethroinids have tetramethrine as active substance; the dichlorvos is the only one to be detected as organophosphate and that in some insecticides, the detected molecules are not avowed or different from those avowed or different from those avowed by the manufacturer.

Limonene--A Natural Insecticide.

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Beatty, Joseph H.

1986-01-01

Describes a high school chemistry student's research project in which limonene was isolated from the oil of lemons and oranges. Outlines the students' tests on the use of this chemical as an insecticide. Discusses possible extensions of the exercises based on questions generated by the students. (TW)

Insecticide resistance, control failure likelihood and the First Law of Geography.

Science.gov (United States)

Guedes, Raul Narciso C

2017-03-01

Insecticide resistance is a broadly recognized ecological backlash resulting from insecticide use and is widely reported among arthropod pest species with well-recognized underlying mechanisms and consequences. Nonetheless, insecticide resistance is the subject of evolving conceptual views that introduces a different concept useful if recognized in its own right - the risk or likelihood of control failure. Here we suggest an experimental approach to assess the likelihood of control failure of an insecticide allowing for consistent decision-making regarding management of insecticide resistance. We also challenge the current emphasis on limited spatial sampling of arthropod populations for resistance diagnosis in favor of comprehensive spatial sampling. This necessarily requires larger population sampling - aiming to use spatial analysis in area-wide surveys - to recognize focal points of insecticide resistance and/or control failure that will better direct management efforts. The continuous geographical scale of such surveys will depend on the arthropod pest species, the pattern of insecticide use and many other potential factors. Regardless, distance dependence among sampling sites should still hold, following the maxim that the closer two things are, the more they resemble each other, which is the basis of Tobler's First Law of Geography. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Chemical composition and insecticidal properties of essential oil ...

African Journals Online (AJOL)

Purpose: To determine the insecticidal properties of essential oil from Mosla soochowensis aerial parts against two insect pests, Sitophilus zeamais and Tribolium castaneum. Methods: Hydro-distillation of M. soochowensis was used to extract the essential oil. Gas chromatography/mass spectrometry (GC/MS) analysis was ...

Eupatorium Capillifolium Essential Oil: Chemical Composition, Antifungal Activity, and Insecticidal Activity

Science.gov (United States)

2010-01-01

deionized water. One percent oil concentration was used based on commercial botanical insecticides such as Neem (Azadiractin), Ecotrol (Rosmarinus...analyses for E. capillifolium oil and two commercial insecticides (Malathion, Neem ) topically applied to adult azalea lace bugs, S. pyrioides...0.93 (0.06) . . . 262.58 < 0.0001 exposure time . 695 0.44 (0.04) . . . 135.87 < 0.0001 a Malathion and Neem used as positive baseline controls for

Pest insect olfaction in an insecticide-contaminated environment: info-disruption or hormesis effect.

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Tricoire-Leignel, Hélène; Thany, Steeve Hervé; Gadenne, Christophe; Anton, Sylvia

2012-01-01

Most animals, including pest insects, live in an "odor world" and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs) are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an "info-disruptor" by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favoring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests.

Pest insect olfaction in an insecticide-contaminated environment : info-disruption or hormesis effect

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Hélène eTricoire-Leignel

2012-03-01

Full Text Available Most animals, including pest insects, live in an odour world and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an info-disruptor by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favouring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests.

Chemical composition and insecticidal property of Myrsine stolonifera (Koidz.) walker (Family: Myrsinaceae) on Musca domestica (Diptera: Muscidae).

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Wang, Xue Gui; Li, Qian; Jiang, Su Rong; Li, Pei; Yang, Ji Zhi

2017-06-01

Musca domestica is one of the most important pests of human health, and has developed strong resistance to many chemicals used for its control. One important approach for creating new pesticides is the exploration of novel compounds from plants. During a wide screening of plants with insecticidal properties that grow in southern China, we found that the methanolic extracts of Myrsine stolonifera had insecticidal activity against the adults of M. domestica. However, the insecticidal constituents and mechanisms of the M. stolonifera extracts remain unclear. The insecticidal components of the methanolic extracts of M. stolonifera were isolated with activity-guided fractionation. From the spectra of nuclear magnetic resonance (NMR) and mass spectrometry (MS), the compounds were identified as syringing (1), 2,6-dimethoxy-4-hydroxyphenol-1-O-β-d-glu (2), kaempferol-3-O-glu-rha-glu (3), and quercetin-3-O-glu-rha-glu (4). This study is the first to report the spectral data for compounds 3 and 4, and their LC 50 values were 0.52mg/g sugar and 0.36mg/g sugar 24h after treatment of the adults of M. domestica, respectively. Compounds 3 and 4 (LC 25 ) also inhibited the activities of the enzymes carboxylesterase, glutathione S-transferase, mixed function oxidase, and acetylcholine esterase of adult M. domestica, particularly mixed function oxidase and acetylcholine esterase. The cytotoxic effects of compounds 3 and 4 on cell proliferation, mitochondrial membrane potentials (MMP) and reactive oxygen species (ROS) were demonstrated on SL-1 cells. From the extracts of M. stolonifera, quercetin-3-O-glu-rha-glu and kaempferol-3-O-glu-rha-glu have displayed comparable toxicities to rotenone on M. domestica and also exhibited cytotoxic effects on SL-1 cells; therefore, the extracts of M. stolonifera and their compounds have potential as botanical insecticides to control M. domestica. Copyright © 2017 Elsevier B.V. All rights reserved.

Is Apis mellifera more sensitive to insecticides than other insects?

Science.gov (United States)

Hardstone, Melissa C; Scott, Jeffrey G

2010-11-01

Honey bees (Apis mellifera L.) are among the most important pollinators in natural and agricultural settings. They commonly encounter insecticides, and the effects of insecticides on honey bees have been frequently noted. It has been suggested that honey bees may be (as a species) uniquely sensitive to insecticides, although no comparative toxicology study has been undertaken to examine this claim. An extensive literature review was conducted, using data in which adult insects were topically treated with insecticides. The goal of this review was to summarize insecticide toxicity data between A. mellifera and other insects to determine the relative sensitivity of honey bees to insecticides. It was found that, in general, honey bees were no more sensitive than other insect species across the 62 insecticides examined. In addition, honey bees were not more sensitive to any of the six classes of insecticides (carbamates, nicotinoids, organochlorines, organophosphates, pyrethroids and miscellaneous) examined. While honey bees can be sensitive to individual insecticides, they are not a highly sensitive species to insecticides overall, or even to specific classes of insecticides. However, all pesticides should be used in a way that minimizes honey bee exposure, so as to minimize possible declines in the number of bees and/or honey contamination. Copyright © 2010 Society of Chemical Industry.

Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth.

Science.gov (United States)

David, Jean-Philippe; Ismail, Hanafy Mahmoud; Chandor-Proust, Alexia; Paine, Mark John Ingraham

2013-02-19

The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementation of control interventions and reduce their environmental impact on Earth. Recent technological advances are helping us to build a functional profile of the P450 determinants of insecticide metabolic resistance in mosquitoes. Alongside, the cross-responses of mosquito P450s to insecticides and pollutants are also being investigated. Such research will provide the means to produce diagnostic tools for early detection of P450s linked to resistance. It will also enable the design of new insecticides with optimized efficacy in different environments.

Radioligand Recognition of Insecticide Targets.

Science.gov (United States)

Casida, John E

2018-04-04

Insecticide radioligands allow the direct recognition and analysis of the targets and mechanisms of toxic action critical to effective and safe pest control. These radioligands are either the insecticides themselves or analogs that bind at the same or coupled sites. Preferred radioligands and their targets, often in both insects and mammals, are trioxabicyclooctanes for the γ-aminobutyric acid (GABA) receptor, avermectin for the glutamate receptor, imidacloprid for the nicotinic receptor, ryanodine and chlorantraniliprole for the ryanodine receptor, and rotenone or pyridaben for NADH + ubiquinone oxidoreductase. Pyrethroids and other Na + channel modulator insecticides are generally poor radioligands due to lipophilicity and high nonspecific binding. For target site validation, the structure-activity relationships competing with the radioligand in the binding assays should be the same as that for insecticidal activity or toxicity except for rapidly detoxified or proinsecticide analogs. Once the radioligand assay is validated for relevance, it will often help define target site modifications on selection of resistant pest strains, selectivity between insects and mammals, and interaction with antidotes and other chemicals at modulator sites. Binding assays also serve for receptor isolation and photoaffinity labeling to characterize the interactions involved.

The use of insecticides to control insect pests

OpenAIRE

M Wojciechowska; P Stepnowski; M Gołębiowski

2016-01-01

Pesticides are used as plants protection products. Among those, insecticides serve as agents to control insects. When incorrectly applied, however these substances may negatively affect people's health and natural environment. Administration routes of insecticides depend on many factors and vary from spraying to fertilizers. These different methods influence how insects prey and how pests develop. Additionally, too frequent use of the same chemicals can lead to development of resi...

Chemical composition of Rosmarinus officinalis and Lavandula stoechas essential oils and their insecticidal effects on Orgyia trigotephras (Lepidoptera: Lymantriidae

Directory of Open Access Journals (Sweden)

Ben Slimane Badreddine

2015-01-01

Full Text Available Objective: To evaluate toxic activities of essential oils obtained from Rosmarinus officinalis and Lavandula stoechas against the fourth larval instars of Orgyia trigotephras. Methods: A total of 1 200 larvae were divided into three groups-I, II, III. Group I was to investigate the effect of extracted essential oils from these aromatic plants as gastric disturbance. Bacillus thuringiensis was used as referencee and ethanol as control. Group II was used as contact action and Group III was used as fumigant action. For both Groups II and III, Decis was used as reference and ethanol as control. During the three experiments, the effect of essential oils on larvae was assessed. Results: The chemical composition of essential oils from two medicinal plants was determined, and their insecticidal effects on the fourth larval state of Orgyia trigotephras were assessed. They presented an insecticidal activity. Rosmarinus officinalis essential oil was less efficient compared to Lavandula stoechas. Conclusions: The relationship between the chemical composition and the biological activities is confirmed by the present findings. Therefore the potential uses of these essential oils as bioinsecticides can be considered as an alternative to the use of synthetic products.

Flupyradifurone: a brief profile of a new butenolide insecticide

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Nauen, Ralf; Jeschke, Peter; Velten, Robert; Beck, Michael E; Ebbinghaus-Kintscher, Ulrich; Thielert, Wolfgang; Wölfel, Katharina; Haas, Matthias; Kunz, Klaus; Raupach, Georg

2015-01-01

BACKGROUND The development and commercialisation of new chemical classes of insecticides for efficient crop protection measures against destructive invertebrate pests is of utmost importance to overcome resistance issues and to secure sustainable crop yields. Flupyradifurone introduced here is the first representative of the novel butenolide class of insecticides active against various sucking pests and showing an excellent safety profile. RESULTS The discovery of flupyradifurone was inspired by the butenolide scaffold in naturally occurring stemofoline. Flupyradifurone acts reversibly as an agonist on insect nicotinic acetylcholine receptors but is structurally different from known agonists, as shown by chemical similarity analysis. It shows a fast action on a broad range of sucking pests, as demonstrated in laboratory bioassays, and exhibits excellent field efficacy on a number of crops with different application methods, including foliar, soil, seed treatment and drip irrigation. It is readily taken up by plants and translocated in the xylem, as demonstrated by phosphor imaging analysis. Flupyradifurone is active on resistant pests, including cotton whiteflies, and is not metabolised by recombinantly expressed CYP6CM1, a cytochrome P450 conferring metabolic resistance to neonicotinoids and pymetrozine. CONCLUSION The novel butenolide insecticide flupyradifurone shows unique properties and will become a new tool for integrated pest management around the globe, as demonstrated by its insecticidal, ecotoxicological and safety profile. © 2014 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25351824

Insecticidal Activity and Chemical Composition of the Morinda lucida Essential Oil against Pulse Beetle Callosobruchus maculatus

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Moses S. Owolabi

2014-01-01

Full Text Available Insecticidal activity of essential oil extracted from Morinda lucida was tested on pulse beetle Callosobruchus maculatus, which is a pest that causes serious damage to several pulses. The insecticidal activity was compared with two pesticides, Phostoxin and Primo-ban-20. 120 mixed sex adult C. maculatus were introduced, along with 30 g of cowpeas. Four concentrations (0.40, 0.20, 0.10, and 0.05 μg/mL of the M. lucida essential oil, Phostoxin, and Primo-ban-20 were tested. Essential oil chemical composition was analyzed by GC-MS. M. lucida essential oil showed a high toxicological effect, producing 100% mortality after 72 hours at a dose of 0.20 μg/mL. M. lucida essential oil had a potent insecticidal activity (LC90 = 0.629 μg/mL compared to both pesticides, Phostoxin (LC90 = 0.652 μg/mL and Primo-ban-20 (LC90 = 0.726 μg/mL, at 24 h. The main compounds of the essential oil were the oxygenated monoterpenoids, 1,8-cineole (43.4%, and α-terpinyl acetate (14.5%, and the monoterpene hydrocarbons, mostly sabinene (8.2% and β-pinene (4.0%. Results clearly indicate that M. lucida essential oil can be used as an effective alternative for pulse beetle C. maculatus control, and it could be tested against other pulse beetles affecting Asia and Africa and throughout the world, thereby reducing use of synthetic pesticides.

Chemical composition, antimicrobial, insecticidal, phytotoxic and antioxidant activities of Mediterranean Pinus brutia and Pinus pinea resin essential oils.

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Ulukanli, Zeynep; Karabörklü, Salih; Bozok, Fuat; Ates, Burhan; Erdogan, Selim; Cenet, Menderes; Karaaslan, Merve Göksin

2014-12-01

Essential oils of the resins of Pinus brutia and Pinus pinea were evaluated for their biological potential. Essential oils were characterized using GC-MS and GC/FID. in vitro antimicrobial, phytotoxic, antioxidant, and insecticidal activities were carried out using the direct contact and the fumigant assays, respectively. The chemical profile of the essential oils of the resins of P. pinea and P. brutia included mainly α-pinene (21.39% and 25.40%), β-pinene (9.68% and 9.69%), and caryophyllene (9.12% and 4.81%). The essential oils of P. pinea and P. brutia exerted notable antimicrobial activities on Micrococcus luteus and Bacillus subtilis, insecticidal activities on Ephestia kuehniella eggs, phytotoxic activities on Lactuca sativa, Lepidium sativum, and Portulaca oleracea, as well as antioxidant potential. Indications of the biological activities of the essential oils suggest their use in the formulation of ecofriendly and biocompatible pharmaceuticals. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Pachira glabra Pasq. essential oil: chemical constituents, antimicrobial and insecticidal activities.

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Lawal, Oladipupo A; Ogunwande, Isiaka A; Salvador, Atinuke F; Sanni, Adetayo A; Opoku, Andy R

2014-01-01

The chemical composition of essential oil obtained by hydrodistillation of the leaves of Pachira glabra Pasq., (PgEO) has been studied by Gas Chromatography (GC) and Gas Chromatography coupled with Mass Spectrometry (GC/MS). Thirty three constituents representing 98.4% of total contents were identified from the essential oil. The major constituents of oil were limonene (23.2%), β-caryophyllene (14.5%), phtyol (8.5%) and β-bisabolene (6.3%). The antimicrobial activity of the PgEO was evaluated against a panel of ten bacteria and three fungal strain using agar diffusion and broth microdilution methods. Results have shown that the PgEO exhibited moderate to strong antimicrobial activity against the tested microorganisms except Citrobacter youagae, Micrococcus spp. and Proteus spp. The activity zones of inhibition (ZI) and minimum inhibitory concentrations (MIC) ranged between 13.7 mm-24.0 mm and 0.3 mg/mL-2.5 mg/mL, respectively. The insecticidal activity of PgEO was assayed against the adult Sitophilus zeamais. The lethal concentrations (LC50 and LC90) of the PgEO showed it to be toxic against adult S. zeamais at 32.2 and 53.7 mg/mL, respectively. This is the first report on the chemical composition and in vitro biological activities of essential oil of P. glabra growing in Nigeria.

Insect P450 inhibitors and insecticides: challenges and opportunities.

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Feyereisen, René

2015-06-01

P450 enzymes are encoded by a large number of genes in insects, often over a hundred. They play important roles in insecticide metabolism and resistance, and growing numbers of P450 enzymes are now known to catalyse important physiological reactions, such as hormone metabolism or cuticular hydrocarbon synthesis. Ways to inhibit P450 enzymes specifically or less specifically are well understood, as P450 inhibitors are found as drugs, as fungicides, as plant growth regulators and as insecticide synergists. Yet there are no P450 inhibitors as insecticides on the market. As new modes of action are constantly needed to support insecticide resistance management, P450 inhibitors should be considered because of their high potential for insect selectivity, their well-known mechanisms of action and the increasing ease of rational design and testing. © 2014 Society of Chemical Industry.

Metaflumizone is a novel sodium channel blocker insecticide.

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Salgado, V L; Hayashi, J H

2007-12-15

Metaflumizone is a novel semicarbazone insecticide, derived chemically from the pyrazoline sodium channel blocker insecticides (SCBIs) discovered at Philips-Duphar in the early 1970s, but with greatly improved mammalian safety. This paper describes studies confirming that the insecticidal action of metaflumizone is due to the state-dependent blockage of sodium channels. Larvae of the moth Spodoptera eridania injected with metaflumizone became paralyzed, concomitant with blockage of all nerve activity. Furthermore, tonic firing of abdominal stretch receptor organs from Spodoptera frugiperda was blocked by metaflumizone applied in the bath, consistent with the block of voltage-dependent sodium channels. Studies on native sodium channels, in primary-cultured neurons isolated from the CNS of the larvae of the moth Manduca sexta and on Para/TipE sodium channels heterologously expressed in Xenopus (African clawed frog) oocytes, confirmed that metaflumizone blocks sodium channels by binding selectively to the slow-inactivated state, which is characteristic of the SCBIs. The results confirm that metaflumizone is a novel sodium channel blocker insecticide.

Insecticide solvents: interference with insecticidal action.

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Brattsten, L B; Wilkinson, C F

1977-06-10

Several commercial solvent mixtures commonly used as insecticide carriers in spray formulations increase by more than threefold the microsomal N-demethylation of p-chloro N-methylaniline in midgut preparations of southern army-worm (Spodoptera eridania) larvae exposed orally to the test solvents. Under laboratory conditions, the same solvent mixtures exhibit a protective action against the in vivo toxicity of the insecticide carbaryl to the larvae. The data are discussed with respect to possible solvent-insecticide interactions occurring under field conditions and, more broadly, to potential toxicological hazards of these solvents to humans.

Pyrethrum flowers and pyrethroid insecticides.

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Casida, J E

1980-01-01

The natural pyrethrins from the daisy-like flower, Tanacetum or Chrysanthemum cinerariifolium, are nonpersistent insecticides of low toxicity to mammals. Synthetic analogs or pyrethroids, evolved from the natural compounds by successive isosteric modifications, are more potent and stable and are the newest important class of crop protection chemicals. They retain many of the favorable properties of the pyrethrins.

Insecticide mixtures for mosquito net impregnation against malaria vectors

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Corbel V.

2002-09-01

Full Text Available Insecticides belonging to the pyrethroid family are the only compounds currently available for the treatment of mosquito nets. Unfortunately, some malaria vector species have developed resistance to pyrethroids and the lack of alternative chemical categories is a great concern. One strategy for resistance management would be to treat mosquito nets with a mixture associating two insecticides having different modes of action. This study presents the results obtained with insecticide mixtures containing several proportions of bifenthrin (a pyrethroid insecticide and carbosulfan (a carbamate insecticide. The mixtures were sprayed on mosquito net samples and their efficacy were tested against a susceptible strain of Anopheles gambiae, the major malaria vector in Africa. A significant synergism was observed with a mixture containing 25 mg/m2 of bifenthrin (half the recommended dosage for treated nets and 6.25 mg/m2 of carbosulfan (about 2 % of the recommended dosage. The observed mortality was significantly more than expected in the absence of any interaction (80 % vs 41 % and the knock-down effect was maintained, providing an effective barrier against susceptible mosquitoes.

Ecotoxicological study of insecticide effects on arthropods in common bean.

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de Barros, Emerson Cristi; Ventura, Hudson Vaner; Gontijo, Pablo Costa; Pereira, Renata Ramos; Picanço, Marcelo Coutinho

2015-01-01

Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon-Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Insecticide Exposures on Commercial Aircraft: A Literature Review and Screening Level Assessment

Energy Technology Data Exchange (ETDEWEB)

Maddalena, Randy I.; McKone, Thomas E.

2008-10-01

on a thin-film polymer-coated glass design, was developed specifically for deployment in the airliner ventilation system for long-term unattended monitoring of insecticide loading in the aircraft. Because access was not available for either treated aircraft or treatment records during the course of this study, the development and calibration of the passive samplers was halted prior to completion. Continued development of a field ready passive sampler for insecticides in aircraft would require collaboration with the airline industry to finalize the method for deployment and calibration conditions for the sampler. The Task 3 screening level modeling assessment used a dynamic two-box mass balance model that includes treated surfaces and air to explore the time-concentration history of insecticides in the cabin. The model was parameterized using information gathered during the literature review and run for several different insecticide use scenarios. Chemical degradation or sequestration in the surface compartment and mass transfer from the surface to the air limit the rate at which insecticides are removed from the system. This rate limiting process can result in an accumulation of insecticide in the airliner cabin following repeated applications. The extent of accumulation is a function of the overall persistence of the chemical in the system and the amount of chemical applied during each treatment.

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

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Liu Yangyang

2011-12-01

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

Managing fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), with Bt maize and insecticides in southern Brazil.

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Burtet, Leonardo M; Bernardi, Oderlei; Melo, Adriano A; Pes, Maiquel P; Strahl, Thiago T; Guedes, Jerson Vc

2017-12-01

Maize plants expressing insecticidal proteins of Bacillus thuringiensis are valuable options for managing fall armyworm (FAW), Spodoptera frugiperda, in Brazil. However, control failures were reported, and therefore insecticides have been used to control this species. Based on these, we evaluated the use of Bt maize and its integration with insecticides against FAW in southern Brazil. Early-planted Agrisure TL, Herculex, Optimum Intrasect and non-Bt maize plants were severely damaged by FAW and required up to three insecticidal sprays. In contrast, YieldGard VT Pro, YieldGard VT Pro 3, PowerCore, Agrisure Viptera and Agrisure Viptera 3 showed little damage and did not require insecticides. Late-planted Bt maize plants showed significant damage by FAW and required up to four sprays, with the exceptions of Agrisure Viptera and Agrisure Viptera 3. Exalt (first and second sprays); Lannate + Premio (first spray) and Avatar (second spray); and Karate + Match (first spray) and Ampligo (second spray) were the most effective insecticides against FAW larvae in Bt and non-Bt maize. Maize plants expressing Cry proteins exhibited FAW control failures in southern Brazil, necessitating insecticidal sprays. In contrast, Bt maize containing the Vip3Aa20 protein remained effective against FAW. However, regardless of the insecticide used against FAW surviving on Bt maize, grain yields were similar. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Toxicity of insecticides to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies.

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Bacci, Leandro; Crespo, André L B; Galvan, Tederson L; Pereira, Eliseu J G; Picanço, Marcelo C; Silva, Gerson A; Chediak, Mateus

2007-07-01

Efficient chemical control is achieved when insecticides are active against insect pests and safe to natural enemies. In this study, the toxicity of 17 insecticides to the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the selectivity of seven insecticides to natural enemies of this insect pest were evaluated. To determine the insecticide toxicity, B. tabaci adults were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion, methamidophos, bifenthrin, cypermethrin, deltamethrin, esfenvalerate, fenitrothion, fenpropathrin, fenthion, phenthoate, permethrin and trichlorphon at 50 and 100% of the field rate (FR), and to water (untreated control). To determine the insecticide selectivity, adults of Encarsia sp., Acanthinus sp., Discodon sp. and Lasiochilus sp. were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion and methamidophos at 50 and 100% FR, and to water. Groups of each insect species were exposed to kale leaves preimmersed in each treatment under laboratory conditions. Mortality of exposed individuals was recorded 24 h after treatment. Cartap and imidacloprid at 50 and 100% FR and abamectin and acetamiprid at 100% FR showed insecticidal activity to B. tabaci adults. Abamectin at 50 and 100% FR was the least insecticidal compound to the natural enemies Acanthinus sp., Discodon sp. and Lasiochilus sp. The present results suggest that abamectin at 100% FR may decrease B. tabaci field populations but can still be harmless to predators. Implications of these results within an integrated pest management context are discussed. Copyright (c) 2007 Society of Chemical Industry.

Rice Production without Insecticide in Smallholder Farmer's Field

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M. P. Ali

2017-05-01

Full Text Available Highlights:Use of perching, sweeping, and need based insecticide (IPM technique useage produce at par yields compared to prophylactic insecticide useage in rice fields.There exists a technique that can reduce 75% of insecticide useage in rice field.The results were obtained in cooperation between smallholder rice farmers and researchers of Bangladesh.Currently rice protection from insect pests solely depends on chemical pesticides which have tremendous impact on biodiversity, environment, animal, and human health. To reduce their impact from our society we need to cut pesticide use from agricultural practices. To address this issue, we did an experiment to identify realistic solutions that could help farmers build sustainable crop protection systems and minimize useage of insecticides and thus reduce the impact of pesticides in the environment. Innovations developed jointly by farmers and researchers and evaluated for their potential to be adopted by more farmers. In this paper we tested four management practices jointly with smallholder farmer fields in order to select the best one. Four management practices were used namely, T1 = Prophylactic use of insecticide where insecticide was applied in rice field at every 15 days interval without judging the infestation level; T2 = Perching (that is, placing roosting (perching sites for insectivorous birds within the rice field and concurrent sweep net samples along with need-based insecticide application; T3 = Perching only; and T4 = Farmer's own practices. The results revealed that routine application of insecticides for crop protection is not mandatory which is commonly found at use in rice farmers. In our experiment, where prophylactic method or farmers used 3–4 times insecticides without judging the insect pests infestation level, the similar pest population was found when compared to the field where insecticide was not applied. Our management system reduced by 75% the use of insecticides even

Insecticidal and Nematicidal Activities of Novel Mimosine Derivatives

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Binh Cao Quan Nguyen

2015-09-01

Full Text Available Mimosine, a non-protein amino acid, is found in several tropical and subtropical plants, which has high value for medicine and agricultural chemicals. Here, in continuation of works aimed to development of natural product-based pesticidal agents, we present the first significant findings for insecticidal and nematicidal activities of novel mimosine derivatives. Interestingly, mimosinol and deuterated mimosinol (D-mimosinol from mimosine had strong insecticidal activity which could be a result of tyrosinase inhibition (IC50 = 31.4 and 46.1 μM, respectively. Of synthesized phosphoramidothionate derivatives from two these amino alcohols, two compounds (1a and 1b showed high insecticidal activity (LD50 = 0.5 and 0.7 μg/insect, respectively with 50%–60% mortality at 50 μg/mL which may be attributed to acetylcholinesterase inhibition. Compounds 1a and 1b also had strong nematicidal activity with IC50 = 31.8 and 50.2 μM, respectively. Our results suggest that the length of the alkyl chain and the functional group at the C5-position of phosphoramidothionates derived from mimosinol and d-mimosinol are essential for the insecticidal and nematicidal activities. These results reveal an unexplored scaffold as new insecticide and nematicide.

Quantitative structure-activity relationship (QSAR) for insecticides: development of predictive in vivo insecticide activity models.

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Naik, P K; Singh, T; Singh, H

2009-07-01

Quantitative structure-activity relationship (QSAR) analyses were performed independently on data sets belonging to two groups of insecticides, namely the organophosphates and carbamates. Several types of descriptors including topological, spatial, thermodynamic, information content, lead likeness and E-state indices were used to derive quantitative relationships between insecticide activities and structural properties of chemicals. A systematic search approach based on missing value, zero value, simple correlation and multi-collinearity tests as well as the use of a genetic algorithm allowed the optimal selection of the descriptors used to generate the models. The QSAR models developed for both organophosphate and carbamate groups revealed good predictability with r(2) values of 0.949 and 0.838 as well as [image omitted] values of 0.890 and 0.765, respectively. In addition, a linear correlation was observed between the predicted and experimental LD(50) values for the test set data with r(2) of 0.871 and 0.788 for both the organophosphate and carbamate groups, indicating that the prediction accuracy of the QSAR models was acceptable. The models were also tested successfully from external validation criteria. QSAR models developed in this study should help further design of novel potent insecticides.

Insecticide resistance and intracellular proteases.

Science.gov (United States)

Wilkins, Richard M

2017-12-01

Pesticide resistance is an example of evolution in action with mechanisms of resistance arising from mutations or increased expression of intrinsic genes. Intracellular proteases have a key role in maintaining healthy cells and in responding to stressors such as pesticides. Insecticide-resistant insects have constitutively elevated intracellular protease activity compared to corresponding susceptible strains. This increase was shown for some cases originally through biochemical enzyme studies and subsequently putatively by transcriptomics and proteomics methods. Upregulation and expression of proteases have been characterised in resistant strains of some insect species, including mosquitoes. This increase in proteolysis results in more degradation products (amino acids) of intracellular proteins. These may be utilised in the resistant strain to better protect the cell from stress. There are changes in insect intracellular proteases shortly after insecticide exposure, suggesting a role in stress response. The use of protease and proteasome inhibitors or peptide mimetics as synergists with improved application techniques and through protease gene knockdown using RNA interference (possibly expressed in crop plants) may be potential pest management strategies, in situations where elevated intracellular proteases are relevant. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.

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Mougabure-Cueto, Gastón; Picollo, María Inés

2015-09-01

Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid

Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

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Kanniah Rajasekaran

2013-04-01

Full Text Available The antimicrobial properties of essential oils have been documented, and their use as “biocides” is gaining popularity. The aims of this study were to analyze the chemical composition and assess the biological activities of Hedychium essential oils. Oils from 19 Hedychium species and cultivars were analyzed by gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS techniques. The antifungal and insecticidal activities of these oils were tested against Colletotrichum acutatum, C. fragariae, and C. gloeosporioides, and three insects, the azalea lace bug (Stephanitis pyrioides, the yellow fever mosquito (Aedes aegypti, and the red imported fire ant (Solenopsis invicta. Hedychium oils were rich in monoterpenes and sesquiterpenes, especially 1,8-cineole (0.1%–42%, linalool (<0.1%–56%, a-pinene (3%–17%, b-pinene (4%–31%, and (E-nerolidol (0.1%–20%. Hedychium oils had no antifungal effect on C. gloeosporioides, C. fragariae, and C. acutatum, but most Hedychium oils effectively killed azalea lace bugs. The oils also show promise as an adult mosquito repellent, but they would make rather poor larvicides or adulticides for mosquito control. Hedychium oils acted either as a fire ant repellent or attractant, depending on plant genotype and oil concentration.

The Effectiveness of Lemongrass, Garlic, and Tree Marigold as Botanical Insecticides in Controlling of Cocoa Mirid,Helopeltis antonii

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Endang Sulistyowati

2014-05-01

Full Text Available Control of cocoa mirid, Helopeltis antoniiso far uses chemicalinsecticides as the main alternative. Therefore, it is necessary to find out the environment friendly control techniques. Lemongrass, garlic, and tree marigold have been known as an efectiveness botanical insecticides for horticulture. A research with aim to study the effectiveness of lemongrass (Cymbopogon nardus, garlic (Allium sativum and tree marigold (Tithonia diversifoliafor controlling H. antoniihave been carried out in cocoa plantation at Kaliwining experimental garden of Indonesian Coffee and Cocoa Research Institute. The research was arranged in split plot design in three replication, with the main plot infestation time of H. antoniiand sub-plot kind of botanical insecticides. Concentration of botanical insecticides used in this study was 5% and applied on 12 cm cocoa pod in length by using knapsack sprayer. Infestation of H. antonii nymphes were conducted before and after insecticide applications. Observation was conducted on the mortality and the lesion of H. antonii. The results of orthogonal contrast test on feeding activity based on the number of lesion and percentage of mortality of H. antoniishowed that there were significantly different between insecticide treatment and control, between chemical insecticide and botanical insecticides, but there was no significant different on kind of botanical insecticides. The lowest number of lesion due to H. antonii was shown by chemical insecticide with an average 34.0, followed by garlic and lemongrass botanical insecticide with number of lesion were 51.2 and 64.7 respectively, whereas the number of lesion in the control reached 84.2. The highest percentage mortality of H. antoniiwas shown by chemical insecticide with active ingredient teta-cypermethrin at 84.3%, followed by garlic, lemon grass and tree marigold botanical insecticide were 65.8%; 65.0%; and 63.8% respectively and significantly different with control by 8

Evolution of resistance to pyrethroid insecticides in Musca domestica.

Science.gov (United States)

Scott, Jeffrey G

2017-04-01

Houseflies, Musca domestica L., are a significant pest because of the numerous diseases they transmit. Control of housefly populations, particularly at animal production facilities, is frequently done using pyrethroid insecticides which kill insects by prolonging the open time of the voltage-sensitive sodium channel (VSSC). Houseflies have evolved resistance to pyrethroids owing to mutations in Vssc and by cytochrome-P450-mediated detoxification. Three Vssc mutations are known: kdr (L1014F), kdr-his (L1014H) and super-kdr (M918T + L1014F). Generally, the levels of resistance conferred by these mutations are kdr-his resistance than kdr. P450-mediated resistance can result from overexpression of CYP6D1 or another P450 (unidentified) whose overexpression is linked to autosomes II or V. The initial use of field-stable pyrethroids resulted in different patterns of evolution across the globe, but with time these mutations have become more widespread in their distribution. What is known about the fitness costs of the resistance alleles in the absence of insecticide is discussed, particularly with respect to the current and future utility of pyrethroid insecticides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Insecticide control of vector-borne diseases: when is insecticide resistance a problem?

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Ana Rivero

Full Text Available Many of the most dangerous human diseases are transmitted by insect vectors. After decades of repeated insecticide use, all of these vector species have demonstrated the capacity to evolve resistance to insecticides. Insecticide resistance is generally considered to undermine control of vector-transmitted diseases because it increases the number of vectors that survive the insecticide treatment. Disease control failure, however, need not follow from vector control failure. Here, we review evidence that insecticide resistance may have an impact on the quality of vectors and, specifically, on three key determinants of parasite transmission: vector longevity, competence, and behaviour. We argue that, in some instances, insecticide resistance is likely to result in a decrease in vector longevity, a decrease in infectiousness, or in a change in behaviour, all of which will reduce the vectorial capacity of the insect. If this effect is sufficiently large, the impact of insecticide resistance on disease management may not be as detrimental as previously thought. In other instances, however, insecticide resistance may have the opposite effect, increasing the insect's vectorial capacity, which may lead to a dramatic increase in the transmission of the disease and even to a higher prevalence than in the absence of insecticides. Either way-and there may be no simple generality-the consequence of the evolution of insecticide resistance for disease ecology deserves additional attention.

Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex

International Nuclear Information System (INIS)

Asselman, J.; Janssen, C.R.; Smagghe, G.; De Schamphelaere, K.A.C.

2014-01-01

In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms. - Highlights:: • 2 of 4 insecticide-Microcystis combinations showed no interactive effect on Daphnia. • One insecticide showed antagonistic deviation patterns. • For one other insecticide the results depended on the reference model used. • Interactive effects between insecticides and Microcystis cannot be generalized. • The concentration addition model provides conservative estimates of mixture effects. - Interactive effects between insecticides and cyanobacterial stressors cannot be generalized, not even for insecticides with closely related known modes of action

Susceptibility of natural enemies of pests of agriculture to commonly applied insecticides in Honduras

International Nuclear Information System (INIS)

Bustamante, M.; Sabillon, A.; Velasquez, C.; Ordonez, J.; Baquedano, F.

1999-01-01

Insecticides are commonly used by Honduran farmers to control pest insects in agricultural crops such as corn, melons and tomatoes. However, the insecticides have the potential for toxicity to the natural enemies of the pest insects also. Therefore, efforts are being made to identify insecticides which, when used within the Inegerated Pest Management (IPM) programme, are selectively more toxic to the pest insects than their natural enemies. A number of selected chemical insecticides and a biological insecticide (NPV) were tested in three different tests to determine toxicity to two beneficial insects: Telenomus remus Nixon (Hymenoptera: Scelionidae) and Chrysoperla carnea Steph. (Neuroptera: Chrysopidae). All insecticides were toxic to T. remus which suffered high mortality. There was no significant difference in mortality of the insect due to the method of exposure to the insecticides. There were some differences in the toxicity of the insecticides to C. carnea, and abamectin, bifenthrin, cypermethrin, diafenthiuron, imidacloprid and fenpropathrin were relatively less toxic and could be used in IPM for the control of pest insects. (author)

Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

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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

Chemical Compositions and Insecticidal Activities of Alpinia kwangsiensis Essential Oil against Lasioderma serricorne

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Yan Wu

2015-12-01

Full Text Available The essential oil obtained by hydrodistillation from Alpinia kwangsiensis rhizomes was investigated by GC-MS. A total of 31 components representing 92.45% of the oil were identified and the main compounds in the oil were found to be camphor (17.59%, eucalyptol (15.16%, β-pinene (11.15% and α-pinene (10.50%. These four compounds were subsequently isolated and the essential oil and four isolated compounds exhibited potent insecticidal activity against Lasioderma serricorne adults. During the assay, it was shown that the essential oil exhibited both potential contact (LD50 = of 24.59 μg/adult and fumigant (LC50 = of 9.91 mg/L air toxicity against Lasioderma serricorne. The study revealed that the insecticidal activity of the essential oil can be attributed to the synergistic effects of its diverse major components, which indicates that oil of Alpinia kwangsiensis and its isolated compounds have potential to be developed into natural insecticides to control insects in stored grains and traditional Chinese medicinal materials.

Laboratory Evaluation of Toxicity of Insecticide Formulations from Different Classes against American Cockroach (Dictyoptera: Blattidae.

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Ruhma Syed

2014-06-01

Full Text Available The present study was designed to investigate the insecticidal efficacy of four different classes of insecticides: pyrethroids, organophosphates, phenyl-pyrazoles and neo-nicotenoids. One representative chemical from each class was selected to compare the toxicity: deltamethrin from pyrethroids, Dichlorovinyl Dimethyl Phosphate (DDVP from organophosphates, fipronil from phenyl-pyrazoles and imidacloprid from neo-nicotenoids. The objective of this study was to determine which of these insecticides were most effective against American cockroach.These insecticides were tested for their LC50 values against Periplaneta americana under topical bioassay method, using different concentrations for each chemical.Fipronil 2.5% EC was highly effective at all concentrations applied, while DDVP 50% EC was least toxic amongst all. One way analysis of variance confirmed significant differences between mortality of P. americana and different concentrations applied (P< 0.05.Locality differentiation is an important factor in determining the range of resistance between various localities, as all three localities behaved differently in terms of their levels of resistance.

Multiple mitigation mechanisms: Effects of submerged plants on the toxicity of nine insecticides to aquatic animals.

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Brogan, William R; Relyea, Rick A

2017-01-01

Understanding the processes that regulate contaminant impacts in nature is an increasingly important challenge. For insecticides in surface waters, the ability of aquatic plants to sorb, or bind, hydrophobic compounds has been identified as a primary mechanism by which toxicity can be mitigated (i.e. the sorption-based model). However, recent research shows that submerged plants can also rapidly mitigate the toxicity of the less hydrophobic insecticide malathion via alkaline hydrolysis (i.e. the hydrolysis-based model) driven by increased water pH resulting from photosynthesis. However, it is still unknown how generalizable these mitigation mechanisms are across the wide variety of insecticides applied today, and whether any general rules can be ascertained about which types of chemicals may be mitigated by each mechanism. We quantified the degree to which the submerged plant Elodea canadensis mitigated acute (48-h) toxicity to Daphnia magna using nine commonly applied insecticides spanning three chemical classes (carbamates: aldicarb, carbaryl, carbofuran; organophosphates: malathion, diazinon, chlorpyrifos; pyrethroids: permethrin, bifenthrin, lambda-cyhalothrin). We found that insecticides possessing either high octanol-water partition coefficients (log K ow ) values (i.e. pyrethroids) or high susceptibility to alkaline hydrolysis (i.e. carbamates and malathion) were all mitigated to some degree by E. canadensis, while the plant had no effect on insecticides possessing intermediate log K ow values and low susceptibility to hydrolysis (i.e. chlorpyrifos and diazinon). Our results provide the first general insights into which types of insecticides are likely to be mitigated by different mechanisms based on known chemical properties. We suggest that current models and mitigation strategies would be improved by the consideration of both mitigation models. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

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2013-04-11

Hedychiums have been reported to possess antibacterial, antifungal, and insecticidal activities [4,5]. Strawberry anthracnose, caused by the plant...pathogens Colletotrichum species is one of the most important diseases affecting strawberries worldwide [6]. Colletotrichum fragariae Brooks is most...often associated with anthracnose crown rot of strawberries grown in hot, humid areas such as the southeastern United States [7]. The azalea lace bug

DIRProt: a computational approach for discriminating insecticide resistant proteins from non-resistant proteins.

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Meher, Prabina Kumar; Sahu, Tanmaya Kumar; Banchariya, Anjali; Rao, Atmakuri Ramakrishna

2017-03-24

Insecticide resistance is a major challenge for the control program of insect pests in the fields of crop protection, human and animal health etc. Resistance to different insecticides is conferred by the proteins encoded from certain class of genes of the insects. To distinguish the insecticide resistant proteins from non-resistant proteins, no computational tool is available till date. Thus, development of such a computational tool will be helpful in predicting the insecticide resistant proteins, which can be targeted for developing appropriate insecticides. Five different sets of feature viz., amino acid composition (AAC), di-peptide composition (DPC), pseudo amino acid composition (PAAC), composition-transition-distribution (CTD) and auto-correlation function (ACF) were used to map the protein sequences into numeric feature vectors. The encoded numeric vectors were then used as input in support vector machine (SVM) for classification of insecticide resistant and non-resistant proteins. Higher accuracies were obtained under RBF kernel than that of other kernels. Further, accuracies were observed to be higher for DPC feature set as compared to others. The proposed approach achieved an overall accuracy of >90% in discriminating resistant from non-resistant proteins. Further, the two classes of resistant proteins i.e., detoxification-based and target-based were discriminated from non-resistant proteins with >95% accuracy. Besides, >95% accuracy was also observed for discrimination of proteins involved in detoxification- and target-based resistance mechanisms. The proposed approach not only outperformed Blastp, PSI-Blast and Delta-Blast algorithms, but also achieved >92% accuracy while assessed using an independent dataset of 75 insecticide resistant proteins. This paper presents the first computational approach for discriminating the insecticide resistant proteins from non-resistant proteins. Based on the proposed approach, an online prediction server DIRProt has

The contribution of agricultural insecticide use to increasing insecticide resistance in African malaria vectors

OpenAIRE

Reid, Molly C.; McKenzie, F. Ellis

2016-01-01

The fight against malaria is increasingly threatened by failures in vector control due to growing insecticide resistance. This review examines the recent primary research that addresses the putative relationship between agricultural insecticide use and trends in insecticide resistance. To do so, descriptive evidence offered by the new research was categorized, and additional factors that impact the relationship between agricultural insecticide use and observed insecticide resistance in malari...

Three-input gate logic circuits on chemically assembled single-electron transistors with organic and inorganic hybrid passivation layers.

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Majima, Yutaka; Hackenberger, Guillaume; Azuma, Yasuo; Kano, Shinya; Matsuzaki, Kosuke; Susaki, Tomofumi; Sakamoto, Masanori; Teranishi, Toshiharu

2017-01-01

Single-electron transistors (SETs) are sub-10-nm scale electronic devices based on conductive Coulomb islands sandwiched between double-barrier tunneling barriers. Chemically assembled SETs with alkanethiol-protected Au nanoparticles show highly stable Coulomb diamonds and two-input logic operations. The combination of bottom-up and top-down processes used to form the passivation layer is vital for realizing multi-gate chemically assembled SET circuits, as this combination enables us to connect conventional complementary metal oxide semiconductor (CMOS) technologies via planar processes. Here, three-input gate exclusive-OR (XOR) logic operations are demonstrated in passivated chemically assembled SETs. The passivation layer is a hybrid bilayer of self-assembled monolayers (SAMs) and pulsed laser deposited (PLD) aluminum oxide (AlO[Formula: see text]), and top-gate electrodes were prepared on the hybrid passivation layers. Top and two-side-gated SETs showed clear Coulomb oscillation and diamonds for each of the three available gates, and three-input gate XOR logic operation was clearly demonstrated. These results show the potential of chemically assembled SETs to work as logic devices with multi-gate inputs using organic and inorganic hybrid passivation layers.

Mass spectrometric analyses of organophosphate insecticide oxon protein adducts.

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Thompson, Charles M; Prins, John M; George, Kathleen M

2010-01-01

Organophosphate (OP) insecticides continue to be used to control insect pests. Acute and chronic exposures to OP insecticides have been documented to cause adverse health effects, but few OP-adducted proteins have been correlated with these illnesses at the molecular level. Our aim was to review the literature covering the current state of the art in mass spectrometry (MS) used to identify OP protein biomarkers. We identified general and specific research reports related to OP insecticides, OP toxicity, OP structure, and protein MS by searching PubMed and Chemical Abstracts for articles published before December 2008. A number of OP-based insecticides share common structural elements that result in predictable OP-protein adducts. The resultant OP-protein adducts show an increase in molecular mass that can be identified by MS and correlated with the OP agent. Customized OP-containing probes have also been used to tag and identify protein targets that can be identified by MS. MS is a useful and emerging tool for the identification of proteins that are modified by activated organophosphate insecticides. MS can characterize the structure of the OP adduct and also the specific amino acid residue that forms the key bond with the OP. Each protein that is modified in a unique way by an OP represents a unique molecular biomarker that with further research can lead to new correlations with exposure.

Synthesis of the Insecticide Prothrin and Its Analogues from Biomass-Derived 5-(Cloromethyl)furfural

Science.gov (United States)

2013-12-19

Synthesis of the Insecticide Prothrin and Its Analogues from Biomass-Derived 5‑(Chloromethyl) furfural Fei Chang,† Saikat Dutta,† James J. Becnel...derived platform chemical 5- (chloromethyl) furfural in six steps and overall 65% yield. Two structural analogues of prothrin were also prepared following...insecticidal activities. KEYWORDS: biomass, furans, pyrethroids, synthesis, 5-(chloromethyl) furfural ■ INTRODUCTION Previously, we have described the

The contribution of agricultural insecticide use to increasing insecticide resistance in African malaria vectors.

Science.gov (United States)

Reid, Molly C; McKenzie, F Ellis

2016-02-19

The fight against malaria is increasingly threatened by failures in vector control due to growing insecticide resistance. This review examines the recent primary research that addresses the putative relationship between agricultural insecticide use and trends in insecticide resistance. To do so, descriptive evidence offered by the new research was categorized, and additional factors that impact the relationship between agricultural insecticide use and observed insecticide resistance in malaria vectors were identified. In 23 of the 25 relevant recent publications from across Africa, higher resistance in mosquito populations was associated with agricultural insecticide use. This association appears to be affected by crop type, farm pest management strategy and urban development.

Management of Mango Hopper, Idioscopus clypealis, Using Chemical Insecticides and Neem Oil

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S. M. Adnan

2014-01-01

Full Text Available An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%, Endosulfan (0.5%, and Cypermethrin (0.4%, and natural Neem oil (3% with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02 at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64 of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil.

Management of mango hopper, Idioscopus clypealis, using chemical insecticides and Neem oil.

Science.gov (United States)

Adnan, S M; Uddin, M M; Alam, M J; Islam, M S; Kashem, M A; Rafii, M Y; Latif, M A

2014-01-01

An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02) at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64) of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil.

Management of Mango Hopper, Idioscopus clypealis, Using Chemical Insecticides and Neem Oil

Science.gov (United States)

Adnan, S. M.; Uddin, M. M.; Alam, M. J.; Islam, M. S.; Kashem, M. A.; Rafii, M. Y.; Latif, M. A.

2014-01-01

An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02) at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64) of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil. PMID:25140344

Compatibility of the entomopathogenic fungus Lecanicillium muscarium and insecticides for eradication of sweetpotato whitefly, Bemisia tabaci.

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Cuthbertson, Andrew G S; Walters, Keith F A; Deppe, Carola

2005-08-01

The compatibility of the entomopathogenic fungus Lecanicillium muscarium and chemical insecticides used to control the second instar stages of the sweetpotato whitefly, Bemisia tabaci, was investigated. The effect on spore germination of direct exposure for 24 h to the insecticides imidacloprid, buprofezin, teflubenzuron and nicotine was determined. Only exposure to buprofezin was followed by acceptable spore germination. However, all chemicals significantly reduced spore germination when compared to a water control. Infectivity of L. muscarium in the presence of dry residues of buprofezin, teflubenzuron and nicotine (imidacloprid is a systemic pesticide) on foliage were also investigated. No significant detrimental effects on the level of control of B. tabaci was recorded when compared with fungi applied to residue free foliage on either tomato or verbena plants. Fungi in combination with imidacloprid gave higher B. tabaci mortality on verbena foliage compared to either teflubenzuron or nicotine and fungi combinations. Use of these chemical insecticides with L. muscarium in integrated control programmes for B. tabaci is discussed.

A short history of insecticides

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Oberemok Volodymyr Volodymyrovych

2015-07-01

Full Text Available This review contains a brief history of the use of insecticides. The peculiarities, main advantages, and disadvantages of some modern insecticides are described. The names of the discoverers of some of the most popular insecticide preparations on the world market, are listed. The tendencies to find new insecticides to control the quantity of phytophagous insects are discussed. Special attention is paid to the perspective of creating preparations based on nucleic acids, in particular DNA insecticides. The use of insect-specific, short single-stranded DNA fragments as DNA insecticides, is paving the way in the field of “intellectual” insecticides that “think” before they act. It is worth noting, though, that in the near future, the quantity of produced insecticides will increase due to the challenges associated with food production for a rapidly growing population. It is concluded, that an agreeable interaction of scientists and manufacturers of insecticides should lead to the selection of the most optimal solutions for insect pest control, which would be safe, affordable, and effective at the same time.

Testing insecticidal activity of novel chemically synthesized siRNA against Plutella xylostella under laboratory and field conditions.

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Liang Gong

Full Text Available BACKGROUND: Over the last 60 years, synthetic chemical pesticides have served as a main tactic in the field of crop protection, but their availability is now declining as a result of the development of insect resistance. Therefore, alternative pest management agents are needed. However, the demonstration of RNAi gene silencing in insects and its successful usage in disrupting the expression of vital genes opened a door to the development of a variety of novel, environmentally sound approaches for insect pest management. METHODOLOGY/PRINCIPAL FINDINGS: Six small interfering RNAs (siRNAs were chemically synthesized and modified according to the cDNA sequence of P. xylostella acetylcholine esterase genes AChE1 and AChE2. All of them were formulated and used in insecticide activity screening against P. xylostella. Bioassay data suggested that Si-ace1_003 and Si-ace2_001 at a concentration of 3 µg cm(-2 displayed the best insecticidal activity with 73.7% and 89.0%, mortality, respectively. Additional bioassays were used to obtain the acute lethal concentrations of LC50 and LC90 for Si-ace2_001, which were 53.66 µg/ml and 759.71 µg/ml, respectively. Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2 were reduced by 5.7-fold compared to the control group. Consequently, AChE activity was also reduced by 1.7-fold. Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses. Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions. CONCLUSIONS: The most important finding of this study is the discovery that chemically synthesized and modified siRNA corresponding to P. xylostella AChE genes cause significant mortality of the insect both under laboratory and field conditions, which provides a novel strategy to control P

Responses of striped stem borer, Chilo suppressalis (Lepidoptera: Pyralidae), from Taiwan to a range of insecticides.

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Cheng, Xuan; Chang, Cheng; Dai, Shu-Mei

2010-07-01

Information on the insecticide susceptibility of striped stem borer, Chilo suppressalis (Walker), is essential for an effective pest management programme. An early detection of resistance development can prompt the modification of current control methods and increase the lifespan of insecticides through the rotation of chemicals with different modes of action. In this study, the susceptibility of this pest in Taiwan to four classes of insecticides has been examined. Over 1000-fold resistance to carbofuran was detected in C. suppressalis collected from Chiayi and Changhua prefectures, with estimated LC(50) values of > 3 mg cm(-2). In addition, 61-fold resistance to cartap was found in the Chiayi population. On the other hand, all tested populations of rice stem borer were still relatively susceptible to chlorpyrifos, fipronil and permethrin, with LC(50) values ranging from 30 to 553 ng cm(-2). Chilo suppressalis populations collected from the central parts of Taiwan have a higher degree of resistance to the tested insecticides than those from northern areas. The occurrence of high resistance to carbofuran in the Chiayi and Changhua areas suggests that this compound should be replaced with chemicals having a different mode of action, such as chlorpyrifos, fipronil and permethrin, to which low cross-resistance has been detected. Copyright (c) 2010 Society of Chemical Industry.

Comparative analysis of response to selection with three insecticides in the dengue mosquito Aedes aegypti using mRNA sequencing.

Science.gov (United States)

David, Jean-Philippe; Faucon, Frédéric; Chandor-Proust, Alexia; Poupardin, Rodolphe; Riaz, Muhammad Asam; Bonin, Aurélie; Navratil, Vincent; Reynaud, Stéphane

2014-03-05

Mosquito control programmes using chemical insecticides are increasingly threatened by the development of resistance. Such resistance can be the consequence of changes in proteins targeted by insecticides (target site mediated resistance), increased insecticide biodegradation (metabolic resistance), altered transport, sequestration or other mechanisms. As opposed to target site resistance, other mechanisms are far from being fully understood. Indeed, insecticide selection often affects a large number of genes and various biological processes can hypothetically confer resistance. In this context, the aim of the present study was to use RNA sequencing (RNA-seq) for comparing transcription level and polymorphism variations associated with adaptation to chemical insecticides in the mosquito Aedes aegypti. Biological materials consisted of a parental susceptible strain together with three child strains selected across multiple generations with three insecticides from different classes: the pyrethroid permethrin, the neonicotinoid imidacloprid and the carbamate propoxur. After ten generations, insecticide-selected strains showed elevated resistance levels to the insecticides used for selection. RNA-seq data allowed detecting over 13,000 transcripts, of which 413 were differentially transcribed in insecticide-selected strains as compared to the susceptible strain. Among them, a significant enrichment of transcripts encoding cuticle proteins, transporters and enzymes was observed. Polymorphism analysis revealed over 2500 SNPs showing > 50% allele frequency variations in insecticide-selected strains as compared to the susceptible strain, affecting over 1000 transcripts. Comparing gene transcription and polymorphism patterns revealed marked differences among strains. While imidacloprid selection was linked to the over transcription of many genes, permethrin selection was rather linked to polymorphism variations. Focusing on detoxification enzymes revealed that permethrin

Decrease of insecticide resistance over generations without exposure to insecticides in Nilaparvata lugens (Hemipteran: Delphacidae).

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Yang, Yajun; Dong, Biqin; Xu, Hongxing; Zheng, Xusong; Tian, Junce; Heong, Kongleun; Lu, Zhongxian

2014-08-01

The brown planthopper, Nilaparvata lugens (Stål), is one of the most important insect pests on paddy rice in tropical and temperate Asia. Overuse and misuse of insecticides have resulted in the development of high resistance to many different insecticides in this pest. Studies were conducted to evaluate the change of resistance level to four insecticides over 15 generations without any exposure to insecticides in brown planthopper. After 15 generations' rearing without exposure to insecticide, brown planthopper could reverse the resistance to imidacloprid, chlorpyrifos, fipronil, and fenobucarb. The range and style of resistance reversal of brown planthopper differed when treated with four different insecticides. To monitor potential changes in insect physiological responses, we measured the activity of each of the three selected enzymes, including acetylcholinesterases (AChE), general esterases (EST), and glutathione S-transferases. After multiple generations' rearing without exposure to insecticide, AChE and EST activities of brown planthopper declined with the increased generations, suggesting that the brown planthopper population adjusted activities of EST and AChE to adapt to the non-insecticide environment. These findings suggest that the reducing, temporary stop, or rotation of insecticide application could be incorporated into the brown planthopper management.

Characterization of UDP-glucuronosyltransferase genes and their possible roles in multi-insecticide resistance in Plutella xylostella (L.).

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Li, Xiuxia; Shi, Haiyan; Gao, Xiwu; Liang, Pei

2018-03-01

Uridine diphosphate-glucuronosyltransferases (UGTs), as multifunctional detoxification enzymes, play important roles in the biotransformation of various compounds. However, their roles in insecticide resistance are still unclear. This study presents a genome-wide identification of the UGTs in diamondback moth, Plutella xylostella (L.), a notorious insect pest of cruciferous crops worldwide. The possible roles of these UGTs in insecticide resistance were evaluated. A total of 21 putative UGTs in P. xylostella were identified. Quantitative real-time polymerase chain reaction (PCR)-based analyses showed that all the UGT genes were expressed in all tested developmental stages and tissues. Bioassay results indicated that a field-collected population (BL) was resistant to 9 of 10 commonly used insecticides, and 10 of 21 UGT mRNAs were upregulated in the BL population. Exposure to the LC 50 of each insecticide affected the expression of most UGT genes. Among these, the expression levels of UGT40V1, UGT45B1 and UGT33AA4 were induced by more than five insecticides, whereas indoxacarb and metaflumizone significantly repressed the expression of most UGT genes. UGTs may play important roles in the metabolism of commonly used insecticides in P. xylostella. These findings provide valuable information for further research on the physiological and toxicological functions of specific UGT genes in P. xylostella. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effect of an insecticide on growth and metabolism of some non-target soil micro-organisms

International Nuclear Information System (INIS)

Balasubramanian, A.; Nilakantan, Gita

1975-01-01

Aldicarb, a systemic insecticide, enhanced the growth of Rhizobium japonicum in vitro at 1 ppm concentration but inhibited it at 5 ppm level. The cell yields of Azotobacter chroococcum and Pseudomonas solanacearum were reduced by both the concentrations of the chemical. 1 and 5 ppm levels of the insecticide the incorporation of 14 C-glucose by R. japonicum, but it was stimulated in the case of R. chroococcum. In the case of P. solanacearum, however, 1 ppm level of the insecticide enhanced the incorporation of the label. Uptake of 32 P-di-potassium hydrogen phosphate by the cells was also significantly reduced indicating that the metabolic activities of these non-target soil micro-organisms are altered by the insecticide treatment. (author)

Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

Science.gov (United States)

Beloti, Vitor Hugo; Alves, Gustavo Rodrigues; Araújo, Diogo Feliciano Dias; Picoli, Mateus Manara; Moral, Rafael de Andrade; Demétrio, Clarice Garcia Borges; Yamamoto, Pedro Takao

2015-01-01

Huanglongbing (HLB) is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston), the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1), 12% as slightly harmful (Class 2), 12% as moderately harmful (Class 3) and 56% as harmful (Class 4), according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful) were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless) were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

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Vitor Hugo Beloti

Full Text Available Huanglongbing (HLB is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston, the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1, 12% as slightly harmful (Class 2, 12% as moderately harmful (Class 3 and 56% as harmful (Class 4, according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

Determination of insecticidal activity of Heliopsis longipes A. Gray Blake, an endemic plant of Guanajuato state

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Alejandro Hernández Morales

2012-09-01

Full Text Available Mosquitoes are involved in transmission of infectious diseases like malaria which affect human health, causing economic losses due to expensive treatments and job incapacity of patients. Strategies to minimize transmission of this disease are the employ of chemical insecticides that are excellent methods to reduce insect populations; however it causes deleterious effects on human health and environmental damage. Therefore is necessary to explore harmless alternatives, such as plant extracts which are potential source of natural insecticides. In this work we evaluated insecticidal properties of Heliopsis longipes A. Gray Blake against third instar larvae of Anopheles albimanus, malaria vector. Results showed that H.longipes A. Gray Blake has insecticide properties to control insect involved in malaria transmission.

Consequences of co-applying insecticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae) on onion.

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Nault, Brian A; Hsu, Cynthia L; Hoepting, Christine A

2013-07-01

Insecticides and fungicides are commonly co-applied in a tank mix to protect onions from onion thrips, Thrips tabaci Lindeman, and foliar pathogens. Co-applications reduce production costs, but past research shows that an insecticide's performance can be reduced when co-applied with a fungicide. An evaluation was made of the effects of co-applying spinetoram, abamectin and spirotetramat with commonly used fungicides, with and without the addition of a penetrating surfactant, on onion thrips control in onion fields. Co-applications of insecticides with chlorothalonil fungicides reduced thrips control by 25-48% compared with control levels provided by the insecticides alone in three of five trials. Inclusion of a penetrating surfactant at recommended rates with the insecticide and chlorothalonil fungicide did not consistently overcome this problem. Co-applications of insecticides with other fungicides did not interfere with thrips control. Co-applications of pesticides targeting multiple organisms should be examined closely to ensure that control of each organism is not compromised. To manage onion thrips in onion most effectively, insecticides should be applied with a penetrating surfactant, and should be applied separately from chlorothalonil fungicides. © 2012 Society of Chemical Industry.

Bioassay method for toxicity studies of insecticide formulations to Tuta absoluta (meyrick, 1917)

OpenAIRE

Galdino, Tarcísio Visintin da Silva; Picanço, Marcelo Coutinho; Morais, Elisangela Gomes Fidelis de; Silva, Nilson Rodrigues; Silva, Geverson Aelton Rezende da; Lopes, Mayara Cristina

2011-01-01

Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that repre...

Bioassay method for toxicity studies of insecticide formulations to tuta absoluta (meyrick, 1917).

OpenAIRE

GALDINO, T. V. da S.; PICANÇO, M. C.; MORAIS, E. G. F. de; SILVA, N. R.; SILVA, G. A. R da; LOPES, M. C.

2014-01-01

Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that repre...

Costs and benefits of insecticide and foliar nutrient applications to huanglongbing-infected citrus trees.

Science.gov (United States)

Tansey, James A; Vanaclocha, Pilar; Monzo, Cesar; Jones, Moneen; Stansly, Philip A

2017-05-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors Candidatus Liberibacter asiaticus, which causes huanglongbing (HLB). In Florida, HLB incidence is approaching 100% statewide. Yields have decreased and production costs have increased since 2005. Despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. However, the value of these practices is debated. A replicated field study was initiated in 2008 in a commercial block of 'Valencia' sweet orange trees to evaluate individual and combined effects of foliar nutrition and ACP control. Results from 2012-2016 are presented. Insecticides consistently reduced ACP populations. However, neither insecticide nor nutrition applications significantly influenced HLB incidence or PCR copy number in mature trees. In reset trees, infection continued to build and reached 100% in all treatments. Greatest yields (kg fruit ha -1 ) and production (kg solids ha -1 ) were obtained from trees receiving both insecticides and foliar nutrition. All treatments resulted in production and financial gains relative to controls. However, material and application costs associated with the nutrition component offset these gains, resulting in lesser benefits than insecticides applied alone. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

GESAMP Working Group 38, The Atmospheric Input of Chemicals to the Ocean

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Duce, Robert; Liss, Peter

2014-05-01

There is growing recognition of the impact of the atmospheric input of both natural and anthropogenic substances on ocean chemistry, biology, and biogeochemistry as well as climate. These inputs are closely related to a number of important global change issues. For example, the increasing input of anthropogenic nitrogen species from the atmosphere to much of the ocean may cause a low level fertilization that could result in an increase in marine 'new' productivity of up to ~3% and thus impact carbon drawdown from the atmosphere. Similarly, much of the oceanic iron, which is a limiting nutrient in significant areas of the ocean, originates from the atmospheric input of minerals as a result of the long-range transport of mineral dust from continental regions. The increased supply of soluble phosphorus from atmospheric anthropogenic sources (through large-scale use of fertilizers) may also have a significant impact on surface-ocean biogeochemistry, but estimates of any effects are highly uncertain. There have been few assessments of the atmospheric inputs of sulfur and nitrogen oxides to the ocean and their impact on the rates of ocean acidification. These inputs may be particularly critical in heavily trafficked shipping lanes and in ocean regions proximate to highly industrialized land areas. Other atmospheric substances may also have an impact on the ocean, in particular lead, cadmium, and POPs. To address these and related issues the United Nations Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) initiated Working Group 38, The Atmospheric Input of Chemicals to the Ocean, in 2008. This Working Group has had four meetings. To date four peer reviewed papers have been produced from this effort, with a least eight others in the process of being written or published. This paper will discuss some of the results of the Working Group's deliberations and its plans for possible future work.

Insecticide resistance status of Aedes aegypti (L.) from Colombia.

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Fonseca-González, Idalyd; Quiñones, Martha L; Lenhart, Audrey; Brogdon, William G

2011-04-01

To evaluate the insecticide susceptibility status of Aedes aegypti (L.) in Colombia, and as part of the National Network of Insecticide Resistance Surveillance, 12 mosquito populations were assessed for resistance to pyrethroids, organophosphates and DDT. Bioassays were performed using WHO and CDC methodologies. The underlying resistance mechanisms were investigated through biochemical assays and RT-PCR. All mosquito populations were susceptible to malathion, deltamethrin and cyfluthrin, and highly resistant to DDT and etofenprox. Resistance to lambda-cyhalothrin, permethrin and fenitrothion ranged from moderate to high in some populations from Chocó and Putumayo states. In Antioquia state, the Santa Fe population was resistant to fenitrothion. Biochemical assays showed high levels of both cytochrome P450 monooxygenases (CYP) and non-specific esterases (NSE) in some of the fenitrothion- and pyrethroid-resistant populations. All populations showed high levels of glutathione-S-transferase (GST) activity. GSTe2 gene was found overexpressed in DDT-resistant populations compared with Rockefeller susceptible strain. Differences in insecticide resistance status were observed between insecticides and localities. Although the biochemical assay results suggest that CYP and NSE could play an important role in the pyrethroid and fenitrothion resistance detected, other mechanisms remain to be investigated, including knockdown resistance. Resistance to DDT was high in all populations, and GST activity is probably the main enzymatic mechanism associated with this resistance. The results of this study provide baseline data on insecticide resistance in Colombian A. aegypti populations, and will allow comparison of changes in susceptibility status in this vector over time. Copyright © 2011 Society of Chemical Industry.

Comparison of chemical inputs consumption in saffron and wheat fields in Qaenat region

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Fatemeh Yaghoubi

2014-09-01

Full Text Available Commercialization of agricultural operations and use of pesticides and chemical fertilizers in agricultural production has been created serious environmental impacts. Due to this issue and in order to assess the amount of chemical fertilizer and pesticide inputs in saffron and wheat production systems, a study was conducted in Qaenat region (South Khorasan province, 50 wheat fields and 48 saffron fields were investigated during 2011-12. The results showed that average nitrogen fertilizer consumption was 222.38 and 57.83 kg.ha-1 in wheat and saffron production systems, respectively, which from sstatistically point of view the difference was significant. In addition, unlike wheat, the use of pesticides very low in saffron cultivation and in many saffron farms it was zero. Therefore, the results can be considered saffron is an healthier product and have greater potential to organic product. Also, the amounts of nitrogen, phosphorus and potassium fertilizers which were using in wheat in the study area were significantly different with recommended values. While in saffron production there was no significant difference between the values of consumed and recommended. Therefore, it seems, performing soil testing in each region and providing appropriate fertilizer formulas and required promotional-educational services in this regard, and raising public awareness is a good strategy for reducing the use of chemical inputs.

Adaptation to toxic hosts as a factor in the evolution of insecticide resistance.

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Alyokhin, Andrei; Chen, Yolanda H

2017-06-01

Insecticide resistance is a serious economic problem that jeopardizes sustainability of chemical control of herbivorous insects and related arthropods. It can be viewed as a specific case of adaptation to toxic chemicals, which has been driven in large part, but not exclusively, by the necessity for insect pests to tolerate defensive compounds produced by their host plants. Synthetic insecticides may simply change expression of specific sets of detoxification genes that have evolved due to ancestral associations with host plants. Feeding on host plants with more abundant or novel secondary metabolites has even been shown to prime insect herbivores to tolerate pesticides. Clear understanding of basic evolutionary processes is important for achieving lasting success in managing herbivorous arthropods. Copyright © 2017 Elsevier Inc. All rights reserved.

Botanical Insecticides in Plant Protection

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Grdiša, Martina; Gršić, Kristina

2013-01-01

Botanical insecticides are natural compounds with insecticidal properties and their use in crop protection is as old as agricultural practice. Although they have been in use for over one hundred years, the advent of synthetic insecticides has unfortunately displaced their use today. Due to fast action, low cost, easy application and efficiency against a wide range of harmful species, synthetic insecticides have become an important part of pest management in modern agricultural systems....

Effects of the amphibian chytrid fungus and four insecticides on Pacific treefrogs (Pseudacris regilla)

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Kleinhez, Peter; Boone, Michelle D.; Fellers, Gary

2012-01-01

Chemical contamination may influence host-pathogen interactions, which has implications for amphibian population declines. We examined the effects of four insecticides alone or as a mixture on development and metamorphosis of Pacific Treefrogs (Pseudacris regilla) in the presence or absence of the amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Bd exposure had a negative impact on tadpole activity, survival to metamorphosis, time to metamorphosis, and time of tail absorption (with a marginally negative effect on mass at metamorphosis); however, no individuals tested positive for Bd at metamorphosis. The presence of sublethal concentrations of insecticides alone or in a mixture did not impact Pacific Treefrog activity as tadpoles, survival to metamorphosis, or time and size to metamorphosis. Insecticide exposure did not influence the effect of Bd exposure. Our study did not support our prediction that effects of Bd would be greater in the presence of expected environmental concentrations of insecticide(s), but it did show that Bd had negative effects on responses at metamorphosis that could reduce the quality of juveniles recruited into the population.

Chemical constituents and insecticidal activity from fruits extracts of Trichilia elegans and T. catigua (Meliaceae)

International Nuclear Information System (INIS)

Matos, Andreia Pereira; Nebo, Liliane; Vieira, Paulo Cezar; Fernandes, Joao Batista; Silva, Maria Fatima das Gracas Fernandes da; Rodrigues, Ricardo Ribeiro

2009-01-01

Phytochemical investigation of the fruits extracts of Trichilia elegans and Trichilia catigua (Meliaceae) has led to the identification of the limonoids 11β-acetoxyobacunone, cedrelone, methylangolensate and epimeric mixture of photogedunin besides known coumarins (scoparone, scopoletin, umbeliferone) and the steroids stigmasterol, β-sitosterol, sitostenone and campesterol. The structures of the compounds were proposed by spectroscopic analysis and comparison with literature data. An evaluation of the insecticidal activity of the fruits extracts of Trichilia ssp. was carried out and the extracts of T. elegans revealed to have strong insecticidal activity and the extracts of T. catigua showed moderate larval mortality on Spodoptera frugiperda. (author)

[Susceptibility of natural populations of dengue vector to insecticides in Colombia].

Science.gov (United States)

Santacoloma, Liliana; Chaves, Bernardo; Brochero, Helena Luisa

2012-09-01

Physiological resistance of natural population of Aedes aegypti to insecticides contribute to the decreased efficacy of chemical control as a main control strategy during dengue outbreaks. The susceptibility status of Ae. aegypti was assessed for the carbamate propoxur, the adulticide malathion and the larvicide temephos on 13 natural populations of Ae. aegypti immature forms were taken from 8 Colombian localities. These included the following: Bucaramanga (1), Sabana de Torres (2), Girardot (2), La Mesa (2), Villavicencio (2), Puerto López (2), San José del Guaviare (1) and Florencia (1). Susceptibility tests mainly consisted of the standardized bioassay outlined by WHO (1981) and CDC bottles (1998). Colorimetric tests were undertaken to determine enzyme levels possibly responsible for the reduction of susceptibility to organophosphate and carbamate insecticides. All specimens demonstrated susceptibility to malathion and propoxur insecticides. Four of the 13 populations revealed susceptibility to the temephos larvicide. Seven of 11 populations showed a limited increase in values for nonspecific esterase enzymes. The Bucaramanga population was the only one which showed an increase in the cytochrome P450 monooxygenases enzymes. Neither population was found with modified acetilcolinesterase. The widespread susceptibility to organophosphates used as adulticides indicated that malathion, the most used insecticide in Colombia, remains effective in interrupting the transmission of dengue. Physiological resistance to insecticides occurring in communities of a single township proved to be a localized phenomenon.

Combining the essential oil of Piper aduncum L. with commercial insecticides

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Murilo Fazolin

2016-12-01

Full Text Available The use of synergists is important to minimize the amount of chemical insecticide required for insect control. Their use may contribute to reducing environmental contamination and preserving beneficial insects. The aim of this study was to evaluate the synergy and uniformity of the response of Spodoptera frugiperda (Noctuidae larvae to doses of an essential oil of an Amazon chemotype, Piper aduncum (Piperaceae, when combinationed with the following commercial insecticides: cypermethrin, zeta-cypermethrin, permethrin and esfenvarelate, compared to piperonyl butoxide (PBO. Through the relationship between CL50 and DL50 of insecticides taken separately and their synergistic combinations with the essential oil and PBO, synergism factors (SF were obtained for comparison with each other. With residual contact, there was a significant enhancement of commercial insecticides formulated with cypermethrin (SF = 73.03, zeta-cypermethrin (SF = 16.51 and permethrin (SF = 8.46-17.22, when combined with the P. aduncum essential oil; in turn, with topical application, there was only an observed significant enhancement for zeta-cypermethrin (SF = 0.40-4.26, permethrin (SF = 2.10-4.79 and esfenvarelate (SF = 3.80 insecticides when combined with the essential oil. With the exception of esfenvarelate, the other synergistic combinations showed homogeneous responses for topical application and residual contact for at least one synergistic combination with P. aduncum essential oil. The significance of the SF values from combining P. aduncum essential oil with cypermethrin, zeta-cypermethrin, permethrin and esfenvarelate insecticides may indicate that this essential oil is an alternative option to PBO.

Chemical Composition and Insecticidal Activity of Essential Oils from Zanthoxylum dissitum Leaves and Roots against Three Species of Storage Pests.

Science.gov (United States)

Wang, Cheng-Fang; Yang, Kai; You, Chun-Xue; Zhang, Wen-Juan; Guo, Shan-Shan; Geng, Zhu-Feng; Du, Shu-Shan; Wang, Yong-Yan

2015-05-04

This work aimed to investigate chemical composition of essential oils obtained from Zanthoxylum dissitum leaves and roots and their insecticidal activities against several stored product pests, namely the cigarette beetle (Lasioderma serricorne), red flour beetle (Tribolium castaneum) and black carpet beetle (Attagenus piceus). The analysis by GC-MS of the essential oils allowed the identification of 28 and 22 components, respectively. It was found that sesquiterpenoids comprised a fairly high portion of the two essential oils, with percentages of 74.0% and 80.9% in the leaves and roots, respectively. The main constituents identified in the essential oil of Z. dissitum leaves were δ-cadinol (12.8%), caryophyllene (12.7%), β-cubebene (7.9%), 4-terpineol (7.5%) and germacrene D-4-ol (5.7%), while humulene epoxide II (29.4%), caryophyllene oxide (24.0%), diepicedrene-1-oxide (10.7%) and Z,Z,Z-1,5,9,9-tetramethyl-1,4,7-cycloundecatriene (8.7%) were the major components in the essential oil of Z. dissitum roots. The insecticidal activity results indicated that the essential oil of Z. dissitum roots exhibited moderate contact toxicity against three species of storage pests, L. serricorne,T. castaneum and A. piceus, with LD50 values of 13.8, 43.7 and 96.8 µg/adult, respectively.

The comparative insecticidal and residual efficacy of sniper and ...

African Journals Online (AJOL)

Otoigiakih

Chemical control is still the main approach for urban pest control (Castle et al., 1999; Rozendaal, 1997; Marrs,. 1993; Lee and Yap, 2003; Tidwell et al., 1994). The use of insecticides is seen as the most effective tool in cockroach control program (WHO, 1996; Chavasse and. Yap, 1997; Lee and Yap, 2003; Tidwell et al., ...

Spiroindolines identify the vesicular acetylcholine transporter as a novel target for insecticide action.

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Ann Sluder

Full Text Available The efficacy of all major insecticide classes continues to be eroded by the development of resistance mediated, in part, by selection of alleles encoding insecticide insensitive target proteins. The discovery of new insecticide classes acting at novel protein binding sites is therefore important for the continued protection of the food supply from insect predators, and of human and animal health from insect borne disease. Here we describe a novel class of insecticides (Spiroindolines encompassing molecules that combine excellent activity against major agricultural pest species with low mammalian toxicity. We confidently assign the vesicular acetylcholine transporter as the molecular target of Spiroindolines through the combination of molecular genetics in model organisms with a pharmacological approach in insect tissues. The vesicular acetylcholine transporter can now be added to the list of validated insecticide targets in the acetylcholine signalling pathway and we anticipate that this will lead to the discovery of novel molecules useful in sustaining agriculture. In addition to their potential as insecticides and nematocides, Spiroindolines represent the only other class of chemical ligands for the vesicular acetylcholine transporter since those based on the discovery of vesamicol over 40 years ago, and as such, have potential to provide more selective tools for PET imaging in the diagnosis of neurodegenerative disease. They also provide novel biochemical tools for studies of the function of this protein family.

Ion channels: molecular targets of neuroactive insecticides.

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Raymond-Delpech, Valérie; Matsuda, Kazuhiko; Sattelle, Benedict M; Rauh, James J; Sattelle, David B

2005-11-01

Many of the insecticides in current use act on molecular targets in the insect nervous system. Recently, our understanding of these targets has improved as a result of the complete sequencing of an insect genome, i.e., Drosophila melanogaster. Here we examine the recent work, drawing on genetics, genomics and physiology, which has provided evidence that specific receptors and ion channels are targeted by distinct chemical classes of insect control agents. The examples discussed include, sodium channels (pyrethroids, p,p'-dichlorodiphenyl-trichloroethane (DDT), dihydropyrazoles and oxadiazines); nicotinic acetylcholine receptors (cartap, spinosad, imidacloprid and related nitromethylenes/nitroguanidines); gamma-aminobutyric acid (GABA) receptors (cyclodienes, gamma-BHC and fipronil) and L-glutamate receptors (avermectins). Finally, we have examined the molecular basis of resistance to these molecules, which in some cases involves mutations in the molecular target, and we also consider the future impact of molecular genetic technologies in our understanding of the actions of neuroactive insecticides.

Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides.

Science.gov (United States)

Tillman, P Glynn

2006-06-01

Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.

Activity of the Antioxidant Defense System in a Typical Bioinsecticide-and Synthetic Insecticide-treated Cowpea Storage Beetle F. (Coleoptera: Chrysomelidae

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Ayodele O. Kolawole

2014-01-01

Full Text Available The non-enzymatic and enzymatic antioxidant defense systems play a major role in detoxification of pro-oxidant endobiotics and xenobiotics. The possible involvement of beetle non-enzymatic [α-tocopherol, glutathione (GSH, and ascorbic acid] and enzymatic [catalase (CAT, superoxide dismutase (SOD, peroxidase (POX, and polyphenol oxidase (PPO] antioxidant defense system on the insecticidal activity of synthetic insecticides (cypermethrin, 2,2-dicholorovinyl dimethyl phosphate, and λ-cyhalothrin and ethanolic plant extracts of Tithonia diversifolia, Cyperus rotundus, Hyptis suaveolens leaves , and Jatropha Curcas seeds was investigated. 2,2-Dicholorovinyl dimethyl phosphate (DDVP; 200 ppm, LC 50 = 13.24 ppm and T. diversifolia (20,000 ppm resulted in 100% beetle mortality at 96-hour post-treatment. The post-treatments significantly increased the beetle α-tocopherol and GSH contents. Activities of CAT, SOD, POX, and PPO were modulated by the synthetic insecticides and bioinsecticides to diminish the adverse effect of the chemical stresses. Quantitative and qualitative allelochemical compositions of bioinsecticides and chemical structure of synthetic insecticides possibly account and for modulation of their respective enzyme activities. Altogether, oxidative stress was enormous enough to cause maladaptation in insects. This study established that oxidative imbalance created could be the molecular basis of the efficacy of both insecticides and bio-insecticides. Two, there was development of functional but inadequate antioxidant defense mechanism in the beetle.

Exploration of Novel Botanical Insecticide Leads: Synthesis and Insecticidal Activity of β-Dihydroagarofuran Derivatives.

Science.gov (United States)

Zhao, Ximei; Xi, Xin; Hu, Zhan; Wu, Wenjun; Zhang, Jiwen

2016-02-24

The discovery of novel leads and new mechanisms of action is of vital significance to the development of pesticides. To explore lead compounds for botanical insecticides, 77 β-dihydroagarofuran derivatives were designed and synthesized. Their structures were mainly confirmed by (1)H NMR, (13)C NMR, DEPT-135°, IR, MS, and HRMS. Their insecticidal activity was evaluated against the third-instar larvae of Mythimna separata Walker, and the results indicated that, of these derivatives, eight exhibited more promising insecticidal activity than the positive control, celangulin-V. Particularly, compounds 5.7, 6.6, and 6.7 showed LD50 values of 37.9, 85.1, and 21.1 μg/g, respectively, which were much lower than that of celangulin-V (327.6 μg/g). These results illustrated that β-dihydroagarofuran ketal derivatives can be promising lead compounds for developing novel mechanism-based and highly effective botanical insecticides. Moreover, some newly discovered structure-activity relationships are discussed, which may provide some important guidance for insecticide development.

Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

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Vlaming, V. de [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States)]. E-mail: vldevlaming@ucdavis.edu; DiGiorgio, C. [Department of Water Resources, P.O. Box 942836, Sacramento, CA 94236 (United States); Fong, S. [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States); Deanovic, L.A. [Aquatic Toxicology Laboratory, VM: APC, 1321 Haring Hall, University of California, Davis, CA 95616 (United States); Paz Carpio-Obeso, M. de la [Colorado River Basin Region Water Quality Control Board, 73-720 Fred Waring Drive, Suite 100, Palm Desert, CA 92260 (United States); Miller, J.L. [AQUA-Science, 17 Arboretum Drive, Davis, CA 95616 (United States); Miller, M.J. [AQUA-Science, 17 Arboretum Drive, Davis, CA 95616 (United States); Richard, N.J. [Division of Water Quality, State Water Resources Control Board, 1001 I Street, Sacramento, CA 95814 (United States)

2004-11-01

The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts. - Capsule: Organophosphorous insecticides in runoff water from the USA and Mexico have impacted rivers in the Imperial Valley, California.

Irrigation runoff insecticide pollution of rivers in the Imperial Valley, California (USA)

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Vlaming, V. de; DiGiorgio, C.; Fong, S.; Deanovic, L.A.; Paz Carpio-Obeso, M. de la; Miller, J.L.; Miller, M.J.; Richard, N.J.

2004-01-01

The Alamo and New Rivers located in the Imperial Valley, California receive large volumes of irrigation runoff and discharge into the ecologically sensitive Salton Sea. Between 1993 and 2002 we conducted a series of studies to assess water quality using three aquatic species: a cladoceran (Ceriodaphnia dubia), a mysid (Neomysis mercedis), and a larval fish (Pimephales promelas). Although no mortality was observed with the P. promelas, high-level toxicity to the invertebrate species was documented in samples from both rivers during many months of each year. Toxicity identifications and chemical analyses identified the organophosphorus insecticides (OP), chlorpyrifos and diazinon, as the cause of C. dubia toxicity. The extent of the C. dubia mortality was highly correlated with quantities of these OPs applied in the river watersheds. C. dubia mortality occurred during more months of our 2001/2002 study than in the 1990s investigations. During 2001/2002, the extensive C. dubia mortality observed in New River samples was caused by OP insecticide pollution that originated from Mexico. Mortality to N. mercedis in New River samples was likely caused by contaminants other than OP insecticides. Our studies document OP insecticide-caused pollution of the Alamo River over a 10-year period and provide the necessary information for remediation efforts. - Capsule: Organophosphorous insecticides in runoff water from the USA and Mexico have impacted rivers in the Imperial Valley, California

Chemical composition and insecticidal activity of the essential oil from Helichrysum faradifani endemic to Madagascar.

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Benelli, Giovanni; Pavela, Roman; Rakotosaona, Rianasoambolanoro; Randrianarivo, Emmanuel; Nicoletti, Marcello; Maggi, Filippo

2017-11-03

Helichrysum faradifani (Asteraceae) is a perennial shrub growing in rocky and sandy places of Madagascar. The plant is used in the Malagasy traditional medicine as a wound-healing agent, disinfectant and for the treatment of syphilis, diarrhea, cough and headache. In the present work, we analysed the chemical composition of the essential oil distilled from the aerial parts of H. faradifani by GC-MS and evaluated its insecticidal activity against 2nd, 3rd and 4th instar larvae of the lymphatic filariasis vector Culex quinquefasciatus by acute toxicity assays. The most sensitive were 2nd instar (LC 50  = 85.7 μL L -1 ) larvae. For the 3rd and 4th instar larvae, the estimated LC 50 were 156.8 and 134.1 μL L -1 , respectively. Monoterpene hydrocarbons (51.6%) were the major fraction of the essential oil, with the bicyclic α-fenchene (35.6%) as the predominant component. Sesquiterpene hydrocarbons (34.0%) were the second major group characterising the oil, with γ-curcumene (17.7%) as the most abundant component.

Impact of neonicotinoid insecticides on natural enemies in greenhouse and interiorscape environments.

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Cloyd, Raymond A; Bethke, James A

2011-01-01

The neonicotinoid insecticides imidacloprid, acetamiprid, dinotefuran, thiamethoxam and clothianidin are commonly used in greenhouses and/or interiorscapes (plant interiorscapes and conservatories) to manage a wide range of plant-feeding insects such as aphids, mealybugs and whiteflies. However, these systemic insecticides may also be harmful to natural enemies, including predators and parasitoids. Predatory insects and mites may be adversely affected by neonicotinoid systemic insecticides when they: (1) feed on pollen, nectar or plant tissue contaminated with the active ingredient; (2) consume the active ingredient of neonicotinoid insecticides while ingesting plant fluids; (3) feed on hosts (prey) that have consumed leaves contaminated with the active ingredient. Parasitoids may be affected negatively by neonicotinoid insecticides because foliar, drench or granular applications may decrease host population levels so that there are not enough hosts to attack and thus sustain parasitoid populations. Furthermore, host quality may be unacceptable for egg laying by parasitoid females. In addition, female parasitoids that host feed may inadvertently ingest a lethal concentration of the active ingredient or a sublethal dose that inhibits foraging or egg laying. There are, however, issues that require further consideration, such as: the types of plant and flower that accumulate active ingredients, and the concentrations in which they are accumulated; the influence of flower age on the level of exposure of natural enemies to the active ingredient; the effect of neonicotinoid metabolites produced within the plant. As such, the application of neonicotinoid insecticides in conjunction with natural enemies in protected culture and interiorscape environments needs further investigation. Copyright © 2010 Society of Chemical Industry.

The evolution of insecticide resistance in the brown planthopper (Nilaparvata lugens Stål) of China in the period 2012-2016.

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Wu, Shun-Fan; Zeng, Bin; Zheng, Chen; Mu, Xi-Chao; Zhang, Yong; Hu, Jun; Zhang, Shuai; Gao, Cong-Fen; Shen, Jin-Liang

2018-03-15

The brown planthopper, Nilaparvata lugens, is an economically important pest on rice in Asia. Chemical control is still the most efficient primary way for rice planthopper control. However, due to the intensive use of insecticides to control this pest over many years, resistance to most of the classes of chemical insecticides has been reported. In this article, we report on the status of eight insecticides resistance in Nilaparvata lugens (Stål) collected from China over the period 2012-2016. All of the field populations collected in 2016 had developed extremely high resistance to imidacloprid, thiamethoxam, and buprofezin. Synergism tests showed that piperonyl butoxide (PBO) produced a high synergism of imidacloprid, thiamethoxam, and buprofezin effects in the three field populations, YA2016, HX2016, and YC2016. Functional studies using both double-strand RNA (dsRNA)-mediated knockdown in the expression of CYP6ER1 and transgenic expression of CYP6ER1 in Drosophila melanogaster showed that CYP6ER1 confers imidacloprid, thiamethoxam and buprofezin resistance. These results will be beneficial for effective insecticide resistance management strategies to prevent or delay the development of insecticide resistance in brown planthopper populations.

Chemical Composition and Insecticidal Activity of the Essential Oil of Illicium pachyphyllum Fruits against Two Grain Storage Insects

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Hui-Wen Dong

2012-12-01

Full Text Available The aim of this research was to determine chemical composition and insecticidal activity of the essential oil of Illicium pachyphyllum fruits against two grain storage insects, Sitophilus zeamais and Tribolium castaneum, and to isolate any insecticidal constituents from the essential oil. The essential oil of I. pachyphyllum fruits was obtained by hydrodistillation and analyzed by GC-MS. A total of 36 components of the essential oil were identified, with the principal compounds in the essential oil being trans-ρ-mentha-1(7,8-dien-2-ol (24.56%, D-limonene (9.79%, caryophyllene oxide (9.32%, and cis-carveol (5.26% followed by β-caryophyllene (4.63% and bornyl acetate. Based on bioactivity-guided fractionation, the three active constituents were isolated and identified as trans-ρ-mentha-1(7,8-dien-2-ol, D-limonene and caryophyllene oxide. The essential oil of I. pachyphyllum fruits exhibited contact toxicity against S. zeamais and T. castaneum adults, with LD50 values of 17.33 μg/adult and 28.94 μg/adult, respectively. trans-p-Mentha-1(7,8-dien-2-ol (LD50 = 8.66 μg/adult and 13.66 μg/adult, respectively exhibited stronger acute toxicity against S. zeamais and T. castaneum adults than either caryophyllene oxide (LD50 = 34.09 μg/adult and 45.56 μg/adult and D-limonene (LD50 = 29.86 μg/adult and 20.14 μg/adult. The essential oil of I. pachyphyllum possessed fumigant toxicity against S. zeamais and T. castaneum adults with LC50 values of 11.49 mg/L and 15.08 mg/L, respectively. trans-p-Mentha-1(7,8-dien-2-ol exhibited stronger fumigant toxicity against S. zeamais and T. castaneum adults, respectively, with LC50 values of 6.01 mg/L and 8.14 mg/L, than caryophyllene oxide (LC50 = 17.02 mg/L and 15.98 mg/L and D-limonene (LC50 = 33.71 mg/L and 21.24 mg/L. The results indicate that the essential oil of I. pachyphyllum fruits and its constituent compounds have potential for development into natural insecticides or fumigants for the control of

Assessing Insecticide Susceptibility of Laboratory Lutzomyia longipalpis and Phlebotomus papatasi Sand Flies (Diptera: Psychodidae: Phlebotominae).

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Denlinger, David S; Lozano-Fuentes, Saul; Lawyer, Phillip G; Black, William C; Bernhardt, Scott A

2015-09-01

Chemical insecticides are effective for controlling Lutzomyia and Phlebotomus sand fly (Diptera: Psychodidae) vectors of Leishmania parasites. However, repeated use of certain insecticides has led to tolerance and resistance. The objective of this study was to determine lethal concentrations (LCs) and lethal exposure times (LTs) to assess levels of susceptibility of laboratory Lutzomyia longipalpis (Lutz and Nieva) and Phlebotomus papatasi (Scopoli) to 10 insecticides using a modified version of the World Health Organization (WHO) exposure kit assay and Centers for Disease Control and Prevention (CDC) bottle bioassay. Sand flies were exposed to insecticides coated on the interior of 0.5-gallon and 1,000-ml glass bottles. Following exposure, the flies were allowed to recover for 24 h, after which mortality was recorded. From dose-response survival curves for L. longipalpis and P. papatasi generated with the QCal software, LCs causing 50, 90, and 95% mortality were determined for each insecticide. The LCs and LTs from this study will be useful as baseline reference points for future studies using the CDC bottle bioassays to assess insecticide susceptibility of sand fly populations in the field. There is a need for a larger repository of sand fly insecticide susceptibility data from the CDC bottle bioassays, including a range of LCs and LTs for more sand fly species with more insecticides. Such a repository would be a valuable tool for vector management. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Use of water by eastern hemlock: implications for systemic insecticide application

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Chelcy R. Ford; James M. Vose; Michael Daley; Nathan Phillips

2007-01-01

The hemlock woolly adelgid (HWA, Adelges tsugae Annand) is causing widespread decline and mortality of eastern hemlock (Tsuga canadensis (L.) Carr.) throughout most of the range of eastern hemlock. Stem injection of insecticide is widely used as a chemical control measure, but the effectiveness of this method depends on the...

[Discriminating concentrations for three insecticides used in public health in a Lutzomyia longipalpis experimental strain from Colombia].

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Marceló, Catalina; Cabrera, Olga Lucía; Santamaría, Erika

2014-01-01

In Colombia, periurban populations of Lutzomyia longipalpis , vector of the causative agent of visceral leishmaniasis in the upper and middle valley of the Magdalena River, may be exposed to insecticide applications with different purposes. Thus, it is important to begin a susceptibility surveillance of this species to insecticides. To determine indicators of susceptibility to three insecticides habitually used in public health, such as malathion, deltamethrin and lambda-cyhalothrin in an experimental strain of L. longipalpis . We used the method proposed by the Centers for Disease Control and Prevention. Groups of 10 to 15 unfed females were exposed to different concentrations of the insecticides using 250 ml glass bottles as test chambers. Mortality was registered every five minutes for an hour. Diagnostic concentrations and lethal times for each insecticide were calculated. In the evaluated L. longipalpis strain, the diagnostic concentrations and times were 75 µg/ml and 25 minutes for malathion, 10 µg/ml and 35 minutes for deltamethrin, and 15 µg/ml during 30 minutes for lambda-cyhalothrin. Baseline data over mortality response to three insecticides were established in a susceptibility strain of L. longipalpis vector. These indicators will allow establishing comparisons with populations of L. longipalpis exposed regularly or sporadically to chemical control measures to detect changes in their resistance to these insecticides.

Imidacloprid does not induce Cyp genes involved in insecticide resistance of a mutant Drosophila melanogaster line.

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Kalajdzic, Predrag; Markaki, Maria; Oehler, Stefan; Savakis, Charalambos

2013-10-01

Certain xenobiotics have the capacity to induce the expression of genes involved in various biological phenomena, including insecticide resistance. The induction potential of different chemicals, among them different insecticides, has been documented for a number of insect species. In this study, we have analyzed the induction potential of Imidacloprid, a widely used member of the neonicotinoid insecticide family. Genes Cyp6g1 and Cyp6a2, known to be involved in the resistance of mutant Drosophila melanogaster line MiT[W⁻]3R2 to Imidacloprid and DDT were included in the analyzed sample. We find that Imidacloprid does not induce expression of the analyzed genes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioefficacy, dissipation kinetics and safety evaluation of selected insecticides in Allium cepa L.

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Srinivas P, Satya; Banerjee, Kaushik; Jadhav, Manjusha R; Ghaste, Manoj S; Lawande, K E

2012-01-01

This paper reports the bioefficacy of selected insecticides against thrips and their pre-harvest intervals (PHI) in onion pertaining to their recommended application rates and maximum residue limits. Profenophos, methomyl and imidacloprid showed comparatively higher bioefficacy against thrips. GC-MS and LC-MS/MS-based residue analysis methods in onion bulbs and composite matrix of bulbs+leaves were thoroughly validated. The residue data for bulb+leaves was assessed with reference to the EU-MRLs applicable for spring onion. Dimethoate was the most stable chemical with PHI of 52.5 days, followed by monocrotophos (24 days) and carbofuran (20.5 days). The PHIs of profenophos, chlorpyrifos, methomyl and cypermethrin were similar and within the range of 10-13 days. Imidacloprid and λ-cyhalothrin had similar PHI of 4.5 days. Spinosad was the fastest-degrading chemical with PHI of 2 days. The combined bioefficacy and residue dynamics information will support label-claim of these insecticides for the management of thrips in onion, help in scheduling their applications in pest management program as per relative PHIs and minimize the residue accumulations at harvest. The dietary exposure was less than the maximum permissible intake for most of the insecticides on all sampling days except for dimethoate and monocrotophos.

Arthropod Pest Control for UK Oilseed Rape - Comparing Insecticide Efficacies, Side Effects and Alternatives.

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Han Zhang

Full Text Available Oilseed rape (Brassica napus is an important combinable break crop in the UK, which is largely protected from arthropod pests by insecticidal chemicals. Despite ongoing debate regarding the use of neonicotinoids, the dominant seed treatment ingredients used for this crop, there is little publicly available data comparing the efficacy of insecticides in controlling key arthropod pests or comparing the impacts on non-target species and the wider environment. To provide an insight into these matters, a UK-wide expert survey targeting agronomists and entomologists was conducted from March to June 2015. Based on the opinions of 90 respondents, an average of 20% yield loss caused by the key arthropod pests was expected to have occurred in the absence of insecticide treatments. Relatively older chemical groups were perceived to have lower efficacy for target pests than newer ones, partly due to the development of insecticide resistance. Without neonicotinoid seed treatments, a lack of good control for cabbage stem flea beetle was perceived. Wide spectrum foliar insecticide sprays were perceived to have significantly greater negative impacts than seed treatments on users' health, natural enemies, pollinators, soil and water, and many foliar active ingredients have had potential risks for non-target arthropod species in UK oilseed rape fields for the past 25 years. Overall, 72% of respondents opposed the neonicotinoid restriction, while 10% supported it. Opposition and support of the restriction were largely based on concerns for pollinators and the wider environment, highlighting the uncertainty over the side effects of neonicotinoid use. More people from the government and research institutes leaned towards neutrality over the issue, compared to those directly involved in growing the crop. Neonicotinoid restriction was expected to result in greater effort and expenditure on pest control and lower production (0-1 t/ha less. Alternatives for future

Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex.

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Asselman, J; Janssen, C R; Smagghe, G; De Schamphelaere, K A C

2014-05-01

In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of diamide insecticides co-applied with other agrochemicals at various times to manage Ostrinia nubilalis in processing snap bean.

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Huseth, Anders S; Groves, Russell L; Chapman, Scott A; Nault, Brian A

2015-12-01

Multiple applications of pyrethroid insecticides are used to manage European corn borer, Ostrinia nubilalis Hübner, in snap bean, but new diamide insecticides may reduce application frequency. In a 2 year small-plot study, O. nubilalis control was evaluated by applying cyantraniliprole (diamide) and bifenthrin (pyrethroid) insecticides at one of three phenological stages (bud, bloom and pod formation) of snap bean development. Co-application of these insecticides with either herbicides or fungicides was also examined as a way to reduce the total number of sprays during a season. Cyantraniliprole applications timed either during bloom or during pod formation controlled O. nubilalis better than similar timings of bifenthrin. Co-applications of insecticides with fungicides controlled O. nubilalis as well as insecticide applications alone. Insecticides applied either alone or with herbicides during bud stage did not control this pest. Diamides are an alternative to pyrethroids for the management of O. nubilalis in snap bean. Adoption of diamides by snap bean growers could improve the efficiency of production by reducing the number of sprays required each season. © 2015 Society of Chemical Industry.

FragIt: a tool to prepare input files for fragment based quantum chemical calculations.

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Casper Steinmann

Full Text Available Near linear scaling fragment based quantum chemical calculations are becoming increasingly popular for treating large systems with high accuracy and is an active field of research. However, it remains difficult to set up these calculations without expert knowledge. To facilitate the use of such methods, software tools need to be available to support these methods and help to set up reasonable input files which will lower the barrier of entry for usage by non-experts. Previous tools relies on specific annotations in structure files for automatic and successful fragmentation such as residues in PDB files. We present a general fragmentation methodology and accompanying tools called FragIt to help setup these calculations. FragIt uses the SMARTS language to locate chemically appropriate fragments in large structures and is applicable to fragmentation of any molecular system given suitable SMARTS patterns. We present SMARTS patterns of fragmentation for proteins, DNA and polysaccharides, specifically for D-galactopyranose for use in cyclodextrins. FragIt is used to prepare input files for the Fragment Molecular Orbital method in the GAMESS program package, but can be extended to other computational methods easily.

Evaluating the efficacy of biological and conventional insecticides with the new 'MCD bottle' bioassay.

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Sternberg, Eleanore D; Waite, Jessica L; Thomas, Matthew B

2014-12-16

Control of mosquitoes requires the ability to evaluate new insecticides and to monitor resistance to existing insecticides. Monitoring tools should be flexible and low cost so that they can be deployed in remote, resource poor areas. Ideally, a bioassay should be able to simulate transient contact between mosquitoes and insecticides, and it should allow for excito-repellency and avoidance behaviour in mosquitoes. Presented here is a new bioassay, which has been designed to meet these criteria. This bioassay was developed as part of the Mosquito Contamination Device (MCD) project and, therefore, is referred to as the MCD bottle bioassay. Presented here are two experiments that serve as a proof-of-concept for the MCD bottle bioassay. The experiments used four insecticide products, ranging from fast-acting, permethrin-treated, long-lasting insecticide nets (LLINs) that are already widely used for malaria vector control, to the slower acting entomopathogenic fungus, Beauveria bassiana, that is currently being evaluated as a prospective biological insecticide. The first experiment used the MCD bottle to test the effect of four different insecticides on Anopheles stephensi with a range of exposure times (1 minute, 3 minutes, 1 hour). The second experiment is a direct comparison of the MCD bottle and World Health Organization (WHO) cone bioassay that tests a subset of the insecticides (a piece of LLIN and a piece of netting coated with B. bassiana spores) and a further reduced exposure time (5 seconds) against both An. stephensi and Anopheles gambiae. Immediate knockdown and mortality after 24 hours were assessed using logistic regression and daily survival was assessed using Cox proportional hazards models. Across both experiments, fungus performed much more consistently than the chemical insecticides but measuring the effect of fungus required monitoring of mosquito mortality over several days to a week. Qualitatively, the MCD bottle and WHO cone performed comparably

Neonicotinoid Insecticides Alter Induced Defenses and Increase Susceptibility to Spider Mites in Distantly Related Crop Plants

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Szczepaniec, Adrianna; Raupp, Michael J.; Parker, Roy D.; Kerns, David; Eubanks, Micky D.

2013-01-01

Background Chemical suppression of arthropod herbivores is the most common approach to plant protection. Insecticides, however, can cause unintended, adverse consequences for non-target organisms. Previous studies focused on the effects of pesticides on target and non-target pests, predatory arthropods, and concomitant ecological disruptions. Little research, however, has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae), in multiple, distantly related crop plants. Methodology/Principal Findings Using cotton (Gossypium hirsutum), corn (Zea mays) and tomato (Solanum lycopersicum) plants, we show that transcription of phenylalanine amonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment. Conclusions/Significance Our findings are important because applications of neonicotinoid insecticides have been associated with outbreaks of spider mites in several unrelated plant species. More importantly, this is the first study to document insecticide-mediated disruption of plant defenses and link it to increased population growth of a non-target herbivore. This study adds to growing evidence that bioactive agrochemicals can have unanticipated ecological effects and suggests that the direct effects of insecticides on plant defenses should be considered when the ecological costs of insecticides are evaluated. PMID

Formulation of insecticide profenofos using Surfactant Diethanolamide (DEA) based on palm olein

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Dewi, H. S.; Rahayuningsih, M.; Hambali, E.

2017-05-01

Soybean is one of the major food commodities in Indonesia that the consumption is increasing each year, but this is not in line with the domestic soybean production capacity. One cause of the low production capacity is the armyworm attact. Generally, the armyworm attack controled by spread insecticide profenofos. Profenofos need to be dissolved, but profenofos couldn’t dissolved in water. So that, it need the right formulation between the solvent and other ingredients which can supprotprofenofos performance. One of that ingredient is surfactant. This research used surfactant diethanolamide (DEA) based on palm olein. DEAfunction in insecticide formulation are as homogenizer, dispersant, sticker and spreader agent.The aims of this research are to obtain the best emultion insecticide product based on profenofos as the active ingredients and DEA as the surfactant, moreover it also to obtain information of the physico-chemical properties. The formulation test performed with compeletely randomized design (CRD) with two factors, first factor is DEA concentrationand the second factor is profenofos concentration. Data of physico-chemical properties test was analyzed by analysis of variance (ANOVA) and significant result tested by Duncant Multiple Range Test (DMRT).The result showed that, surfactant DEA could make good emultion between profenofos and sodium ethoxide as the solvent. The best treatment which obtain from formulation stage is concentrate with DEA 10% and profenofos 40%. Physico-chemical properties test result showed that droplet size is 1,76-2,07 µm, contact angle 11,575-24,218°, density 0,996-0,998 g/cm3, surface tension 16,56-40,72 dyne/cm, viscosity 1,032-1,078 Cp and pH 6,87-8,22.

Screening and Validation of Highly-Efficient Insecticidal Conotoxins from a Transcriptome-Based Dataset of Chinese Tubular Cone Snail

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Bingmiao Gao

2017-07-01

Full Text Available Most previous studies have focused on analgesic and anti-cancer activities for the conotoxins identified from piscivorous and molluscivorous cone snails, but little attention has been devoted to insecticidal activity of conotoxins from the dominant vermivorous species. As a representative vermivorous cone snail, the Chinese tubular cone snail (Conus betulinus is the dominant Conus species inhabiting the South China Sea. We sequenced related venom transcriptomes from C. betulinus using both the next-generation sequencing and traditional Sanger sequencing technologies, and a comprehensive library of 215 conotoxin transcripts was constructed. In our current study, six conotoxins with potential insecticidal activity were screened out from our conotoxin library by homologous search with a reported positive control (alpha-conotoxin ImI from C. imperialis as the query. Subsequently, these conotoxins were synthesized by chemical solid-phase and oxidative folding for further insecticidal activity validation, such as MTT assay, insect bioassay and homology modeling. The final results proved insecticidal activities of our achieved six conotoxins from the transcriptome-based dataset. Interestingly, two of them presented a lot of high insecticidal activity, which supports their usefulness for a trial as insecticides in field investigations. In summary, our present work provides a good example for high throughput development of biological insecticides on basis of the accumulated genomic resources.

Weevil x Insecticide: Does 'Personality' Matter?

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Morales, Juliana A; Cardoso, Danúbia G; Della Lucia, Terezinha Maria C; Guedes, Raul Narciso C

2013-01-01

An insect's behavior is the expression of its integrated physiology in response to external and internal stimuli, turning insect behavior into a potential determinant of insecticide exposure. Behavioral traits may therefore influence insecticide efficacy against insects, compromising the validity of standard bioassays of insecticide activity, which are fundamentally based on lethality alone. By extension, insect 'personality' (i.e., an individual's integrated set of behavioral tendencies that is inferred from multiple empirical measures) may also be an important determinant of insecticide exposure and activity. This has yet to be considered because the behavioral studies involving insects and insecticides focus on populations rather than on individuals. Even among studies of animal 'personality', the relative contributions of individual and population variation are usually neglected. Here, we assessed behavioral traits (within the categories: activity, boldness/shyness, and exploration/avoidance) of individuals from 15 populations of the maize weevil (Sitophilus zeamais), an important stored-grain pest with serious problems of insecticide resistance, and correlated the behavioral responses with the activity of the insecticide deltamethrin. This analysis was performed at both the population and individual levels. There was significant variation in weevil 'personality' among individuals and populations, but variation among individuals within populations accounted for most of the observed variation (92.57%). This result emphasizes the importance of individual variation in behavioral and 'personality' studies. When the behavioral traits assessed were correlated with median lethal time (LT50) at the population level and with the survival time under insecticide exposure, activity traits, particularly the distance walked, significantly increased survival time. Therefore, behavioral traits are important components of insecticide efficacy, and individual variation should be

Risk assessment of insecticides used in rice on miridbug, Cyrtorhinus lividipennis Reuter, the important predator of brown planthopper, Nilaparvata lugens (Stal.).

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Preetha, G; Stanley, J; Suresh, S; Samiyappan, R

2010-07-01

The green miridbug, Cyrtorhinus lividipennis, an important natural enemy of the rice brown planthopper (BPH), Nilaparvata lugens plays a major role as a predator in suppressing the pest population. The study assessed the impact of certain potential insecticides used in the rice ecosystem on the miridbug predator and brown planthopper through contact toxicity. Eleven insecticides, including neonicotinoids, diamides, azomethine pyridines, carbamates, pyrethroids, organophosphates and cyclodienes were selected to test their toxicities against the nymphs of C. lividipennis and N. lugens. Median lethal concentration (LC(50)) was determined for each insecticide using an insecticide-coated vial (scintillation) residue bioassay, which revealed BPMC as the highly toxic chemical with an LC(50) of 0.003mga.iL(-1) followed by ethofenprox and clothianidin with LC(50) of 0.006mga.iL(-1) at 48 HAT against C. lividipennis and ethofenprox as the highly toxic chemical with an LC(50) of 0.009mga.iL(-1) followed by clothianidin with an LC(50) of 0.211mga.iL(-1) at 48h after treatment (HAT) against N. lugens. Among the insecticides tested, the cyclodiene compound, endosulfan had the lowest acute contact toxicity (LC(50)=66.65mga.iL(-1) at 48 HAT) to C. lividipennis. Among the insecticides tested, endosulfan, chlorpyriphos, acephate and methyl parathion are regarded as safer to C. lividipennis based on selectivity ratio, hazard quotient and probit substitution method of risk assessments. 2010 Elsevier Ltd. All rights reserved.

Target and non-target toxicity of botanical insecticide derived from Couroupita guianensis L. flower against generalist herbivore, Spodoptera litura Fab. and an earthworm, Eisenia foetida Savigny

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Novel chemistries in botanical insecticides may provide alternatives to, or development of synthetic insecticides suitable for controlling the Lepidopteran pests, like Spodoptera litura (F.). Many botanical chemistries are biodegradable, and have lower mammalian toxicity. Eight natural chemical comp...

GC-MS Analysis of Insecticidal Essential Oil of Aerial Parts of Echinops latifolius Tausch

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Xin Chao Liu

2013-01-01

Full Text Available The roots of Echinops latifolius Tausch (Asteraceae have been used in the traditional medicine. However, no report on chemical composition and insecticidal activities of the essential oil of this plant exists. The aim of this research was to determine chemical composition and insecticidal activities of the essential oil of E. latifolius aerial parts against maize weevils (Sitophilus zeamais Motschulsky for the first time. Essential oil of E. latifolius aerial parts at flowering stage was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS. A total of 35 components of the essential oil of E. latifolius aerial parts were identified. The major compounds in the essential oil were 1,8-cineole (19.63%, (Z-β-ocimene (18.44%, and β-pinene (15.56% followed by β-myrcene (4.75% and carvone (4.39%. The essential oil of E. latifolius possessed contact toxicity against S. zeamais with an LD50 value of 36.40 µg/adult. The essential oil also exhibited fumigant toxicity against S. zeamais with an LC50 value of 9.98 mg/L. The study indicates that the essential oil of E. latifolius aerial parts has a potential for development into a natural insecticide/fumigant for control of insects in stored grains.

The Genus Artemisia: A 2012–2017 Literature Review on Chemical Composition, Antimicrobial, Insecticidal and Antioxidant Activities of Essential Oils

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Singh, Pooja

2017-01-01

Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess several active constituents that work through several modes of action. The genus Artemisia includes the largest genus of family Asteraceae has several medicinal uses in human and plant diseases aliments. Extensive investigations on essential oil composition, antimicrobial, insecticidal and antioxidant studies have been conducted for various species of this genus. In this review, we have compiled data of recent literature (2012–2017) on essential oil composition, antimicrobial, insecticidal and antioxidant activities of different species of the genus Artemisia. Regarding the antimicrobial and insecticidal properties we have only described here efficacy of essential oils against plant pathogens and insect pests. The literature revealed that 1, 8-cineole, beta-pinene, thujone, artemisia ketone, camphor, caryophyllene, camphene and germacrene D are the major components in most of the essential oils of this plant species. Oils from different species of genus Artemisia exhibited strong antimicrobial activity against plant pathogens and insecticidal activity against insect pests. However, only few species have been explored for antioxidant activity. PMID:28930281

The Genus Artemisia: a 2012–2017 Literature Review on Chemical Composition, Antimicrobial, Insecticidal and Antioxidant Activities of Essential Oils

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Abhay K. Pandey

2017-09-01

Full Text Available Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess several active constituents that work through several modes of action. The genus Artemisia includes the largest genus of family Asteraceae has several medicinal uses in human and plant diseases aliments. Extensive investigations on essential oil composition, antimicrobial, insecticidal and antioxidant studies have been conducted for various species of this genus. In this review, we have compiled data of recent literature (2012–2017 on essential oil composition, antimicrobial, insecticidal and antioxidant activities of different species of the genus Artemisia. Regarding the antimicrobial and insecticidal properties we have only described here efficacy of essential oils against plant pathogens and insect pests. The literature revealed that 1, 8-cineole, beta-pinene, thujone, artemisia ketone, camphor, caryophyllene, camphene and germacrene D are the major components in most of the essential oils of this plant species. Oils from different species of genus Artemisia exhibited strong antimicrobial activity against plant pathogens and insecticidal activity against insect pests. However, only few species have been explored for antioxidant activity.

Evaluation of toxicity of biorational insecticides against larvae of the alfalfa weevil

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Gadi V.P. Reddy

Full Text Available The alfalfa weevil, Hypera postica (Coleoptera: Curculionidae, is a major pest of alfalfa Medicago sativa L. (Fabaceae. While H. postica usually causes the most damage before the first cutting, in summer of 2015 damaging levels of the pest persisted in Montana well after the first harvest of alfalfa. Although conventional insecticides can control H. postica, these chemicals have adverse effects on non-target organisms including pollinators and natural enemy insects. In this context, use of biorational insecticides would be the best alternative options, as they are known to pose less risk to non-target organisms. We therefore examined the six commercially available biorational insecticides against H. postica under laboratory condition: Mycotrol® ESO (Beauveria bassiana GHA, Aza-Direct® (Azadirachtin, Met52® EC (Metarhizium brunneum F52, Xpectro OD® (B. bassiana GHA + pyrethrins, Xpulse OD® (B. bassiana GHA + Azadirachtin and Entrust WP® (spinosad 80%. Concentrations of 0.1, 0.5, 1.0, and 2.0 times the lowest labelled rates were tested for all products. However, in the case of Entrust WP, additional concentrations of 0.001 and 0.01 times the lowest label rate were also assessed. Mortality rates were determined at 1–9 days post treatment. Based on lethal concentrations and relative potencies, this study clearly showed that Entrust was the most effective, causing 100% mortality within 3 days after treatment among all the tested materials. With regard to other biorational, Xpectro was the second most effective insecticide followed by Xpulse, Aza-Direct, Met52, and Mycotrol. Our results strongly suggested that these biorational insecticides could potentially be applied for H. postica control. Keywords: Low risk insecticides, Insect pathogenic fungi, Efficacy, Lethal concentration, Mortality rate

A Comparative Study of the Persistence, Movement and Metabolism of Six Insecticides in Soils and Plants

International Nuclear Information System (INIS)

Fuhremann, T.W.; Lichtenstein, E.P.

1981-01-01

Full text: Two soil types and oat plants grown in these soils were incubated under identical environmental conditions. The insecticides used in order to increase the water solubility were 14 C-DDT, 14 C-lindane, 14 C-fonofos, 14 C-parathion, 14 C-phorate and 14 C-carbofuran. Total amounts of 14 C-residues recovered from insecticide-treated loam soils plus oats grown in these soils were similar with DDT and oarbofuran. They were also higher than those observed with the other insecticides. While most of the 14 C-DDT residues remained in the soils, most of the 14 C-carbofuran residues were recovered from oat leaves in the form of carbofuran and 3-hydroxycarbofuran. 14 C-residues of all insecticides were more persistent in loam than in sandy soil and sand-grown oats took up more 14 C-insecticide residues than loamgrown oats. The more water-soluble insecticides, 14 C-phorate and Ccarbofuran were more mobile and were metabolized to a greater extent than insecticides of lower water solubilities. Unextractable (bound) 14 C-residues in loam soil ranged from 2.8% to 29.1% of the applied doses of 14 C-DDT and 14 C-parathion, respectively. Bound 14 C-residues were lower in the sandy soil than in the loam soil, however, plant-bound 14 C-residues were higher in oats grown in the sandy soil than in loam grown oats. Insecticide metabolites recovered from soils and plants were identified and quantitated whenever possible. The oxygen analog metabolites of the organophosphorus insecticides were most abundant in the sandy soil and in oats grown therein. Data illustrate the importance of chemical structure, water solubility and soil type in predicting the comparative environmental behaviour of pesticides. (author)

Usage Possibilities of Insecticide Effective Biocidals in Organic Agriculture

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Şimşek, Muharrem; Yağcı, Mürşide; Yaşarer, Haluk

2016-01-01

In conventional agriculture it is aimed that mainly increase in the amount of products, synthetic chemicals and fertilizers are used extensively to provide it. Today, terms such as safe food, human and environment health have become more important. Therefore, it is necessary to increase the share of organic agriculture which have less negative impacts to human health and environment, and sustainable use of natural resources. Herein environmentally insecticide effective biocidals to pest contr...

Evaluation of Environmental Risks in the Use of Insecticide in Hashtgerd Area using EIQ

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seyae jala yadollahi Nooshabadi

2018-02-01

Full Text Available Introduction Recently, there is an increasing concern about the effects of pesticides on non-target organisms. Residual of pesticides cause environmental pollution and put in danger the human health. The problem is always in contact with pesticides, there are numerous risks related to the environmental and human health threat at different levels of their cycle, including production, sale, use in the field and ultimately for residue in food occurs. This study consider the harmful effects of pesticides in Hashtgerd study area and their potential and environmental risks using EIQ index. Environmental Impact Quotient (EIQ is a model based on algebraic equations which by it can be classification chemical pesticides based on environmental hazards and risks to human health and toxins that cause minimal risk are selected. The ultimate purpose of this study was to determine 5 insecticide have been the highest consumption in the region Hashtgerd and then determine the potential environmental risks of them by EIQ index, so that eventually we can identify and eliminate hazardous insecticides. Materials and Methods Hashtgerd study area is one of 609 countries study area that is located in the Alborz province. This area with an extent of about 1170 square km because of the proximity to the metropolis of Tehran and focus a large number of agricultural, industrial and service units has an important economic and political position. The numerical value of the EIQ is average of the three main components include of the potential damage to the health of farm workers, the potential damage to consumers through the direct effect of toxic residues in food products or through ground water contamination and potential negative effects on the environment, including aquatic and terrestrial organisms show. The describes components of the EIQ are contains 11 variables. All input data for the impact of low, medium and high are judged to be harmful than, the one, three or five

Malaria Vector Control Still Matters despite Insecticide Resistance.

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Alout, Haoues; Labbé, Pierrick; Chandre, Fabrice; Cohuet, Anna

2017-08-01

Mosquito vectors' resistance to insecticides is usually considered a major threat to the recent progresses in malaria control. However, studies measuring the impact of interventions and insecticide resistance reveal inconsistencies when using entomological versus epidemiological indices. First, evaluation tests that do not reflect the susceptibility of mosquitoes when they are infectious may underestimate insecticide efficacy. Moreover, interactions between insecticide resistance and vectorial capacity reveal nonintuitive outcomes of interventions. Therefore, considering ecological interactions between vector, parasite, and environment highlights that the impact of insecticide resistance on the malaria burden is not straightforward and we suggest that vector control still matters despite insecticide resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of the insecticide prothrin and its analogues from biomass-derived 5-(Chloromethyl) furfural

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Prothrin, a synthetic pyrethroid insecticide, was synthesized from the biomass-derived platform chemical 5 (chloromethyl)furfural in six steps and overall 65% yield. Two structural analogues of prothrin were also prepared following the same synthetic approach. Preliminary testing of these furan-base...

Impact of environment on mosquito response to pyrethroid insecticides: facts, evidences and prospects.

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Nkya, Theresia Estomih; Akhouayri, Idir; Kisinza, William; David, Jean-Philippe

2013-04-01

By transmitting major human diseases such as malaria, dengue fever and filariasis, mosquito species represent a serious threat worldwide in terms of public health, and pose a significant economic burden for the African continent and developing tropical regions. Most vector control programmes aiming at controlling life-threatening mosquitoes rely on the use of chemical insecticides, mainly belonging to the pyrethroid class. However, resistance of mosquito populations to pyrethroids is increasing at a dramatic rate, threatening the efficacy of control programmes throughout insecticide-treated areas, where mosquito-borne diseases are still prevalent. In the absence of new insecticides and efficient alternative vector control methods, resistance management strategies are therefore critical, but these require a deep understanding of adaptive mechanisms underlying resistance. Although insecticide resistance mechanisms are intensively studied in mosquitoes, such adaptation is often considered as the unique result of the selection pressure caused by insecticides used for vector control. Indeed, additional environmental parameters, such as insecticides/pesticides usage in agriculture, the presence of anthropogenic or natural xenobiotics, and biotic interactions between vectors and other organisms, may affect both the overall mosquito responses to pyrethroids and the selection of resistance mechanisms. In this context, the present work aims at updating current knowledge on pyrethroid resistance mechanisms in mosquitoes and compiling available data, often from different research fields, on the impact of the environment on mosquito response to pyrethroids. Key environmental factors, such as the presence of urban or agricultural pollutants and biotic interactions between mosquitoes and their microbiome are discussed, and research perspectives to fill in knowledge gaps are suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

Developmental neurotoxicity of the organophosphorus insecticide chlorpyrifos: from clinical findings to preclinical models and potential mechanisms.

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Burke, Richard D; Todd, Spencer W; Lumsden, Eric; Mullins, Roger J; Mamczarz, Jacek; Fawcett, William P; Gullapalli, Rao P; Randall, William R; Pereira, Edna F R; Albuquerque, Edson X

2017-08-01

Organophosphorus (OP) insecticides are pest-control agents heavily used worldwide. Unfortunately, they are also well known for the toxic effects that they can trigger in humans. Clinical manifestations of an acute exposure of humans to OP insecticides include a well-defined cholinergic crisis that develops as a result of the irreversible inhibition of acetylcholinesterase (AChE), the enzyme that hydrolyzes the neurotransmitter acetylcholine (ACh). Prolonged exposures to levels of OP insecticides that are insufficient to trigger signs of acute intoxication, which are hereafter referred to as subacute exposures, have also been associated with neurological deficits. In particular, epidemiological studies have reported statistically significant correlations between prenatal subacute exposures to OP insecticides, including chlorpyrifos, and neurological deficits that range from cognitive impairments to tremors in childhood. The primary objectives of this article are: (i) to address the short- and long-term neurological issues that have been associated with acute and subacute exposures of humans to OP insecticides, especially early in life (ii) to discuss the translational relevance of animal models of developmental exposure to OP insecticides, and (iii) to review mechanisms that are likely to contribute to the developmental neurotoxicity of OP insecticides. Most of the discussion will be focused on chlorpyrifos, the top-selling OP insecticide in the United States and throughout the world. These points are critical for the identification and development of safe and effective interventions to counter and/or prevent the neurotoxic effects of these chemicals in the developing brain. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms. © 2017 International Society for Neurochemistry.

Modeling global distribution of agricultural insecticides in surface waters

International Nuclear Information System (INIS)

Ippolito, Alessio; Kattwinkel, Mira; Rasmussen, Jes J.; Schäfer, Ralf B.; Fornaroli, Riccardo; Liess, Matthias

2015-01-01

Agricultural insecticides constitute a major driver of animal biodiversity loss in freshwater ecosystems. However, the global extent of their effects and the spatial extent of exposure remain largely unknown. We applied a spatially explicit model to estimate the potential for agricultural insecticide runoff into streams. Water bodies within 40% of the global land surface were at risk of insecticide runoff. We separated the influence of natural factors and variables under human control determining insecticide runoff. In the northern hemisphere, insecticide runoff presented a latitudinal gradient mainly driven by insecticide application rate; in the southern hemisphere, a combination of daily rainfall intensity, terrain slope, agricultural intensity and insecticide application rate determined the process. The model predicted the upper limit of observed insecticide exposure measured in water bodies (n = 82) in five different countries reasonably well. The study provides a global map of hotspots for insecticide contamination guiding future freshwater management and conservation efforts. - Highlights: • First global map on insecticide runoff through modelling. • Model predicts upper limit of insecticide exposure when compared to field data. • Water bodies in 40% of global land surface may be at risk of adverse effects. • Insecticide application rate, terrain slope and rainfall main drivers of exposure. - We provide the first global map on insecticide runoff to surface water predicting that water bodies in 40% of global land surface may be at risk of adverse effects

Soil application of neonicotinoid insecticides for control of insect pests in wine grape vineyards.

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Van Timmeren, Steven; Wise, John C; Isaacs, Rufus

2012-04-01

Soil application of systemic neonicotinoid insecticides can provide opportunities for long-term control of insect pests in vineyards, with minimal risk of pesticide drift or worker exposure. This study compared the effectiveness of neonicotinoid insecticides applied via irrigation injection on key early-season and mid-season insect pests of vineyards in the eastern United States. On vines trained to grow on drip irrigation, early-season application of imidacloprid, clothianidin, thiamethoxam and dinotefuran provided high levels of control against the potato leafhopper, Empoasca fabae. Protection of vines against Japanese beetle, Popillia japonica, and grape berry moth, Paralobesia viteana, was also observed after mid-season applications. Efficacy was poor in commercial vineyards when treatments were applied to the soil before irrigation or rain, indicating that vines must be grown with an irrigation system for efficient uptake of the insecticide. In drip-irrigated vineyards, soil-applied neonicotinoids can be used to provide long residual control of either early-season or mid- to late-season foliage pests of vineyards. This approach can reduce the dependence on foliar-applied insecticides, with associated benefits for non-target exposure to workers and natural enemies. Copyright © 2012 Society of Chemical Industry.

Effect of two organophosphorus insecticides on the growth, respiration and (14C)-glucose metabolism of Azobacter chroococcum Beij

International Nuclear Information System (INIS)

Balasubramanian, A.; Narayanan, R.

1980-01-01

The two organophosphorus insecticides, commonly applied to soil, viz., disulfoton (0,0-diethyl S-2-ethyl thio ethyl phosphorodithioate) and fensulfothion (0,0-diethyl 0-4-methyl sulphinyl phenyl phosphorothioate) did not affect the in vitro growth of Azotobacter chroococcum Beij., the free-living, nitrogen fixing soil bacterium, at 2 ppm (lower level), while the normal dose (5 ppm) and the higher level (10 ppm) suppressed the growth. Respiration of the organism (glucose oxidation) was adversely affected by the insecticides in the growth medium and the inhibition increased with the concentration of the chemical. Both the insecticides suppressed the assimilation of ( 14 C)-glucose in the cold-TCA soluble, hot-TCA soluble fractions and insoluble residue of the cells whereas the 14 C-incorporation in the alcohol soluble and alcohol-ether soluble fractions was enhanced indicating that the insecticides considerably altered the glucose metabolism of the bacterium. (author)

Recent trends of modern bacterial insecticides for pest control practice in integrated crop management system.

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Chattopadhyay, Pritam; Banerjee, Goutam; Mukherjee, Sayantan

2017-05-01

Food security and safety are the major concern in ever expanding human population on the planet earth. Each and every year insect pests cause a serious damage in agricultural field that cost billions of dollars annually to farmers. The loss in term of productivity and high cost of chemical pesticides enhance the production cost. Irrespective use of chemical pesticides (such as Benzene hexachloride, Endosulfan, Aldicarb, and Fenobucarb) in agricultural field raised several types of environmental issues. Furthermore, continuous use of chemical pesticides creates a selective pressure which helps in emerging of resistance pest. These excess chemical pesticide residues also contaminate the environment including the soil and water. Therefore, the biological control of insect pest in the agricultural field gains more importance due to food safety and environment friendly nature. In this regard, bacterial insecticides offer better alternative to chemical pesticides. It not only helps to establish food security through fighting against insect pests but also ensure the food safety. In this review, we have categorized insect pests and the corresponding bacterial insecticides, and critically analyzed the importance and mode of action of bacterial pesticides. We also have summarized the use of biopesticides in integrated pest management system. We have tried to focus the future research area in this field for the upcoming scientists.

Modeling global distribution of agricultural insecticides in surface waters.

Science.gov (United States)

Ippolito, Alessio; Kattwinkel, Mira; Rasmussen, Jes J; Schäfer, Ralf B; Fornaroli, Riccardo; Liess, Matthias

2015-03-01

Agricultural insecticides constitute a major driver of animal biodiversity loss in freshwater ecosystems. However, the global extent of their effects and the spatial extent of exposure remain largely unknown. We applied a spatially explicit model to estimate the potential for agricultural insecticide runoff into streams. Water bodies within 40% of the global land surface were at risk of insecticide runoff. We separated the influence of natural factors and variables under human control determining insecticide runoff. In the northern hemisphere, insecticide runoff presented a latitudinal gradient mainly driven by insecticide application rate; in the southern hemisphere, a combination of daily rainfall intensity, terrain slope, agricultural intensity and insecticide application rate determined the process. The model predicted the upper limit of observed insecticide exposure measured in water bodies (n = 82) in five different countries reasonably well. The study provides a global map of hotspots for insecticide contamination guiding future freshwater management and conservation efforts. Copyright © 2014 Elsevier Ltd. All rights reserved.

A potential target for organophosphate insecticides leading to spermatotoxicity.

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Suzuki, Himiko; Tomizawa, Motohiro; Ito, Yuki; Abe, Keisuke; Noro, Yuki; Kamijima, Michihiro

2013-10-16

Organophosphate (OP) insecticides as an anticholinesterase also act on the diverse serine hydrolase targets, thereby revealing secondary or unexpected toxic effects including male reproductive toxicity. The present investigation detects a possible target molecule(s) for OP-induced spermatotoxicity (sperm deformity, underdevelopment, and reduced motility) from a chemical standpoint. The activity-based protein profiling (ABPP) approach with a phosphonofluoridate fluorescent probe pinpointed the molecular target for fenitrothion (FNT, a major OP insecticide) oxon (bioactive metabolite of FNT) in the mouse testicular membrane proteome, i.e., FNT oxon phosphorylates the fatty acid amide hydrolase (FAAH), which plays pivotal roles in spermatogenesis and sperm motility acquirement. Subsequently, mice were treated orally with vehicle or FNT for 10 days, and FAAH activity in testis or epididymis cauda was markedly reduced by the subacute exposure. ABPP analysis revealed that FAAH was selectively inhibited among the FNT-treated testicular membrane proteome. Accordingly, FAAH is a potential target for OP-elicited spermatotoxicity.

Removal of chlorpyrifos insecticide in constructed wetlands with different plant species

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Tamara D. de Souza

Full Text Available ABSTRACT The objective of this study was to evaluate the remediation of water containing the insecticide chlorpyrifos by using constructed wetlands (CW cultivated with Polygonum punctatum, Cynodon spp. and Mentha aquatica, operated under different hydraulic retention times: 24, 48, 96, 144 and 192 h. The system efficiency was based on reduction of the initial concentration of chlorpyrifos and toxicity of the contaminated water. The results showed that constructed wetlands are an excellent alternative for remediation of the insecticide chlorpyrifos in aqueous medium. It was observed that the average overall removal efficiency of the insecticide was 98.6%, and in the first hydraulic retention time, 24 h, chlorpyrifos was removed to levels below the detection limit in all CW. This result is mainly attributed to adsorption and microbial degradation. For the qualitative standard acute toxicity tests with Daphnia similis, for most samples there was a reduction in toxicity greater than 80%. It was reported that the ecotoxicological tests with the effluents of the constructed wetland are a good option as an indicator of the effectiveness of treatments and a promising alternative to complement the physical and chemical analyses.

Describing the role of Drosophila melanogaster ABC transporters in insecticide biology using CRISPR-Cas9 knockouts.

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Denecke, Shane; Fusetto, Roberto; Batterham, Philip

2017-12-01

ABC transporters have a well-established role in drug resistance, effluxing xenobiotics from cells and tissues within the organism. More recently, research has been dedicated to understanding the role insect ABC transporters play in insecticide toxicity, but progress in understanding the contribution of specific transporters has been hampered by the lack of functional genetic tools. Here, we report knockouts of three Drosophila melanogaster ABC transporter genes, Mdr49, Mdr50, and Mdr65, that are homologous to the well-studied mammalian ABCB1 (P-glycoprotein). Each knockout mutant was created in the same wild type background and tested against a panel of insecticides representing different chemical classes. Mdr65 knockouts were more susceptible to all neuroactive insecticides tested, but Mdr49 and Mdr50 knockouts showed increased susceptibility or resistance depending on the insecticide used. Mdr65 was chosen for further analysis. Calculation of LC 50 values for the Mdr65 knockout allowed the substrate specificity of this transporter to be examined. No obvious distinguishing structural features were shared among MDR65 substrates. A role for Mdr65 in insecticide transport was confirmed by testing the capacity of the knockout to synergize with the ABC inhibitor verapamil and by measuring the levels of insecticide retained in the body of knockout flies. These data unambiguously establish the influence of ABC transporters on the capacity of wild type D. melanogaster to tolerate insecticide exposure and suggest that both tissue and substrate specificity underpin this capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

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Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

2017-04-01

Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Evaluation of the efficacy of insecticidal coatings based on teflutrin and chlorpyrifos against Rhynchophorus ferrugineus.

Science.gov (United States)

Pugliese, Massimo; Rettori, Andrea Alberto; Martinis, Roberto; Al-Rohily, Khalid; Velate, Suresh; Moideen, Mohamed Ashraf; Al-Maashi, Ali

2017-08-01

The date palm (Phoenix dactylifera L.), an important economic resource for many nations worldwide, has recently been threatened by the presence of different insect pests, like the red palm weevil (RPW) Rhynchophorus ferrugineus. Two products, a glue (polyvinyl acetate) and an oil (raw linseed oil) were used as coatings and applied together with a repellent and two insecticides (teflutrin and chlorpyrifos) at different dosages on two species of palm (P. dactylifera and P. canariensis). Phytotoxic effects of the treatments were evaluated in a greenhouse on 260 potted palms (130 P. dactylifera and 130 P. canariensis) and no negative effects were observed. Afterwards, a trial lasting 400 days was carried out in a nursery located in Sicily (south Italy), treating 572 potted palm trees (286 P. dactylifera and 286 P. canariensis) with an average diameter at the base of 18-20 cm. After 400 days, 48% of the untreated palms were infested, while only 3% of date palms and 7% of Canary palms treated with insecticide at lower dosages were infested. The application of an insecticide-based coating is a good strategy to control and prevent the red palm weevil infestation, in particular on date palms. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Synergistic interactions between a variety of insecticides and an ergosterol biosynthesis inhibitor fungicide in dietary exposures of bumble bees (Bombus terrestris L.).

Science.gov (United States)

Raimets, Risto; Karise, Reet; Mänd, Marika; Kaart, Tanel; Ponting, Sally; Song, Jimao; Cresswell, James E

2018-03-01

In recent years, concern has been raised over honey bee colony losses, and also among wild bees there is evidence for extinctions and range contractions in Europe and North America. Pesticides have been proposed as a potential cause of this decline. Bees are exposed simultaneously to a variety of agrochemicals, which may cause synergistically detrimental impacts, which are incompletely understood. We investigated the toxicity of the fungicide imazalil in mixture with four common insecticides: fipronil (phenylpyrazoid), cypermethrin (pyrethroid), thiamethoxam, and imidacloprid (neonicotinoids). Ergosterol biosynthesis inhibitor (EBI) fungicides like imazalil can inhibit P450 detoxification systems in insects and therefore fungicide - insecticide co-occurrence might produce synergistic toxicity in bees. We assessed the impact of dietary fungicide - insecticide mixtures on the mortality and feeding rates of laboratory bumble bees (Bombus terrestris L.). Regarding mortality, imazalil synergised the toxicity of fipronil, cypermethrin and thiamethoxam, but not imidacloprid. We found no synergistic effects on feeding rates. Our findings suggest that P450-based detoxification processes are differentially important in mitigating the toxicity of certain insecticides, even those of the same chemical class. Our evidence that cocktail effects can arise in bumble bees should extend concern about the potential impacts of agrochemical mixtures to include wild bee species in farmland. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

The gut microbiota of insecticide-resistant insects houses insecticide-degrading bacteria: A potential source for biotechnological exploitation

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de Almeida, Luis Gustavo; de Moraes, Luiz Alberto Beraldo; Trigo, José Roberto; Omoto, Celso

2017-01-01

The exploration of new niches for microorganisms capable of degrading recalcitrant molecules is still required. We hypothesized the gut microbiota associated with insect-resistant lines carry pesticide degrading bacteria, and predicted they carry bacteria selected to degrade pesticides they were resistant to. We isolated and accessed the pesticide-degrading capacity of gut bacteria from the gut of fifth instars of Spodoptera frugiperda strains resistant to lambda-cyhalothrin, deltamethrin, chlorpyrifos ethyl, spinosad and lufenuron, using insecticide-selective media. Sixteen isolates belonging to 10 phylotypes were obtained, from which four were also associated with the susceptible strain. However, growth of gut bacteria associated with larvae from the susceptible strain was not obtained in any of the insecticide-based selective media tested. Growth of isolates was affected by the concentration of insecticides in the media, and all grew well up to 40 μg/ml. The insecticide-degrading capacity of selected isolates was assessed by GC or LC-MS/MS analyses. In conclusion, resistant strains of S. frugiperda are an excellent reservoir of insecticide-degrading bacteria with bioremediation potential. Moreover, gut-associated bacteria are subjected to the selection pressure imposed by insecticides on their hosts and may influence the metabolization of pesticides in insects. PMID:28358907

The gut microbiota of insecticide-resistant insects houses insecticide-degrading bacteria: A potential source for biotechnological exploitation.

Directory of Open Access Journals (Sweden)

Luis Gustavo de Almeida

Full Text Available The exploration of new niches for microorganisms capable of degrading recalcitrant molecules is still required. We hypothesized the gut microbiota associated with insect-resistant lines carry pesticide degrading bacteria, and predicted they carry bacteria selected to degrade pesticides they were resistant to. We isolated and accessed the pesticide-degrading capacity of gut bacteria from the gut of fifth instars of Spodoptera frugiperda strains resistant to lambda-cyhalothrin, deltamethrin, chlorpyrifos ethyl, spinosad and lufenuron, using insecticide-selective media. Sixteen isolates belonging to 10 phylotypes were obtained, from which four were also associated with the susceptible strain. However, growth of gut bacteria associated with larvae from the susceptible strain was not obtained in any of the insecticide-based selective media tested. Growth of isolates was affected by the concentration of insecticides in the media, and all grew well up to 40 μg/ml. The insecticide-degrading capacity of selected isolates was assessed by GC or LC-MS/MS analyses. In conclusion, resistant strains of S. frugiperda are an excellent reservoir of insecticide-degrading bacteria with bioremediation potential. Moreover, gut-associated bacteria are subjected to the selection pressure imposed by insecticides on their hosts and may influence the metabolization of pesticides in insects.

Investigation of the lethal and behavioral effects of commercial insecticides on the parasitoid wasp Copidosoma truncatellum.

Science.gov (United States)

Ramos, Rodrigo S; de Araújo, Vitor C R; Pereira, Renata R; Martins, Júlio C; Queiroz, Obiratanea S; Silva, Ricardo S; Picanço, Marcelo C

2018-01-01

Copidosoma truncatellum (Hymenoptera: Encyrtidae) is an important parasitoid wasp of the soybean looper, Chrysodeixis includens, but its effectiveness can be severely curtailed by the application of certain insecticides. Therefore, to identify insecticides that are potentially compatible with C. truncatellum, the lethal and behavioral effects of nine chemicals used to control the soybean looper were evaluated for their toxicity to the wasp. Chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb were the least toxic insecticides to the parasitoid, resulting in mortalities of less than 25%. In contrast, cartap, deltamethrin, and methomyl caused 100% mortality, and acephate and spinosad caused 76% and 78% mortality, respectively. At least one of the detoxifying enzymes (monooxygenase, glutathione S-transferase, and/or esterases) may be involved in the mechanisms underlying the selectivity of chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb for the parasitoid based on the results for the insecticide plus synergist treatment. Changes in the behavioral patterns (walking time and resting time) of the parasitoid were found with exposure to acephate, flubendiamide, indoxacarb and methomyl, but behavioral avoidance was not observed. Our results indicate that the insecticides chlorantraniliprole and chlorfenapyr are the most suitable for inclusion in integrated pest management strategies for the control of C. includens. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anticholinesterase insecticide retrospective.

Science.gov (United States)

Casida, John E; Durkin, Kathleen A

2013-03-25

The anticholinesterase (antiChE) organophosphorus (OP) and methylcarbamate (MC) insecticides have been used very effectively as contact and systemic plant protectants for seven decades. About 90 of these compounds are still in use - the largest number for any insecticide chemotype or mode of action. In both insects and mammals, AChE inhibition and acetylcholine accumulation leads to excitation and death. The cholinergic system of insects is located centrally (where it is protected from ionized OPs and MCs) but not at the neuromuscular junction. Structural differences between insect and mammalian AChE are also evident in their genomics, amino acid sequences and active site conformations. Species selectivity is determined in part by inhibitor and target site specificity. Pest population selection with OPs and MCs has resulted in a multitude of modified AChEs of altered inhibitor specificity some conferring insecticide resistance and others enhancing sensitivity. Much of the success of antiChE insecticides results from a suitable balance of bioactivation and detoxification by families of CYP450 oxidases, hydrolases, glutathione S-transferases and others. Known inhibitors for these enzymes block detoxification and enhance potency which is particularly important in resistant strains. The current market for OPs and MCs of 19% of worldwide insecticide sales is only half of that of 10 years ago for several reasons: there have been no major new compounds for 30 years; resistance has eroded their effectiveness; human toxicity problems are still encountered; the patents have expired reducing the incentive to update registration packages; alternative chemotypes or control methods have been developed. Despite this decline, they still play a major role in pest control and the increasing knowledge on their target sites and metabolism may make it possible to redesign the inhibitors for insensitive AChEs and to target new sites in the cholinergic system. The OPs and MCs are down

Insecticide resistance monitoring and correlation analysis of insecticides in field populations of the brown planthopper Nilaparvata lugens (stål) in China 2012-2014.

Science.gov (United States)

Zhang, Xiaolei; Liao, Xun; Mao, Kaikai; Zhang, Kaixiong; Wan, Hu; Li, Jianhong

2016-09-01

The brown planthopper is a serious rice pest in China. Chemical insecticides have been considered a satisfactory means of controlling the brown planthopper. In the present study, we determined the susceptibility of twenty-one populations of Nilaparvata lugens to eleven insecticides by a rice-stem dipping method from 2012 to 2014 in eight provinces of China. These field-collected populations of N. lugens had developed high levels of resistance to imidacloprid (resistant ratio, RR=233.3-2029-fold) and buprofezin (RR=147.0-1222). Furthermore, N. lugens showed moderate to high levels of resistance to thiamethoxam (RR=25.9-159.2) and low to moderate levels of resistance to dinotefuran (RR=6.4-29.1), clothianidin (RR=6.1-33.6), ethiprole (RR=11.5-71.8), isoprocarb (RR=17.1-70.2), and chlorpyrifos (RR=7.4-30.7). In contrast, the susceptibility of N. lugens to etofenprox (RR=1.1-4.9), thiacloprid (RR=2.9-8.2) and acetamiprid (RR=2.7-26.2) remained susceptible to moderate levels of resistance. Significant correlations were detected between the LC50 values of imidacloprid and thiamethoxam, dinotefuran, buprofezin, and etofenprox, as well as between clothianidin and thiamethoxam, dinotefuran, ethiprole, acetamiprid, and thiacloprid. Similarly, significant correlations were observed between chlorpyrifos and etofenprox, acetamiprid and thiacloprid. Additionally, the activity of the detoxification enzymes of N. lugens showed a significant correlation with the log LC50 values of imidacloprid, dinotefuran and ethiprole. These results will be beneficial for effective insecticide resistance management strategies to prevent or delay the development of insecticide resistance. Copyright © 2015 Elsevier B.V. All rights reserved.

Field efficacy of Heterorhabditis bacteriophora (Nematoda: Heterorhabditidae), Metarhizium brunneum (Hypocreales: Clavicipitaceae), and chemical insecticide combinations for Diabrotica virgifera virgifera larval management

DEFF Research Database (Denmark)

Rauch, Hannes; Steinwender, Bernhardt Michael; Mayerhofer, Johanna

2017-01-01

A two-year field study using a blend of entomopathogens in conjunction with chemical insecticides was carried out to determine to which extent they affect western corn rootworm (WCR), Diabrotica virgifera virgifera, survival, maize root damages, and grain yield and to assess the potential for sid...... is considerably higher than the stipulated economic threshold under favourable growing conditions, but a systematic crop rotation is recommended as an integral part of the WCR management both as a prophylaxis and as a background for the best treatment....

Diagnostic Doses of Insecticides for Adult Aedes aegypti to Assess Insecticide Resistance in Cuba.

Science.gov (United States)

Rodríguez, María Magdalena; Crespo, Ariel; Hurtado, Daymi; Fuentes, Ilario; Rey, Jorge; Bisset, Juan Andrés

2017-06-01

The objective of this study was to determine diagnostic doses (DDs) of 5 insecticides for the Rockefeller susceptible strain of Aedes aegypti , using the Centers for Disease Control and Prevention (CDC) bottle bioassay as a tool for monitoring insecticide resistance in the Cuban vector control program. The 30-min DD values determined in this study were 13.5 μg/ml, 6.5 μg/ml, 6 μg/ml, 90.0 μg/ml, and 15.0 μg/ml for cypermethrin, deltamethrin, lambda-cyhalothrin, chlorpyrifos, and propoxur, respectively. To compare the reliability of CDC bottle bioassay with the World Health Organization susceptible test, 3 insecticide-resistant strains were evaluated for deltamethrin and lambda-cyhalothrin. Results showed that the bottles can be used effectively from 21 to 25 days after treatment and reused up to 4 times, depending on the storage time. The CDC bottle bioassay is an effective tool to assess insecticide resistance in field populations of Ae. aegypti in Cuba and can be incorporated into vector management programs using the diagnostic doses determined in this study.

Effect of two organophosphorus insecticides on the growth, respiration and (/sup 14/C)-glucose metabolism of Azobacter chroococcum Beij

Energy Technology Data Exchange (ETDEWEB)

Balasubramanian, A; Narayanan, R [Tamil Nadu Agricultural Univ., Coimbatore (India)

1980-01-01

The two organophosphorus insecticides, commonly applied to soil, viz., disulfoton (0,0-diethyl S-2-ethyl thio ethyl phosphorodithioate) and fensulfothion (0,0-diethyl 0-4-methyl sulphinyl phenyl phosphorothioate) did not affect the in vitro growth of Azotobacter chroococcum Beij., the free-living, nitrogen fixing soil bacterium, at 2 ppm (lower level), while the normal dose (5 ppm) and the higher level (10 ppm) suppressed the growth. Respiration of the organism (glucose oxidation) was adversely affected by the insecticides in the growth medium and the inhibition increased with the concentration of the chemical. Both the insecticides suppressed the assimilation of (/sup 14/C)-glucose in the cold-TCA soluble, hot-TCA soluble fractions and insoluble residue of the cells whereas the /sup 14/C-incorporation in the alcohol soluble and alcohol-ether soluble fractions was enhanced indicating that the insecticides considerably altered the glucose metabolism of the bacterium.

Evaluation of systemic neonicotinoid insecticides for the management of the Asian citrus psyllid Diaphorina citri on containerized citrus.

Science.gov (United States)

Byrne, Frank J; Daugherty, Matthew P; Grafton-Cardwell, Elizabeth E; Bethke, James A; Morse, Joseph G

2017-03-01

Studies were conducted to evaluate uptake and retention of three systemic neonicotinoid insecticides, dinotefuran, imidacloprid and thiamethoxam, in potted citrus nursery plants treated at standard label rates. Infestation of these plants placed at a field site with moderate levels of Asian citrus psyllid (ACP) was monitored for 14 weeks following treatments, and insecticide residues in leaf tissue were quantified using enzyme-linked immunosorbent assay (ELISA). Bioassays were conducted using leaves harvested on various dates post-treatment to compare the efficacies of residues against adult ACP. Residues of the three neonicotinoids were detected in leaf tissues within 1 week after treatment. Peak concentrations established at 1 week for imidacloprid and dinotefuran and at 2 weeks for thiamethoxam. Imidacloprid and thiamethoxam outperformed the control and dinotefuran treatments at protecting trees from infestations by ACP eggs and nymphs. For a given insecticide concentration in leaf tissue, thiamethoxam induced the highest mortality of the three insecticides, and dinotefuran was the least toxic. If the time needed to achieve effective thresholds of a systemic neonicotinoid is known, treatments at production facilities could be scheduled that would minimize unnecessary post-treatment holding periods and ensure maximum retention of effective concentrations after the plants have shipped to retail outlets. The rapid uptake of the insecticides and retention at effective concentrations in containerized citrus suggest that the current 30 day post-treatment shipping restriction from production facilities to retail outlets outside of quarantine could be shortened to 14 days. Thiamethoxam should be added to the list of approved nursery treatments. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Greenhouse Gases Emission and Global Warming Potential as Affected by Chemicals Inputs for Main Cultivated Crops in Kerman Province: - Cereal

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Rooholla Moradi

2017-10-01

Full Text Available Introduction Agriculture is a major consumer of chemical resources. Increasing use of the inputs in agriculture has led to numerous environmental problems such as high consumption of nonrenewable energy resources, loss of biodiversity and pollution of the aquatic environment (Moradi et al., 2014. This environmental change will have the serious impacts on different growth and development processes of crops. The latest report of the Intergovernmental Panel on Climate Change (IPCC states that future emissions of greenhouse gases (GHGs will continue to increase and cause to climatic change (IPCC, 2007. This condition is also true for Iran. The three greenhouse gases associated with agriculture are carbon dioxide (CO2, methane (CH4, and nitrous oxide (N2O. Consistent with the development of agricultural production systems and move towards modernization in this sector increased dependence of the chemical resource (Salinger, 2005. There is even less data on CO2, N2O, and CH4 gas emission analysis as affected by cultivating various crops in Kerman province. Therefore, this study was conducted to assess the greenhouse gases (GHGs emission and global warming potential (GWP caused by chemical inputs (various chemical fertilizers and pesticides for cultivating wheat, barley and maize in some regions of Kerman province at 2011-2012 growth season. Materials and methods The study was conducted in Kerman province of Iran. Information about planting area of potato, onion and watermelon in various regions of Kerman was collected. Data were collected from potato, onion and watermelon growers by using a face to face questionnaire in 2014 for different regions of Kerman. In addition to the data obtained by surveys, previous studies of related organization (Agricultural Ministry of Kerman were also utilized during the study. The application rates of the chemical inputs were collected by using a face-to-face questionnaire in various regions (Bardsir, Bam, Jiroft

Insecticide susceptibility of the green plant bug, Apolygus lucorum Meyer-Dür (Homoptera: Miridae and two predatory arthropods

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Zhang Zhengqun

2015-12-01

Full Text Available The green plant bug (Apolygus lucorum Meyer-Dür is a key pest of Bt cotton in China. Along with biological control, chemical control is one of the most important strategies in A. lucorum Integrated Pest Management (IPM. The goal of this study was to evaluate the toxicity of eight conventional insecticides to A. lucorum and to assess the susceptibility of two generalist predators Chrysopa sinica (Jieder and Propylaea japonica (Thunbery to insecticides that are commonly used in A. lucorum management. Via glass-vial and leaf-dip bioassay, toxicity tests with selected insecticides at two different life-stages of A. lucorum indicated significant differences between the LD50 or LC50 values for these compounds within different insecticidal classes. Phenylpyrazole fipronil had the highest toxicity to 4th-instar nymphs and adults of A. lucorum, whereas neonicotinoid imidacloprid had the lowest toxicity among the insecticides. Females were more tolerant to insecticides than were males, as shown by the higher LD50 values for females. Furthermore, laboratory tests showed that endosulfan had the highest selectivity to C. sinica and P. japonica: the selective toxicity ratios (STRs were superior to other tested insecticides, particularly imidacloprid, and were 5.396 and 4.749-fold higher than baseline STRs, respectively. From this study, we conclude that fipronil can potentially be used to efficiently control A. lucorum. An alternative control agent worth consideration is endosulfan, owing to its relative safety to non-targeted natural enemies.

Comparison of Fractionation Techniques of CO2 Extracts from Eucalyptus Globulus - Composition and Insecticidal Activity

Czech Academy of Sciences Publication Activity Database

Topiař, Martin; Sajfrtová, Marie; Pavela, R.; Machalová, Zdeňka

2015-01-01

Roč. 97, FEB 2015 (2015), s. 202-210 ISSN 0896-8446 R&D Projects: GA TA ČR TA01010578 Institutional support: RVO:67985858 Keywords : supercritical fractinacion * eucalyptus globulus * insecticidal activity Subject RIV: CI - Industrial Chemistry , Chemical Engineering Impact factor: 2.579, year: 2015

CADDIS Volume 2. Sources, Stressors and Responses: Insecticides - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the insecticides module, when to list insecticides as a candidate cause, ways to measure insecticides, simple and detailed conceptual diagrams for insecticides, insecticides module references and literature reviews.

CADDIS Volume 2. Sources, Stressors and Responses: Insecticides - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the insecticides module, when to list insecticides as a candidate cause, ways to measure insecticides, simple and detailed conceptual diagrams for insecticides, insecticides module references and literature reviews.

Strain improvement of fungal insecticides for controlling insect pests and vector-borne diseases.

Science.gov (United States)

Fang, Weiguo; Azimzadeh, Philippe; St Leger, Raymond J

2012-06-01

Insect pathogenic fungi play an important natural role in controlling insect pests. However, few have been successfully commercialized due to low virulence and sensitivity to abiotic stresses that produce inconsistent results in field applications. These limitations are inherent in most naturally occurring biological control agents but development of recombinant DNA techniques has made it possible to significantly improve the insecticidal efficacy of fungi and their tolerance to adverse conditions, including UV. These advances have been achieved by combining new knowledge derived from basic studies of the molecular biology of these pathogens, technical developments that enable very precise regulation of gene expression, and genes encoding insecticidal proteins from other organisms, particularly spiders and scorpions. Recent coverage of genomes is helping determine the identity, origin, and evolution of traits needed for diverse lifestyles and host switching. In future, such knowledge combined with the precision and malleability of molecular techniques will allow design of multiple pathogens with different strategies and host ranges to be used for different ecosystems, and that will avoid the possibility of the host developing resistance. With increasing public concern over the continued use of synthetic chemical insecticides, these new types of biological insecticides offer a range of environmental-friendly options for cost-effective control of insect pests. Copyright © 2012 Elsevier Ltd. All rights reserved.

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins

OpenAIRE

Martinez, Ana Fl?via Canovas; de Almeida, Lu?s Gustavo; Moraes, Luiz Alberto Beraldo; C?nsoli, Fernando Lu?s

2017-01-01

Background The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted att...

Limonoids from Cipadessa fruticosa and Cedrela fissilis and their insecticidal activity

International Nuclear Information System (INIS)

Leite, Ana C.; Fernandes, Joao B.; Vieira, Paulo C.; Silva, M. Fatima das G. Fernandes da; Bueno, Fabiana C.; Oliveira, Cintia G.; Bueno, Odair C.; Pagnocca, Fernando C.; Hebling, M. Jose A.; Bacci Junior, Mauricio

2005-01-01

The chemical investigation of the fruits of Cipadessa fruticosa (Meliaceae) afforded the new limonoid cipadesin B and the known swietemahonolide. From the roots of Cedrela fissilis (Meliaceae) were isolated the limonoid 3β-acetoxycarapin, new as natural product, along with the triterpenes oleanolic and oleanonic acid. These compounds and other six mexicanolide limonoids previously isolated from C. fruticosa showed insecticidal activity against the leaf-cutting ants Atta sexdens rubropilosa. (author)

Limonoids from andiroba oil and Cedrela fissilis and their insecticidal activity

Directory of Open Access Journals (Sweden)

Ambrozin Alessandra R. P.

2006-01-01

Full Text Available Nine limonoids were isolated from Carapa guianensis and Cedrela fissilis. Among them, 1,2-dihydro-3beta-hydroxy-7-deacetoxy-7-oxogedunin is a new compound. Moreover, the assignments of some chemical shifts of xyloccensin k have been corrected and ¹H NMR data of 7-deacetylgedunin have been assigned for the first time. These isolated limonoids were assayed on Atta sexdens rubropilosa workers showing moderate insecticidal activities.

Limonoids from andiroba oil and Cedrela fissilis and their insecticidal activity

Energy Technology Data Exchange (ETDEWEB)

Ambrozin, Alessandra R.P.; Leite, Ana C.; Vieira, Paulo C.; Fernandes, Joao B.; Silva, M. Fatima das G. Fernandes da [Sao Carlos Univ., SP (Brazil). Dept. de Quimica]. E-mail: paulo@dq.ufscar.br; Bueno, Fabiana C.; Bueno, Odair C.; Pagnocca, Fernando C.; Hebling, Jose A.; Bacci Junior, Mauricio [UNESP, Rio Claro, SP (Brazil). Centro de Estudos de Insetos Sociais

2006-05-15

Nine limonoids were isolated from Carapa guianensis and Cedrela fissilis. Among them, 1,2-dihydro-3{beta}-hydroxy-7-deacetoxy-7-oxogedunin is a new compound. Moreover, the assignments of some chemical shifts of xyloccensin k have been corrected and {sup 1}H NMR data of 7-deacetylgedunin have been assigned for the first time. These isolated limonoids were assayed on Atta sexdens rubropilosa workers showing moderate insecticidal activities. (author)

Insecticide Resistance and Metabolic Mechanisms Involved in Larval and Adult Stages of Aedes aegypti Insecticide-Resistant Reference Strains from Cuba.

Science.gov (United States)

Bisset, Juan Andrés; Rodríguez, María Magdalena; French, Leydis; Severson, David W; Gutiérrez, Gladys; Hurtado, Daymi; Fuentes, Ilario

2014-12-01

Studies were conducted to compare levels of insecticide resistance and to determine the metabolic resistance mechanisms in larval and adult stages of Aedes aegypti from Cuba. Three insecticide-resistant reference strains of Ae. aegypti from Cuba were examined. These strains were derived from a Santiago de Cuba strain isolated in 1997; it was previously subjected to a strong selection for resistance to temephos (SAN-F6), deltamethrin (SAN-F12), and propoxur (SAN-F13) and routinely maintained in the laboratory under selection pressure up to the present time, when the study was carried out. In addition, an insecticide-susceptible strain was used for comparison. The insecticide resistance in larvae and adults was determined using standard World Health Organization methodologies. Insecticide resistance mechanisms were determined by biochemical assays. The esterases (α EST and β EST) and mixed function oxidase (MFO) activities were significantly higher in adults than in the larvae of the three resistant strains studied. The association of resistance level with the biochemical mechanism for each insecticide was established for each stage. The observed differences between larval and adult stages of Ae. aegypti in their levels of insecticide resistance and the biochemical mechanisms involved should be included as part of monitoring and surveillance activities in Ae. aegypti vector control programs.

Entomopathogenic fungi as biological control agents of diamondback moth (Lepidoptera: Plutellidae)and compatibility with chemical insecticides

Science.gov (United States)

The objectives were to evaluate the efficiency of entomopathogenic fungi against Plutella xylostella (L.) and the compatibility of the most virulent isolates with some of the insecticides registered for use on cabbage crops. Pathogenicity tests used isolates of Beauveria bassiana, Metarhizium rileyi...

Identification of Repellent and Insecticidal Constituents of the Essential Oil of Artemisia rupestris L. Aerial Parts against Liposcelis bostrychophila Badonnel

OpenAIRE

Liu, Xin; Li, Yin; Li, He; Deng, Zhi; Zhou, Ligang; Liu, Zhi; Du, Shu

2013-01-01

The aim of this research was to determine the chemical composition and insecticidal and repellent activity of the essential oil of Artemisia rupestris L. aerial parts against the booklice Liposcelis bostrychophila Badonnel and isolation of insecticidal and repellent constituents from the essential oil. The essential oil of A. rupestris was obtained by hydrodistillation and analyzed by GC-MS. A total of 30 components of the essential oil of A. rupestris was identified and the principal compoun...

Insecticide Mixtures Could Enhance the Toxicity of Insecticides in a Resistant Dairy Population of Musca domestica L

Science.gov (United States)

Khan, Hafiz Azhar Ali; Akram, Waseem; Shad, Sarfraz Ali; Lee, Jong-Jin

2013-01-01

House flies, Musca domestica L., are important pests of dairy operations worldwide, with the ability to adapt wide range of environmental conditions. There are a number of insecticides used for their management, but development of resistance is a serious problem. Insecticide mixtures could enhance the toxicity of insecticides in resistant insect pests, thus resulting as a potential resistance management tool. The toxicity of bifenthrin, cypermethrin, deltamethrin, chlorpyrifos, profenofos, emamectin benzoate and fipronil were assessed separately, and in mixtures against house flies. A field-collected population was significantly resistant to all the insecticides under investigation when compared with a laboratory susceptible strain. Most of the insecticide mixtures like one pyrethroid with other compounds evaluated under two conditions (1∶1-“A” and LC50: LC50-“B”) significantly increased the toxicity of pyrethroids in the field population. Under both conditions, the combination indices of pyrethroids with other compounds, in most of the cases, were significantly below 1, suggesting synergism. The enzyme inhibitors, PBO and DEF, when used in combination with insecticides against the resistant population, toxicities of bifenthrin, cypermethrin, deltamethrin and emamectin were significantly increased, suggesting esterase and monooxygenase based resistance mechanism. The toxicities of bifenthrin, cypermethrin and deltamethrin in the resistant population of house flies could be enhanced by the combination with chlorpyrifos, profenofos, emamectin and fipronil. The findings of the present study might have practical significance for resistance management in house flies. PMID:23613758

Evaluation of the effectiveness of insecticide trunk injections for control of Latoia lepida (Cramer) in the sweet olive tree Osmanthus fragrans

OpenAIRE

Jun Huang; Juan Zhang; Yan Li; Jun Li; Xiao-Hua Shi

2016-01-01

The screening of suitable insecticides is a key factor in successfully applying trunk injection technology to ornamental plants. In this study, six chemical pesticides were selected and injected into the trunks of Osmanthus fragrans to control the nettle caterpillar, Latoia lepida (Lepidoptera: Limacodidae), using a no-pressure injection system. The absorption rate of the insecticides, the leaf loss due to insect damage, and the mortality and frass amount of L. lepida larvae were evaluated af...

Susceptibility of Aphelinus certus to foliar-applied insecticides currently or potentially registered for soybean aphid control.

Science.gov (United States)

Frewin, Andrew J; Schaafsma, Arthur W; Hallett, Rebecca H

2012-02-01

Soybean aphid, a serious economic pest of soybean in North America, is currently managed by applying non-selective foliar insecticides during outbreaks according to decision thresholds and crop maturity. Natural enemies, such as the parasitoid Aphelinus certus Yasnosh, potentially play an important role in suppressing soybean aphid. Using selective insecticides that preserve A. certus may enhance the biological control service they provide and thus prevent or reduce the severity of soybean aphid outbreaks. The toxicity of five insecticides (λ-cyhalothrin, dimethoate, flonicamid, mineral oil, spirotetramat) and the biopesticide Beauveria bassiana to A. certus was assessed. The LD50 values of λ-cyhalothrin and dimethoate were similar; however, the hazard quotient of dimethoate was greater than that of λ-cyhalothrin. In a screening bioassay, the descending order of toxicity for the recommended rates 48 h after application was dimethoate>λ-cyhalothrin>flonicamid>mineral oil>Beauveria bassiana>spirotetramat. Overall, λ-cyhalothrin and dimethoate were both harmful to A. certus. The other insecticides tested were harmless to A. certus and are potential candidates for inclusion in soybean aphid management programs. Copyright © 2011 Society of Chemical Industry.

Conifer flavonoid compounds inhibit detoxification enzymes and synergize insecticides.

Science.gov (United States)

Wang, Zhiling; Zhao, Zhong; Cheng, Xiaofei; Liu, Suqi; Wei, Qin; Scott, Ian M

2016-02-01

Detoxification by glutathione S-transferases (GSTs) and esterases are important mechanisms associated with insecticide resistance. Discovery of novel GST and esterase inhibitors from phytochemicals could provide potential new insecticide synergists. Conifer tree species contain flavonoids, such as taxifolin, that inhibit in vitro GST activity. The objectives were to test the relative effectiveness of taxifolin as an enzyme inhibitor and as an insecticide synergist in combination with the organophosphorous insecticide, Guthion (50% azinphos-methyl), and the botanical insecticide, pyrethrum, using an insecticide-resistant Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) strain. Both taxifolin and its isomer, quercetin, increased the mortality of 1(st) instar CPB larvae after 48h when combined with Guthion, but not pyrethrum. Taxifolin had greater in vitro esterase inhibition compared with the commonly used esterase inhibitor, S, S, S-tributyl phosphorotrithioate (DEF). An in vivo esterase and GST inhibition effect after ingestion of taxifolin was measured, however DEF caused a greater suppression of esterase activity. This study demonstrated that flavonoid compounds have both in vitro and in vivo esterase inhibition, which is likely responsible for the insecticide synergism observed in insecticide-resistant CPB. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Comparative acute toxicity of neonicotinoid and pyrethroid insecticides to non-target crayfish (Procambarus clarkii) associated with rice-crayfish crop rotations.

Science.gov (United States)

Barbee, Gary C; Stout, Michael J

2009-11-01

Most insecticides used to control rice water weevil (Lissorhoptrus oryzophilus Kuscel) infestations are pyrethroids. However, pyrethroids are highly toxic to non-target crayfish associated with rice-crayfish crop rotations. One solution to the near-exclusive reliance on pyrethroids in a rice-crayfish pest management program is to incorporate neonicotinoid insecticides, which are insect specific and effective against weevils but not extremely toxic to crayfish. This study aimed to take the first step to assess neonicotinoids as alternatives to pyrethroids in rice-crayfish crop rotations by measuring the acute toxicities of three candidate neonicotinoid insecticides, clothianidin, dinotefuran and thiamethoxam, to juvenile Procambarus clarkii (Girard) crayfish and comparing them with the acute toxicities of two currently used pyrethroid insecticides, lambda-cyhalothrin and etofenprox. Neonicotinoid insecticides are at least 2-3 orders of magnitude less acutely toxic (96 h LC(50)) than pyrethroids to juvenile Procambarid crayfish: lambda-cyhalothrin (0.16 microg AI L(-1)) = etofenprox (0.29 microg AI L(-1)) > clothianidin (59 microg AI L(-1)) > thiamethoxam (967 microg AI L(-1)) > dinotefuran (2032 microg AI L(-1)). Neonicotinoid insecticides appear to be much less hazardous alternatives to pyrethroids in rice-crayfish crop rotations. Further field-level neonicotinoid acute and chronic toxicity testing with crayfish is needed. (c) 2009 Society of Chemical Industry.

Biotype Characterization, Developmental Profiling, Insecticide Response and Binding Property of Bemisia tabaci Chemosensory Proteins: Role of CSP in Insect Defense.

Directory of Open Access Journals (Sweden)

Guoxia Liu

Full Text Available Chemosensory proteins (CSPs are believed to play a key role in the chemosensory process in insects. Sequencing genomic DNA and RNA encoding CSP1, CSP2 and CSP3 in the sweet potato whitefly Bemisia tabaci showed strong variation between B and Q biotypes. Analyzing CSP-RNA levels showed not only biotype, but also age and developmental stage-specific expression. Interestingly, applying neonicotinoid thiamethoxam insecticide using twenty-five different dose/time treatments in B and Q young adults showed that Bemisia CSP1, CSP2 and CSP3 were also differentially regulated over insecticide exposure. In our study one of the adult-specific gene (CSP1 was shown to be significantly up-regulated by the insecticide in Q, the most highly resistant form of B. tabaci. Correlatively, competitive binding assays using tryptophan fluorescence spectroscopy and molecular docking demonstrated that CSP1 protein preferentially bound to linoleic acid, while CSP2 and CSP3 proteins rather associated to another completely different type of chemical, i.e. α-pentyl-cinnamaldehyde (jasminaldehyde. This might indicate that some CSPs in whiteflies are crucial to facilitate the transport of fatty acids thus regulating some metabolic pathways of the insect immune response, while some others are tuned to much more volatile chemicals known not only for their pleasant odor scent, but also for their potent toxic insecticide activity.

Mixture for Controlling Insecticide-Resistant Malaria Vectors

OpenAIRE

Pennetier, Cédric; Costantini, Carlo; Corbel, Vincent; Licciardi, Séverine; Dabire, R. K.; Lapied, B.; Chandre, Fabrice; Hougard, Jean-Marc

2008-01-01

The spread of resistance to pyrethroids in the major Afrotropical malaria vectors Anopheles gambiae s.s. necessitates the development of new strategies to control resistant mosquito populations. To test the efficacy of nets treated with repellent and insecticide against susceptible and insecticide-resistant An. gambiae mosquito populations, we impregnated mosquito bed nets with an insect repellent mixed with a low dose of organophosphorous insecticide and tested them in a rice-growing area ne...

Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations

Science.gov (United States)

Viana-Medeiros, Priscila Fernandes; Araújo, Simone Costa; Martins, Ademir J.; Lima, José Bento Pereira

2016-01-01

Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP) and pyrethroids (PY) are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR) are also employed in the control of larvae. We quantified resistance to temephos (OP), deltamethrin (PY), and diflubenzuron (IGR) of A. aegypti samples from 12 municipalities distributed throughout the country, collected between 2010 and 2012. High levels of resistance to neurotoxic insecticides were detected in almost all populations: RR95 to temephos varied between 4.0 and 27.1; the lowest RR95 to deltamethrin was 13.1, and values higher than 70.0 were found. In contrast, all samples were susceptible to diflubenzuron (RR95 < 2.3). Biochemical tests performed with larvae and adults discarded the participation of acetylcholinesterase, the OP target, and confirmed involvement of the detoxifying enzymes esterases, mixed function oxidases, and glutathione-S-transferases. The results obtained were discussed taking into account the public chemical control component and the increase in the domestic use of insecticides during dengue epidemic seasons in the evaluated municipalities. PMID:27419140

The Effect of Early Mosquito Insecticides Exposure on Spraque Dawley Rat Testis: A Histopathological Feature Towards Malignancy?

Science.gov (United States)

Indah Winarni, Tri; Auzan Aziman, Milzam; Abshar Andar, Anindyo; Pawitra, Ika

2017-02-01

The incidence of health problems associated with endocrine-disruption have increased. Many studies suggesting that endocrine disruptor chemicals (EDC) do contribute to cancer through estrogen-related receptors. Many chemicals have EDCs properties including insecticides. Early life exposure to EDCs can increased the risk of testicular cancer have been reported in the last decade. This study was aimed to determine the effect of insecticides exposure on histopathological tumor cell development of germ and Leydig cell. True experiment research design with posttest only control group design was applied. Sprague Dawley (SD) rat (n = 25) were randomly divided into 5 groups (control group, 25 mg β estradiol 3-benzoate, spiral mosquito coil repellent, 3 ml of liquid mosquito repellent, and 4 ml of liquid mosquito repellent). The exposure were administered for 20 days started at aged 3 days. At the age of 100 days (older adult), testis was stained using Hematoxyllin Eosin (HE) and histological features predicting malignancy were observed. The number of tumor cell development in both testicular germ cells and Leydig cells significantly increased in all treated group compared to those of control and the changes towards malignancy were also observed in all treated group. Exposure to mosquito insecticides causes significant changes in testicular germ and Leydig cell histological features that leads to malignancy.

International workshop on insecticide resistance in vectors of arboviruses, December 2016, Rio de Janeiro, Brazil.

Science.gov (United States)

Corbel, Vincent; Fonseca, Dina M; Weetman, David; Pinto, João; Achee, Nicole L; Chandre, Fabrice; Coulibaly, Mamadou B; Dusfour, Isabelle; Grieco, John; Juntarajumnong, Waraporn; Lenhart, Audrey; Martins, Ademir J; Moyes, Catherine; Ng, Lee Ching; Raghavendra, Kamaraju; Vatandoost, Hassan; Vontas, John; Muller, Pie; Kasai, Shinji; Fouque, Florence; Velayudhan, Raman; Durot, Claire; David, Jean-Philippe

2017-06-02

Vector-borne diseases transmitted by insect vectors such as mosquitoes occur in over 100 countries and affect almost half of the world's population. Dengue is currently the most prevalent arboviral disease but chikungunya, Zika and yellow fever show increasing prevalence and severity. Vector control, mainly by the use of insecticides, play a key role in disease prevention but the use of the same chemicals for more than 40 years, together with the dissemination of mosquitoes by trade and environmental changes, resulted in the global spread of insecticide resistance. In this context, innovative tools and strategies for vector control, including the management of resistance, are urgently needed. This report summarizes the main outputs of the first international workshop on Insecticide resistance in vectors of arboviruses held in Rio de Janeiro, Brazil, 5-8 December 2016. The primary aims of this workshop were to identify strategies for the development and implementation of standardized insecticide resistance management, also to allow comparisons across nations and across time, and to define research priorities for control of vectors of arboviruses. The workshop brought together 163 participants from 28 nationalities and was accessible, live, through the web (> 70,000 web-accesses over 3 days).

Degradation of Insecticides in Poultry Manure: Determining the Insecticidal Treatment Interval for Managing House Fly (Diptera: Muscidae) Populations in Poultry Farms.

Science.gov (United States)

Ong, Song-Quan; Ab Majid, Abdul Hafiz; Ahmad, Hamdan

2016-04-01

It is crucial to understand the degradation pattern of insecticides when designing a sustainable control program for the house fly, Musca domestica (L.), on poultry farms. The aim of this study was to determine the half-life and degradation rates of cyromazine, chlorpyrifos, and cypermethrin by spiking these insecticides into poultry manure, and then quantitatively analyzing the insecticide residue using ultra-performance liquid chromatography. The insecticides were later tested in the field in order to study the appropriate insecticidal treatment intervals. Bio-assays on manure samples were later tested at 3, 7, 10, and 15 d for bio-efficacy on susceptible house fly larvae. Degradation analysis demonstrated that cyromazine has the shortest half-life (3.01 d) compared with chlorpyrifos (4.36 d) and cypermethrin (3.75 d). Cyromazine also had a significantly greater degradation rate compared with chlorpyrifos and cypermethrin. For the field insecticidal treatment interval study, 10 d was the interval that had been determined for cyromazine due to its significantly lower residue; for ChCy (a mixture of chlorpyrifos and cypermethrin), the suggested interval was 7 d. Future work should focus on the effects of insecticide metabolites on targeted pests and the poultry manure environment.

Removal of 14C-Prothiofos Insecticide from Chamomile Oil Using Agricultural and Industrial Wastes

International Nuclear Information System (INIS)

Hegazi, B.; Abdel-Gawad, H.; Zayed, S.M.D.; Nowwar, G.A.M.

2011-01-01

The removal of prothiofos from chamomile oil has been investigated as a function of adsorbent type, adsorbent concentration, time and temperature. Therefore, 14 C-prothiofos was prepared in our laboratory. Low cost adsorbent such as agricultural wastes (Rice bran, rice husk, and watermelon peels), industrial by-products (sawdust-bagasse) in addition to calcium oxide as a chemical adsorbent were used. It was found that, the best adsorbent concentration for the insecticide removal is 0.016 g adsorbent/g oil. The maximum removal of prothiofos from chamomile oil was 87%, 90% by using calcium oxide and watermelon peels, respectively at 30 degree C for 2 hours. Saw dust, bagasse and rice bran proved to be better for the insecticide removal at 40 degree C

Insecticide mixtures could enhance the toxicity of insecticides in a resistant dairy population of Musca domestica L [corrected].

Directory of Open Access Journals (Sweden)

Hafiz Azhar Ali Khan

Full Text Available House flies, Musca domestica L., are important pests of dairy operations worldwide, with the ability to adapt wide range of environmental conditions. There are a number of insecticides used for their management, but development of resistance is a serious problem. Insecticide mixtures could enhance the toxicity of insecticides in resistant insect pests, thus resulting as a potential resistance management tool. The toxicity of bifenthrin, cypermethrin, deltamethrin, chlorpyrifos, profenofos, emamectin benzoate and fipronil were assessed separately, and in mixtures against house flies. A field-collected population was significantly resistant to all the insecticides under investigation when compared with a laboratory susceptible strain. Most of the insecticide mixtures like one pyrethroid with other compounds evaluated under two conditions (1∶1-"A" and LC50: LC50-"B" significantly increased the toxicity of pyrethroids in the field population. Under both conditions, the combination indices of pyrethroids with other compounds, in most of the cases, were significantly below 1, suggesting synergism. The enzyme inhibitors, PBO and DEF, when used in combination with insecticides against the resistant population, toxicities of bifenthrin, cypermethrin, deltamethrin and emamectin were significantly increased, suggesting esterase and monooxygenase based resistance mechanism. The toxicities of bifenthrin, cypermethrin and deltamethrin in the resistant population of house flies could be enhanced by the combination with chlorpyrifos, profenofos, emamectin and fipronil. The findings of the present study might have practical significance for resistance management in house flies.

Trends in Exposure to Chemicals in Personal Care and Consumer Products.

Science.gov (United States)

Calafat, Antonia M; Valentin-Blasini, Liza; Ye, Xiaoyun

2015-12-01

Synthetic organic chemicals can be used in personal care and consumer products. Data on potential human health effects of these chemicals are limited-sometimes even contradictory-but because several of these chemicals are toxic in experimental animals, alternative compounds are entering consumer markets. Nevertheless, limited information exists on consequent exposure trends to both the original chemicals and their replacements. Biomonitoring (measuring concentrations of chemicals or their metabolites in people) provides invaluable information for exposure assessment. We use phthalates and bisphenol A-known industrial chemicals-and organophosphate insecticides as case studies to show exposure trends to these chemicals and their replacements (e.g., other phthalates, non-phthalate plasticizers, various bisphenols, pyrethroid insecticides) among the US general population. We compare US trends to national trends from Canada and Germany. Exposure to the original compounds is still prevalent among these general populations, but exposures to alternative chemicals may be increasing.

Homology modelling of Drosophila cytochrome P450 enzymes associated with insecticide resistance.

Science.gov (United States)

Jones, Robert T; Bakker, Saskia E; Stone, Deborah; Shuttleworth, Sally N; Boundy, Sam; McCart, Caroline; Daborn, Phillip J; ffrench-Constant, Richard H; van den Elsen, Jean M H

2010-10-01

Overexpression of the cytochrome P450 gene Cyp6g1 confers resistance against DDT and a broad range of other insecticides in Drosophila melanogaster Meig. In the absence of crystal structures of CYP6G1 or complexes with its substrates, structural studies rely on homology modelling and ligand docking to understand P450-substrate interactions. Homology models are presented for CYP6G1, a P450 associated with resistance to DDT and neonicotinoids, and two other enzymes associated with insecticide resistance in D. melanogaster, CYP12D1 and CYP6A2. The models are based on a template of the X-ray structure of the phylogenetically related human CYP3A4, which is known for its broad substrate specificity. The model of CYP6G1 has a much smaller active site cavity than the template. The cavity is also 'V'-shaped and is lined with hydrophobic residues, showing high shape and chemical complementarity with the molecular characteristics of DDT. Comparison of the DDT-CYP6G1 complex and a non-resistant CYP6A2 homology model implies that tight-fit recognition of this insecticide is important in CYP6G1. The active site can accommodate differently shaped substrates ranging from imidacloprid to malathion but not the pyrethroids permethrin and cyfluthrin. The CYP6G1, CYP12D1 and CYP6A2 homology models can provide a structural insight into insecticide resistance in flies overexpressing P450 enzymes with broad substrate specificities.

Distribution and toxicity of current-use insecticides in sediment of a lake receiving waters from areas in transition to urbanization

International Nuclear Information System (INIS)

Wang Jizhong; Li Huizhen; You Jing

2012-01-01

Current-use insecticides including organophosphate (OPs) and synthetic pyrethroid (SPs) insecticides were analyzed in 35 sediment samples collected from Chaohu Lake in China, where a transition from a traditional agricultural to a modern urbanized society is ongoing. Total concentrations of five OPs and eight SPs ranged from 0.029 to 0.681 ng/g dry weight and 0.016–301 ng/g dry weight, respectively. Toxic unit analysis showed that 13% of the sediment samples likely produced over 50% of the mortality for benthic invertebrates. Analysis also showed that cypermethrin was the principal contributor to the toxicity. Spatial distribution evaluation implied that OPs were mainly from non-point sources associated with agricultural activities. Conversely, SPs may have been derived from runoff of inflowing rivers through urban regions, as their concentrations were well-correlated with concentrations of other urban-oriented contaminants. - Highlights: ► Though lower than urban sites, pyrethroid insecticides in Chaohu Lake, China may cause toxicity to benthic invertebrates. ► Concentrations of pyrethroids were well correlated with those of other urban-oriented contaminants, e.g. PAHs and LABs. ► Spatial distribution showed urban runoff was the major source of pyrethroids deposited in the lake sediment. ► Conversely, organophosphate insecticides were mainly associated with agricultural non-point sources. - Evaluation of the distribution, potential toxicity, and input sources of organophosphate and pyrethroid insecticides in sediment from Chaohu Lake, China.

Evaluation of the effectiveness of insecticide trunk injections for control of Latoia lepida (Cramer) in the sweet olive tree Osmanthus fragrans

Science.gov (United States)

Li, Yan; Shi, Xiao-Hua

2016-01-01

The screening of suitable insecticides is a key factor in successfully applying trunk injection technology to ornamental plants. In this study, six chemical pesticides were selected and injected into the trunks of Osmanthus fragrans to control the nettle caterpillar, Latoia lepida (Lepidoptera: Limacodidae), using a no-pressure injection system. The absorption rate of the insecticides, the leaf loss due to insect damage, and the mortality and frass amount of L. lepida larvae were evaluated after 77 and 429 days. The results showed that 4% imidacloprid + carbosulfan and 21% abamectin + imidacloprid + omethoate had the fastest conductivity and were completely absorbed into the trunkswithin14 days; however, the efficiencies of these insecticides in controlling L. lepidawere extremely low. Additionally, the treatment 10% emamectin benzoate + clothianidin and 2.5% emamectin benzoate was almost completely absorbed within 30 days and exhibited a longer duration of insecticide efficiency (>80% mortality) in the upper and lower leaves of the canopy. Treatment with these insecticides also resulted in significantly lower leaf loss and frass amounts. We conclude that emamectin benzoate and emamectin benzoate + clothianidin have a rapid uptake into O. fragrans, and are effective as insecticides over long durations. Hence, they may be a suitable control option for L. lepida in O. fragrans plants. PMID:27688974

Evaluation of the effectiveness of insecticide trunk injections for control of Latoia lepida (Cramer in the sweet olive tree Osmanthus fragrans

Directory of Open Access Journals (Sweden)

Jun Huang

2016-09-01

Full Text Available The screening of suitable insecticides is a key factor in successfully applying trunk injection technology to ornamental plants. In this study, six chemical pesticides were selected and injected into the trunks of Osmanthus fragrans to control the nettle caterpillar, Latoia lepida (Lepidoptera: Limacodidae, using a no-pressure injection system. The absorption rate of the insecticides, the leaf loss due to insect damage, and the mortality and frass amount of L. lepida larvae were evaluated after 77 and 429 days. The results showed that 4% imidacloprid + carbosulfan and 21% abamectin + imidacloprid + omethoate had the fastest conductivity and were completely absorbed into the trunkswithin14 days; however, the efficiencies of these insecticides in controlling L. lepidawere extremely low. Additionally, the treatment 10% emamectin benzoate + clothianidin and 2.5% emamectin benzoate was almost completely absorbed within 30 days and exhibited a longer duration of insecticide efficiency (>80% mortality in the upper and lower leaves of the canopy. Treatment with these insecticides also resulted in significantly lower leaf loss and frass amounts. We conclude that emamectin benzoate and emamectin benzoate + clothianidin have a rapid uptake into O. fragrans, and are effective as insecticides over long durations. Hence, they may be a suitable control option for L. lepida in O. fragrans plants.

Evaluation of the effectiveness of insecticide trunk injections for control of Latoia lepida (Cramer) in the sweet olive tree Osmanthus fragrans.

Science.gov (United States)

Huang, Jun; Zhang, Juan; Li, Yan; Li, Jun; Shi, Xiao-Hua

2016-01-01

The screening of suitable insecticides is a key factor in successfully applying trunk injection technology to ornamental plants. In this study, six chemical pesticides were selected and injected into the trunks of Osmanthus fragrans to control the nettle caterpillar, Latoia lepida (Lepidoptera: Limacodidae), using a no-pressure injection system. The absorption rate of the insecticides, the leaf loss due to insect damage, and the mortality and frass amount of L. lepida larvae were evaluated after 77 and 429 days. The results showed that 4% imidacloprid + carbosulfan and 21% abamectin + imidacloprid + omethoate had the fastest conductivity and were completely absorbed into the trunkswithin14 days; however, the efficiencies of these insecticides in controlling L. lepidawere extremely low. Additionally, the treatment 10% emamectin benzoate + clothianidin and 2.5% emamectin benzoate was almost completely absorbed within 30 days and exhibited a longer duration of insecticide efficiency (>80% mortality) in the upper and lower leaves of the canopy. Treatment with these insecticides also resulted in significantly lower leaf loss and frass amounts. We conclude that emamectin benzoate and emamectin benzoate + clothianidin have a rapid uptake into O. fragrans, and are effective as insecticides over long durations. Hence, they may be a suitable control option for L. lepida in O. fragrans plants.

Chemicals for crop protection and pest control

National Research Council Canada - National Science Library

Green, Maurice B; Hartley, Gilbert Spencer; West, Trustham Frederick

1977-01-01

.... For the most part, the conventional classification into insecticides, herbicides and fungicides has been followed and some more specialized chemicals are also classified according to their biological...

Insecticide resistance is mediated by multiple mechanisms in recently introduced Aedes aegypti from Madeira Island (Portugal).

Science.gov (United States)

Seixas, Gonçalo; Grigoraki, Linda; Weetman, David; Vicente, José Luís; Silva, Ana Clara; Pinto, João; Vontas, John; Sousa, Carla Alexandra

2017-07-01

Aedes aegypti is a major mosquito vector of arboviruses, including dengue, chikungunya and Zika. In 2005, Ae. aegypti was identified for the first time in Madeira Island. Despite an initial insecticide-based vector control program, the species expanded throughout the Southern coast of the island, suggesting the presence of insecticide resistance. Here, we characterized the insecticide resistance status and the underlying mechanisms of two populations of Ae. aegypti from Madeira Island, Funchal and Paúl do Mar. WHO susceptibility bioassays indicated resistance to cyfluthrin, permethrin, fenitrothion and bendiocarb. Use of synergists significantly increased mortality rates, and biochemical assays indicated elevated activities of detoxification enzymes, suggesting the importance of metabolic resistance. Microarray-based transcriptome analysis detected significant upregulation in both populations of nine cytochrome P450 oxidase genes (including four known pyrethroid metabolizing enzymes), the organophosphate metabolizer CCEae3a, Glutathione-S-transferases, and multiple putative cuticle proteins. Genotyping of knockdown resistance loci linked to pyrethroid resistance revealed fixation of the 1534C mutation, and presence with moderate frequencies of the V1016I mutation in each population. Significant resistance to three major insecticide classes (pyrethroid, carbamate and organophosphate) is present in Ae. aegypti from Madeira Island, and appears to be mediated by multiple mechanisms. Implementation of appropriate resistance management strategies including rotation of insecticides with alternative modes of action, and methods other than chemical-based vector control are strongly advised to delay or reverse the spread of resistance and achieve efficient control.

Insecticide resistance of Anopheles sinensis and An. vagus in Hainan Island, a malaria-endemic area of China.

Science.gov (United States)

Qin, Qian; Li, Yiji; Zhong, Daibin; Zhou, Ning; Chang, Xuelian; Li, Chunyuan; Cui, Liwang; Yan, Guiyun; Chen, Xiao-Guang

2014-03-03

Malaria is one of the most important public health problems in Southeast Asia, including Hainan Island, China. Vector control is the main malaria control measure, and insecticide resistance is a major concern for the effectiveness of chemical insecticide control programs. The objective of this study is to determine the resistance status of the main malaria vector species to pyrethroids and other insecticides recommended by the World Health Organization (WHO) for indoor residual sprays. The larvae and pupae of Anopheles mosquitoes were sampled from multiple sites in Hainan Island, and five sites yielded sufficient mosquitoes for insecticide susceptibility bioassays. Bioassays of female adult mosquitoes three days after emergence were conducted in the two most abundant species, Anopheles sinensis and An. vagus, using three insecticides (0.05% deltamethrin, 4% DDT, and 5% malathion) and following the WHO standard tube assay procedure. P450 monooxygenase, glutathione S-transferase and carboxylesterase activities were measured. Mutations at the knockdown resistance (kdr) gene and the ace-1 gene were detected by DNA sequencing and PCR-RFLP analysis, respectively. An. sinensis and An. vagus were the predominant Anopheles mosquito species. An. sinensis was found to be resistant to DDT and deltamethrin. An. vagus was susceptible to deltamethrin but resistant to DDT and malathion. Low kdr mutation (L1014F) frequency (P450 monooxygenase and carboxylesterase activities were detected in deltamethrin-resistant An. sinensis, and significantly higher P450 monooxygenase, glutathione S-transferase and carboxylesterase activities were found in malathion-resistant An. vagus mosquitoes. Multiple insecticide resistance was found in An. sinensis and An. vagus in Hainan Island, a malaria-endemic area of China. Cost-effective integrated vector control programs that go beyond synthetic insecticides are urgently needed.

Microbes as interesting source of novel insecticides: A review ...

African Journals Online (AJOL)

... strains with good insecticidal properties can be identified, evaluated and utilized for pest control. This paper reviews the insecticidal properties of microbes and their potential utility in pest management. Keywords: Microbes, insecticides, metabolites, pest management. African Journal of Biotechnology, Vol 13(26) 2582- ...

Mechanistic modeling of insecticide risks to breeding birds in ...

Science.gov (United States)

Insecticide usage in the United States is ubiquitous in urban, suburban, and rural environments. In evaluating data for an insecticide registration application and for registration review, scientists at the United States Environmental Protection Agency (USEPA) assess the fate of the insecticide and the risk the insecticide poses to the environment and non-target wildlife. At the present time, current USEPA risk assessments do not include population-level endpoints. In this paper, we present a new mechanistic model, which allows risk assessors to estimate the effects of insecticide exposure on the survival and seasonal productivity of birds known to use agricultural fields during their breeding season. The new model was created from two existing USEPA avian risk assessment models, the Terrestrial Investigation Model (TIM v.3.0) and the Markov Chain Nest Productivity model (MCnest). The integrated TIM/MCnest model has been applied to assess the relative risk of 12 insecticides used to control corn pests on a suite of 31 avian species known to use cornfields in midwestern agroecosystems. The 12 insecticides that were assessed in this study are all used to treat major pests of corn (corn root worm borer, cutworm, and armyworm). After running the integrated TIM/MCnest model, we found extensive differences in risk to birds among insecticides, with chlorpyrifos and malathion (organophosphates) generally posing the greatest risk, and bifenthrin and ë-cyhalothrin (

Ecdysone Agonist: New Insecticides with Novel Mode of Action

Directory of Open Access Journals (Sweden)

Y. Andi Trisyono

2002-12-01

Full Text Available Development of insect resistance to insecticide has been the major driving force for the development of new insecticides. Awareness and demand from public for more environmentally friendly insecticides have contributed in shifting the trend from using broad spectrum to selective insecticides. As a result, scientists have looked for new target sites beyond the nervous system. Insect growth regulators (IGRs are more selective insecticides than conventional insecticides, and ecdysone agonists are the newest IGRs being commercialized, e.g. tebufenozide, methoxyfenozide, and halofenozide. Ecdysone agonists bind to the ecdysteroid receptors, and they act similarly to the molting hormone 20-hydroxyecdysone. The binding provides larvae or nymphs with a signal to enter a premature and lethal molting cycle. In addition, the ecdysone agonists cause a reduction in the number of eggs laid by female insects. The ecdysone agonists are being developed as selective biorational insecticides. Tebufenozide and methoxyfenozide are used to control lepidopteran insect pests, whereas halofenozide is being used to control coleopteran insect pests. Their selectivity is due to differences in the binding affinity between these compounds to the receptors in insects from different orders. The selectivity of these compounds makes them candidates to be used in combinations with other control strategies to develop integrated pest management programs in agricultural ecosystems. Key words: new insecticides, selectivity, ecdysone agonists

Chemical weathering and loess inputs to soils in New Zealand's Wairarapa region

Science.gov (United States)

Lukens, C. E.; Norton, K. P.

2017-12-01

Geochemical mass-balance approaches are commonly used in soils to evaluate patterns in chemical weathering. In conjuction with cosmogenic nuclide measurements of total denudation or soil production, mass-balance approaches have been used to constrain rates of chemical weathering across a variety of landscapes. Here we present geochemical data from a series of soil pits in the Wairarapa region of New Zealand's North Island, where rates of soil production equal rates of total denudation measured using 10Be at sites nearby (i.e., the landscape is in steady state). Soil density increases with depth, consistent with steady weathering over the average soil residence time. However, soil geochemistry indicates very little chemical weathering has occurred, and immobile elements (Zr, Ti, and V) are depleted in soils relative to bedrock. This is contrary to the expected observation, wherein immobile elements should be enriched in soils relative to parent bedrock as weathered mobile solutes are progressively removed from soil. Our geochemical measurements suggest contributions from an exernal source, which has a different chemical composition than the underlying bedrock. We hypothesize that loess constitutes a substantial influx of additional material, and use a mixing model to predict geochemical patterns within soil columns. We evaluate the relative contributions of several likely loess sources, including tephra from the nearby Taupo Volcanic Center, local loess deposits formed during glacial-interglacial transitions, and far-travelling Australian dust. Using an established mass-balance approach with multiple immobile elements, we calculate the fraction of mass in soils contributed by loess to be as much as 25%. Combined with 10Be-derived estimates of soil production, we calculate average loess fluxes up to 320 t/km2/yr, which are consistent with previous estimates of loess acculumation over the late Holocene. Accounting for loess input, we find that chemical weathering

Effects of a herbicide-insecticide mixture in freshwater microcosms: Risk assessment and ecological effect chain

International Nuclear Information System (INIS)

Brink, Paul J. van den; Crum, Steven J.H.; Gylstra, Ronald; Bransen, Fred; Cuppen, Jan G.M.; Brock, Theo C.M.

2009-01-01

Effects of chronic application of a mixture of the herbicide atrazine and the insecticide lindane were studied in indoor freshwater plankton-dominated microcosms. The macroinvertebrate community was seriously affected at all but the lowest treatment levels, the zooplankton community at the three highest treatment levels, with crustaceans, caddisflies and dipterans being the most sensitive groups. Increased abundance of the phytoplankton taxa Cyclotella sp. was found at the highest treatment level. Threshold levels for lindane, both at population and community level, corresponded well with those reported in the literature. Atrazine produced fewer effects than expected, probably due to decreased grazer stress on the algae as a result of the lindane application. The safety factors set by the Uniform Principles for individual compounds were also found to ensure protection against chronic exposure to a mixture of a herbicide and insecticide at community level, though not always at the population level. - Effects of chronic application of a herbicide-insecticide mixture were studied in indoor freshwater plankton-dominated microcosms. Effects could well be explained by the effects of the individual chemicals alone, no synergetic effects were reported

Insecticide Resistance Reducing Effectiveness of Malaria Control

Centers for Disease Control (CDC) Podcasts

Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field.

Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti: a case study in Martinique Island (French West Indies).

Science.gov (United States)

Marcombe, Sébastien; Poupardin, Rodolphe; Darriet, Frederic; Reynaud, Stéphane; Bonnet, Julien; Strode, Clare; Brengues, Cecile; Yébakima, André; Ranson, Hilary; Corbel, Vincent; David, Jean-Philippe

2009-10-26

The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies). Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71%) of the sodium channel 'knock down resistance' (kdr) mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT-PCR. These results suggest that the high level of

Insecticide resistance in the West African malaria vector Anopheles gambiae and investigation of alternative tools for its delay

NARCIS (Netherlands)

N'Guessan, R.

2009-01-01

There is a current policy to eliminate malaria in the African continent. Pyrethroid-incorporated Long Lasting Insecticidal Nets (LLINs) and/or Indoor Residual Spraying (IRS) are the chemical weapons being deployed to achieve that goal. Rather worryingly, resistance to pyrethroids is well documented

Plant Essential Oils from Apiaceae Family as Alternatives to Conventional Insecticides

Directory of Open Access Journals (Sweden)

Asgar Ebadollahi

2013-06-01

Full Text Available Main method to control insect pest is using synthetic insecticides, but the development of insect resistance to this products, the high operational cost, environmental pollution, toxicity to humans and harmful effect on non-target organisms have created the need for developing alternative approaches to control insect pest. Furthermore, the demand for organic crops, especially vegetables for the fresh market, has greatly increased worldwide. The ideal insecticide should control target pests adequately and should be target-specific, rapidly degradable, and low in toxicity to humans and other mammals. Plant essential oils could be an alternative source for insect pest control because they constitute a rich source of bioactive chemicals and are commonly used as flavoring agents in foods. These materials may be applied to food crops shortly before harvest without leaving excessive residues. Moreover, medically safe of these plant derivatives has emphasized also. For these reasons, much effort has been focused on plant essential oils or their constituents as potential sources of insect control agents. In this context, Apiaceae (Umbelliferae family would rank among the most important families of plants. In the last few years more and more studies on the insecticidal properties of essential oils from Apiaceae family have been published and it seemed worthwhile to compile them. The focus of this review lies on the lethal (ovicidal, larvicidal, pupicidal and adulticidal and sublethal (antifeedant, repellent, oviposition deterrent, Growth inhibitory and progeny production activities of plant essential oils and theirmain components from Apiaceae family. These features indicate that pesticides based on Apiaceae essential oils could be used in a variety of ways to control a large number of pests. It can be concluded that essential oils and phytochemicals isolated from Apiaceae family may be efficacious and safe replacements for conventional synthetic

Effect of selected insecticides on SF9 insect cell line

International Nuclear Information System (INIS)

Saleh, M.; Rahmo, A.; Hajjar, J.

2013-01-01

The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3- (4,5- dimethylthiazol - 2-yl) - 2,5 - diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC 20). The IC 20 values obtained for deltamethrin, acetamipridand dimethoate were: 46.8, 61.6 and 68.9 μM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides. (author)

Susceptibility of Sogatella furcifera and Laodelphax striatellus (Hemiptera: Delphacidae) to Six Insecticides in China.

Science.gov (United States)

Zhang, Kai; Zhang, Wei; Zhang, Shuai; Wu, Shun-Fan; Ban, Lan-Feng; Su, Jian-Ya; Gao, Cong-Fen

2014-10-01

The whitebacked planthopper, Sogatella furcifera (Horváth), and small brown planthopper, Laodelphax striatellus (Fallén), both are important crop pests throughout China, especially in rice. Application of chemical insecticides is the major control practice. Consequently, insecticide resistance has become an urgent issue. In this study, resistance levels to six conventional insecticides were evaluated for these two species collected from major occurring areas of China. Additionally, imidacloprid- (resistance ratio [RR] = 10.4-fold) and buprofezin (RR = 15.1-fold)-resistant strains of whitebacked planthopper were obtained through laboratory selections for cross-resistance profiling and synergism assessment to understand resistance mechanisms. The results showed that all tested populations of both species exhibited low to high levels of resistance to chlorpyrifos, while remaining susceptible to thiamethoxam. Three of the 14 whitebacked planthopper populations showed low to moderate resistance to imidacloprid, while all small brown planthopper populations reminded susceptible. All small brown planthopper and whitebacked planthopper (except one) populations showed at least moderate resistance (RR = 10.1-271.1) to buprofezin. All small brown planthopper populations remained susceptible to pymetrozine and nitenpyram, and all whitebacked planthopper populations remained susceptible to isoprocarb. The imidacloprid-resistant whitebacked planthopper strain showed no significant cross-resistance to other tested insecticides. However, the buprofezin-resistant strain exhibited a low-level cross-resistance (CR = 3.1) to imidacloprid. Piperonyl butoxide, triphenyl phosphate, and diethylmaleate displayed no synergism effect on the resistant whitebacked planthopper strains. © 2014 Entomological Society of America.

Toxicity and sublethal effects of seven insecticides to eggs of the flower bug Orius insidiosus (Say) (Hemiptera: Anthocoridae).

Science.gov (United States)

Moscardini, Valéria Fonseca; Gontijo, Pablo da Costa; Carvalho, Geraldo Andrade; Oliveira, Rodrigo Lopes de; Maia, Jader Braga; Silva, Fernanda Fonseca e

2013-07-01

The predatory bug Orius insidiosus is an important biological control agent of several insect pests, and is one of the most commonly used species in biological control programs worldwide. This study assessed the lethal and sublethal effects of insecticides on this species through life table, and classified the insecticides according to the definitions of toxicity given by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). A bioassay was carried out using a completely randomized design with eight treatments and 40 replicates. Eggs of O. insidiosus laid naturally in plant stems were immersed in aqueous solutions of the chemical products. Egg viability, duration of the embryonic period, survival of nymphs, and duration of the nymphal period were assessed daily. Insects that reached adulthood were paired and their reproduction assessed. The number of eggs produced and the survival of adults were assessed daily. The insecticides abamectin, cartap hydrochloride, spirotetramat+imidacloprid, and flubendiamid were classified as harmful. Pyriproxyfen and rynaxypyr were categorized as harmless and pymetrozine was classified as slightly harmful. Pyriproxyfen affected the population parameters rm, GT, DT, and λ, whereas other insecticides did not. Copyright © 2013 Elsevier Ltd. All rights reserved.

Insecticide resistance in two Aedes aegypti (Diptera: Culicidae) strains from Costa Rica.

Science.gov (United States)

Bisset, J A; Marín, R; Rodríguez, M M; Severson, D W; Ricardo, Y; French, L; Díaz, M; Pérez, O

2013-03-01

Dengue (family Flaviridae, genus Flavivirus, DENV) and dengue hemorrhagic fever (DHF) are presently important public health problems in Costa Rica. The primary strategy for disease control is based on reducing population densities of the main mosquito vector Aedes aegypti (L.) (Diptera: Culicidae). This is heavily dependent on use of chemical insecticides, thus the development of resistance is a frequent threat to control program effectiveness. The objective of this study was to determine the levels of insecticide resistance and the metabolic resistance mechanisms involved in two Ae. aegypti strains collected from two provinces (Puntarenas and Limon) in Costa Rica. Bioassays with larvae were performed according to World Health Organization guidelines and resistance in adults was measured through standard bottle assays. The activities of beta-esterases, cytochrome P450 monooxygenases, and glutathione S-transferases (GST), were assayed through synergists and biochemical tests, wherein the threshold criteria for each enzyme was established using the susceptible Rockefeller strain. The results showed higher resistance levels to the organophosphate (OP) temephos and the pyrethroid deltamethrin in larvae. The efficacy of commercial formulations of temephos in controlling Ae. aegypti populations was 100% mortality up to 11 and 12 d posttreatment with daily water replacements in test containers. Temephos and deltamethrin resistance in larvae were associated with high esterase activity, but not to cytochrome P450 monooxygenase or GST activities. Adult mosquitoes were resistant to deltamethrin, and susceptible to bendiocarb, chlorpyrifos, and cypermethrin. Because temephos and deltamethrin resistance are emerging at the studied sites, alternative insecticides should be considered. The insecticides chlorpyrifos and cypermethrin could be good candidates to use as alternatives for Ae. aegypti control.

Bacillus thuringiensis monogenic strains: screening and interactions with insecticides used against rice pests

Science.gov (United States)

Pinto, Laura M.N.; Dörr, Natália C.; Ribeiro, Ana Paula A.; de Salles, Silvia M.; de Oliveira, Jaime V.; Menezes, Valmir G.; Fiuza, Lidia M.

2012-01-01

The screening of Bacillus thuringiensis (Bt) Cry proteins with high potential to control insect pests has been the goal of numerous research groups. In this study, we evaluated six monogenic Bt strains (Bt dendrolimus HD-37, Bt kurstaki HD-1, Bt kurstaki HD-73, Bt thuringiensis 4412, Bt kurstaki NRD-12 and Bt entomocidus 60.5, which codify the cry1Aa, cry1Ab, cry1Ac, cry1Ba, cry1C, cry2A genes respectively) as potential insecticides for the most important insect pests of irrigated rice: Spodoptera frugiperda, Diatraea saccharalis, Oryzophagus oryzae, Oebalus poecilus and Tibraca limbativentris. We also analyzed their compatibility with chemical insecticides (thiamethoxam, labdacyhalothrin, malathion and fipronil), which are extensively used in rice crops. The bioassay results showed that Bt thuringiensis 4412 and Bt entomocidus 60.5 were the most toxic for the lepidopterans, with a 93% and 82% mortality rate for S. frugiperda and D. saccharalis, respectively. For O. oryzae, the Bt kurstaki NRD-12 (64%) and Bt dendrolimus HD-37 (62%) strains were the most toxic. The Bt dendrolimus HD-37 strain also caused high mortality (82%) to O. poecilus, however the strains assessed to T. limbativentris caused a maximum rate of 5%. The assays for the Bt strains interaction with insecticides revealed the compatibility of the six strains with the four insecticides tested. The results from this study showed the high potential of cry1Aa and cry1Ba genes for genetic engineering of rice plants or the strains to biopesticide formulations. PMID:24031872

Comparison of Insecticide Susceptibilities of Empoasca vitis (Hemiptera: Cicadellidae) from Three Main Tea-Growing Regions in China.

Science.gov (United States)

Wei, Qi; Yu, Hua-Yang; Niu, Chun-Dong; Yao, Rong; Wu, Shun-Fan; Chen, Zhuo; Gao, Cong-Fen

2015-06-01

Empoasca vitis (Göthe) is an important insect pest in tea-growing areas of China, and chemical control is the main tactic for the management of this pest. Due to the pressure of increasing insecticide resistance and more stringent food safety regulations, development of sound IPM strategies for E. vitis is an urgent matter. This study comparatively evaluated four field populations of E. vitis from three different tea-growing regions in China for their susceptibilities to eight insecticides using a simple leaf-dip methodology. E. vitis was found to be most sensitive to indoxacarb (LC505 mg/liter) and sophocarpidine (LC50>95 mg/liter, a botanical pesticide) regardless of populations. Population (geographical) variations were higher for indoxacarb and imidacloprid than other compounds. Judging by the 95% fiducial limits of LC50 values, all populations had similar susceptibilities to chlorfenapyr, bifenthrin, and acetamiprid or imidacloprid. Correlation analysis suggested that chlorfenapyr and indoxacarb or isoprocarb may have a high risk of cross resistance. Considering potency (LC50) and maximum residual levels, chlorfenapyr and bifenthrin are good insecticide options followed by acetamiprid and indoxacarb. These results provide valuable information to intelligently select insecticides for IPM programs that are efficacious against E. vitis while also managing insecticide resistance and maximum residual levels for tea production in China. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Insecticidal Activity of Tanacetum parthenium (L.) Schultz Bip. Extracts Obtained by Supercritical Fluid Extraction and Hydrodistillation

Czech Academy of Sciences Publication Activity Database

Pavela, R.; Sajfrtová, Marie; Sovová, Helena; Bárnet, M.; Karban, Jindřich

2010-01-01

Roč. 31, č. 3 (2010), s. 449-454 ISSN 0926-6690 R&D Projects: GA MŠk 2B06049 Institutional research plan: CEZ:AV0Z40720504 Keywords : botanical insecticides * spodoptera littoralis * tanacetum parthenium Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.507, year: 2010

Insecticide-driven patterns of genetic variation in the dengue vector Aedes aegypti in Martinique Island.

Directory of Open Access Journals (Sweden)

Sébastien Marcombe

Full Text Available Effective vector control is currently challenged worldwide by the evolution of resistance to all classes of chemical insecticides in mosquitoes. In Martinique, populations of the dengue vector Aedes aegypti have been intensively treated with temephos and deltamethrin insecticides over the last fifty years, resulting in heterogeneous levels of resistance across the island. Resistance spreading depends on standing genetic variation, selection intensity and gene flow among populations. To determine gene flow intensity, we first investigated neutral patterns of genetic variability in sixteen populations representative of the many environments found in Martinique and experiencing various levels of insecticide pressure, using 6 microsatellites. Allelic richness was lower in populations resistant to deltamethrin, and consanguinity was higher in populations resistant to temephos, consistent with a negative effect of insecticide pressure on neutral genetic diversity. The global genetic differentiation was low, suggesting high gene flow among populations, but significant structure was found, with a pattern of isolation-by-distance at the global scale. Then, we investigated adaptive patterns of divergence in six out of the 16 populations using 319 single nucleotide polymorphisms (SNPs. Five SNP outliers displaying levels of genetic differentiation out of neutral expectations were detected, including the kdr-V1016I mutation in the voltage-gated sodium channel gene. Association tests revealed a total of seven SNPs associated with deltamethrin resistance. Six other SNPs were associated with temephos resistance, including two non-synonymous substitutions in an alkaline phosphatase and in a sulfotransferase respectively. Altogether, both neutral and adaptive patterns of genetic variation in mosquito populations appear to be largely driven by insecticide pressure in Martinique.

Botanical insecticides in controlling Kelly's citrus thrips (Thysanoptera: Thripidae) on organic grapefruits.

Science.gov (United States)

Vassiliou, V A

2011-12-01

Kelly's citrus thrips, Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) was first recorded in Cyprus in 1996 and became an economic citrus pest. In Cyprus, Kelly's citrus thrips larvae cause feeding damage mainly on immature lemon and grapefruit fruits. Use of botanical insecticides is considered an alternative tool compared with synthetic chemicals, in offering solutions for healthy and sustainable citrus production. During 2008-2010, the efficacy of the botanical insecticides azadirachtin (Neemex 0.3%W/W and Oikos 10 EC), garlic extract (Alsa), and pyrethrins (Vioryl 5%SC) was evaluated in field trials against Kelly's citrus thrips larval stage I and II aiming at controlling the pest's population and damage to organic grapefruit fruits. In each of the trial years treatments with pyrethrins and azadirachtin (Neemex 0.3%W/W) were the most effective against Kelly's citrus thrips compared with the untreated control (for 2008: P extract showed the lowest effect from all the botanicals used compared with the untreated control.

An insecticidal toxin from Nephila clavata spider venom.

Science.gov (United States)

Jin, Lin; Fang, Mingqian; Chen, Mengrou; Zhou, Chunling; Ombati, Rose; Hakim, Md Abdul; Mo, Guoxiang; Lai, Ren; Yan, Xiuwen; Wang, Yumin; Yang, Shilong

2017-07-01

Spiders are the most successful insect predators given that they use their venom containing insecticidal peptides as biochemical weapons for preying. Due to the high specificity and potency of peptidic toxins, discoveries of insecticidal toxins from spider venom have provided an opportunity to obtain natural compounds for agricultural applications without affecting human health. In this study, a novel insecticidal toxin (μ-NPTX-Nc1a) was identified and characterized from the venom of Nephila clavata. Its primary sequence is GCNPDCTGIQCGWPRCPGGQNPVMDKCVSCCPFCPPKSAQG which was determined by automated Edman degradation, cDNA cloning, and MS/MS analysis. BLAST search indicated that Nc1a shows no similarity with known peptides or proteins, indicating that Nc1a belongs to a novel family of insecticidal peptide. Nc1a displayed inhibitory effects on Na V and K V channels in cockroach dorsal unpaired median neurons. The median lethal dose (LD50) of Nc1a on cockroach was 573 ng/g. Herein, a study that identifies a novel insecticidal toxin, which can be a potential candidate and/or template for the development of bioinsecticides, is presented.

Sensitivity of Bemisia Tabaci (Hemiptera: Aleyrodidae) to Several New Insecticides in China: Effects of Insecticide Type and Whitefly Species, Strain, and Stage

Science.gov (United States)

Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

2014-01-01

Abstract Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC 50 values were higher for Lab-Q than for Lab-B; avermectin LC 50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. PMID:25434040

Insecticides suppress natural enemies and increase pest damage in cabbage.

Science.gov (United States)

Bommarco, Riccardo; Miranda, Freddy; Bylund, Helena; Björkman, Christer

2011-06-01

Intensive use of pesticides is common and increasing despite a growing and historically well documented awareness of the costs and hazards. The benefits from pesticides of increased yields from sufficient pest control may be outweighed by developed resistance in pests and killing of beneficial natural enemies. Other negative effects are human health problems and lower prices because of consumers' desire to buy organic products. Few studies have examined these trade-offs in the field. Here, we demonstrate that Nicaraguan cabbage (Brassica spp.) farmers may suffer economically by using insecticides as they get more damage by the main pest diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), at the same time as they spend economic resources on insecticides. Replicated similarly sized cabbage fields cultivated in a standardized manner were either treated with insecticides according common practice or not treated with insecticides over two seasons. Fields treated with insecticides suffered, compared with nontreated fields, equal or, at least in some periods of the seasons, higher diamondback moth pest attacks. These fields also had increased leaf damage on the harvested cabbage heads. Weight and size of the heads were not affected. The farmers received the same price on the local market irrespective of insecticide use. Rates of parasitized diamondback moth were consistently lower in the treated fields. Negative effects of using insecticides against diamondback moth were found for the density of parasitoids and generalist predatory wasps, and tended to affect spiders negatively. The observed increased leaf damages in insecticide-treated fields may be a combined consequence of insecticide resistance in the pest, and of lower predation and parasitization rates from naturally occurring predators that are suppressed by the insecticide applications. The results indicate biological control as a viable and economic alternative pest management strategy

Protective effect and economic impact of insecticide application methods on barley

Directory of Open Access Journals (Sweden)

Alfred Stoetzer

2014-03-01

Full Text Available The objective of this work was to evaluate the protective effect of different forms of insecticide application on the transmission of yellow dwarf disease in barley cultivars, as well as to determine the production costs and the net profit of these managements. The experiments were carried out during 2011 and 2012 growing seasons, using the following managements at main plots: T1, seed treatment with insecticide (ST + insecticide on shoots at 15-day interval; T2, just ST; T3, insecticide applied on shoots, when aphid control level (CL was reached; T4, without insecticide; and T5, ST + insecticide on shoots when CL was reached. Different barley cultivars - BRS Cauê, BRS Brau and MN 6021 - were arranged in the subplots. Insecticides lambda cyhalothrin (pyrethroid and thiamethoxam (neonicotinoid were used. There were differences on yellow dwarf disease index in both seasons for the different treatments, while damage to grain yield was influenced by year and aphid population. Production costs and net profit were different among treatments. Seed treatment with insecticide is sufficient to reduce the transmission of yellow dwarf disease in years with low aphid population pressure, while in years with larger populations, the application of insecticide on shoots is also required.

Leaching of 14 C-endosulfan insecticide in soils from Sao Paulo State, Brazil

International Nuclear Information System (INIS)

Tornisielo, V.L.; Costa, M.A.; Furlan, G.R.; Pinho, R.S.

1995-01-01

Leaching of 14 C-endosulfan insecticide was studied in soil columns for three soils of Sao Paulo State with different physical-chemical properties. A water flux of 0.41 ml/min., was established, simulating a pluviometric precipitation of 200 mm in 48 h. For all soils, an average of 78% of the total applied was retained in the first centimeters of the soil profile. As expected, the soil with the lowest soil organic matter and clay contents (sandy soil), was the soil with the largest amount of the insecticide leached. The higher the organic matter and the organic matter content of a soil, the higher its sorption and consequently there is less available in soil solution to be leached. In all soils, however, the amount of endosulfan found in the leachate was low, being 0.17% the maximum radioactivity measured. (author). 5 refs, 3 tabs

Amplification of a cytochrome P450 gene is associated with resistance to neonicotinoid insecticides in the aphid Myzus persicae.

Science.gov (United States)

Puinean, Alin M; Foster, Stephen P; Oliphant, Linda; Denholm, Ian; Field, Linda M; Millar, Neil S; Williamson, Martin S; Bass, Chris

2010-06-24

The aphid Myzus persicae is a globally significant crop pest that has evolved high levels of resistance to almost all classes of insecticide. To date, the neonicotinoids, an economically important class of insecticides that target nicotinic acetylcholine receptors (nAChRs), have remained an effective control measure; however, recent reports of resistance in M. persicae represent a threat to the long-term efficacy of this chemical class. In this study, the mechanisms underlying resistance to the neonicotinoid insecticides were investigated using biological, biochemical, and genomic approaches. Bioassays on a resistant M. persicae clone (5191A) suggested that P450-mediated detoxification plays a primary role in resistance, although additional mechanism(s) may also contribute. Microarray analysis, using an array populated with probes corresponding to all known detoxification genes in M. persicae, revealed constitutive over-expression (22-fold) of a single P450 gene (CYP6CY3); and quantitative PCR showed that the over-expression is due, at least in part, to gene amplification. This is the first report of a P450 gene amplification event associated with insecticide resistance in an agriculturally important insect pest. The microarray analysis also showed over-expression of several gene sequences that encode cuticular proteins (2-16-fold), and artificial feeding assays and in vivo penetration assays using radiolabeled insecticide provided direct evidence of a role for reduced cuticular penetration in neonicotinoid resistance. Conversely, receptor radioligand binding studies and nucleotide sequencing of nAChR subunit genes suggest that target-site changes are unlikely to contribute to resistance to neonicotinoid insecticides in M. persicae.

Insecticidal potency of RNAi-based catalase knockdown in Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae).

Science.gov (United States)

Al-Ayedh, Hassan; Rizwan-Ul-Haq, Muhammad; Hussain, Abid; Aljabr, Ahmed M

2016-11-01

Palm trees around the world are prone to notorious Rhynchophorus ferrugineus, which causes heavy losses of palm plantations. In Middle Eastern countries, this pest is a major threat to date palm orchards. Conventional pest control measures with the major share of synthetic insecticides have resulted in insect resistance and environmental issues. Therefore, in order to explore better alternatives, the RNAi approach was employed to knock down the catalase gene in fifth and tenth larval instars with different dsRNA application methods, and their insecticidal potency was studied. dsRNA of 444 bp was prepared to knock down catalase in R. ferrugineus. Out of the three dsRNA application methods, dsRNA injection into larvae was the most effective, followed by dsRNA application by artificial feeding. Both methods resulted in significant catalase knockdown in various tissues, especially the midgut. As a result, the highest growth inhibition of 123.49 and 103.47% and larval mortality of 80 and 40% were observed in fifth-instar larvae, whereas larval growth inhibition remained at 86.83 and 69.08% with larval mortality at 30 and 10% in tenth-instar larvae after dsRNA injection and artificial diet treatment. The topical application method was the least efficient, with the lowest larval growth inhibition of 57.23 and 45.61% and 0% mortality in fifth- and tenth-instar larvae. Generally, better results were noted at the high dsRNA dose of 5 µL. Catalase enzyme is found in most insect body tissues, and thus its dsRNA can cause broad-scale gene knockdown within the insect body, depending upon the application method. Significant larval mortality and growth inhibition after catalase knockdown in R. ferrugineus confirms its insecticidal potency and suggests a bright future for RNAi-based bioinsecticides in pest control. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

In silico models for predicting vector control chemicals targeting Aedes aegypti

Science.gov (United States)

Devillers, J.; Lagneau, C.; Lattes, A.; Garrigues, J.C.; Clémenté, M.M.; Yébakima, A.

2014-01-01

Human arboviral diseases have emerged or re-emerged in numerous countries worldwide due to a number of factors including the lack of progress in vaccine development, lack of drugs, insecticide resistance in mosquitoes, climate changes, societal behaviours, and economical constraints. Thus, Aedes aegypti is the main vector of the yellow fever and dengue fever flaviviruses and is also responsible for several recent outbreaks of the chikungunya alphavirus. As for the other mosquito species, the A. aegypti control relies heavily on the use of insecticides. However, because of increasing resistance to the different families of insecticides, reduction of Aedes populations is becoming increasingly difficult. Despite the unquestionable utility of insecticides in fighting mosquito populations, there are very few new insecticides developed and commercialized for vector control. This is because the high cost of the discovery of an insecticide is not counterbalanced by the ‘low profitability’ of the vector control market. Fortunately, the use of quantitative structure–activity relationship (QSAR) modelling allows the reduction of time and cost in the discovery of new chemical structures potentially active against mosquitoes. In this context, the goal of the present study was to review all the existing QSAR models on A. aegypti. The homology and pharmacophore models were also reviewed. Specific attention was paid to show the variety of targets investigated in Aedes in relation to the physiology and ecology of the mosquito as well as the diversity of the chemical structures which have been proposed, encompassing man-made and natural substances. PMID:25275884

Comparative field evaluation of some newer versus conventional insecticides for the control of aphids (homoptera: aphididae) on oilseed rape (brassica napus l.)

International Nuclear Information System (INIS)

Sarwar, M.; Ahmad, N.; Bux, M.; Nasrullah, A.; Tofique, M.

2011-01-01

This study was designed to evaluate the effects of new insecticides like, Imidacloprid (Confidor 200 EC), Thiomethoxam (Actara 25 WG) and Acetamiprid (Megamos 20 SL) belonging to Nitroguanidine group along with conventional insecticides such as, Chlorpyrifos (Lorsban 40 EC) and Dimethoate (Systoate 40 EC) belonging to Organophosphate group against aphids' population on oilseed rape (Brassica napus L.). A perusal of data, based on the overall performance of the test compounds, reflected that newer insecticides were superior in reducing the population of aphids and yield enhancement as compared to conventional insecticides. The best results were achieved with the application of Imidacloprid by recording the lowest number of aphids (2.2 per plant) than obtained with Thiomethoxam and Acetamiprid (3.22 and 4.66, respectively). Other insecticides, viz., Chlorpyrifos and Dimethoate were also found to be effective in maintaining the aphids' population at lower levels per plant (16.2 and 17.5, respectively) over untreated control (227.7). Imidacloprid was responsible for increasing the grain yield to 3722.85 Kg per Hectare, approached by Thiomethoxam, Acetamiprid, Chlorpyrifos and Dimethoate as against unsprayed control (2980.0, 2542.85, 1542.85, 540.0 and 604.85 Kg per Hectare, respectively). Study indicated that selective use of newer insecticides would seem a reasonable strategy in aphids controlling and integration of such chemicals in insects' management package could help to reduce pest densities. (author)

Machine learning for toxicity characterization of organic chemical emissions using USEtox database: Learning the structure of the input space.

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Marvuglia, Antonino; Kanevski, Mikhail; Benetto, Enrico

2015-10-01

Toxicity characterization of chemical emissions in Life Cycle Assessment (LCA) is a complex task which usually proceeds via multimedia (fate, exposure and effect) models attached to models of dose-response relationships to assess the effects on target. Different models and approaches do exist, but all require a vast amount of data on the properties of the chemical compounds being assessed, which are hard to collect or hardly publicly available (especially for thousands of less common or newly developed chemicals), therefore hampering in practice the assessment in LCA. An example is USEtox, a consensual model for the characterization of human toxicity and freshwater ecotoxicity. This paper places itself in a line of research aiming at providing a methodology to reduce the number of input parameters necessary to run multimedia fate models, focusing in particular to the application of the USEtox toxicity model. By focusing on USEtox, in this paper two main goals are pursued: 1) performing an extensive exploratory analysis (using dimensionality reduction techniques) of the input space constituted by the substance-specific properties at the aim of detecting particular patterns in the data manifold and estimating the dimension of the subspace in which the data manifold actually lies; and 2) exploring the application of a set of linear models, based on partial least squares (PLS) regression, as well as a nonlinear model (general regression neural network--GRNN) in the seek for an automatic selection strategy of the most informative variables according to the modelled output (USEtox factor). After extensive analysis, the intrinsic dimension of the input manifold has been identified between three and four. The variables selected as most informative may vary according to the output modelled and the model used, but for the toxicity factors modelled in this paper the input variables selected as most informative are coherent with prior expectations based on scientific knowledge

Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti: a case study in Martinique Island (French West Indies

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Yébakima André

2009-10-01

Full Text Available Abstract Background The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. Results The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies. Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71% of the sodium channel 'knock down resistance' (kdr mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT

Sensitivity of Bemisia tabaci (Hemiptera: Aleyrodidae) to several new insecticides in China: effects of insecticide type and whitefly species, strain, and stage.

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Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

2014-01-01

Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Metabolic resistance in Nilaparvata lugens to etofenprox, a non-ester pyrethroid insecticide.

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Sun, Huahua; Yang, Baojun; Zhang, Yixi; Liu, Zewen

2017-03-01

Etofenprox, a non-ester pyrethroid insecticide, will be registered to control rice pests such as the brown planthopper (BPH, Nilaparvata lugens Stål) in mainland China. Insecticide resistance is always a problem to the effective control of N. lugens by chemical insecticides. An etofenprox resistance selection of N. lugens was performed in order to understand the related mechanisms. Through successive selection by etofenprox for 16 generations in the laboratory, an etofenprox-resistant strain (G16) with the resistance ratio (RR) of 422.3-fold was obtained. The resistance was partly synergised (2.68-fold) with the metabolic inhibitor PBO, suggesting a role for P450 monooxygenases. In this study, 11 P450 genes were significantly up-regulated in G16, among which eight genes was above 2.0-fold higher than that in US16, a population with the same origin of G16 but without contacting any insecticide in the laboratory. The expression level of four genes (CYP6AY1, CYP6FU1 and CYP408A1 from Clade 3, and CYP425A1 from Clade 4) were above 4.0-fold when compared to US16. RNA interference (RNAi) was performed to evaluate the importance of the selected P450s in etofenprox resistance. When CYP6FU1, CYP425A1 or CYP6AY1 was interfered, the susceptibility was significantly recovered in both G16 and US16, while the knockdown of CYP408A1 or CYP353D1 did not cause significant changes in etofenprox susceptibility. We supposed that CYP6FU1 was the most important P450 member for etofenprox resistance because of the highest expression level and the most noticeable effects on resistance ratios following RNAi. Copyright © 2016 Elsevier Inc. All rights reserved.

Insecticides promote viral outbreaks by altering herbivore competition.

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Pan, Huipeng; Preisser, Evan L; Chu, Dong; Wang, Shaoli; Wu, Qingjun; Carriére, Yves; Zhou, Xuguo; Zhang, Youjun

2015-09-01

While the management of biological invasions is often characterized by a series of single-specieg decisions, invasive species exist within larger food webs. These biotic interactions can alter the impact of control/eradication programs and may cause suppression efforts to inadvertently facilitate invasion spread and impact. We document the rapid replacement of the invasive Bemisia Middle East-Asia Minor I (MEAM1) cryptic biotype by the cryptic Mediterranean (MED) biotype throughout China and demonstrate that MED is more tolerant of insecticides and a better vector of tomato yellow leaf curl virus (TYLCV) than MEAMJ. While MEAM1 usually excludes MED under natural conditions, insecticide application reverses the MEAM1-MED competitive hierarchy and allows MED to exclude MEAMI. The insecticide-mediated success of MED has led to TYLCV outbreaks throughout China. Our work strongly supports the hypothesis that insecticide use in China reverses the MEAMl-MED competitive hierarchy and allows MED to displace MEAM1 in managed landscapes. By promoting the dominance of a Bemisia species that is a competent viral vector, insecticides thus increase the spread and impact of TYLCV in heterogeneous agroecosystems.

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

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Jairo Campos

2003-08-01

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

Insecticide resistance in the dengue vector Aedes aegypti from Martinique: distribution, mechanisms and relations with environmental factors.

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Marcombe, Sébastien; Mathieu, Romain Blanc; Pocquet, Nicolas; Riaz, Muhammad-Asam; Poupardin, Rodolphe; Sélior, Serge; Darriet, Frédéric; Reynaud, Stéphane; Yébakima, André; Corbel, Vincent; David, Jean-Philippe; Chandre, Fabrice

2012-01-01

Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control interventions. In this study, we investigated the distribution of resistance and the underlying mechanisms in nine Ae. aegypti populations. Statistical multifactorial approach was used to investigate the correlations between insecticide resistance levels, associated mechanisms and environmental factors characterizing the mosquito populations. Bioassays revealed high levels of resistance to temephos and deltamethrin and susceptibility to Bti in the 9 populations tested. Biochemical assays showed elevated detoxification enzyme activities of monooxygenases, carboxylesterases and glutathione S-tranferases in most of the populations. Molecular screening for common insecticide target-site mutations, revealed the presence of the "knock-down resistance" V1016I Kdr mutation at high frequency (>87%). Real time quantitative RT-PCR showed the potential involvement of several candidate detoxification genes in insecticide resistance. Principal Component Analysis (PCA) performed with variables characterizing Ae. aegypti from Martinique permitted to underline potential links existing between resistance distribution and other variables such as agriculture practices, vector control interventions and urbanization. Insecticide resistance is widespread but not homogeneously distributed across Martinique. The influence of environmental and operational factors on the evolution of the resistance and mechanisms are discussed.

Insecticide resistance in the dengue vector Aedes aegypti from Martinique: distribution, mechanisms and relations with environmental factors.

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Sébastien Marcombe

Full Text Available Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies. The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control interventions. In this study, we investigated the distribution of resistance and the underlying mechanisms in nine Ae. aegypti populations. Statistical multifactorial approach was used to investigate the correlations between insecticide resistance levels, associated mechanisms and environmental factors characterizing the mosquito populations. Bioassays revealed high levels of resistance to temephos and deltamethrin and susceptibility to Bti in the 9 populations tested. Biochemical assays showed elevated detoxification enzyme activities of monooxygenases, carboxylesterases and glutathione S-tranferases in most of the populations. Molecular screening for common insecticide target-site mutations, revealed the presence of the "knock-down resistance" V1016I Kdr mutation at high frequency (>87%. Real time quantitative RT-PCR showed the potential involvement of several candidate detoxification genes in insecticide resistance. Principal Component Analysis (PCA performed with variables characterizing Ae. aegypti from Martinique permitted to underline potential links existing between resistance distribution and other variables such as agriculture practices, vector control interventions and urbanization. Insecticide resistance is widespread but not homogeneously distributed across Martinique. The influence of environmental and operational factors on the evolution of the resistance and mechanisms are discussed.

Repellant and insecticidal activities of shyobunone and isoshyobunone derived from the essential oil of Acorus calamus rhizomes.

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Chen, Hai-Ping; Yang, Kai; Zheng, Li-Shi; You, Chun-Xue; Cai, Qian; Wang, Cheng-Fang

2015-01-01

It was found that the essential oil of Acorus calamus rhizomes showed insecticidal activity. The aim of this study was to determine the chemical composition of the essential oil from A. calamus rhizomes, evaluate insecticidal and repellant activity against Lasioderma serricorne (LS) and Tribolium castaneum (TC), and to isolate any insecticidal constituents from the essential oil. Essential oil from A. calamus was obtained by hydrodistillation and analyzed by gas chromatography (GC) flame ionization detector and GC-mass spectrometry. The insecticidal and repellant activity of the essential oil and isolated compounds was tested using a variety of methods. The main components of the essential oil were identified to be isoshyobunone (15.56%), β-asarone (10.03%), bicyclo[6.1.0]non-1-ene (9.67%), shyobunone (9.60%) and methylisoeugenol (6.69%). Among them, the two active constituents were isolated and identified as shyobunone and isoshyobunone. The essential oil showed contact toxicity against LS and TC with LD50 values of 14.40 and 32.55 μg/adult, respectively. The isolated compounds, shyobunone and isoshyobunone also exhibited strong contact toxicity against LS adults with LD50 values of 20.24 and 24.19 μg/adult, respectively, while the LD50 value of isoshyobunone was 61.90 μg/adult for TC adults. The essential oil, shyobunone and isoshyobunone were strongly repellent (98%, 90% and 94%, respectively, at 78.63 nL/cm(2), after 2 h treatment) against TC. The essential oil, shyobunone and isoshyobunone possessed insecticidal and repellant activity against LS and TC.

Novel and viable acetylcholinesterase target site for developing effective and environmentally safe insecticides.

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Pang, Yuan-Ping; Brimijoin, Stephen; Ragsdale, David W; Zhu, Kun Yan; Suranyi, Robert

2012-04-01

Insect pests are responsible for human suffering and financial losses worldwide. New and environmentally safe insecticides are urgently needed to cope with these serious problems. Resistance to current insecticides has resulted in a resurgence of insect pests, and growing concerns about insecticide toxicity to humans discourage the use of insecticides for pest control. The small market for insecticides has hampered insecticide development; however, advances in genomics and structural genomics offer new opportunities to develop insecticides that are less dependent on the insecticide market. This review summarizes the literature data that support the hypothesis that an insect-specific cysteine residue located at the opening of the acetylcholinesterase active site is a promising target site for developing new insecticides with reduced off-target toxicity and low propensity for insect resistance. These data are used to discuss the differences between targeting the insect-specific cysteine residue and targeting the ubiquitous catalytic serine residue of acetylcholinesterase from the perspective of reducing off-target toxicity and insect resistance. Also discussed is the prospect of developing cysteine-targeting anticholinesterases as effective and environmentally safe insecticides for control of disease vectors, crop damage, and residential insect pests within the financial confines of the present insecticide market.

Implications of sequence and timing of exposure for synergy between the pyrethroid insecticide alpha-cypermethrin and the entomopathogenic fungus Beauveria bassiana.

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Meyling, Nicolai V; Arthur, Samuel; Pedersen, Kathrine E; Dhakal, Suraj; Cedergreen, Nina; Fredensborg, Brian L

2018-03-30

Combining low doses of chemical insecticides with entomopathogens constitutes a sustainable pest control method, but the significance of the timing and sequence of exposures needs clarification. We studied lethal effects of combinations of the entomopathogenic fungus Beauveria bassiana (KVL03-122) and the pyrethroid alpha-cypermethrin on the beetle Tenebrio molitor under varying timing and sequence of exposure. Synergy over time was evaluated in relation to the model of independent action (IA). We expected that increased progression of disease caused by B. bassiana would make beetles more susceptible to the insecticide, leading to enhanced synergy. Synergistic effects between B. bassiana and alpha-cypermethrin were observed when B. bassiana was applied first, but only when the interval between applications was >48 h. With 72 h between exposures, mortality had increased to 100% after 8 days, in contrast to the 60% mortality expected. No synergy was observed when the insecticide was applied prior to fungal exposure within 24 h. The sequence and timing of exposure do matter to achieve synergistic mortality by combining B. bassiana and alpha-cypermethrin, and the IA model proved to be a strong tool with which to evaluate the interactions of the two stressors over time. Pest control strategies could include B. bassiana followed by low-dose exposures to alpha-cypermethrin after 2-3 days. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

2 Assessmen of the Efficiency of Insecticide

African Journals Online (AJOL)

Administrator

malaria vectors and nuisance in West Africa – a-part. 2. Field evaluation. Malar J. 9: 341. Mosqueira B., Duchon S., Chandre F., Hougard, J. M., Carnevale P. and Mas-Coma S. (2010). Efficacy of an insecticide paint against insecticide- susceptible and resistant mosquitoes – b- Part 1: Laboratory evaluation. Malar J. 9: 340.

Insecticide Resistance Reducing Effectiveness of Malaria Control

Centers for Disease Control (CDC) Podcasts

2007-01-24

Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field.  Created: 1/24/2007 by Emerging Infectious Diseases.   Date Released: 3/13/2007.

Degradation of Organophosphorus and Pyrethroid Insecticides in Beverages: Implications for Risk Assessment

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Samantha A. Radford

2018-02-01

Full Text Available Since urinary insecticide metabolites are commonly used as biomarkers of exposure, it is important that we quantify whether insecticides degrade in food and beverages in order to better perform risk assessment. This study was designed to quantify degradation of organophosphorus and pyrethroid insecticides in beverages. Purified water, white grape juice, orange juice, and red wine were fortified with 500 ng/mL diazinon, malathion, chlorpyrifos, permethrin, cyfluthrin, cypermethrin, and deltamethrin, and aliquots were extracted several times over a 15-day storage period at 2.5 °C. Overall, statistically significant loss of at least one insecticide was observed in each matrix, and at least five out of seven insecticides demonstrated a statistically significant loss in all matrices except orange juice. An investigation of an alternative mechanism of insecticide loss—adsorption onto the glass surface of the storage jars—was carried out, which indicated that this mechanism of loss is insignificant. Results of this work suggest that insecticides degrade in these beverages, and this degradation may lead to pre-existing insecticide degradates in the beverages, suggesting that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk.

Biological efficacy of the ecotoxically favourable insecticides and ...

African Journals Online (AJOL)

Administrator

2011-05-30

May 30, 2011 ... different, studies done in natural conditions should be favored. Key words: Insecticides ... insecticide was applied on synthetic or natural food of the target insect ..... Pozsgay M, Fast P, Kaplan H, Carey PR (1987). The effect of ...

Chemical composition, insecticidal and insect repellent activity of Schinus molle L. leaf and fruit essential oils against Trogoderma granarium and Tribolium castaneum.

Science.gov (United States)

Abdel-Sattar, Essam; Zaitoun, Ahmed A; Farag, Mohamed A; Gayed, Sabah H El; Harraz, Fathalla M H

2010-02-01

Fruit and leaf essential oils of Schinus molle showed insect repellent and insecticidal activity against Trogoderma granarium and Tribolium castaneum. In these oils, 65 components were identified by GC-MS analysis. Hydrocarbons dominated the oil composition with monoterpenes occurring in the largest amounts in fruits and leaves, 80.43 and 74.84%, respectively. p-Cymene was identified as a major component in both oils. The high yield and efficacy of S. molle essential oil against T. granarium and T. castaneum suggest that it may provide leads for active insecticidal agents.

Dog poisoning with furadan 35-ST (carbamate insecticide

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Aleksić Jelena

2011-01-01

Full Text Available The first case of poisoning of a dog with Furadan 35-ST in Serbia is described. The active ingredient of Furadan 35-ST is carbofuran (2,3-dihydro-2,2-dimethyl-7- benzofuranyl methyl carbamate, a carbamate insecticide, acaricide and nematocide. This highly poisonous substance is classified by the World Health Organisation into Class 1 b and in Serbia into Group 1 of The List of Poisons. Pathological assessment revealed hyperaemia and degenerative and necrotic changes in the liver, kidneys and heart. In addition, lysis of the nuclei in the motor neurons, loss of tigroid substance and pericellular oedema in the ventral horns of the spinal cord, and acute pancreatitis were found. In addition to the non-specific changes (hyperaemia, degenerative and necrotic changes in the parenchymal organs, the ones in the ventral horns of the spinal cord and acute pancreatitis may lead to carbamate poisoning being suspected. The diagnosis was established on the grounds of toxicological-chemical conformation of carbofuran by means of GC-MS in addition to the macroscopic, microscopic findings in tissue samples taken from the stomach and the liver, which confirmed the suspicion of the dog having been poisoned with the carbamate insecticide. In the current case the results of the diagnostic procedures provided foundations for the initiation of criminal proceedings.

Induced tolerance from a sublethal insecticide leads to cross-tolerance to other insecticides.

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Hua, Jessica; Jones, Devin K; Relyea, Rick A

2014-04-01

As global pesticide use increases, the ability to rapidly respond to pesticides by increasing tolerance has important implications for the persistence of nontarget organisms. A recent study of larval amphibians discovered that increased tolerance can be induced by an early exposure to low concentrations of a pesticide. Since natural systems are often exposed to a variety of pesticides that vary in mode of action, we need to know whether the induction of increased tolerance to one pesticide confers increased tolerance to other pesticides. Using larval wood frogs (Lithobates sylvaticus), we investigated whether induction of increased tolerance to the insecticide carbaryl (AChE-inhibitor) can induce increased tolerance to other insecticides that have the same mode of action (chlorpyrifos, malathion) or a different mode of action (Na(+)channel-interfering insecticides; permethrin, cypermethrin). We found that embryonic exposure to sublethal concentrations of carbaryl induced higher tolerance to carbaryl and increased cross-tolerance to malathion and cypermethrin but not to chlorpyrifos or permethrin. In one case, the embryonic exposure to carbaryl induced tolerance in a nonlinear pattern (hormesis). These results demonstrate that that the newly discovered phenomenon of induced tolerance also provides induced cross-tolerance that is not restricted to pesticides with the same mode of action.

Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA

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Rosen, Michael R.; Van Metre, P.C.

2010-01-01

Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

Impact of some selected insecticides application on soil microbial respiration.

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Latif, M A; Razzaque, M A; Rahman, M M

2008-08-15

The aim of present study was to investigate the impact of selected insecticides used for controlling brinjal shoot and fruit borer on soil microorganisms and to find out the insecticides or nontoxic to soil microorganism the impact of nine selected insecticides on soil microbial respiration was studied in the laboratory. After injection of different insecticides solutions, the soil was incubated in the laboratory at room temperature for 32 days. The amount of CO2 evolved due to soil microbial respiration was determined at 2, 4, 8, 16, 24 and 32 days of incubation. Flubendiamide, nimbicidine, lambda-cyhalothrin, abamectin and thiodicarb had stimulatory effect on microbial respiration during the initial period of incubation. Chlorpyriphos, cartap and carbosulfan had inhibitory effect on microbial respiration and cypermethrin had no remarkable effect during the early stage of incubation. The negative effect of chlorpyriphos, cartap and carbosulfan was temporary, which was disappeared after 4 days of insecticides application. No effect of the selected insecticides on soil microorganisms was observed after 24 or 32 days of incubation.

Effectiveness and profitability of insecticide formulations used for ...

African Journals Online (AJOL)

To identify optimal pest control with lower economic risks to farmers, we investigated the effectiveness and profitability of different insecticides and insecticide formulations against bean fly (Ophiomyia spp.) and bean flower thrips (Megalurothrips sjostedtii). Two separate experiments were conducted during 2009 to 2012.

Efficacy of insecticide residues on adult Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) mortality and injury in apple and peach orchards.

Science.gov (United States)

Leskey, Tracy C; Short, Brent D; Lee, Doo-Hyung

2014-07-01

The primary threat from Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) originates from populations continuously dispersing from and among wild and cultivated hosts, so many individuals may not be directly sprayed with insecticides. Limited information exists regarding field-based residual activity of insecticides for management of H. halys in tree fruit. Thus, we conducted field-based bioassays in apple and peach orchards to evaluate residual activity of insecticides commonly applied against H. halys. Adults used in these trials were collected from wild and cultivated hosts less than one week prior to testing to more accurately reflect the susceptibility of wild H. halys populations in the field throughout the season. Significantly higher mortality rates of Halyomorpha halys were observed early in the growing season, when overwintered adults were prevalent, compared with populations present later in the growing season that included new generation adults. Significantly higher mortality was recorded for adults exposed to fresh insecticide applications compared with three- and seven-day old residues. Typically, the addition of an adjuvant did not enhance efficacy or residual activity of insecticides. Significantly fewer injury sites were recorded on apples treated with dinotefuran and fenpropathrin compared with the untreated apples for all residue ages. Overwintered Halyomorpha halys populations are easier to kill with insecticide applications than the first and second generation which are present in the field during the mid- to late-season. Residual activity of nearly all insecticides decreased significantly three days after application and adjuvants generally did not increase residual activity. These factors should be considered in developing season-long programs for management of this invasive species in tree fruit. © 2013 Society of Chemical Industry.

Impact of reduced-risk insecticides on soybean aphid and associated natural enemies.

Science.gov (United States)

Ohnesorg, Wayne J; Johnson, Kevin D; O'Neal, Matthew E

2009-10-01

Insect predators in North America suppress Aphis glycines Matsumura (Hemiptera: Aphididae) populations; however, insecticides are required when populations reach economically damaging levels. Currently, insecticides used to manage A. glycines are broad-spectrum (pyrethroids and organophosphates), and probably reduce beneficial insect abundance in soybean, Glycine max (L.) Merr. Our goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphid's natural enemies. We compared three insecticides (imidacloprid, thiamethoxam, and pymetrozine,) to a broad-spectrum insecticide (lamda-cyhalothrin) and an untreated control using two application methods. We applied neonicotinoid insecticides to seeds (imidacloprid and thiamethoxam) as well as foliage (imidacloprid); pymetrozine and lamda-cyhalothrin were applied only to foliage. Foliage-applied insecticides had lower A. glycines populations and higher yields than the seed-applied insecticides. Among foliage-applied insecticides, pymetrozine and imidacloprid had an intermediate level of A. glycines population and yield protection compared with lamda-cyhalothrin and the untreated control. We monitored natural enemies with yellow sticky cards, sweep-nets, and direct observation. Before foliar insecticides were applied (i.e., before aphid populations developed) seed treatments had no observable effect on the abundance of natural enemies. After foliar insecticides were applied, differences in natural enemy abundance were observed when sampled with sweep-nets and direct observation but not with yellow sticky cards. Based on the first two sampling methods, pymetrozine and the foliage-applied imidacloprid had intermediate abundances of natural enemies compared with the untreated control and lamda-cyhalothrin.

Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides.

Science.gov (United States)

Rocha, Hélio Daniel Ribeiro; Paiva, Marcelo Henrique Santos; Silva, Norma Machado; de Araújo, Ana Paula; Camacho, Denise Dos Reis da Rosa de Azevedo; Moura, Aires Januário Fernandes da; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira; Santos, Maria Alice Varjal de Melo

2015-12-01

In 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortality<80%) and temephos (RR90=4.4) but susceptibility to malathion (mortality≥98%), Bti and diflubenzuron. The low level of resistance to temephos did not affect the effectiveness of Abate(®). The enzymatic analysis conducted in 2012 revealed slight changes in the activities of GST (25%), MFO (18%), α-esterase (19%) and β-esterase (17%), but no significant changes in 2014. Target site resistance mutations were not detected. Our results suggest that the A. aegypti population from Santiago is resistant to two major

Chemical and Plant-Based Insect Repellents: Efficacy, Safety, and Toxicity.

Science.gov (United States)

Diaz, James H

2016-03-01

Most emerging infectious diseases today are arthropod-borne and cannot be prevented by vaccinations. Because insect repellents offer important topical barriers of personal protection from arthropod-borne infectious diseases, the main objectives of this article were to describe the growing threats to public health from emerging arthropod-borne infectious diseases, to define the differences between insect repellents and insecticides, and to compare the efficacies and toxicities of chemical and plant-derived insect repellents. Internet search engines were queried with key words to identify scientific articles on the efficacy, safety, and toxicity of chemical and plant-derived topical insect repellants and insecticides to meet these objectives. Data sources reviewed included case reports; case series; observational, longitudinal, and surveillance studies; and entomological and toxicological studies. Descriptive analysis of the data sources identified the most effective application of insect repellents as a combination of topical chemical repellents, either N-diethyl-3-methylbenzamide (formerly N, N-diethyl-m-toluamide, or DEET) or picaridin, and permethrin-impregnated or other pyrethroid-impregnated clothing over topically treated skin. The insecticide-treated clothing would provide contact-level insecticidal effects and provide better, longer lasting protection against malaria-transmitting mosquitoes and ticks than topical DEET or picaridin alone. In special cases, where environmental exposures to disease-transmitting ticks, biting midges, sandflies, or blackflies are anticipated, topical insect repellents containing IR3535, picaridin, or oil of lemon eucalyptus (p-menthane-3, 8-diol or PMD) would offer better topical protection than topical DEET alone. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Insecticide Exposure in Parkinsonism

National Research Council Canada - National Science Library

Bloomquist, Jeffrey

2002-01-01

Behavioral, neurochemical, and immunocytochemical studies characterized the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and permethrin (PM...

Insecticide Exposure in Parkinsonism

National Research Council Canada - National Science Library

Bloomquist, Jeffrey

2001-01-01

Behavioral, neurochemical, and immunocytochemical studies characterized the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and permethrin (PM...

Insecticides -a cure or curse and rational use of integrated pest management in Pakistan

International Nuclear Information System (INIS)

Irshad, M.

2005-01-01

Chemical based control in crops has increased the pest problem, disturbed the agro ecosystem and has killed the non-target and environmentally friendly organisms and misuse of insecticides has led to resistance to insecticides, resurgence of secondary pests, polluting soil, water and food with contaminates. In addition to this, irrigation and drinking water, cottonseed oil, lint and cattle feed and animal milk are also contaminated having deleterious effects on human life. To reduce chemical control, Integrated Pest Management (IPM) emerged. Its emphasis is on non-disturbance of ecosystem but to manage the insect pest populations with all the available means on economic basis. IPM approach is knowledge based with in-depth information. In spite of IPM studies and work unfortunately reliance on pesticides has not been reduced in Pakistan. Conservation/augmentation, releases of new biotic agents may disturb the ecosystem. The stress on IPM is made in the developed countries primarily due to human health factor. These societies even risk the reduction in yield in the IPM fields. Successful stories of IPM in Pakistan has not been cashed to due merits. The bottlenecks must be removed so that better results can be obtained. The main reason seems to be lack of in depth involvement of the growers in this activity. (author)

Insecticidal effects of essential oils extracted from aromatic plants on Ceratitis capitata (Wied.) in Lebanon

Energy Technology Data Exchange (ETDEWEB)

Abi Chahine, M [Lebanese Agricultural Research Institute, Jdeidet el-Metn (Lebanon); Khoury, N; Webeh, E [Lebanese Agricultural Research Institute, Jdeidet el-Metn (Lebanon)

2005-07-01

Full text: The excessive use of chemical pesticides to control agricultural pests is becoming alarming. The objective of this study is to search for biopesticides of plant origin that could be used to control one of the major pest of fruit production; the Mediterranean fruit fly (Ceratitis capitata Wied.). A colony of the Lebanese wild strain of this insect was reared under laboratory condition to provide biological material. The insecticidal activity of the essential oils extracted from aromatic plants in Lebanon was assessed. The tested plants are: Foeniculum vulgare, Thymbra spicata, Artemisia herba alba, Origanum syriacum, Ruta chalepensis, Lavandula stoechas, Salvia fruticosa, Mentha microphylla, Juniperus oxycedrus, Rosmarinus officinalis, Myrtus communis, Laurus nobilis and Ocimum gratissimum. Results show that essential oils isolated from F. vulgare, T. spicata, A. herba alba, O. syriacum and R. chalepensis have promising insecticidal potential. (author)

The Red Queen in a potato field: integrated pest management versus chemical dependency in Colorado potato beetle control.

Science.gov (United States)

Alyokhin, Andrei; Mota-Sanchez, David; Baker, Mitchell; Snyder, William E; Menasha, Sandra; Whalon, Mark; Dively, Galen; Moarsi, Wassem F

2015-03-01

Originally designed to reconcile insecticide applications with biological control, the concept of integrated pest management (IPM) developed into the systems-based judicious and coordinated use of multiple control techniques aimed at reducing pest damage to economically tolerable levels. Chemical control, with scheduled treatments, was the starting point for most management systems in the 1950s. Although chemical control is philosophically compatible with IPM practices as a whole, reduction in pesticide use has been historically one of the main goals of IPM practitioners. In the absence of IPM, excessive reliance on pesticides has led to repeated control failures due to the evolution of resistance by pest populations. This creates the need for constant replacement of failed chemicals with new compounds, known as the 'insecticide treadmill'. In evolutionary biology, a similar phenomenon is known as the Red Queen principle - continuing change is needed for a population to persevere because its competitors undergo constant evolutionary adaptation. The Colorado potato beetle, Leptinotarsa decemlineata (Say), is an insect defoliator of potatoes that is notorious for its ability to develop insecticide resistance. In the present article, a review is given of four case studies from across the United States to demonstrate the importance of using IPM for sustainable management of a highly adaptable insect pest. Excessive reliance on often indiscriminate insecticide applications and inadequate use of alternative control methods, such as crop rotation, appear to expedite evolution of insecticide resistance in its populations. Resistance to IPM would involve synchronized adaptations to multiple unfavorable factors, requiring statistically unlikely genetic changes. Therefore, integrating different techniques is likely to reduce the need for constant replacement of failed chemicals with new ones. © 2014 Society of Chemical Industry.

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins.

Science.gov (United States)

Martinez, Ana Flávia Canovas; de Almeida, Luís Gustavo; Moraes, Luiz Alberto Beraldo; Cônsoli, Fernando Luís

2017-06-27

The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted attention as a source of new bioactive molecules because these microbes are exposed to various selection pressures in their association with insects. Analytical techniques must be used to isolate and characterize new compounds, and sensitive analytical tools such as mass spectrometry and high-resolution chromatography are required to identify the least-abundant molecules. We used classical fermentation techniques combined with tandem mass spectrometry to prospect for insecticidal substances produced by the ant symbiont Streptomyces caniferus. Crude extracts from this bacterium showed low biological activity (less than 10% mortality) against the larval stage of the fall armyworm Spodoptera frugiperda. Because of the complexity of the crude extract, we used fractionation-guided bioassays to investigate if the low toxicity was related to the relative abundance of the active molecule, leading to the isolation of porphyrins as active molecules. Porphyrins are a class of photoactive molecules with a broad range of bioactivity, including insecticidal. The active fraction, containing a mixture of porphyrins, induced up to 100% larval mortality (LD 50  = 37.7 μg.cm -2 ). Tandem mass-spectrometry analyses provided structural information for two new porphyrin structures. Data on the availability of porphyrins in 67 other crude extracts of ant ectosymbionts were also obtained with ion-monitoring experiments. Insect-associated bacterial symbionts are a rich source of bioactive compounds. Exploring

Monitoring Trends in Insecticide Resistance of Field Populations of Sogatella furcifera (Hemiptera: Delphacidae) in Guizhou Province, China, 2012–2015

Science.gov (United States)

Jin, Jian-Xue; Li, Wen-Hong; Cheng, Ying; Li, Feng-Liang; Ye, Zhao-Chun

2017-01-01

Abstract Sogatella furcifera (Horváth) is a migratory insect that is one of the most important pest species on rice in many Asian countries. Control of S. furcifera (Hemiptera: Delphacidae) primarily depends on the use of chemical insecticides, and with this extensive reliance on pesticides, determining the degree of resistance of S. furcifera populations to the chemicals used for its control is essential. In this study, the resistance level to six conventional insecticides in five populations of S. furcifera from Guizhou Province was monitored yearly using the rice-stem dipping method in 2012–2015 to precisely understand current resistance levels and to estimate trends in the development of insecticide resistance in S. furcifera in Guizhou. Overall, S. furcifera from five regions in Guizhou showed a trend toward decreased susceptibility to isoprocarb (resistance ratio [RR] 0.82–3.59), susceptibility to low resistance against thiamethoxam (RR 0.27–9.69), susceptibility to moderate resistance to imidacloprid (RR 0.71–26.06), and decreased susceptibility to moderate resistance to chlorpyrifos (RR 4.63–19.58). The resistance to pymetrozine (RR 10.48–84.65) was moderate to high, and that to buprofezin (RR 6.36–412.43) was low to very high. In conclusion, the use of buprofezin and pymetrozine to control S. furcifera should be reduced in Guizhou Province, whereas prudent use at a reasonable frequency of chlorpyrifos and imidacloprid can continue. Isoprocarb and thiamethoxam are the best choices for effective management of S. furcifera. Rotations using alternative insecticides with different modes of action are recommended for regions in which resistance is at a moderate level. PMID:28334150

Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.).

Science.gov (United States)

Xia, Xiaofeng; Sun, Botong; Gurr, Geoff M; Vasseur, Liette; Xue, Minqian; You, Minsheng

2018-01-01

The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L.), a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes), Enterobacter sp. (Proteobacteria), and Serratia sp. (Proteobacteria) from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella , while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species.

Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.

Directory of Open Access Journals (Sweden)

Xiaofeng Xia

2018-01-01

Full Text Available The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L., a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes, Enterobacter sp. (Proteobacteria, and Serratia sp. (Proteobacteria from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella, while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species.

Evaluation of insecticides in different dosages to control cicadas in parica plantations

Directory of Open Access Journals (Sweden)

Odineila Martins Monteiro

2014-07-01

Full Text Available This study aimed to determine the more efficient and economically viable dosage of chemical insecticide to control Quesada gigas (Hemiptera: Cicadidae nymphs in parica plantations. Three dosages of three products (carbofuran, imidacloprid and thiamethoxam were tested based on the maximum recommended dosage for the control of cicadas in coffee plants and applied in total area. The dosage of one kilogram of a commercial product based in thiamethoxam per hectare was more efficient economically and environmentally to control nymphs of Q. gigas in parica plantations.

Expression of melanin and insecticidal protein from Rhodotorula ...

African Journals Online (AJOL)

Both the salmon/red melanin and the insecticidal producing genes of Rhodotorula glutinis was successfully expressed in Escherichia coli using plasmid pZErO-1. This work suggests that in Rhodotorula species melanin and insecticidal toxin are co-expressed and therefore possibly co-evolved. Keywords: Rhodotorula ...

Pyrosequencing the transcriptome of the greenhouse whitefly, Trialeurodes vaporariorum reveals multiple transcripts encoding insecticide targets and detoxifying enzymes

Directory of Open Access Journals (Sweden)

Gorman Kevin

2011-01-01

Full Text Available Abstract Background The whitefly Trialeurodes vaporariorum is an economically important crop pest in temperate regions that has developed resistance to most classes of insecticides. However, the molecular mechanisms underlying resistance have not been characterised and, to date, progress has been hampered by a lack of nucleotide sequence data for this species. Here, we use pyrosequencing on the Roche 454-FLX platform to produce a substantial and annotated EST dataset. This 'unigene set' will form a critical reference point for quantitation of over-expressed messages via digital transcriptomics. Results Pyrosequencing produced around a million sequencing reads that assembled into 54,748 contigs, with an average length of 965 bp, representing a dramatic expansion of existing cDNA sequences available for T. vaporariorum (only 43 entries in GenBank at the time of this publication. BLAST searching of non-redundant databases returned 20,333 significant matches and those gene families potentially encoding gene products involved in insecticide resistance were manually curated and annotated. These include, enzymes potentially involved in the detoxification of xenobiotics and those encoding the targets of the major chemical classes of insecticides. A total of 57 P450s, 17 GSTs and 27 CCEs were identified along with 30 contigs encoding the target proteins of six different insecticide classes. Conclusion Here, we have developed new transcriptomic resources for T. vaporariorum. These include a substantial and annotated EST dataset that will serve the community studying this important crop pest and will elucidate further the molecular mechanisms underlying insecticide resistance.

Insecticide Exposure in Parkinsonism

National Research Council Canada - National Science Library

Bloomquist, Jeffrey

2003-01-01

Behavioral, neurochemical, and immunocytochemical studies are characterizing the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and/or permethrin (PM...

Insecticides and Biological Control

Science.gov (United States)

Furness, G. O.

1972-01-01

Use of insecticides has been questioned due to their harmful effects on edible items. Biological control of insects along with other effective practices for checking spread of parasites on crops are discussed. (PS)

Insecticidal effects of Ocimum sanctum var. cubensis essential oil on the diseases vector Chrysomya putoria

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Idelsy Chil-Núñez

2018-05-01

Full Text Available Context: The blowfly Chrysomya putoria is widely distributed throughout the Neotropical region and, besides transmitting pathogens; they could cause secondary myiasis. Botanical insecticides provide an alternative to synthetic pesticides because the excessive use of synthetic insecticides resulted in a progressive resistance of the pests to these chemicals, diminishing their effectiveness and generating consequences with negative environmental impact. The essential oil extracted from Ocimum sanctum (basil has showed insecticidal activity against some insects but has no reported studies on the activity of this plant against flies. Aims: To evaluate the insecticidal effects of Ocimum sanctum var. cubensis Gomes essential oil on the post embryonic development of Chrysomya putoria. Methods: The colonies of Chrysomya putoria were established and maintained at the Laboratório de Entomologia Médica e Forense (FIOCRUZ, Rio de Janeiro, Brazil. The basil essential oil was tested in six concentrations (4.13, 8.25, 20.63, 41.25, 61.87 and 80,25 mg/mL. Mortality and changes in life cycle were recorded daily. Results: β-caryophyllene, β-selinene and eugenol, were the main constituents of the basil essential oil. The experiments demonstrated that in all concentrations tested, this essential oil shortening the duration of all post embryonic stages having a direct impact in the viability of this fly estimating the LC50 in 7.47 mg/mL of concentration. In addition, the essential oil caused morphological alterations in abdomen, wings and ptilinum at lower concentrations. Conclusions: This essential oil emerge as a good option for the control of the disease vector blowfly Chrysomya putoria.

Monitoring Trends in Insecticide Resistance of Field Populations of Sogatella furcifera (Hemiptera: Delphacidae) in Guizhou Province, China, 2012-2015.

Science.gov (United States)

Jin, Jian-Xue; Jin, Dao-Chao; Li, Wen-Hong; Cheng, Ying; Li, Feng-Liang; Ye, Zhao-Chun

2017-04-01

Sogatella furcifera (Horváth) is a migratory insect that is one of the most important pest species on rice in many Asian countries. Control of S. furcifera (Hemiptera: Delphacidae) primarily depends on the use of chemical insecticides, and with this extensive reliance on pesticides, determining the degree of resistance of S. furcifera populations to the chemicals used for its control is essential. In this study, the resistance level to six conventional insecticides in five populations of S. furcifera from Guizhou Province was monitored yearly using the rice-stem dipping method in 2012-2015 to precisely understand current resistance levels and to estimate trends in the development of insecticide resistance in S. furcifera in Guizhou. Overall, S. furcifera from five regions in Guizhou showed a trend toward decreased susceptibility to isoprocarb (resistance ratio [RR] 0.82-3.59), susceptibility to low resistance against thiamethoxam (RR 0.27-9.69), susceptibility to moderate resistance to imidacloprid (RR 0.71-26.06), and decreased susceptibility to moderate resistance to chlorpyrifos (RR 4.63-19.58). The resistance to pymetrozine (RR 10.48-84.65) was moderate to high, and that to buprofezin (RR 6.36-412.43) was low to very high. In conclusion, the use of buprofezin and pymetrozine to control S. furcifera should be reduced in Guizhou Province, whereas prudent use at a reasonable frequency of chlorpyrifos and imidacloprid can continue. Isoprocarb and thiamethoxam are the best choices for effective management of S. furcifera. Rotations using alternative insecticides with different modes of action are recommended for regions in which resistance is at a moderate level. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

La biosynthèse des isoprénoïdes chez les pucerons : une cible potentielle de nouveaux bio-insecticides ?

Directory of Open Access Journals (Sweden)

Haubruge E.

2008-01-01

Full Text Available Isoprenoid metabolism in aphids: a new target for bio-insecticides development? Currently, the control of aphids is largely dependent on the use of broad-spectrum chemical insecticides. Their adverse effects on the environment, combined with the ability of insects to quickly develop resistance to them, has prompted a search for alternative control products. One of the approaches currently under consideration involves the design of novel bio-rational insecticides targeting and disrupting specific biochemical processes in the insect. As a result of their high specificity, these pest control products generally present little risk to the environment, non-target organisms and human health. In the context of aphid control, isoprenoid metabolism and, more specifically, enzymes of the short-chain isoprenyl diphosphate synthases family constitute promising targets for the development of new control products. Indeed, in aphids, isoprenoid metabolism is associated with the production of mono- and sesquiterpenes, which are compounds playing important roles in the physiology of these insects.

The activity of the pyrrole insecticide chlorfenapyr in mosquito bioassay: towards a more rational testing and screening of non-neurotoxic insecticides for malaria vector control.

Science.gov (United States)

Oxborough, Richard M; N'Guessan, Raphael; Jones, Rebecca; Kitau, Jovin; Ngufor, Corine; Malone, David; Mosha, Franklin W; Rowland, Mark W

2015-03-24

The rapid selection of pyrethroid resistance throughout sub-Saharan Africa is a serious threat to malaria vector control. Chlorfenapyr is a pyrrole insecticide which shows no cross resistance to insecticide classes normally used for vector control and is effective on mosquito nets under experimental hut conditions. Unlike neurotoxic insecticides, chlorfenapyr owes its toxicity to disruption of metabolic pathways in mitochondria that enable cellular respiration. A series of experiments explored whether standard World Health Organization (WHO) guidelines for evaluation of long-lasting insecticidal nets, developed through testing of pyrethroid insecticides, are suitable for evaluation of non-neurotoxic insecticides. The efficacy of WHO recommended cone, cylinder and tunnel tests was compared for pyrethroids and chlorfenapyr. To establish bioassay exposure times predictive of insecticide-treated net (ITN) efficacy in experimental hut trials, standard three-minute bioassays of pyrethroid and chlorfenapyr ITNs were compared with longer exposures. Mosquito behaviour and response to chlorfenapyr ITN in bioassays conducted at night were compared to day and across a range of temperatures representative of highland and lowland transmission. Standard three-minute bioassay of chlorfenapyr produced extremely low levels of mortality compared to pyrethroids. Thirty-minute day-time bioassay produced mortality closer to hut efficacy of chlorfenapyr ITN but still fell short of the WHO threshold. Overnight tunnel test with chlorfenapyr produced 100% mortality and exceeded the WHO threshold of 80%. The endogenous circadian activity rhythm of anophelines results in inactivity by day and raised metabolism and flight activity by night. A model which explains improved toxicity of chlorfenapyr ITN when tested at night, and during the day at higher ambient temperature, is that activation of chlorfenapyr and disruption of respiratory pathways is enhanced when the insect is more metabolically

Field and Laboratory Evaluations of Insecticides for Southern Pine Beetle Control

Science.gov (United States)

Felton L. Hastings; Jack E. Coster; [Editors

1981-01-01

Reports results of laboratory screenings and field studies of insecticides for use against the southern pine beetle. Preventive as webas remedial efficacywere observed, along with phytotoxicity to pine and understory hardwood species, effects of insecticides on soil microbial and mesofaunal populations, and degradation of insecticides by selected soil microbes.

Influence of Varroa Mite (Varroa destructor Management Practices on Insecticide Sensitivity in the Honey Bee (Apis mellifera

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Frank D. Rinkevich

2017-01-01

Full Text Available Since Varroa mites may cause devastating losses of honey bees through direct feeding, transmitting diseases, and increasing pathogen susceptibility, chemical and mechanical practices commonly are used to reduce mite infestation. While miticide applications are typically the most consistent and efficacious Varroa mite management method, miticide-induced insecticide synergism in honey bees, and the evolution of resistance in Varroa mites are reasonable concerns. We treated colonies with the miticide amitraz (Apivar®, used IPM practices, or left some colonies untreated, and then measured the effect of different levels of mite infestations on the sensitivity of bees to phenothrin, amitraz, and clothianidin. Sensitivity to all insecticides varied throughout the year among and within treatment groups. Clothianidin sensitivity decreased with increasing mite levels, but no such correlation was seen with phenothrin or amitraz. These results show that insecticide sensitivity is dynamic throughout the 5 months test. In-hive amitraz treatment according to the labeled use did not synergize sensitivity to the pesticides tested and this should alleviate concern over potential synergistic effects. Since IPM practices were largely ineffective at reducing Varroa mite infestation, reliance on chemical methods of Varroa mite management is likely to continue. However, miticides must be used judiciously so the long term effectiveness of these compounds can be maximized. These data demonstrate the complex and dynamic variables that contribute to honey bee colony health. The results underscore the importance of controlling for as many of these variables as possible in order to accurately determine the effects of each of these factors as they act alone or in concert with others.

Insecticide toxicity to the borer Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae): developmental and egg-laying effects.

Science.gov (United States)

Silva, R S; Arcanjo, L P; Soares, J R S; Ferreira, D O; Serrão, J E; Martins, J C; Costa, Á H; Picanço, M C

2018-04-01

Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is one of the major pests of solanaceous plants in South America. It is considered a great threat by the European and Mediterranean Plant Protection Organization due to the serious economic damage that it causes on tomato farms; therefore, controlling this pest is a challenging task in South America. Controlling N. elegantalis at the egg stage is the best way to prevent it from damaging crops; however, thorough studies about the effectiveness of chemicals on the different life stages of this insect pest are lacking. In this study, the effects of different chemical classes were evaluated on N. elegantalis adults, female oviposition behavior, larvae, eggs, and embryonic development. None of the tested insecticides demonstrated toxicity to the adults; however, the results showed that cartap hydrochloride affects oviposition behavior. Moreover, methomyl and cartap hydrochloride exhibited high toxicity against the eggs and larvae, with higher than 80% of mortality. These insecticides interrupted larval hatching and caused alterations in the chorion layer. Flubendiamide and deltamethrin demonstrated toxicity on N. elegantalis larvae; however, lufenuron, indoxacarb, methoxyfenozide, and chlorantraniliprole demonstrated low toxicity on both eggs and larvae, with lower than 70% of mortality. Fruit treated with cartap hydrochloride had a deterrent effect. The ovicidal activity revealed by methomyl and cartap hydrochloride might provide new approaches regarding insecticide effects on eggs. Methomyl, cartap hydrochloride, flubendiamide, and deltamethrin demonstrated toxicity on larvae. The evaluation of the chorion of the eggshell in this study has clarified the toxic effect of methomyl and cartap hydrochloride on eggs.

3 Insecticide Use Practice

African Journals Online (AJOL)

Administrator

500,000 metric tonnes in the 1964/1965 season. Problems ... insecticides on the open market. ... effective in the management of insect pests of cocoa. .... Effectiveness and profitability of pest ... Youth in Agriculture; Programme Policy, Strategy.

Biological alterations and self-reported symptoms among insecticides-exposed workers in Burkina Faso.

Science.gov (United States)

Toe, Adama M; Ilboudo, Sylvain; Ouedraogo, Moustapha; Guissou, Pierre I

2012-03-01

Occupationally exposed workers, farm workers and plant protection agents in the Sahel region of Burkina Faso were interviewed to assess adverse health effects of insecticides. The subjects were also examined for changes in both hematological and biochemical parameters. The prevalence of liver and kidney dysfunction was found to be quite high among insecticide applicators, especially among plant protection agents. The prevalence of biochemical alterations seems to be correlated to the frequency of insecticide use. However, no significant differences were found between the hematological parameters among farm workers and plant protection agents. The hematological parameters of all the insecticide applicators were normal. The great majority of insecticide applicators (85%) reported symptoms related to insecticide exposure. The use of insecticides in the agriculture of Burkina Faso is threatening to human health.

The effect of temperature on the toxicity of insecticides against Musca domestica L.: implications for the effective management of diarrhea.

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Hafiz Azhar Ali Khan

Full Text Available BACKGROUND: Diarrhea is an important cause of childhood mortality in developing countries like Pakistan because of unhygienic conditions, lack of awareness, and unwise use of preventive measures. Mechanical transmission of diarrheal pathogens by house flies, Musca domestica, is believed as the most effective route of diarrhea transmission. Although the use of insecticides as a preventive measure is common worldwide for the management of house flies, success of the measure could be compromised by the prevailing environmental temperature since it significantly affects toxicity of insecticides and thus their efficacy. Peaks of the house fly density and diarrheal cases are usually coincided and season specific, yet little is known about the season specific use of insecticides. METHODOLOGY/PRINCIPAL FINDINGS: To determine the temperature-toxicity relationship in house flies, the effect of post-bioassays temperature (range, 20-34°C on the toxicity of seven insecticides from organophosphate (chlorpyrifos, profenofos, pyrethroid (cypermethrin, deltamethrin and new chemical (emamectin benzoate, fipronil, spinosad classes was evaluated by using a feeding bioassay method. From 20-34°C, the toxicities of chlorpyrifos, profenofos, emamectin and fipronil increased 2.10, 2.93, 2.40 and 3.82 fold (i.e. positive temperature coefficient, respectively. Whereas, the toxicities of cypermethrin, deltamethrin and spinosad decreased 2.21, 2.42 and 3.16 fold (i.e. negative temperature coefficient, respectively. CONCLUSION/SIGNIFICANCE: These findings suggest that for the reduction in diarrheal cases, house flies should be controlled with insecticides according to the prevailing environmental temperature. Insecticides with a positive temperature coefficient may serve as potential candidates in controlling house flies and diarrhea epidemics in hot season and vice versa.

Impact of repeated insecticide application on soil microbial activity

International Nuclear Information System (INIS)

Xu Bujin; Zhang Yongxi; Chen Meici; Zhu Nanwen; Ming Hong

2001-01-01

The effects of repeated insecticide application on soil microbial activity were studied both in a cotton field and in the laboratory. The results of experiment show that there are some effects on soil microbial activities, such as the population of soil microorganisms, soil respiration, dehydrogenase activity and nitrogen fixation. The degree of effects depends on the chemical dosage. Within the range of 0.5-10.0 μg/g air-dry-soil, the higher the concentration, the stronger effect. In this experiment, the effect disappeared within 4, 8 or 16 days after treatment, depending on the dose applied. In field conditions, the situation is more complex and the data of field experiment show greater fluctuation. (author)

Evaluation of the Insecticidal Efficacy of Wild Type and Recombinant Baculoviruses.

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Popham, Holly J R; Ellersieck, Mark R; Li, Huarong; Bonning, Bryony C

2016-01-01

A considerable amount of work has been undertaken to genetically enhance the efficacy of baculovirus insecticides. Following construction of a genetically altered baculovirus, laboratory bioassays are used to quantify various parameters of insecticidal activity such as the median lethal concentration (or dose) required to kill 50 % of infected larvae (LC50 or LD50), median survival of larvae infected (ST50), and feeding damage incurred by infected larvae. In this chapter, protocols are described for a variety of bioassays and the corresponding data analyses for assessment of the insecticidal activity of baculovirus insecticides.

Guide to testing insecticides on coniferous forest defoliators

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Carroll B Jr. Williams; David A. Sharpnack; Liz Maxwell; Patrick J. Shea; Mark D. McGregor

1985-01-01

This report provides a guide to techniques for designing field tests of candidate insecticides, and for carrying out pilot tests and control projects. It describes experimental designs for testing hypotheses, and for sampling trees to estimate insect population densities and percent reduction after treatments. Directions for applying insecticides by aircraft and for...

Transcriptome-based identification and characterization of genes commonly responding to five different insecticides in the diamondback moth, Plutella xylostella.

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Gao, Yue; Kim, Kyungmun; Kwon, Deok Ho; Jeong, In Hong; Clark, J Marshall; Lee, Si Hyeock

2018-01-01

When the 3rd instar larvae of the diamondback moth (DBM), Plutella xylostella, were pretreated with sublethal doses (LC 10 ) and then subsequently exposed to lethal doses (LC 50 ) of chlorantraniliprole, cypermethrin, dinotefuran, indoxacarb and spinosad via leaf dipping, their tolerance to insecticides was significantly enhanced. To identify genes that commonly respond to the treatment of different insecticides and are responsible for the tolerance enhancement, transcriptomic profiles of larvae treated with sublethal doses of the five insecticides were compared with that of untreated control. A total of 117,181 transcripts with a mean length of 662bp were generated by de novo assembly, of which 35,329 transcripts were annotated. Among them, 125, 143, 182, 215 and 149 transcripts were determined to be up-regulated whereas 67, 45, 60, 60 and 38 genes were down-regulated following treatments with chlorantraniliprole, cypermethrin, dinotefuran, indoxacarb and spinosad, respectively. Gene ontology (GO) analysis of differentially expressed genes (DEGs) revealed little differences in their GO profiles between treatments with different insecticides except for spinosad. Finally, the DEGs commonly responding to all insecticides were selected for further characterization, and some of their over-transcription levels were confirmed by quantitative PCR. The most notable examples of commonly responding over-transcribed genes were two cytochrome P450 genes (Cyp301a1 and Cyp9e2) and nine cuticular protein genes. In contrast, several genes composing the mitochondrial energy generation system were significantly down-regulated in all treated larvae. Considering the distinct structure and mode of action of the five insecticides tested, the differentially expressed genes identified in this study appear to be involved in general chemical defense at the initial stage of intoxication. Their possible roles in the tolerance/resistance development were discussed. Copyright © 2017 Elsevier

Design, Synthesis and Insecticidal Activity of Novel Phenylurea Derivatives

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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.

Noninvasive Biomonitoring Approaches to Determine Dosimetry and Risk Following Acute Chemical Exposure: Analysis of Lead or Organophosphate Insecticide in Saliva

International Nuclear Information System (INIS)

Timchalk, Chuck; Poet, Torka S.; Kousba, Ahmed A.; Campbell, James A.; Lin, Yuehe

2004-01-01

There is a need to develop approaches for assessing risk associated with acute exposures to a broad-range of chemical agents and to rapidly determine the potential implications to human health. Non-invasive biomonitoring approaches are being developed using reliable portable analytical systems to quantitate dosimetry utilizing readily obtainable body fluids, such as saliva. Saliva has been used to evaluate a broad range of biomarkers, drugs, and environmental contaminants including heavy metals and pesticides. To advance the application of non-invasive biomonitoring a microfluidic/ electrochemical device has also been developed for the analysis of lead (Pb), using square wave anodic stripping voltammetry. The system demonstrates a linear response over a broad concentration range (1 2000 ppb) and is capable of quantitating saliva Pb in rats orally administered acute doses of Pb-acetate. Appropriate pharmacokinetic analyses have been used to quantitate systemic dosimetry based on determination of saliva Pb concentrations. In addition, saliva has recently been used to quantitate dosimetry following exposure to the organophosphate insecticide chlorpyrifos in a rodent model system by measuring the major metabolite, trichloropyridinol, and saliva cholinesterase inhibition following acute exposures. These results suggest that technology developed for non-invasive biomonitoring can provide a sensitive, and portable analytical tool capable of assessing exposure and risk in real-time. By coupling these non-invasive technologies with pharmacokinetic modeling it is feasible to rapidly quantitate acute exposure to a broad range of chemical agents. In summary, it is envisioned that once fully developed, these monitoring and modeling approaches will be useful for accessing acute exposure and health risk

Implications of insecticide resistance for malaria vector control with long-lasting insecticidal nets: a WHO-coordinated, prospective, international, observational cohort study.

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Kleinschmidt, Immo; Bradley, John; Knox, Tessa Bellamy; Mnzava, Abraham Peter; Kafy, Hmooda Toto; Mbogo, Charles; Ismail, Bashir Adam; Bigoga, Jude D; Adechoubou, Alioun; Raghavendra, Kamaraju; Cook, Jackie; Malik, Elfatih M; Nkuni, Zinga José; Macdonald, Michael; Bayoh, Nabie; Ochomo, Eric; Fondjo, Etienne; Awono-Ambene, Herman Parfait; Etang, Josiane; Akogbeto, Martin; Bhatt, Rajendra M; Chourasia, Mehul Kumar; Swain, Dipak K; Kinyari, Teresa; Subramaniam, Krishanthi; Massougbodji, Achille; Okê-Sopoh, Mariam; Ogouyemi-Hounto, Aurore; Kouambeng, Celestin; Abdin, Mujahid Sheikhedin; West, Philippa; Elmardi, Khalid; Cornelie, Sylvie; Corbel, Vincent; Valecha, Neena; Mathenge, Evan; Kamau, Luna; Lines, Jonathan; Donnelly, Martin James

2018-04-09

Scale-up of insecticide-based interventions has averted more than 500 million malaria cases since 2000. Increasing insecticide resistance could herald a rebound in disease and mortality. We aimed to investigate whether insecticide resistance was associated with loss of effectiveness of long-lasting insecticidal nets and increased malaria disease burden. This WHO-coordinated, prospective, observational cohort study was done at 279 clusters (villages or groups of villages in which phenotypic resistance was measurable) in Benin, Cameroon, India, Kenya, and Sudan. Pyrethroid long-lasting insecticidal nets were the principal form of malaria vector control in all study areas; in Sudan this approach was supplemented by indoor residual spraying. Cohorts of children from randomly selected households in each cluster were recruited and followed up by community health workers to measure incidence of clinical malaria and prevalence of infection. Mosquitoes were assessed for susceptibility to pyrethroids using the standard WHO bioassay test. Country-specific results were combined using meta-analysis. Between June 2, 2012, and Nov 4, 2016, 40 000 children were enrolled and assessed for clinical incidence during 1·4 million follow-up visits. 80 000 mosquitoes were assessed for insecticide resistance. Long-lasting insecticidal net users had lower infection prevalence (adjusted odds ratio [OR] 0·63, 95% CI 0·51-0·78) and disease incidence (adjusted rate ratio [RR] 0·62, 0·41-0·94) than did non-users across a range of resistance levels. We found no evidence of an association between insecticide resistance and infection prevalence (adjusted OR 0·86, 0·70-1·06) or incidence (adjusted RR 0·89, 0·72-1·10). Users of nets, although significantly better protected than non-users, were nevertheless subject to high malaria infection risk (ranging from an average incidence in net users of 0·023, [95% CI 0·016-0·033] per person-year in India, to 0·80 [0·65-0·97] per person

Mosquitocidal carbamates with low toxicity to agricultural pests: an advantageous property for insecticide resistance management.

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Swale, Daniel R; Carlier, Paul R; Hartsel, Joshua A; Ma, Ming; Bloomquist, Jeffrey R

2015-08-01

Insecticide resistance in the malaria mosquito Anopheles gambiae is well documented, and widespread agricultural use of pyrethroids may exacerbate development of resistance when pyrethroids are used in vector control. We have developed carbamate anticholinesterases that possess a high degree of An. gambiae:human selectivity for enzyme inhibition. The purpose of this study was to assess the spectrum of activity of these carbamates against other mosquitoes and agricultural pests. Experimental carbamates were potent inhibitors of mosquito acetylcholinesterases, with IC50 values in the nanomolar range. Similar potencies were observed for Musca domestica and Drosophila melanogaster enzymes. Although meta-substituted carbamates were potent inhibitors, two ortho-substituted carbamates displayed poor enzyme inhibition (IC50 ≥ 10(-6)  M) in honey bee (Apis mellifera), Asian citrus psyllid (Diaphorina citri) and lepidopteran agricultural pests (Plutella xylostella and Ostrinia nubilalis). Enzyme inhibition results were confirmed by toxicity studies in caterpillars, where the new carbamates were 2-3-fold less toxic than propoxur and up to tenfold less active than bendiocarb, indicating little utility of these compounds for crop protection. The experimental carbamates were broadly active against mosquito species but not agricultural pests, which should mitigate selection for mosquito insecticide resistance by reducing agricultural uses of these compounds. © 2014 Society of Chemical Industry. © 2014 Society of Chemical Industry.

Identification of Repellent and Insecticidal Constituents from Artemisia mongolica Essential Oil against Lasioderma serricorne

OpenAIRE

You, Chunxue; Guo, Shanshan; Zhang, Wenjuan; Yang, Kai; Geng, Zhufeng; Du, Shushan; Wang, Chengfang; Deng, Zhiwei

2015-01-01

The aims of this research were to determine the chemical composition and insecticidal and repellent activities of the Artemisia mongolica essential oil against Lasioderma serricorne and to isolate active constituents from the essential oil. The essential oil of A. mongolica was obtained by hydrodistillation and 36 components were identified with GC-MS. Eucalyptol (39.88%), (S)-cis-verbenol (14.93%), 4-terpineol (7.20%), (−)-camphor (6.02%), and α-terpineol (4.20%) were found to be major compo...

Synthesis and Insecticidal Activities of New Ester-Derivatives of Celangulin-V

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Wenjun Wu

2011-12-01

Full Text Available In order to develop new biorational pesticides, ten new 6-substituted ester derivatives of Celangulin-V were designed and synthesized. The structures of the new derivatives were confirmed by IR, 1H-NMR, 13C-NMR and ESI-MS spectral analysis. Insecticidal activities of these compounds were tested against the third-instar larvae of Mythimna separata. Two derivatives (1.1, 1.2 showed higher insecticidal activities than Celangulin-V, with mortality of 75.0% and 83.3%, respectively. While four compounds (1.3, 1.4, 1.7, 1.8 denoted lower insecticidal activities, the others (1.5, 1.6, 1.9, 1.10 revealed no activities at a concentration of 10 mg.mL−1. The results suggest that C-6 substitutions of Celangulin-V are very important in determining the insecticidal activities of its ester-derivatives. That the acetyl (1.1 and propionyl (1.2 derivatives possessed much higher insecticidal activities than Celangulin-V itself supported the view that Celangulin-V has the potential to be a lead structure of semi-synthetic green insecticides.

Interactions of an insecticide, herbicide, and natural stressors in amphibian community mesocosms

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Boone, M.D.; James, S.M.

2003-01-01

Amphibians developing in wetlands embedded within or near agricultural lands may frequently encounter chemical mixtures. The objectives of our study were to determine the effects that post-application concentrations of an insecticide (carbaryl) and an herbicide (atrazine) have on body mass, development, and survival of two anuran species (southern leopard frog, Rana sphenocephala; American toad, Bufo americanus) and two caudate species (spotted salamander, Ambystoma maculatum; small-mouthed salamander, A. texanum) reared in outdoor cattle tank mesocosms. In one experiment, we manipulated tadpole density (low or high), carbaryl exposure (0, 3.5, 7.0 mg/L), and atrazine exposure (0 or 200 μg/L) to test for effects on development, mass, and survival of larvae. In a second experiment, we manipulated pond hydroperiod (constant or drying), carbaryl exposure (0 or 5 mg/L), and atrazine exposure (0 or 200 μg/L) to test for effects on mass, time, and survival to metamorphosis. Salamanders were virtually eliminated in carbaryl treatments, indicating that at realistic levels, this insecticide could cause population declines for salamanders in contaminated habitats. Carbaryl also had negative effects on toad survival. Exposure to atrazine had negative effects on body size, development, and time to metamorphosis in anuran species, which were associated with reduced chlorophyll levels. Both chemicals interacted significantly with density or hydroperiod, indicating that the environmental conditions could influence the impact of a contaminant. A significant atrazine-by-carbaryl interaction resulted in smaller and less developed spotted salamander larvae than in control ponds. Atrazine exposure, however, appeared to moderate negative effects of carbaryl for spotted salamanders. Our research suggests that important changes in the community's food web result from chemical exposure, which influence the susceptibility of amphibian species to contaminants.

Azobenzene Modified Imidacloprid Derivatives as Photoswitchable Insecticides: Steering Molecular Activity in a Controllable Manner

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Xu, Zhiping; Shi, Lina; Jiang, Danping; Cheng, Jiagao; Shao, Xusheng; Li, Zhong

2015-10-01

Incorporating the photoisomerizable azobenzene into imidacloprid produced a photoswitchable insecticidal molecule as the first neonicotinoid example of remote control insecticide performance with spatiotemporal resolution. The designed photoswitchable insecticides showed distinguishable activity against Musca both in vivo and in vitro upon irradiation. Molecular docking study further suggested the binding difference of the two photoisomers. The generation of these photomediated insecticides provides novel insight into the insecticidal activity facilitating further investigation on the functions of insect nicotinic acetylcholine receptors and opens a novel way to control and study insect behavior on insecticide poisoning using light.

Characterizing the insecticide resistance of Anopheles gambiae in Mali.

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Cisse, Moussa B M; Keita, Chitan; Dicko, Abdourhamane; Dengela, Dereje; Coleman, Jane; Lucas, Bradford; Mihigo, Jules; Sadou, Aboubacar; Belemvire, Allison; George, Kristen; Fornadel, Christen; Beach, Raymond

2015-08-22

The impact of indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs), key components of the national malaria control strategy of Mali, is threatened by vector insecticide resistance. The objective of this study was to assess the level of insecticide resistance in Anopheles gambiae sensu lato populations from Mali against four classes of insecticide recommended for IRS: organochlorines (OCs), pyrethroids (PYs), carbamates (CAs) and organophosphates (OPs). Characterization of resistance was done in 13 sites across southern Mali and assessed presence and distribution of physiological mechanisms that included target-site modifications: knockdown resistance (kdr) and altered acetycholinesterase (AChE), and/or metabolic mechanisms: elevated esterases, glutathione S-transferases (GSTs), and monooxygenases. The World Health Organization (WHO) tube test was used to determine phenotypic resistance of An. gambiae s.l. to: dichlorodiphenyltrichloroethane (DDT) (OC), deltamethrin (PY), lambda-cyhalothrin (PY), bendiocarb (CA), and fenitrothion (OP). Identification of sibling species and presence of the ace-1 (R) and Leu-Phe kdr, resistance-associated mutations, were determined using polymerase chain reaction (PCR) technology. Biochemical assays were conducted to detect increased activity of GSTs, oxidases and esterases. Populations tested showed high levels of resistance to DDT in all 13 sites, as well as increased resistance to deltamethrin and lambda-cyhalothrin in 12 out of 13 sites. Resistance to fenitrothion and bendiocarb was detected in 1 and 4 out of 13 sites, respectively. Anopheles coluzzii, An. gambiae sensu stricto and Anopheles arabiensis were identified with high allelic frequencies of kdr in all sites where each of the species were found (13, 12 and 10 sites, respectively). Relatively low allelic frequencies of ace-1 (R) were detected in four sites where this assessment was conducted. Evidence of elevated insecticide metabolism, based on oxidase

Pharmacological treatment of organophosphorus insecticide poisoning: the old and the (possible) new.

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Eddleston, Michael; Chowdhury, Fazle Rabbi

2016-03-01

Despite being a major clinical and public health problem across the developing world, responsible for at least 5 million deaths over the last three decades, the clinical care of patients with organophosphorus (OP) insecticide poisoning has little improved over the last six decades. We are still using the same two antidotes - atropine and oximes - that first came into clinical use in the late 1950s. Clinical research in South Asia has shown how improved regimens of atropine can prevent deaths. However, we are still unsure about which patients are most likely to benefit from the use of oximes. Supplemental antidotes, such as magnesium, clonidine and sodium bicarbonate, have all been proposed and studied in small trials without production of definitive answers. Novel antidotes such as nicotinic receptor antagonists, beta-adrenergic agonists and lipid emulsions are being studied in large animal models and in pilot clinical trials. Hopefully, one or more of these affordable and already licensed antidotes will find their place in routine clinical care. However, the large number of chemically diverse OP insecticides, the varied poisoning they produce and their varied response to treatment might ultimately make it difficult to determine definitively whether these antidotes are truly effective. In addition, the toxicity of the varied solvents and surfactants formulated with the OP active ingredients complicates both treatment and studies. It is possible that the only effective way to reduce deaths from OP insecticide poisoning will be a steady reduction in their agricultural use worldwide. © 2015 The British Pharmacological Society.

Probabilistic risk assessment of insecticide concentrations in agricultural surface waters: a critical appraisal.

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Stehle, Sebastian; Knäbel, Anja; Schulz, Ralf

2013-08-01

Due to the specific modes of action and application patterns of agricultural insecticides, the insecticide exposure of agricultural surface waters is characterized by infrequent and short-term insecticide concentration peaks of high ecotoxicological relevance with implications for both monitoring and risk assessment. Here, we apply several fixed-interval strategies and an event-based sampling strategy to two generalized and two realistic insecticide exposure patterns for typical agricultural streams derived from FOCUS exposure modeling using Monte Carlo simulations. Sampling based on regular intervals was found to be inadequate for the detection of transient insecticide concentrations, whereas event-triggered sampling successfully detected all exposure incidences at substantially lower analytical costs. Our study proves that probabilistic risk assessment (PRA) concepts in their present forms are not appropriate for a thorough evaluation of insecticide exposure. Despite claims that the PRA approach uses all available data to assess exposure and enhances risk assessment realism, we demonstrate that this concept is severely biased by the amount of insecticide concentrations below detection limits and therefore by the sampling designs. Moreover, actual insecticide exposure is of almost no relevance for PRA threshold level exceedance frequencies and consequential risk assessment outcomes. Therefore, we propose a concept that features a field-relevant ecological risk analysis of agricultural insecticide surface water exposure. Our study quantifies for the first time the environmental and economic consequences of inappropriate monitoring and risk assessment concepts used for the evaluation of short-term peak surface water pollutants such as insecticides.

The impact of insecticides to local honey bee colony Apis cerana indica in laboratory condition

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Putra, Ramadhani E.; Permana, Agus D.; Nuriyah, Syayidah

2014-03-01

Heavy use of insecticides considered as one of common practice at local farming systems. Even though many Indonesian researchers had stated the possible detrimental effect of insecticide on agriculture environment and biodiversity, researches on this subject had been neglected. Therefore, our purpose in this research is observing the impact of insecticides usage by farmer to non target organisme like local honey bee (Apis cerana indica), which commonly kept in area near agriculture system. This research consisted of field observations out at Ciburial, Dago Pakar, Bandung and laboratory tests at School of Life Sciences and Technology, Institut Teknologi Bandung. The field observations recorded visited agriculture corps and types of pollen carried by bees to the nest while laboratory test recorderd the effect of common insecticide to mortality and behavior of honey bees. Three types of insecticides used in this research were insecticides A with active agent Chlorantraniliprol 50 g/l, insecticide B with active agent Profenofos 500 g/l, and insecticides C with active agent Chlorantraniliprol 100 g/l and λ-cyhalotrin 50g/l. The results show that during one week visit, wild flower, Wedelia montana, visited by most honey bees with average visit 60 honey bees followed by corn, Zea mays, with 21 honey bees. The most pollen carried by foragers was Wedelia montana, Calliandra callothyrsus, and Zea mays. Preference test show that honeybees tend move to flowers without insecticides as the preference to insecticides A was 12.5%, insecticides B was 0%, and insecticides was C 4.2%. Mortality test showed that insecticides A has LD50 value 0.01 μg/μl, insecticide B 0.31 μg/μl, and insecticides C 0.09 μg/μl which much lower than suggested dosage recommended by insecticides producer. This research conclude that the use of insecticide could lower the pollination service provide by honey bee due to low visitation rate to flowers and mortality of foraging bees.

Tea saponin reduces the damage of Ectropis obliqua to tea crops, and exerts reduced effects on the spiders Ebrechtella tricuspidata and Evarcha albaria compared to chemical insecticides

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Chi Zeng

2018-03-01

Full Text Available Background Tea is one of the most economically important crops in China. However, the tea geometrid (Ectropis obliqua, a serious leaf-feeding pest, causes significant damage to tea crops and reduces tea yield and quality. Spiders are the most dominant predatory enemies in the tea plantation ecosystem, which makes them potentially useful biological control agents of E. obliqua. These highlight the need for alternative pest control measures. Our previous studies have shown that tea saponin (TS exerts insecticidal activity against lepidopteran pests. Here, we investigate whether TS represents a potentially new alternative insecticide with no harm to spiders. Methods We investigated laboratory bioactivities and the field control properties of TS solution against E. obliqua. (i A leaf-dip bioassay was used to evaluate the toxicity of TS to 3rd-instar E. obliqua larvae and effects of TS on the activities of enzymes glutathione-S-transferase (GST, acetylcholinesterase (AChE, carboxylesterase (CES and peroxidase (POD of 3rd-instar E. obliqua larvae in the laboratory. (ii Topical application was used to measure the toxicity of 30% TS (w/v and two chemical insecticides (10% bifenthrin EC and 50% diafenthiuron SC to two species of spider, Ebrechtella tricuspidata and Evarcha albaria. (iii Field trials were used to investigate the controlling efficacy of 30% TS against E. obliqua larvae and to classify the effect of TS to spiders in the tea plantation. Results The toxicity of TS to 3rd-instar E. obliqua larvae occurred in a dose-dependent manner and the LC50 was 164.32 mg/mL. Activities of the detoxifying-related enzymes, GST and POD, increased in 3rd-instar E. obliqua larvae, whereas AChE and CES were inhibited with time by treatment with TS. Mortalities of E. tricuspidata and E. albaria after 48 h with 30% TS treatment (16.67% and 20%, respectively were significantly lower than those with 10% bifenthrin EC (80% and 73.33%, respectively and 50

Insights from agriculture for the management of insecticide resistance in disease vectors.

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Sternberg, Eleanore D; Thomas, Matthew B

2018-04-01

Key to contemporary management of diseases such as malaria, dengue, and filariasis is control of the insect vectors responsible for transmission. Insecticide-based interventions have contributed to declines in disease burdens in many areas, but this progress could be threatened by the emergence of insecticide resistance in vector populations. Insecticide resistance is likewise a major concern in agriculture, where insect pests can cause substantial yield losses. Here, we explore overlaps between understanding and managing insecticide resistance in agriculture and in public health. We have used the Global Plan for Insecticide Resistance Management in malaria vectors, developed under the auspices of the World Health Organization Global Malaria Program, as a framework for this exploration because it serves as one of the few cohesive documents for managing a global insecticide resistance crisis. Generally, this comparison highlights some fundamental differences between insect control in agriculture and in public health. Moreover, we emphasize that the success of insecticide resistance management strategies is strongly dependent on the biological specifics of each system. We suggest that the biological, operational, and regulatory differences between agriculture and public health limit the wholesale transfer of knowledge and practices from one system to the other. Nonetheless, there are some valuable insights from agriculture that could assist in advancing the existing Global Plan for Insecticide Resistance Management framework.

Insecticide use in hybrid onion seed production affects pre- and postpollination processes.

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Gillespie, Sandra; Long, Rachael; Seitz, Nicola; Williams, Neal

2014-02-01

Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields.

Susceptibility of Australian Myzus persicae (Hemiptera: Aphididae) to Three Recently Registered Insecticides: Spirotetramat, Cyantraniliprole, and Sulfoxaflor.

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de Little, Siobhan C; Umina, Paul A

2017-08-01

The green peach aphid, Myzus persicae (Sulzer), is a significant agricultural pest that has developed resistance to a large number of insecticides globally. Within Australia, resistance has previously been confirmed for multiple chemical groups, including pyrethroids, carbamates, organophosphates, and neonicotinoids. In this study, we use leaf-dip and topical bioassays to investigate susceptibility and potential cross-resistance of 12 field-collected populations of Australian M. persicae to three recently registered insecticides: sulfoxaflor, spirotetramat, and cyantraniliprole. Despite all 12 populations carrying known resistance mechanisms to carbamates, organophosphates, and pyrethroids, and two populations also exhibiting low-level metabolic resistance to neonicotinoids, we found little evidence of variation in susceptibility to sulfoxafor, spirotetramat, or cyantraniliprole. This provides further evidence that cross-resistance to spirotetramat, cyantraniliprole, and sulfoxaflor in M. persicae is not conferred by the commonly occurring resistance mechanisms MACE, super-kdr, amplification of the E4 esterase gene, or enhanced expression and copy number of the P450 gene, CYP6CY3. Importantly, this study also established toxicity baseline data that will be important for future monitoring of insecticide responses of M. persicae from both broadacre and horticultural crops. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Posttreatment Feeding Affects Mortality of Bed Bugs (Hemiptera: Cimicidae) Exposed to Insecticides.

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Singh, Narinderpal; Wang, Changlu; Cooper, Richard

2016-02-01

Insecticide sprays and dusts are used for controlling bed bugs, Cimex lectularius L. In natural environments, bed bugs have daily access to hosts after they are exposed to insecticides. The established laboratory insecticide bioassay protocols do not provide feeding after insecticide treatments, which can result in inflated mortality compared with what would be encountered in the field. We evaluated the effect of posttreatment feeding on mortality of bed bugs treated with different insecticides. None of the insecticides tested had a significant effect on the amount of blood consumed and percent feeding. The effect of posttreatment feeding on bed bug mortality varied among different insecticides. Feeding significantly reduced mortality in bed bugs exposed to deltamethrin spray, an essential oil mixture (Bed Bug Fix) spray, and diatomaceous earth dust. Feeding increased the mean survival time for bed bugs treated with chlorfenapyr spray and a spray containing an essential oil mixture (Ecoraider), but did not affect the final mortality. First instars hatched from eggs treated with chlorfenapyr liquid spray had reduced feeding compared with nymphs hatched from nontreated eggs. Those nymphs hatched from eggs treated with chlorfenapyr liquid spray and successfully fed had reduced mortality and a higher mean survival time than those without feeding. We conclude that the availability of a bloodmeal after insecticide exposure has a significant effect on bed bug mortality. Protocols for insecticide efficacy testing should consider offering a bloodmeal to the treated bed bugs within 1 to 3 d after treatment. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Modes of Action, Resistance and Toxicity of Insecticides Targeting Nicotinic Acetylcholine Receptors.

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Ihara, Makoto; Buckingham, Steven D; Matsuda, Kazuhiko; Sattelle, David B

2017-01-01

Nicotinic acetylcholine receptors (nAChRs) of insects play a key role in fast excitatory neurotransmission. Several classes of insecticides target insect nAChRs, which are composed of subunit members of a family of multiple subunit encoding genes. Alternative splicing and RNA A-to-I editing can add further to receptor diversity. Native and recombinant receptors have been explored as sites of insecticide action using radioligands, electrophysiology and site-directed mutagenesis. We have reviewed the properties of native and recombinant insect nAChRs, the challenges of functional recombinant insect nAChR expression, nAChR interactions with ligands acting at orthosteric and allosteric sites and in particular their interactions with insecticides. Actions on insect nAChRs of cartap, neonicotinoids, spinosyns, sulfoxamines, butenolides and mesoionic insecticides are reviewed and current knowledge of their modes of action are addressed. Mutations that add to our understanding of insecticide action and those leading to resistance are discussed. Co-crystallisation of neonicotinoids with the acetylcholine binding protein (AChBP), a surrogate for the nAChR ligand binding domain, has proved instructive. Toxicity issues relating to insecticides targeting nAChRs are also considered. An overview of insecticide classes targeting insect nAChRs has enhanced our understanding of these important receptors and their insecticide binding sites. However, the subunit composition of native nAChRs remains poorly understood and functional expression still presents difficulties. These topics together with improved understanding of the precise sites of insecticide actions on insect nAChRs will be the subject of future research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Insecticidal activities and phytochemical screening of crude extracts and its derived fractions from three medicinal plants Nepeta leavigata, Nepeta kurramensis and Rhynchosia reniformis

International Nuclear Information System (INIS)

Ahmad, N.; Shinwari, Z.K.

2016-01-01

The extracts and its derived fractions from three medicinal plants species Nepeta leavigata, Nepeta kurramensis and Rhynchosia reniformis were tested for insecticidal activities and preliminary phytochemical evaluation with the intention of standardization and proper manage of bioactive principles in such heterogonous botanicals and to encourage drug finding work with plants. The crude extracts and fractions from Nepeta plants showed moderate to strong insecticidal activity. Among the fractions from Nepeta kurramensis the n-butanol fraction showed strongest insecticidal activity with 89% mortality rate against Tribolium castaneum followed by methanol extract with 88% mortality ratio and in case of Nepeta leavigata the potential activity was showed by methanol extracts with 93% mortality rate against the tested insect. Surprisingly none of the extract / fractions obtained from Rhynchosia reniformis plant exhibited any insecticidal activity. The phytochemicals screening results revealed that both species of Nepeta showed similar phytochemicals profile. The group of chemicals terpenes, flavonoids and glycosides were observed in all the extracts/fractions of Nepeta plants. While phenolic compounds, acidic compounds and alkaloids were found in methanolic extracts, chloroform fraction and ethyl acetate fraction. The Rhynchosia reniformis was observed to be a good source of phenolic compounds, flavonoids, terpenes, alkaloids and fats. (author)

Seasonal fluctuation in susceptibility to insecticides within natural populations of Drosophila melanogaster. II. Features of genetic variation in susceptibility to organophosphate insecticides within natural populations of D. melanogaster.

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Miyo, Takahiro; Oguma, Yuzuru; Charlesworth, Brian

2006-08-01

To elucidate genetic variation in susceptibility to organophosphate insecticides within natural populations of Drosophila melanogaster, we conducted an analysis of variance for mortality data sets of isofemale lines (10-286 lines) used in the previous studies. Susceptibility of isofemale lines to the three organophosphate insecticides was continuously distributed within each natural population, ranging from susceptible to resistant. Analysis of variance showed highly significant variation among isofemale lines in susceptibility to each insecticide for each natural population. Significant genetic variances in susceptibility to the three chemicals were estimated for the Katsunuma population; 0.0529-0.2722 for malathion, 0.0492-0.1603 for prothiophos, and 0.0469-0.1696 for fenitrothion. Contrary to the consistent seasonal tendency towards an increase in mean susceptibility in the fall, reported in the previous study, genetic variances in susceptibility to the three organophosphates did not change significantly in 1997 but tended to increase by 2- to 5-times in 1998. We tested whether both the observed situations, maintenance and increase in genetic variance in organophosphate resistance, can be generated under circumstances in which the levels of resistance to the three organophosphates tended to decrease, by conducting a simulation analysis, based on the hypothesis that resistant genotypes have lower fitnesses than susceptible ones under the density-independent condition. The simulation analysis generally explained the pattern in the mean susceptibility and genetic variances in susceptibility to the three organophosphates, observed in the Katsunuma population of D. melanogaster. It was suggested that the differences in the frequencies of resistance genes in the summer population could affect the patterns in genetic variance in organophosphate resistance in the fall population.

The Insecticide Imidacloprid Causes Mortality of the Freshwater Amphipod Gammarus pulex by Interfering with Feeding Behavior

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Nyman, Anna-Maija; Hintermeister, Anita; Schirmer, Kristin; Ashauer, Roman

2013-01-01

If an organism does not feed, it dies of starvation. Even though some insecticides which are used to control pests in agriculture can interfere with feeding behavior of insects and other invertebrates, the link from chemical exposure via affected feeding activity to impaired life history traits, such as survival, has not received much attention in ecotoxicology. One of these insecticides is the neonicotinoid imidacloprid, a neurotoxic substance acting specifically on the insect nervous system. We show that imidacloprid has the potential to indirectly cause lethality in aquatic invertebrate populations at low, sublethal concentrations by impairing movements and thus feeding. We investigated feeding activity, lipid content, immobility, and survival of the aquatic arthropod Gammarus pulex under exposure to imidacloprid. We performed experiments with 14 and 21 days duration, both including two treatments with two high, one day pulses of imidacloprid and one treatment with a low, constant concentration. Feeding of G. pulex as well as lipid content were significantly reduced under exposure to the low, constant imidacloprid concentration (15 µg/L). Organisms were not able to move and feed – and this caused high mortality after 14 days of constant exposure. In contrast, feeding and lipid content were not affected by repeated imidacloprid pulses. In these treatments, animals were mostly immobilized during the chemical pulses but did recover relatively fast after transfer to clean water. We also performed a starvation experiment without exposure to imidacloprid which showed that starvation alone does not explain the mortality in the constant imidacloprid exposure. Using a multiple stressor toxicokinetic-toxicodynamic modeling approach, we showed that both starvation and other toxic effects of imidacloprid play a role for determining mortality in constant exposure to the insecticide. PMID:23690941

The insecticide imidacloprid causes mortality of the freshwater amphipod Gammarus pulex by interfering with feeding behavior.

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Anna-Maija Nyman

Full Text Available If an organism does not feed, it dies of starvation. Even though some insecticides which are used to control pests in agriculture can interfere with feeding behavior of insects and other invertebrates, the link from chemical exposure via affected feeding activity to impaired life history traits, such as survival, has not received much attention in ecotoxicology. One of these insecticides is the neonicotinoid imidacloprid, a neurotoxic substance acting specifically on the insect nervous system. We show that imidacloprid has the potential to indirectly cause lethality in aquatic invertebrate populations at low, sublethal concentrations by impairing movements and thus feeding. We investigated feeding activity, lipid content, immobility, and survival of the aquatic arthropod Gammarus pulex under exposure to imidacloprid. We performed experiments with 14 and 21 days duration, both including two treatments with two high, one day pulses of imidacloprid and one treatment with a low, constant concentration. Feeding of G. pulex as well as lipid content were significantly reduced under exposure to the low, constant imidacloprid concentration (15 µg/L. Organisms were not able to move and feed--and this caused high mortality after 14 days of constant exposure. In contrast, feeding and lipid content were not affected by repeated imidacloprid pulses. In these treatments, animals were mostly immobilized during the chemical pulses but did recover relatively fast after transfer to clean water. We also performed a starvation experiment without exposure to imidacloprid which showed that starvation alone does not explain the mortality in the constant imidacloprid exposure. Using a multiple stressor toxicokinetic-toxicodynamic modeling approach, we showed that both starvation and other toxic effects of imidacloprid play a role for determining mortality in constant exposure to the insecticide.

Insecticidal activity of Piper essential oils from the Amazon against the fire ant Solenopsis saevissima (Smith) (Hymenoptera: Formicidae).

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Souto, R N P; Harada, A Y; Andrade, E H A; Maia, J G S

2012-12-01

Pepper plants in the genus Piper (Piperales: Piperaceae) are common in the Brazilian Amazon and many produce compounds with biological activity against insect pests. We evaluated the insecticidal effect of essential oils from Piper aduncum, Piper marginatum (chemotypes A and B), Piper divaricatum and Piper callosum against workers of the fire ant Solenopsis saevissima (Smith) (Hymenoptera: Formicidae), as well as their chemical composition by gas chromatography and gas chromatography-mass spectrometry. The lowest median lethal concentration (LC50) in 48 h was obtained with the oil of P. aduncum (58.4 mg/L), followed by the oils of P. marginatum types A (122.4 mg/L) and B (167.0 mg/L), P. divaricatum (301.7 mg/L), and P. callosum (312.6 mg/L). The major chemical constituents were dillapiole (64.4%) in the oil of P. aduncum; p-mentha-1(7),8-diene (39.0%), 3,4-methylenedioxypropiophenone (19.0%), and (E)-β-ocimene (9.8%) in P. marginatum chemotype A and (E)-isoosmorhizole (32.2%), (E)-anethole (26.4%), isoosmorhizole (11.2%), and (Z)-anethole (6.0%) in P. marginatum chemotype B; methyleugenol (69.2%) and eugenol (16.2%) in P. divaricatum; and safrole (69.2%), methyleugenol (8.6%), and β-pinene (6.2%) in P. callosum. These chemical constituents have been previously known to possess insecticidal properties.

Development of Environment-Friendly Insecticides Based on Enantioselectivity: Bifenthrin as a Case.

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Qian, Yi; Zhou, Peixue; Zhang, Quan

2017-01-01

Chiral insecticides significantly contribute to the environmental pollutions recently. As the development of industry and agriculture, increasing number of chiral insecticides are to be introduced into the market. However, their enantioselective toxicology to ecosystem still remains uncertain. In this review, we embarked on a structured search of bibliographic databases for peer-reviewed articles regarding the enantioselective effects of bifenthrin, a typical chiral insecticide, on both target and non-target species. With this enantioselective property of chiral insecticides, they often exhibit adverse effects on non-target species enantioselectively. Specifically, the enantioselective effects of bifenthrin on target and non-target organisms were discussed. In target species, R-bifenthrin exerts more significant activities in deinsectization, compared with S-bifenthrin. On the other hand, Sbifenthrin is more toxic to non-target species than R-bifenthrin, which suggests that the application of sole enantiomer is more efficient and environment-friendly than that of racemate. This review confirms the choice of environment-friendly insecticides from the perspective of the enantioselectivity of chiral insecticides. To make insecticides more efficient to target species and less toxic to non-target species, further research should be done to investigated the potential effects of targetactive enantiomers on non-target organisms as well as the enantioselective fate of enantiomers in multiple environmental matrix.

Identification and cloning of two insecticidal protein genes from ...

African Journals Online (AJOL)

Bacillus thuringiensis (Bt) is the most widely applied type of microbial pesticide due to its high specificity and environmental safety. The activity of Bt is largely attributed to the insecticidal crystal protein encoded by the cry genes. Different insecticidal crystal proteins of Bt have different bioactivity against distinct agricultural ...

Organophosphate insecticide poisoning of Canada geese in the Texas panhandle

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White, D.H.; Mitchell, C.A.; Wynn, L.D.; Flickinger, Edward L.; Kolbe, E.J.

1982-01-01

Sixteen hundred waterfowl, mostly Canada Geese, died near Etter, Texas, in late January 1981 from anticholinesterase poisoning. Winter wheat in the area of the die-off had been treated with organophosphate insecticides to control greenbugs. Cholinesterase (ChE) levels in brains of a sample of geese found dead were 75% below normal, enough to account for death (Ludke et al. 1975). The gastrointestinal (G I) tracts of geese found dead were packed with winter wheat; gas chromatography techniques identified parathion and methyl parathion in the GI tract contents. Residues of both chemicals were confirmed by mass spectrometry. We recommend that less toxic materials, such as malathion, be used on grain crops when waterfowl are in the vicinity of treatment.

Insecticide-mediated apparent displacement between two invasive species of leafminer fly.

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Yulin Gao

Full Text Available BACKGROUND: Closely related invasive species may often displace one another, but it is often difficult to determine mechanisms because of the historical nature of these events. The leafmining flies Liriomyza sativae and Liriomyza trifolii have become serious invasive agricultural pests throughout the world. Where both species have invaded the same region, one predominates over the other. Although L. sativae invaded Hainan Island of China first, it recently has been displaced by the newly invasive L. trifolii. We hypothesized that differential susceptibilities to insecticides could be causing this demographic shift. METHODOLOGY/PRINCIPAL FINDINGS: Avermectin and cyromazine are the most commonly used insecticides to manage leafminers, with laboratory bioassays demonstrating that L. trifolii is significantly less susceptible to these key insecticides than is L. sativae. In trials where similar numbers of larvae of both species infested plants, which subsequently were treated with the insecticides, the eclosing adults were predominately L. trifolii, yet similar numbers of adults of both species eclosed from control plants. The species composition was then surveyed in two regions where L. trifolii has just begun to invade and both species are still common. In field trials, both species occurred in similar proportions before insecticide treatments began. Following applications of avermectin and cyromazine, almost all eclosing adults were L. trifolii in those treatment plots. In control plots, similar numbers of adults of the two species eclosed, lending further credence to the hypothesis that differential insecticide susceptibilities could be driving the ongoing displacement of L. sativae by L. trifolii. CONCLUSIONS/SIGNIFICANCE: Our results show that differential insecticide susceptibility can lead to rapid shifts in the demographics of pest complexes. Thus, successful pest management requires the identification of pest species to understand the

Climate change, agricultural insecticide exposure, and risk for freshwater communities.

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Kattwinkel, Mira; Kühne, Jan-Valentin; Foit, Kaarina; Liess, Matthias

2011-09-01

Climate change exerts direct effects on ecosystems but has additional indirect effects due to changes in agricultural practice. These include the increased use of pesticides, changes in the areas that are cultivated, and changes in the crops cultivated. It is well known that pesticides, and in particular insecticides, affect aquatic ecosystems adversely. To implement effective mitigation measures it is necessary to identify areas that are affected currently and those that will be affected in the future. As a consequence, we predicted potential exposure to insecticide (insecticide runoff potential, RP) under current conditions (1990) and under a model scenario of future climate and land use (2090) using a spatially explicit model on a continental scale, with a focus on Europe. Space-for-time substitution was used to predict future levels of insecticide application, intensity of agricultural land use, and cultivated crops. To assess the indirect effects of climate change, evaluation of the risk of insecticide exposure was based on a trait-based, climate-insensitive indicator system (SPEAR, SPEcies At Risk). To this end, RP and landscape characteristics that are relevant for the recovery of affected populations were combined to estimate the ecological risk (ER) of insecticides for freshwater communities. We predicted a strong increase in the application of, and aquatic exposure to, insecticides under the future scenario, especially in central and northern Europe. This, in turn, will result in a severe increase in ER in these regions. Hence, the proportion of stream sites adjacent to arable land that do not meet the requirements for good ecological status as defined by the EU Water Framework Directive will increase (from 33% to 39% for the EU-25 countries), in particular in the Scandinavian and Baltic countries (from 6% to 19%). Such spatially explicit mapping of risk enables the planning of adaptation and mitigation strategies including vegetated buffer strips and

Residual Acute Toxicity of Some Modern Insecticides Toward Two Mirid Predators of Tomato Pests.

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Wanumen, Andrea C; Carvalho, Geraldo A; Medina, Pilar; Viñuela, Elisa; Adán, Ángeles

2016-03-31

The successful integration of chemical and biological control strategies for crop pests depends on a thorough evaluation of the effects of pesticides on the natural enemies of pests. A case-by-case review is difficult to achieve because of the many combinations of pests, natural enemies, and crops that need to be tested. Within this framework, we tested and compared seven insecticides representative of four different modes of action (MoAs) groups on closely related predators (Miridae): flubendiamide, spirotetramat, metaflumizone, and sulfoxaflor onNesidiocoris tenuisReuter and flubendiamide, spiromesifen, indoxacarb, and imidacloprid onMacrolophus basicornis(Stal). We follow the standardized methodology of the International Organization for Biological Control, a sequential testing exposure scheme. The lethal effect of each insecticide was evaluated in adults after three days of contact with treated surfaces in the laboratory, extended laboratory, and semifield tests (inert substrate, tomato leaves, and tomato plant as the treated surface, respectively). Flubendiamide, spiromesifen, and spirotetramat were classified as harmless (class 1), metaflumizone was slightly harmful (class 2) but persistent, indoxacarb was harmless (class 1), and sulfoxaflor and imidacloprid were toxic (class 4) and exhibited a long residual activity. Our results suggest similarities in the acute toxicities of insecticides from the same MoA group on related species of natural enemies. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Insecticide susceptibility of Anopheles mosquitoes changes in response to variations in the larval environment.

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Owusu, Henry F; Chitnis, Nakul; Müller, Pie

2017-06-16

Insecticide resistance threatens the success achieved through vector control in reducing the burden of malaria. An understanding of insecticide resistance mechanisms would help to develop novel tools and strategies to restore the efficacy of insecticides. Although we have substantially improved our understanding of the genetic basis of insecticide resistance over the last decade, we still know little of how environmental variations influence the mosquito phenotype. Here, we measured how variations in larval rearing conditions change the insecticide susceptibility phenotype of adult Anopheles mosquitoes. Anopheles gambiae and A. stephensi larvae were bred under different combinations of temperature, population density and nutrition, and the emerging adults were exposed to permethrin. Mosquitoes bred under different conditions showed considerable changes in mortality rates and body weight, with nutrition being the major factor. Weight is a strong predictor of insecticide susceptibility and bigger mosquitoes are more likely to survive insecticide treatment. The changes can be substantial, such that the same mosquito colony may be considered fully susceptible or highly resistant when judged by World Health Organization discriminatory concentrations. The results shown here emphasise the importance of the environmental background in developing insecticide resistance phenotypes, and caution for the interpretation of data generated by insecticide susceptibility assays.

Country-level operational implementation of the Global Plan for Insecticide Resistance Management.

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Hemingway, Janet; Vontas, John; Poupardin, Rodolphe; Raman, Jaishree; Lines, Jo; Schwabe, Chris; Matias, Abrahan; Kleinschmidt, Immo

2013-06-04

Malaria control is reliant on the use of long-lasting pyrethroid-impregnated nets and/or indoor residual spraying (IRS) of insecticide. The rapid selection and spread of operationally significant pyrethroid resistance in African malaria vectors threatens our ability to sustain malaria control. Establishing whether resistance is operationally significant is technically challenging. Routine monitoring by bioassay is inadequate, and there are limited data linking resistance selection with changes in disease transmission. The default is to switch insecticides when resistance is detected, but limited insecticide options and resistance to multiple insecticides in numerous locations make this approach unsustainable. Detailed analysis of the resistance situation in Anopheles gambiae on Bioko Island after pyrethroid resistance was detected in this species in 2004, and the IRS program switched to carbamate bendiocarb, has now been undertaken. The pyrethroid resistance selected is a target-site knock-down resistance kdr-form, on a background of generally elevated metabolic activity, compared with insecticide-susceptible A. gambiae, but the major cytochrome P450-based metabolic pyrethroid resistance mechanisms are not present. The available evidence from bioassays and infection data suggests that the pyrethroid resistance mechanisms in Bioko malaria vectors are not operationally significant, and on this basis, a different, long-lasting pyrethroid formulation is now being reintroduced for IRS in a rotational insecticide resistance management program. This will allow control efforts to be sustained in a cost-effective manner while reducing the selection pressure for resistance to nonpyrethroid insecticides. The methods used provide a template for evidence-based insecticide resistance management by malaria control programs.

Interactions of transgenic Bacillus thuringiensis insecticidal crops with spiders (Araneae)

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Genetically modified crops expressing insecticidal proteins from Bacillus thuringiensis (Bt) have dramatically increased in acreage since their introduction in the mid-1990’s. Although the insecticidal mechanisms of Bt target specific pests, concerns persist regarding direct and indirect effects on...

The response of natural enemies to selective insecticides applied to soybean.

Science.gov (United States)

Varenhorst, A J; O'Neal, M E

2012-12-01

Natural enemies of the invasive pest Aphis glycines Matsumura can prevent its establishment and population growth. However, current A. glycines management practices include the application of broad-spectrum insecticides that affect pests and natural enemies that are present in the field at the time of application. An alternative is the use of selective insecticides that affect the targeted pest species, although having a reduced impact on the natural enemies. We tested the effects of esfenvalerate, spirotetramat, imidacloprid, and a combination of spirotetramat and imidacloprid on the natural enemies in soybean during the 2009 and 2010 field season. The natural enemy community that was tested differed significantly between 2009 and 2010 (F = 87.41; df = 1, 598; P natural enemy in 2009 was Harmonia axyridis (Pallas) (56.0%) and in 2010 was Orius insidiosus (Say) (41.0%). During 2009, the abundance of natural enemies did not vary between the broad-spectrum and selective insecticides; however, the abundance of natural enemies was reduced by all insecticide treatments when compared with the untreated control. In 2010, the selective insecticide imidacloprid had more natural enemies than the broad-spectrum insecticide. Although we did not observe a difference in the abundance of the total natural enemy community in 2009, we did observe more H. axyridis in plots treated with spirotetramat. In 2010, we observed more O. insidiosus in plots treated with imidacloprid. We suggest a couple of mechanisms to explain how the varying insecticides have different impacts on separate components of the natural enemy community.

Ternary toxicological interactions of insecticides, herbicides, and a heavy metal on the earthworm Eisenia fetida

International Nuclear Information System (INIS)

Wang, Yanhua; Chen, Chen; Qian, Yongzhong; Zhao, Xueping; Wang, Qiang

2015-01-01

Highlights: • The combined toxicity of insecticides, herbicides, and a heavy metal was examined. • Acute earthworm toxicity assays were conducted in twenty-one ternary mixtures. • Synergism predominated in the majority of the mixtures at low effect levels. • Combination index method could more accurately predict the combined toxicity. - Abstract: The combined toxicities of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor), and a heavy metal (cadmium) have been examined using the acute toxicity test on the earthworm. With a concentration of 2.75 mg/kg being lethal for 50% of the organisms, imidacloprid exhibited the highest acute toxicity toward the earthworm Eisenia fetida. Toxicological interactions of these chemicals in ternary mixtures were studied using the combination-index (CI) equation method. Twenty-one ternary mixtures exhibited various interactive effects, in which 11 combinations showed synergistic effects, four led to dual synergistic/additive behaviors, one exhibited an additive effect, and five showed increasing antagonism within the entire range of effects. The CI method was compared with the classical models of concentration addition and independent action, and it was found that the CI method could accurately predict combined toxicity of the chemicals studied. The predicted synergism in the majority of the mixtures, especially at low-effect levels, might have implications in the real terrestrial environment

Ternary toxicological interactions of insecticides, herbicides, and a heavy metal on the earthworm Eisenia fetida

Energy Technology Data Exchange (ETDEWEB)

Wang, Yanhua [State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021 (China); Chen, Chen [Key Laboratory of Agro-Product Quality and Safety of Ministry of Agriculture, Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); Qian, Yongzhong, E-mail: qyzcaas@aliyun.com [Key Laboratory of Agro-Product Quality and Safety of Ministry of Agriculture, Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081 (China); Zhao, Xueping [State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021 (China); Wang, Qiang, E-mail: qiangwang2003@vip.sina.com [State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control/Key Laboratory for Pesticide Residue Detection of Ministry of Agriculture, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021 (China)

2015-03-02

Highlights: • The combined toxicity of insecticides, herbicides, and a heavy metal was examined. • Acute earthworm toxicity assays were conducted in twenty-one ternary mixtures. • Synergism predominated in the majority of the mixtures at low effect levels. • Combination index method could more accurately predict the combined toxicity. - Abstract: The combined toxicities of five insecticides (chlorpyrifos, avermectin, imidacloprid, λ-cyhalothrin, and phoxim), two herbicides (atrazine and butachlor), and a heavy metal (cadmium) have been examined using the acute toxicity test on the earthworm. With a concentration of 2.75 mg/kg being lethal for 50% of the organisms, imidacloprid exhibited the highest acute toxicity toward the earthworm Eisenia fetida. Toxicological interactions of these chemicals in ternary mixtures were studied using the combination-index (CI) equation method. Twenty-one ternary mixtures exhibited various interactive effects, in which 11 combinations showed synergistic effects, four led to dual synergistic/additive behaviors, one exhibited an additive effect, and five showed increasing antagonism within the entire range of effects. The CI method was compared with the classical models of concentration addition and independent action, and it was found that the CI method could accurately predict combined toxicity of the chemicals studied. The predicted synergism in the majority of the mixtures, especially at low-effect levels, might have implications in the real terrestrial environment.

Comparison of ingestion and topical application of insecticides against the common bed bug, Cimex lectularius (Hemiptera: Cimicidae)

Science.gov (United States)

Sierras, Angela; Schal, Coby

2016-01-01

Background The global prevalence of Cimex lectularius infestations has challenged current intervention efforts, as pyrethroid resistance has become ubiquitous, availability of labeled insecticides for bed bugs is limited, and non-chemical treatment options, such as heat, are often unaffordable. We evaluated representative insecticides toward the goal of developing a novel, ingestible liquid bait for hematophagous arthropods. Results LC50 values were estimated for adult males and first instar nymphs of an insecticide-susceptible strain for abamectin, clothianidin, fipronil and indoxacarb, after ingestion from an in vitro feeder. LD50 values were calculated based on the ingested blood volume. Ingested abamectin, clothianidin and fipronil caused rapid mortality in both life stages. Fipronil was ∼43-fold more effective by ingestion than by topical application. Indoxacarb and its bioactive metabolite decarbomethoxyllated JW062 (DCJW) were ineffective at causing bed bug mortality even at concentrations as high as 1000 ng mL−1 blood. Conclusions Fipronil, clothianidin and abamectin have potential for being incorporated into a liquid bait for bed bug control; indoxacarb and DCJW were not effective. Bed bugs are a good candidate for an ingestible liquid bait because systemic formulations generally require less active ingredient than residual sprays, they remain contained and more effectively target hematophagous arthropods. PMID:27766740

Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.

Science.gov (United States)

Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud

2013-10-01

Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina

Molecular Descriptors Family on Structure Activity Relationships 2. Insecticidal Activity of Neonicotinoid Compounds

Directory of Open Access Journals (Sweden)

Sorana BOLBOACĂ

2005-01-01

Full Text Available The neonicotinoids are the newest major class of insecticides modeled after the basic nicotine molecule having improved insecticide activity and generally low toxicity. The insecticidal activities of neonicotinoids were previous studied using 3D and standard partial least squares regression models. The paper describes the ability of the MDF SAR methodology in prediction of insecticidal activities of neonicotinoid compounds. The best MDF SAR bi-varied model was validated on training and test sets and its ability on prediction of insecticidal activity was compared with previous reported models. Even if the MDF SAR methodology is complex and time consuming the results worth the effort because they are statistical significant better then previous reported results.

[Acute lethal effect of the commercial formulation of the insecticides Imidacloprid, Spinosad y Thiocyclam hidrogenoxalate in Bombus atratus (Hymenoptera: Apidae) workers].

Science.gov (United States)

Riaño Jiménez, Diego; Cure, José Ricardo

2016-12-01

The effect of insecticides on bees has gained great attention, however, there are few studies that explore this issue on Neotropical bees. Bombus atratus is a neotropical species broadly distributed in Colombia and is considered an important pollinator of both Andean ecosystems and agroecosystems. However, as for many wild bees species, the effect of insecticides on B. atratus is unknow. In this study we determined the acute median lethal dose (LD50) of commercial formulations of insecticides Imidacloprid, Spinosad and Thiocyclam hydrogen oxalate, widely used in Colombia to control several pests of important crops. The LD50 was carried out by oral and contact routes, following and modifying the EPPO and OECD guidelines to perform LD50 on A. mellifera. We evaluated five doses for each route and insecticide, in a total of 25 medium-size workers for each dose by duplicate. Mortality was registered at 24, 48 and 72 hours after the experiment; and data were analyzed with the Probit regression model. For Imidacloprid, contacts and oral LD50 were 0.048 µg/bee and 0.010 µg/bee, respectively. For Thiocyclam hydrogen oxalate, topical and oral LD50 were 0.244 µg/bee and 0.056 µg/bee, respectively. For Spinosad, the oral LD50 corresponded to 0.28 µg/bee; it was not possible to establish the LD50 for the contact route. The Hazard Quotient (HQ) and Index of Relative Toxicity indicated that all three active ingredients are highly toxic. We discussed the risk of the insecticides use on B. atratus, considering their chemical nature.

Neurotoxicology of insecticides and pheromones

National Research Council Canada - National Science Library

Narahashi, Toshio

1979-01-01

The purpose of this symposium was to provide a forum where a variety of scientists who were interested in the interactions of insecticides and pheromones with the nervous system got together to exchange their views...

CHEMICAL CONTROL OF BEAN WEEVIL, ACANTHOSCELIDES OBTECTUS SAY IN STORAGE CONDITION

Directory of Open Access Journals (Sweden)

M PORCA

2003-12-01

Full Text Available The paper presents the positive results obtained by some pesticides applied against the bean weevil - Acanthoscelides obtectus Say, after a synthetic rewiew of the potential chemical methods which may be used in the chemical control of the insectes harmful to the stored bean seeds. The chemical control is realised treatments wits syntetic pyrethroid (permetrin, deltametrin and organophosphoric insecticides (malation, pirimifos metil, fenitrotion and chlrorpirifos-metil.

Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides.

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Miarinjara, Adélaïde; Boyer, Sébastien

2016-02-01

Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines). Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur). Only one insecticide (dieldrin) was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin) to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar.

The global status of insect resistance to neonicotinoid insecticides.

Science.gov (United States)

Bass, Chris; Denholm, Ian; Williamson, Martin S; Nauen, Ralf

2015-06-01

The first neonicotinoid insecticide, imidacloprid, was launched in 1991. Today this class of insecticides comprises at least seven major compounds with a market share of more than 25% of total global insecticide sales. Neonicotinoid insecticides are highly selective agonists of insect nicotinic acetylcholine receptors and provide farmers with invaluable, highly effective tools against some of the world's most destructive crop pests. These include sucking pests such as aphids, whiteflies, and planthoppers, and also some coleopteran, dipteran and lepidopteran species. Although many insect species are still successfully controlled by neonicotinoids, their popularity has imposed a mounting selection pressure for resistance, and in several species resistance has now reached levels that compromise the efficacy of these insecticides. Research to understand the molecular basis of neonicotinoid resistance has revealed both target-site and metabolic mechanisms conferring resistance. For target-site resistance, field-evolved mutations have only been characterized in two aphid species. Metabolic resistance appears much more common, with the enhanced expression of one or more cytochrome P450s frequently reported in resistant strains. Despite the current scale of resistance, neonicotinoids remain a major component of many pest control programmes, and resistance management strategies, based on mode of action rotation, are of crucial importance in preventing resistance becoming more widespread. In this review we summarize the current status of neonicotinoid resistance, the biochemical and molecular mechanisms involved, and the implications for resistance management. Copyright © 2015 Elsevier Inc. All rights reserved.

Plant compounds insecticide activity against Coleoptera pests of stored products

Energy Technology Data Exchange (ETDEWEB)

Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Biologia Animal; br, picanco@ufv; br, guedes@ufv; br, mateusc3@yahoo com; br, agronomiasilva@yahoo com

2007-07-15

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD{sub 50} from 2.72 to 39.71 mg g{sup -1} a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

Plant compounds insecticide activity against Coleoptera pests of stored products

International Nuclear Information System (INIS)

Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio; julioufv@yahoo.com.br

2007-01-01

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD 50 from 2.72 to 39.71 mg g -1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

Discovery and quantitative structure-activity relationship study of lepidopteran HMG-CoA reductase inhibitors as selective insecticides.

Science.gov (United States)

Zang, Yang-Yang; Li, Yuan-Mei; Yin, Yue; Chen, Shan-Shan; Kai, Zhen-Peng

2017-09-01

In a previous study we have demonstrated that insect 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) can be a potential selective insecticide target. Three series of inhibitors were designed on the basis of the difference in HMGR structures from Homo sapiens and Manduca sexta, with the aim of discovering potent selective insecticide candidates. An in vitro bioassay showed that gem-difluoromethylenated statin analogues have potent effects on JH biosynthesis of M. sexta and high selectivity between H. sapiens and M. sexta. All series II compounds {1,3,5-trisubstituted [4-tert-butyl 2-(5,5-difluoro-2,2-dimethyl-6-vinyl-4-yl) acetate] pyrazoles} have some effect on JH biosynthesis, whereas most of them are inactive on human HMGR. In particular, the IC 50 value of compound II-12 (37.8 nm) is lower than that of lovastatin (99.5 nm) and similar to that of rosuvastatin (24.2 nm). An in vivo bioassay showed that I-1, I-2, I-3 and II-12 are potential selective insecticides, especially for lepidopteran pest control. A predictable and statistically meaningful CoMFA model of 23 inhibitors (20 as training sets and three as test sets) was obtained with a value of q 2 and r 2 of 0.66 and 0.996 respectively. The final model suggested that a potent insect HMGR inhibitor should contain suitable small and non-electronegative groups in the ring part, and electronegative groups in the side chain. Four analogues were discovered as potent selective lepidopteran HMGR inhibitors, which can specifically be used for lepidopteran pest control. The CoMFA model will be useful for the design of new selective insect HMGR inhibitors that are structurally related to the training set compounds. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Investigation of insecticide-resistance status of Cydia pomonella in Chinese populations.

Science.gov (United States)

Yang, X-Q; Zhang, Y-L

2015-06-01

The codling moth Cydia pomonella (L.) is an economically important fruit pest and it has been directly targeted by insecticides worldwide. Serious resistance to insecticides has been reported in many countries. As one of the most serious invasive pest, the codling moth has populated several areas in China. However, resistance to insecticides has not been reported in China. We investigated the insecticide-resistance status of four field populations from Northwestern China by applying bioassays, enzyme activities, and mutation detections. Diagnostic concentrations of lambda-cyhalothrin, chlorpyrifos-ethyl, carbaryl, and imidacloprid were determined and used in bioassays. Field populations were less susceptible to chlorpyrifos-ethyl and carbaryl than laboratory strain. Insensitive populations displayed an elevated glutathione S-transferases (GSTs) activity. Reduced carboxylesterase (CarE) activity was observed in some insecticide insensitive populations and reduced acetylcholinesterase activity was observed only in the Wuw population. The cytochrome P450 polysubstrate monooxygenases activities in four field populations were not found to be different from susceptible strains. Neither the known-resistance mutation F399V in the acetylcholinesterase (AChE) gene, ace1, nor mutations in CarE gene CpCE-1 were found in adult individuals from our field populations. Native-PAGE revealed that various CarE isozymes and AChE insensitivity were occurring among Chinese populations. Our results indicate that codling moth populations from Northwestern China were insensitivity to chlorpyrifos-ethyl and carbaryl. Increased GST activity was responsible for insecticides insensitivity. Decreased CarE activity, as well as the presence of CarE and AChE polymorphisms might also be involved in insecticides insensitivity. New management strategies for managing this pest are discussed.

POTENTIATION OF COPAÍBA OIL-RESIN WITH SYNTHETIC INSECTICIDES TO CONTROL OF FALL ARMYWORM

OpenAIRE

ALMEIDA, WALDIANE ARAÚJO DE; SILVA, IGOR HONORATO LEDUÍNO DA; SANTOS, ANA CLÁUDIA VIEIRA DOS; BARROS JÚNIOR, AURÉLIO PAES; SOUSA, ADALBERTO HIPÓLITO DE

2017-01-01

ABSTRACT The control of Spodoptera frugiperda (J. E. SMITH) (Lepidoptera: Noctuidae) has been carried out mainly with pyrethroids and organophosphates insecticides. The continuous and indiscriminate use of synthetic insecticides, for decades, has led to the selection of resistant populations and has caused concerns for human health and the environment. An alternative is the use of botanical insecticides, including through the mixtures with synthetic insecticides. This study aimed to investiga...

Status of insecticide resistance in high-risk malaria provinces in Afghanistan.

Science.gov (United States)

Ahmad, Mushtaq; Buhler, Cyril; Pignatelli, Patricia; Ranson, Hilary; Nahzat, Sami Mohammad; Naseem, Mohammad; Sabawoon, Muhammad Farooq; Siddiqi, Abdul Majeed; Vink, Martijn

2016-02-18

Insecticide resistance seriously threatens the efficacy of vector control interventions in malaria endemic countries. In Afghanistan, the status of insecticide resistance is largely unknown while distribution of long-lasting insecticidal nets has intensified in recent years. The main objective of this study was thus to measure the level of resistance to four classes of insecticides in provinces with medium to high risk of malaria transmission. Adult female mosquitoes were reared from larvae successively collected in the provinces of Nangarhar, Kunar, Badakhshan, Ghazni and Laghman from August to October 2014. WHO insecticide susceptibility tests were performed with DDT (4 %), malathion (5 %), bendiocarb (0.1 %), permethrin (0.75 %) and deltamethrin (0.05 %). In addition, the presence of kdr mutations was investigated in deltamethrin resistant and susceptible Anopheles stephensi mosquitoes collected in the eastern provinces of Nangarhar and Kunar. Analyses of mortality rates revealed emerging resistance against all four classes of insecticides in the provinces located east and south of the Hindu Kush mountain range. Resistance is observed in both An. stephensi and Anopheles culicifacies, the two dominant malaria vectors in these provinces. Anopheles superpictus in the northern province of Badakhshan shows a different pattern of susceptibility with suspected resistance observed only for deltamethrin and bendiocarb. Genotype analysis of knock down resistance (kdr) mutations at the voltage-gated channel gene from An. stephensi mosquitoes shows the presence of the known resistant alleles L1014S and L1014F. However, a significant fraction of deltamethrin-resistant mosquitoes were homozygous for the 1014L wild type allele indicating that other mechanisms must be considered to account for the observed pyrethroid resistance. This study confirms the importance of monitoring insecticide resistance for the development of an integrated vector management in Afghanistan. The

Influence of the agrochemicals used for rice and vegetable cultivation on insecticide resistance in malaria vectors in southern Côte d'Ivoire.

Science.gov (United States)

Chouaïbou, Mouhamadou S; Fodjo, Behi K; Fokou, Gilbert; Allassane, Ouattara F; Koudou, Benjamin G; David, Jean-Philippe; Antonio-Nkondjio, Christophe; Ranson, Hilary; Bonfoh, Bassirou

2016-08-24

glyphosate, residues from each of six chemicals tested for were detected in each of the sites visited in the two localities. The study describes the use of insecticides and herbicides on crops and highlights the importance of considering agriculture practices when attempting to manage resistance in malaria vectors. Inter-sectoral collaboration between agriculture and public health is required to develop efficient integrated pest and vector management interventions.

Insecticidal activity of two proteases against Spodoptera frugiperda larvae infected with recombinant baculoviruses

Science.gov (United States)

2010-01-01

Background Baculovirus comprise the largest group of insect viruses most studied worldwide, mainly because they efficiently kill agricutural insect pests. In this study, two recombinant baculoviruses containing the ScathL gene from Sarcophaga peregrina (vSynScathL), and the Keratinase gene from the fungus Aspergillus fumigatus (vSynKerat), were constructed. and their insecticidal properties analysed against Spodoptera frugiperda larvae. Results Bioassays of third-instar and neonate S. frugiperda larvae with vSynScathL and vSynKerat showed a decrease in the time needed to kill the infected insects when compared to the wild type virus. We have also shown that both recombinants were able to increase phenoloxidase activity in the hemolymph of S. frugiperda larvae. The expression of proteases in infected larvae resulted in destruction of internal tissues late in infection, which could be the reason for the increased viral speed of kill. Conclusions Baculoviruses and their recombinant forms constitute viable alternatives to chemical insecticides. Recombinant baculoviruses containing protease genes can be added to the list of engineered baculoviruses with great potential to be used in integrated pest management programs. PMID:20587066

Cytochrome P450s--Their expression, regulation, and role in insecticide resistance.

Science.gov (United States)

Liu, Nannan; Li, Ming; Gong, Youhui; Liu, Feng; Li, Ting

2015-05-01

P450s are known to be critical for the detoxification and/or activation of xenobiotics such as drugs and pesticides and overexpression of P450 genes can significantly affect the disposition of xenobiotics in the tissues of organisms, altering their pharmacological/toxicological effects. In insects, P450s play an important role in detoxifying exogenous compounds such as insecticides and plant toxins and their overexpression can result in increased levels of P450 proteins and P450 activities. This has been associated with enhanced metabolic detoxification of insecticides and has been implicated in the development of insecticide resistance in insects. Multiple P450 genes have been found to be co-overexpressed in individual insect species via several constitutive overexpression and induction mechanisms, which in turn are co-responsible for high levels of insecticide resistance. Many studies have also demonstrated that the transcriptional overexpression of P450 genes in resistant insects is regulated by trans and/or cis regulatory genes/factors. Taken together, these earlier findings suggest not only that insecticide resistance is conferred via multi-resistance P450 genes, but also that it is mediated through the interaction of regulatory genes/factors and resistance genes. This chapter reviews our current understanding of how the molecular mechanisms of P450 interaction/gene regulation govern the development of insecticide resistance in insects and our progress along the road to a comprehensive characterization of P450 detoxification-mediated insecticide resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

Insecticide Resistance in the Dengue Vector Aedes aegypti from Martinique: Distribution, Mechanisms and Relations with Environmental Factors

OpenAIRE

Marcombe , Sébastien; Blanc Mathieu , Romain; Pocquet , Nicolas; Riaz , Muhammad-Asam; Poupardin , Rodolphe; Sélior , Serge; Darriet , Frédéric; Reynaud , Stéphane; Yebakima , André; Corbel , Vincent; David , Jean-Philippe; Chandre , Fabrice

2012-01-01

International audience; Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies). The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control in...

EFFICIENCY OF THE CHEMICAL TREATMENT AGAINST THE EUROPEAN CORN BORER IN SEED MAIZE PRODUCTION

Directory of Open Access Journals (Sweden)

Emilija Raspudić

2013-06-01

Full Text Available The aim of this study was to determine the effectiveness of a chemical treatment against larvae of the European corn borer (Ostrinia nubilalis Hubner. The experiment was set up in 2010 and 2011 in Čepin (eastern Croatia in two treatments: control treatment and insecticide treatment. The trial involved two hybrids of FAO group 400: PR37N01 and PR37F73. Biology of pests was monitored in order to determine population size and larvae development stage as well as the optimal time of insecticide application. After determination of thresholds, maize was treated with chemical formulations of active substance dimethoate. Towards the end of vegetation, length of stem damage, number of larvae in maize stalk and ear as well as grain yield were recorded by dissection of maize stalks. Statistical analysis shows that year, hybrid and chemical treatment significantly influenced the incidence of this pest and justified the use of chemical preparations with mandatory monitoring biology of this pest.

Bioassay method for toxicity studies of insecticide formulations to Tuta absoluta (meyrick, 1917) Metodologia de bioensaio para estudos de toxicidade de formulações comerciais de inseticidas a Tuta absoluta (Meyrick, 1917)

OpenAIRE

Tarcísio Visintin da Silva Galdino; Marcelo Coutinho Picanço; Elisangela Gomes Fidelis de Morais; Nilson Rodrigues Silva; Geverson Aelton Rezende da Silva; Mayara Cristina Lopes

2011-01-01

Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that repre...

Effects of insecticide spray application on insect pest infestation and ...

African Journals Online (AJOL)

USER

2010-03-15

Mar 15, 2010 ... This study provides information on the incidence of major insect pests of cowpea as well as the minimum insecticide control intervention necessary for effectively reducing cowpea yield losses on the field. Two insecticide spray regimes (once at flowering and podding) significantly reduced insect population ...

Substances inertes et plantes à effet insecticide utilisées dans la ...

African Journals Online (AJOL)

Les insecticides naturels tels que les plantes à effet insecticide et les substances inertes (sable, cendre, terres à diatomées,…) méritent d'être valorisées afin de réduire l'utilisation des insecticides chimiques et protéger l'environnement. Ce travail basé sur une revue documentaire fouillée et actualisée vise à faire la genèse ...

FAO/IAEA Consultants Group Meeting on The Potential for Tsetse Flies to Develop Resistance to Insecticides

International Nuclear Information System (INIS)

1993-01-01

Chemical insecticides are playing an increasingly important role in control of tsetse flies (Glossina spp), vectors of human and animal trypanosomiasis in large regions of Africa. Although insecticide resistance has not yet been reported in tsetse, there is no cause for complacency regarding its occurrence in the future. As new reports of insecticide resistance in other disease vectors and agronomic pests continue to accumulate at a rapid rate, it is increasingly clear that no comprehensive approach to tsetse control can afford to ignore the potential resistance problem, as the loss of insecticides from the limited set of options for control would be disastrous. it is likely that one or more of the pyrethroid resistance mechanisms already known from several other species of Diptera will manifest itself in tsetse, in response to the increased selection engendered by the wider adoption of deltamethrin-treated targets in tsetse control at the local level and in eradication efforts. Also, selection for behavioural avoidance of traps and targets could result in decreased control efficiency, although the mechanisms that might cause such behavioural resistance are poorly understood at present. There is thus an increasingly urgent need for information on the potential for resistance development in tsetse, on accurate and feasible methods for detection, monitoring, and characterization of resistance, on properties of resistant strains, and on appropriate tactics for resistance prevention and management. Because of the extraordinary difficulties in rearing posed by tsetse life history, it is essential that these research efforts get underway immediately. The Consultants Group on the Possibility of Development of Insecticide Resistance in Tsetse has accordingly prepared this report with a consideration of the present state of knowledge, a discussion of the essential elements of a resistance research program, and specific recommendations. A summary of the recommendations in

FAO/IAEA Consultants Group Meeting on The Potential for Tsetse Flies to Develop Resistance to Insecticides

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-07-01

Chemical insecticides are playing an increasingly important role in control of tsetse flies (Glossina spp), vectors of human and animal trypanosomiasis in large regions of Africa. Although insecticide resistance has not yet been reported in tsetse, there is no cause for complacency regarding its occurrence in the future. As new reports of insecticide resistance in other disease vectors and agronomic pests continue to accumulate at a rapid rate, it is increasingly clear that no comprehensive approach to tsetse control can afford to ignore the potential resistance problem, as the loss of insecticides from the limited set of options for control would be disastrous. it is likely that one or more of the pyrethroid resistance mechanisms already known from several other species of Diptera will manifest itself in tsetse, in response to the increased selection engendered by the wider adoption of deltamethrin-treated targets in tsetse control at the local level and in eradication efforts. Also, selection for behavioural avoidance of traps and targets could result in decreased control efficiency, although the mechanisms that might cause such behavioural resistance are poorly understood at present. There is thus an increasingly urgent need for information on the potential for resistance development in tsetse, on accurate and feasible methods for detection, monitoring, and characterization of resistance, on properties of resistant strains, and on appropriate tactics for resistance prevention and management. Because of the extraordinary difficulties in rearing posed by tsetse life history, it is essential that these research efforts get underway immediately. The Consultants Group on the Possibility of Development of Insecticide Resistance in Tsetse has accordingly prepared this report with a consideration of the present state of knowledge, a discussion of the essential elements of a resistance research program, and specific recommendations. A summary of the recommendations in

Risk assessments for exposure of deployed military personnel to insecticides and personal protective measures used for disease-vector management.

Science.gov (United States)

Macedo, Paula A; Peterson, Robert K D; Davis, Ryan S

2007-10-01

Infectious diseases are problematic for deployed military forces throughout the world, and, historically, more military service days have been lost to insect-vectored diseases than to combat. Because of the limitations in efficacy and availability of both vaccines and therapeutic drugs, vector management often is the best tool that military personnel have against most vector-borne pathogens. However, the use of insecticides may raise concerns about the safety of their effects on the health of the military personnel exposed to them. Therefore, our objective was to use risk assessment methodologies to evaluate health risks to deployed U.S. military personnel from vector management tactics. Our conservative tier-1, quantitative risk assessment focused on acute, subchronic, and chronic exposures and cancer risks to military personnel after insecticide application and use of personal protective measures in different scenarios. Exposures were estimated for every scenario, chemical, and pathway. Acute, subchronic, and chronic risks were assessed using a margin of exposure (MOE) approach. Our MOE was the ratio of a no-observed-adverse-effect level (NOAEL) to an estimated exposure. MOEs were greater than the levels of concern (LOCs) for all surface residual and indoor space spraying exposures, except acute dermal exposure to lambda-cyhalothrin. MOEs were greater than the LOCs for all chemicals in the truck-mounted ultra-low-volume (ULV) exposure scenario. The aggregate cancer risk for permethrin exceeded 1 x 10(-6), but more realistic exposure refinements would reduce the cancer risk below that value. Overall, results indicate that health risks from exposures to insecticides and personal protective measures used by military personnel are low.

Effects of insecticide spray application on insect pest infestation and ...

African Journals Online (AJOL)

Field studies were conducted during the 2008 - 2009 cropping season to determine the minimal insecticide application which can reduce cowpea yield losses on the field due to insect pest infestations in the Transkei region of South Africa. Treatments consisted of five cowpea varieties and four regimes of insecticide spray ...

Underpinning sustainable vector control through informed insecticide resistance management.

Directory of Open Access Journals (Sweden)

Edward K Thomsen

Full Text Available There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia's programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions.A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids, DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s.Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management plan.

Expression, Delivery and Function of Insecticidal Proteins Expressed by Recombinant Baculoviruses

Science.gov (United States)

Kroemer, Jeremy A.; Bonning, Bryony C.; Harrison, Robert L.

2015-01-01

Since the development of methods for inserting and expressing genes in baculoviruses, a line of research has focused on developing recombinant baculoviruses that express insecticidal peptides and proteins. These recombinant viruses have been engineered with the goal of improving their pesticidal potential by shortening the time required for infection to kill or incapacitate insect pests and reducing the quantity of crop damage as a consequence. A wide variety of neurotoxic peptides, proteins that regulate insect physiology, degradative enzymes, and other potentially insecticidal proteins have been evaluated for their capacity to reduce the survival time of baculovirus-infected lepidopteran host larvae. Researchers have investigated the factors involved in the efficient expression and delivery of baculovirus-encoded insecticidal peptides and proteins, with much effort dedicated to identifying ideal promoters for driving transcription and signal peptides that mediate secretion of the expressed target protein. Other factors, particularly translational efficiency of transcripts derived from recombinant insecticidal genes and post-translational folding and processing of insecticidal proteins, remain relatively unexplored. The discovery of RNA interference as a gene-specific regulation mechanism offers a new approach for improvement of baculovirus biopesticidal efficacy through genetic modification. PMID:25609310

Insecticide resistance and resistance mechanisms in bed bugs, Cimex spp. (Hemiptera: Cimicidae).

Science.gov (United States)

Dang, Kai; Doggett, Stephen L; Veera Singham, G; Lee, Chow-Yang

2017-06-29

The worldwide resurgence of bed bugs [both Cimex lectularius L. and Cimex hemipterus (F.)] over the past two decades is believed in large part to be due to the development of insecticide resistance. The transcriptomic and genomic studies since 2010, as well as morphological, biochemical and behavioral studies, have helped insecticide resistance research on bed bugs. Multiple resistance mechanisms, including penetration resistance through thickening or remodelling of the cuticle, metabolic resistance by increased activities of detoxification enzymes (e.g. cytochrome P450 monooxygenases and esterases), and knockdown resistance by kdr mutations, have been experimentally identified as conferring insecticide resistance in bed bugs. Other candidate resistance mechanisms, including behavioral resistance, some types of physiological resistance (e.g. increasing activities of esterases by point mutations, glutathione S-transferase, target site insensitivity including altered AChEs, GABA receptor insensitivity and altered nAChRs), symbiont-mediated resistance and other potential, yet undiscovered mechanisms may exist. This article reviews recent studies of resistance mechanisms and the genes governing insecticide resistance, potential candidate resistance mechanisms, and methods of monitoring insecticide resistance in bed bugs. This article provides an insight into the knowledge essential for the development of both insecticide resistance management (IRM) and integrated pest management (IPM) strategies for successful bed bug management.

[Susceptibility to insecticides of Anopheles darlingi Root 1840, in two locations of the departments of Santander and Caquetá, Colombia].

Science.gov (United States)

Santacoloma, Liliana; Tibaduiza, Tania; Gutiérrrez, Marcela; Brochero, Helena

2012-03-01

Physiological resistance to insecticides used in public health is the main factor to define strategies for malaria vector control. To determine the physiological status of insecticide susceptibility of natural populations of An. darlingi from two localities in the Santander and Caquetá departments. Wild adult Anopheles darlingi females were collected and bioassays using technical grade insecticides were performed following the methods recommended both by the World Health Organization (WHO, 1981) and the Centers for Diseases Control and Prevention (CDC, 1998). The natural populations of An. darlingi from the villages of Gerumano, Solano, Caqueta and Las Margaritas, San Vicente de Chucurí, Santander, showed susceptibility to the pyrethroids lambdacyhalothrin and deltamethrin, to the organochlorate DDT and to the organophosphate fenitrothion with 100% mortality rates in all of the CDC tests and between 95 and 100% in the tests performed following the WHO methods. For the carbamate propoxur the 88% mortality rate obtained in the village of Gerumano following the methods recommended by WHO coincides with the surveillance methods established for surveillance of this molecule. Chemical products whose active ingredients are the molecules tested are effective for control of An. darlingi in the study sites.

Genetics, Synergists, and Age Affect Insecticide Sensitivity of the Honey Bee, Apis mellifera

Science.gov (United States)

Rinkevich, Frank D.; Margotta, Joseph W.; Pittman, Jean M.; Danka, Robert G.; Tarver, Matthew R.; Ottea, James A.; Healy, Kristen B.

2015-01-01

The number of honey bee colonies in the United States has declined to half of its peak level in the 1940s, and colonies lost over the winter have reached levels that are becoming economically unstable. While the causes of these losses are numerous and the interaction between them is very complex, the role of insecticides has garnered much attention. As a result, there is a need to better understand the risk of insecticides to bees, leading to more studies on both toxicity and exposure. While much research has been conducted on insecticides and bees, there have been very limited studies to elucidate the role that bee genotype and age has on the toxicity of these insecticides. The goal of this study was to determine if there are differences in insecticide sensitivity between honey bees of different genetic backgrounds (Carniolan, Italian, and Russian stocks) and assess if insecticide sensitivity varies with age. We found that Italian bees were the most sensitive of these stocks to insecticides, but variation was largely dependent on the class of insecticide tested. There were almost no differences in organophosphate bioassays between honey bee stocks (bees aged, the sensitivity to phenothrin significantly decreased, but the sensitivity to naled significantly increased. These results demonstrate the variation arising from the genetic background and physiological transitions in honey bees as they age. This information can be used to determine risk assessment, as well as establishing baseline data for future comparisons to explain the variation in toxicity differences for honey bees reported in the literature. PMID:26431171

Organochlorine insecticide poisoning in Golden Langurs Trachypithecus geei

Directory of Open Access Journals (Sweden)

D.C. Pathak

2011-07-01

Full Text Available Organochlorine insecticide poisoning was recorded in three Golden Langurs (Trachypithecus geei in Chakrashila Wildlife Sanctuary (CWS in Kokrajhar district of Assam during the month of December, 2008. The poisoning was due to prolonged ingestion of rubber plant leaves sprayed with the insecticide in a rubber plantation adjacent to the sanctuary. Though no specific gross lesions were observed, histopathologically, centilobular hepatic necrosis, mild renal degeneration, necrotic enteritis, pulmonary congestion and neuronal degeneration were recorded in all three animals.

Plant compounds insecticide activity against Coleoptera pests of stored products

Energy Technology Data Exchange (ETDEWEB)

Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Biologia Animal]. E-mail: marcio.dionizio@gmail.com; picanco@ufv.br; guedes@ufv.br; mateusc3@yahoo.com.br; agronomiasilva@yahoo.com.br

2007-07-15

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD{sub 50} from 2.72 to 39.71 mg g{sup -1} a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

Household use of insecticide consumer products in a dengue-endemic area in México.

Science.gov (United States)

Loroño-Pino, María Alba; Chan-Dzul, Yamili N; Zapata-Gil, Rocio; Carrillo-Solís, Claudia; Uitz-Mena, Ana; García-Rejón, Julián E; Keefe, Thomas J; Beaty, Barry J; Eisen, Lars

2014-10-01

To evaluate the household use of insecticide consumer products to kill mosquitoes and other insect pests, as well as the expenditures for using these products, in a dengue-endemic area of México. A questionnaire was administered to 441 households in Mérida City and other communities in Yucatán to assess household use of insecticide consumer products. A total of 86.6% of surveyed households took action to kill insect pests with consumer products. The most commonly used product types were insecticide aerosol spray cans (73.6%), electric plug-in insecticide emitters (37.4%) and mosquito coils (28.3%). Mosquitoes were targeted by 89.7% of households using insecticide aerosol spray cans and >99% of households using electric plug-in insecticide emitters or mosquito coils. Products were used daily or every 2 days in most of the households for insecticide aerosol spray cans (61.4%), electric plug-in insecticide emitters (76.2%) and mosquito coils (82.1%). For all products used to kill insect pests, the median annual estimated expenditure per household that took action was 408 Mexican pesos ($MXN), which corresponded to approximately 31 $US. These numbers are suggestive of an annual market in excess of 75 million $MXN (>5.7 million $US) for Mérida City alone. Mosquitoes threaten human health and are major nuisances in homes in the study area in México. Households were found to have taken vigorous action to kill mosquitoes and other insect pests and spent substantial amounts of money on insecticide consumer products. © 2014 John Wiley & Sons Ltd.

Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

Science.gov (United States)

Ruma; Lukes, P.; Aoki, N.; Spetlikova, E.; Hosseini, S. H. R.; Sakugawa, T.; Akiyama, H.

2013-03-01

A repetitive pulsed-power modulator, which employs a magnetic pulse compression circuit with a high-speed thyristor switch, was used to study the effects of the pulse repetition rate of input power on the physical and chemical properties of pulsed discharges in water. Positive high-voltage pulses of 20 kV with repetition rates of up to 1 kHz were used to generate a discharge in water using the point-to-plane electrode geometry. By varying the pulse repetition rate, two distinct modes of the discharge plasma were formed in water. The first mode was characterized by the formation of a corona-like discharge propagating through water in the form of streamer channels. The second mode was formed typically above 500 Hz, when the formation of streamer channels in water was suppressed and all plasmas occurred inside a spheroidal aggregate of very fine gas bubbles surrounding the tip of the high-voltage electrode. The production of hydrogen peroxide, degradation of organic dye Acid Orange 7 (AO7) and inactivation of bacteria Escherichia coli by the discharge in water were studied under different discharge plasma modes in dependence on the pulse repetition rate of input power. The efficiency of both chemical and biocidal processes induced by the plasma in water decreased significantly with pulse repetition rates above 500 Hz.

Effects of pulse frequency of input power on the physical and chemical properties of pulsed streamer discharge plasmas in water

International Nuclear Information System (INIS)

Ruma; Aoki, N; Hosseini, S H R; Sakugawa, T; Akiyama, H; Lukes, P; Spetlikova, E

2013-01-01

A repetitive pulsed-power modulator, which employs a magnetic pulse compression circuit with a high-speed thyristor switch, was used to study the effects of the pulse repetition rate of input power on the physical and chemical properties of pulsed discharges in water. Positive high-voltage pulses of 20 kV with repetition rates of up to 1 kHz were used to generate a discharge in water using the point-to-plane electrode geometry. By varying the pulse repetition rate, two distinct modes of the discharge plasma were formed in water. The first mode was characterized by the formation of a corona-like discharge propagating through water in the form of streamer channels. The second mode was formed typically above 500 Hz, when the formation of streamer channels in water was suppressed and all plasmas occurred inside a spheroidal aggregate of very fine gas bubbles surrounding the tip of the high-voltage electrode. The production of hydrogen peroxide, degradation of organic dye Acid Orange 7 (AO7) and inactivation of bacteria Escherichia coli by the discharge in water were studied under different discharge plasma modes in dependence on the pulse repetition rate of input power. The efficiency of both chemical and biocidal processes induced by the plasma in water decreased significantly with pulse repetition rates above 500 Hz. (paper)

Reduced ultraviolet light transmission increases insecticide longevity in protected culture raspberry production.

Science.gov (United States)

Leach, Heather; Wise, John C; Isaacs, Rufus

2017-12-01

High tunnels are large protective structures used for season extension of many crops, including raspberries. These structures are often covered in plastic films to reduce and diffuse ultraviolet light transmission for pest and disease control, but this may also affect the photodegradation and efficacy of pesticides applied under these tunnels. We compared the residue levels of ten insecticides under three tunnel plastics with varying levels of UV transmission and open field conditions. Raspberry plants placed in research-scale tunnels were treated with insecticides and residues on fruit and foliage were monitored for one or two weeks in early 2015 and early and late 2016. Plastics that reduce UV transmission resulted in 50% greater residues of some insecticides compared to transparent plastics, and 60% compared to uncovered tunnels. This increased persistence of residues was evident within 1 day and remained consistently higher for up to 14 days. This pattern was demonstrated for multiple insecticides, including bifenthrin, esfenvalerate, imidacloprid, thiamethoxam, and spinosad. In contrast, the insecticide malathion degraded rapidly regardless of the plastic treatment, indicating less sensitivity to photodegradation. Bioassays using insecticide-treated leaves that were under UV-blocking plastic revealed higher mortality of the invasive fruit pest, Drosophila suzukii, compared to leaves that were uncovered. This indicates that the activity of pesticides under high tunnels covered in UV-reducing plastics may be prolonged, allowing for fewer insecticide applications and longer intervals between sprays. This information can be used to help optimize pest control in protected culture berry production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae from Argentina

Directory of Open Access Journals (Sweden)

Cristina Mónica Montagna

2012-06-01

Full Text Available Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold and deltamethrin (162-fold and a small increase in resistance to the organophosphate azinphos methyl (2-fold were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance. The evolution of pesticide resistance in a field population is a complex and stepwise process that is influenced by several factors, the most significant of which is the insecticide selection pressure, such as the dose and frequency of application. The variation in insecticide susceptibility within a black fly population in the productive area may be related to changes in fruit-pest control. The frequency of individuals with esterase activities higher than the maximum value determined in the susceptible population increased consistently over the sampling period. However, the insecticide resistance was not attributed to glutathione S-transferase activity. In conclusion, esterase activity in black flies from the productive area is one mechanism underlying the high levels of resistance to pyrethroids, which have been recently used infrequently. These enzymes may be reselected by currently used pesticides and enhance the resistance to these insecticides.

Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae) from Argentina.

Science.gov (United States)

Montagna, Cristina Mónica; Gauna, Lidia Ester; D'Angelo, Ana Pechen de; Anguiano, Olga Liliana

2012-06-01

Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold) and deltamethrin (162-fold) and a small increase in resistance to the organophosphate azinphos methyl (2-fold) were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance. The evolution of pesticide resistance in a field population is a complex and stepwise process that is influenced by several factors, the most significant of which is the insecticide selection pressure, such as the dose and frequency of application. The variation in insecticide susceptibility within a black fly population in the productive area may be related to changes in fruit-pest control. The frequency of individuals with esterase activities higher than the maximum value determined in the susceptible population increased consistently over the sampling period. However, the insecticide resistance was not attributed to glutathione S-transferase activity. In conclusion, esterase activity in black flies from the productive area is one mechanism underlying the high levels of resistance to pyrethroids, which have been recently used infrequently. These enzymes may be reselected by currently used pesticides and enhance the resistance to these insecticides.

Identification of insecticide residues with a conducting-polymer electronic nose

Science.gov (United States)

A.D. Wilson

2014-01-01

The identification of insecticide residues on crop foliage is needed to make periodic pest management decisions. Electronic-nose (e-nose) methods were developed and tested as a means of acquiring rapid identifications of insecticide residue types at relatively low cost by detection of headspace volatiles released from inert surfaces in vitro. Detection methods were...

Influence on sensitivity to insecticides: a case study of a settled area ...

African Journals Online (AJOL)

monitoring for successful alternative insecticides. There are currently two ... behaviour or modification avoid landing on insecticide .... aquarium fish food18. When they .... National Statistical Office (NSO) Malawi Government 1998 Census. 16.

The impact of restrictions on neonicotinoid and fipronil insecticides on pest management in maize, oilseed rape and sunflower in eight European Union regions.

Science.gov (United States)

Kathage, Jonas; Castañera, Pedro; Alonso-Prados, José Luis; Gómez-Barbero, Manuel; Rodríguez-Cerezo, Emilio

2018-01-01

In 2013, the European Commission restricted the use of three neonicotinoids (clothianidin, imidacloprid and thiamethoxam) and the pyrazole fipronil, which are widely used to control early-season pests. Here, we used original farm survey data to examine the impact of the restrictions on pest management practices in eight regional case studies including maize, oilseed rape and sunflower in seven European Union (EU) countries. In four case studies, farmers switched to using untreated seeds as no alternative seed treatments were available. In three case studies, farmers switched to using unrestricted neonicotinoid- or pyrethroid-treated seeds. In five case studies, farmers increased the use of soil or foliar treatments, with pyrethroids as the principal insecticide class. Other changes in pest management practices ranged from increased sowing density to more frequent scouting for pests. Many farmers perceived that the time, cost and amount of insecticides required to protect crops increased, along with pest pressure. Alternative seed treatments were mostly perceived as being less effective than the restricted seed treatments. Farmers generally relied on alternative seed treatments or more soil/foliar treatments in the first growing season after the restrictions took effect. Further study is required to assess the effectiveness and sustainability of these alternatives compared with the restricted insecticides. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans.

Science.gov (United States)

Moyes, Catherine L; Vontas, John; Martins, Ademir J; Ng, Lee Ching; Koou, Sin Ying; Dusfour, Isabelle; Raghavendra, Kamaraju; Pinto, João; Corbel, Vincent; David, Jean-Philippe; Weetman, David

2017-07-01

Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus), making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids). Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance.

Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans

Science.gov (United States)

Vontas, John; Martins, Ademir J.; Ng, Lee Ching; Koou, Sin Ying; Dusfour, Isabelle; Raghavendra, Kamaraju; Pinto, João; Corbel, Vincent; David, Jean-Philippe; Weetman, David

2017-01-01

Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus), making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids). Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance. PMID:28727779

Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans.

Directory of Open Access Journals (Sweden)

Catherine L Moyes

2017-07-01

Full Text Available Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus, making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids. Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance.

Household use of insecticide consumer products in a dengue endemic area in México

Science.gov (United States)

Loroño-Pino, María Alba; Chan-Dzul, Yamili N.; Zapata-Gil, Rocio; Carrillo-Solís, Claudia; Uitz-Mena, Ana; García-Rejón, Julián E.; Keefe, Thomas J.; Beaty, Barry J.; Eisen, Lars

2014-01-01

Objectives To evaluate household use of insecticide consumer products to kill mosquitoes and other insect pests, as well as the expenditures for using these products, in a dengue endemic area in México. Methods A questionnaire was administered to 441 households in Mérida City or other communities in Yucatán State to assess household use of insecticide consumer products. Results Most (86.6%) households took action to kill insect pests with consumer products. Among those households, the most commonly used product types were insecticide aerosol spray cans (73.6%), electric plug-in insecticide emitters (37.4%), and mosquito coils (28.3%). Mosquitoes were targeted by 89.7% of households using insecticide aerosol spray cans and >99% of households using electric plug-in insecticide emitters or mosquito coils. During the part of the year when a given product type was used, the frequency of use was daily or every 2 days in most of the households for insecticide aerosol spray cans (61.4%), electric plug-in insecticide emitters (76.2%), and mosquito coils (82.1%). For all products used to kill insect pests, the median annual estimated expenditure per household that took action was 408 Mexican pesos ($MXN), which corresponded to ∼31 $U.S. These numbers are suggestive of an annual market in excess of 75 million $MXN (>5.7 million $U.S.) for Mérida City alone. Conclusion Mosquitoes threaten human health and are major nuisances in homes in the study area in México. Households were found to have taken vigorous action to kill mosquitoes and other insect pests and spent substantial amounts of money on insecticide consumer products. PMID:25040259

The evolution of insecticide resistance in the peach potato aphid, Myzus persicae.

Science.gov (United States)

Bass, Chris; Puinean, Alin M; Zimmer, Christoph T; Denholm, Ian; Field, Linda M; Foster, Stephen P; Gutbrod, Oliver; Nauen, Ralf; Slater, Russell; Williamson, Martin S

2014-08-01

The peach potato aphid, Myzus persicae is a globally distributed crop pest with a host range of over 400 species including many economically important crop plants. The intensive use of insecticides to control this species over many years has led to populations that are now resistant to several classes of insecticide. Work spanning over 40 years has shown that M. persicae has a remarkable ability to evolve mechanisms that avoid or overcome the toxic effect of insecticides with at least seven independent mechanisms of resistance described in this species to date. The array of novel resistance mechanisms, including several 'first examples', that have evolved in this species represents an important case study for the evolution of insecticide resistance and also rapid adaptive change in insects more generally. In this review we summarise the biochemical and molecular mechanisms underlying resistance in M. persicae and the insights study of this topic has provided on how resistance evolves, the selectivity of insecticides, and the link between resistance and host plant adaptation. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Antifeedant and insecticidal activity of Polygonum persicaria extracts on Nomophila indistinctalis

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Luisa Quesada-Romero

2017-05-01

Full Text Available Context: Vegetal extracts represent an alternative to control against agricultural pests that have become resistant to pesticides. Using natural products is considered to be more friendly to the environment and safe. Aims: To determine the insecticidal and antifeedant activity of Polygonum persicaria extracts of two differents populations in Chile (Valparaiso and Curico against Nomophila indistinctalis larvae. Methods: Insecticide Resistance Action Committee (IRAC susceptibility test was used to evaluate the insecticidal activity of the extracts at concentrations of 100, 250, 500 and 1000 mg/L; against first instar larvae of Nomophila indistinctalis. The antifeedant activity was evaluated to determine the percentage of consumption in third instar larvae on treatment. Results: When comparing the control and the treatment groups in the antifeedant activity assay, significant differences (p<0.05 were observed after 90 minutes of exposure. With respect to the insecticidal activity, all extracts showed significant effects at the applied concentrations compared to the negative control. Moreover, the dichloromethane extracts of Curico and Valparaiso at concentrations greater than 500 mg/L showed a similar insecticidal activity as compared to the commercial formulation Neem. Conclusions: This work presents for the first time the results of the anti-feeding and insecticide activity of ethanol, methanol, and dichloromethane extracts from Polygonum persicaria on Nomophila indistinctalis. The results show that the extracts of this species can be used as an alternative for biological control. In addition, the results obtained allow a bioguided fractionation for the identification of secondary metabolites present in these extracts.

Design, Synthesis and Insecticidal Activities of Novel Phenyl Substituted Isoxazolecarboxamides

Institute of Scientific and Technical Information of China (English)

LIU Peng-fei; ZHANG Ji-feng; YAN Tao; XIONG Li-xia; LI Zheng-ming

2012-01-01

Thirteen novel phenyl substituted isoxazolecarboxamides were synthesized,and their structures were characterized by 1H NMR,elementary analysis and high-resolution mass spectrometry(HRMS) techniques.Their evaluated insecticidal activities against oriental armyworm(Mythimna separata) indicate that the phcnyl substituted isoxazolecarboxamides exhibited moderate insecticidal activities,among which compounds 9c and 9k showed comparatively higher activities.

Metabolic control of the insecticides safety use

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L.I. Solomenko

2016-06-01

Full Text Available The results of the conducted research affirm that the phosphororganic insecticides utilization can lead to the break in the nitrogen metabolism, breaking the protein formation, reducing the protein molecules renewal, causing the amino acid and amides accumulation in the active state. It has been revealed that the translocation and transformation of the insecticides under consideration are more closely connected with the changes of insoluble protein fraction. The stagnation point of the Phosphamide and Kaunter impact on the plant has been determined. And only the use of the preparation in optimal norms can influence stimulatingly the course of the process under consideration.

Agricultural insecticides threaten surface waters at the global scale.

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Stehle, Sebastian; Schulz, Ralf

2015-05-05

Compared with nutrient levels and habitat degradation, the importance of agricultural pesticides in surface water may have been underestimated due to a lack of comprehensive quantitative analysis. Increasing pesticide contamination results in decreasing regional aquatic biodiversity, i.e., macroinvertebrate family richness is reduced by ∼30% at pesticide concentrations equaling the legally accepted regulatory threshold levels (RTLs). This study provides a comprehensive metaanalysis of 838 peer-reviewed studies (>2,500 sites in 73 countries) that evaluates, for the first time to our knowledge on a global scale, the exposure of surface waters to particularly toxic agricultural insecticides. We tested whether measured insecticide concentrations (MICs; i.e., quantified insecticide concentrations) exceed their RTLs and how risks depend on insecticide development over time and stringency of environmental regulation. Our analysis reveals that MICs occur rarely (i.e., an estimated 97.4% of analyses conducted found no MICs) and there is a complete lack of scientific monitoring data for ∼90% of global cropland. Most importantly, of the 11,300 MICs, 52.4% (5,915 cases; 68.5% of the sites) exceeded the RTL for either surface water (RTLSW) or sediments. Thus, the biological integrity of global water resources is at a substantial risk. RTLSW exceedances depend on the catchment size, sampling regime, and sampling date; are significantly higher for newer-generation insecticides (i.e., pyrethroids); and are high even in countries with stringent environmental regulations. These results suggest the need for worldwide improvements to current pesticide regulations and agricultural pesticide application practices and for intensified research efforts on the presence and effects of pesticides under real-world conditions.

Insecticide resistance in the western flower thrips, Frankliniella occidentalis

DEFF Research Database (Denmark)

Jensen, Sten Erik

of acetylcholinesterase, the target site enzyme for methiocarb. The results from bioassays with synergists included indicated involvement of cytochrome P450- monooxygenases and esterases in methiocarb resistance in the most resistant populations. Selection with methiocarb on one of the populations to increase the level......The western flower thrips, Frankliniella occidentalis (Pergande) is a serious pest on a wide range of crops throughout the world. In Denmark F. occidentalis is a pest in greenhouses. F. occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance...... to insecticides. Since F. occidentulis spread to become a worldwide pest in 1980’es, resistance to a number of different insecticides has been shown in many populations of F. occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity...

Identification of Insecticidal Constituents from the Essential Oil of Valeriana jatamansi Jones against Liposcelis bostrychophila Badonnel

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Xin Chao Liu

2013-01-01

Full Text Available The aim of this research was to determine chemical composition and insecticidal activities of the essential oil of Valeriana jatamansi Jones roots against booklice, Liposcelis bostrychophila Badonnel, and to isolate insecticidal constituents from the oil. Essential oil of V. jatamansi was obtained by hydrodistillation and analyzed by GC-MS. A total of 27 components in the essential oil were identified. The major compounds were patchoulol (24.3%, α-bulnesene (13.8%, isovaleric acid (12.9%, α-guaiene (8.7%, and 3-methylvaleric acid (8.4%. Based on bioactivity-guided fractionation, isovaleric acid, 3-methylvaleric acid, and patchoulol were isolated and identified as the active constituents. The essential oil exhibited contact toxicity against L. bostrychophila with an LC50 value of 236.4 μg/cm2. Patchoulol (LC50 = 61.35 μg/cm2 exhibited stronger acute toxicity than 3-methylvaleric acid (LC50 = 210.69 μg/cm2 against the booklice. The essential oil also possessed fumigant toxicity against L. bostrychophila with an LC50 value of 6.0 mg/L, while 3-methylvaleric acid and isovaleric acid had LC50 values of 5.53 mg/L and 5.67 mg/L against the booklice, respectively. The results indicated that the essential oil and its constituent compounds have potential to develop into natural insecticides or fumigants for control of insects in stored grains.

Effects of persistent insecticides on beneficial soil arthropod in conventional fields compared to organic fields, puducherry.

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Anbarashan, Padmavathy; Gopalswamy, Poyyamoli

2013-07-15

The usage of synthetic fertilizers/insecticides in conventional farming has dramatically increased over the past decades. The aim of the study was to compare the effects of bio-pesticides and insecticides/pesticides on selected beneficial non targeted arthropods. Orders Collembola, Arachinida/Opiliones, Oribatida and Coleoptera were the main groups of arthropods found in the organic fields and Coleoptera, Oribatida, Gamasida and Collembola in conventional fields. Pesticides/insecticides had a significant effect on non-targeted arthropods order- Collembola, Arachinida/Opiliones, Hymenoptera and Thysonoptera were suppressed after pesticides/insecticides spraying. Bio-insecticides in organic fields had a non-significant effect on non targeted species and they started to increase in abundance after 7 days of spraying, whereas insecticide treatment in conventional fields had a significant long-term effect on non targeted arthropods and short term effect on pests/insects, it started to increase after 21 days of the spraying. These results indicate that insecticide treatment kept non targeted arthropods at low abundance. In conclusion, organic farming does not significantly affected the beneficial-non targeted arthropods biodiversity, whereas preventive insecticide application in conventional fields had significant negative effects on beneficial non targeted arthropods. Therefore, conventional farmers should restrict insecticide applications, unless pest densities reach the thresholds and more desirably can switch to organic farming practices.

Toxicity of some insecticides to the haemocytes of giant honeybee, Apis dorsata F. under laboratory conditions

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Nighat Perveen

2017-07-01

Full Text Available Quantitative studies concerning total and differential haemocyte counts and abnormalities were performed under laboratory conditions for larvae, pupae and adults collected from a wild Apis dorsata colony. Haemolymph samples were observed immediately, thirty and sixty minutes after field recommended concentration exposure of five different insecticides. Total haemocyte counts were significantly higher for larvae and pupae but less for adult bees, however, differential haemocyte counts insignificantly different. Exposure of insecticides showed variable response for tested insecticides with immediate increased change with ethofenprox, diafenthiuron and imidacloprid but decreased for all tested insecticides after sixty minutes. For differential haemocyte counts, plasmatocytes and granulocytes increased with exposure of insecticides. Immune response of haemocytes against insecticides showed different degrees of abnormalities like agglutination, denucleation and cell shape distortion. Such studies may help in possible identification of insect defense mechanisms against their exposure to external hazards for instance insecticide exposure.

The central role of mosquito cytochrome P450 CYP6Zs in insecticide detoxification revealed by functional expression and structural modelling.

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Chandor-Proust, Alexia; Bibby, Jaclyn; Régent-Kloeckner, Myriam; Roux, Jessica; Guittard-Crilat, Emilie; Poupardin, Rodolphe; Riaz, Muhammad Asam; Paine, Mark; Dauphin-Villemant, Chantal; Reynaud, Stéphane; David, Jean-Philippe

2013-10-01

The resistance of mosquitoes to chemical insecticides is threatening vector control programmes worldwide. Cytochrome P450 monooxygenases (CYPs) are known to play a major role in insecticide resistance, allowing resistant insects to metabolize insecticides at a higher rate. Among them, members of the mosquito CYP6Z subfamily, like Aedes aegypti CYP6Z8 and its Anopheles gambiae orthologue CYP6Z2, have been frequently associated with pyrethroid resistance. However, their role in the pyrethroid degradation pathway remains unclear. In the present study, we created a genetically modified yeast strain overexpressing Ae. aegypti cytochrome P450 reductase and CYP6Z8, thereby producing the first mosquito P450-CPR (NADPH-cytochrome P450-reductase) complex in a yeast recombinant system. The results of the present study show that: (i) CYP6Z8 metabolizes PBAlc (3-phenoxybenzoic alcohol) and PBAld (3-phenoxybenzaldehyde), common pyrethroid metabolites produced by carboxylesterases, producing PBA (3-phenoxybenzoic acid); (ii) CYP6Z8 transcription is induced by PBAlc, PBAld and PBA; (iii) An. gambiae CYP6Z2 metabolizes PBAlc and PBAld in the same way; (iv) PBA is the major metabolite produced in vivo and is excreted without further modification; and (v) in silico modelling of substrate-enzyme interactions supports a similar role of other mosquito CYP6Zs in pyrethroid degradation. By playing a pivotal role in the degradation of pyrethroid insecticides, mosquito CYP6Zs thus represent good targets for mosquito-resistance management strategies.

Diagnostic doses and times for Phlebotomus papatasi and Lutzomyia longipalpis sand flies (Diptera: Psychodidae: Phlebotominae) using the CDC bottle bioassay to assess insecticide resistance.

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Denlinger, David S; Creswell, Joseph A; Anderson, J Laine; Reese, Conor K; Bernhardt, Scott A

2016-04-15

Insecticide resistance to synthetic chemical insecticides is a worldwide concern in phlebotomine sand flies (Diptera: Psychodidae), the vectors of Leishmania spp. parasites. The CDC bottle bioassay assesses resistance by testing populations against verified diagnostic doses and diagnostic times for an insecticide, but the assay has been used limitedly with sand flies. The objective of this study was to determine diagnostic doses and diagnostic times for laboratory Lutzomyia longipalpis (Lutz & Nieva) and Phlebotomus papatasi (Scopoli) to ten insecticides, including pyrethroids, organophosphates, carbamates, and DDT, that are used worldwide to control vectors. Bioassays were conducted in 1,000-ml glass bottles each containing 10-25 sand flies from laboratory colonies of L. longipalpis or P. papatasi. Four pyrethroids, three organophosphates, two carbamates and one organochlorine, were evaluated. A series of concentrations were tested for each insecticide, and four replicates were conducted for each concentration. Diagnostic doses were determined only during the exposure bioassay for the organophosphates and carbamates. For the pyrethroids and DDT, diagnostic doses were determined for both the exposure bioassay and after a 24-hour recovery period. Both species are highly susceptible to the carbamates as their diagnostic doses are under 7.0 μg/ml. Both species are also highly susceptible to DDT during the exposure assay as their diagnostic doses are 7.5 μg/ml, yet their diagnostic doses for the 24-h recovery period are 650.0 μg/ml for Lu. longipalpis and 470.0 μg/ml for P. papatasi. Diagnostic doses and diagnostic times can now be incorporated into vector management programs that use the CDC bottle bioassay to assess insecticide resistance in field populations of Lu. longipalpis and P. papatasi. These findings provide initial starting points for determining diagnostic doses and diagnostic times for other sand fly vector species and wild populations using the CDC

Sublethal effects of some synthetic and botanical insecticides on Bemisia tabaci (Hemiptera: Aleyrodidae

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Esmaeily Saeideh

2014-07-01

Full Text Available In addition to direct mortality caused by insecticides, some biological traits of insects may also be affected by sublethal insecticide doses. In this study, we used the age-stage, two-sex life table method to evaluate the sublethal effects of the four synthetic insecticides: abamectin, imidacloprid, diazinon, and pymetrozin as well as the botanical insecticide taken from Calotropis procera (Asclepiadaceae extract, on eggs of the cotton whitefly, Bemisia tabaci (Hem.: Aleyrodidae. The lowest and highest survival rates and oviposition periods were observed in whiteflies treated by diazinon and imidacloprid, respectively. We found significant differences in the net reproductive rate (R0, the intrinsic rate of increase (r, the finite rate of increase (?, and the gross reproductive rate (GRR among different insecticides. Altogether, our results showed that pymetrozin and C. procera induced the most sublethal effects, thus they may be suitable candidates for use in integrated pest management programs of B. tabaci.

A "genome-to-lead" approach for insecticide discovery: pharmacological characterization and screening of Aedes aegypti D(1-like dopamine receptors.

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Jason M Meyer

2012-01-01

Full Text Available BACKGROUND: Many neglected tropical infectious diseases affecting humans are transmitted by arthropods such as mosquitoes and ticks. New mode-of-action chemistries are urgently sought to enhance vector management practices in countries where arthropod-borne diseases are endemic, especially where vector populations have acquired widespread resistance to insecticides. METHODOLOGY/PRINCIPAL FINDINGS: We describe a "genome-to-lead" approach for insecticide discovery that incorporates the first reported chemical screen of a G protein-coupled receptor (GPCR mined from a mosquito genome. A combination of molecular and pharmacological studies was used to functionally characterize two dopamine receptors (AaDOP1 and AaDOP2 from the yellow fever mosquito, Aedes aegypti. Sequence analyses indicated that these receptors are orthologous to arthropod D(1-like (Gα(s-coupled receptors, but share less than 55% amino acid identity in conserved domains with mammalian dopamine receptors. Heterologous expression of AaDOP1 and AaDOP2 in HEK293 cells revealed dose-dependent responses to dopamine (EC(50: AaDOP1 = 3.1±1.1 nM; AaDOP2 = 240±16 nM. Interestingly, only AaDOP1 exhibited sensitivity to epinephrine (EC(50 = 5.8±1.5 nM and norepinephrine (EC(50 = 760±180 nM, while neither receptor was activated by other biogenic amines tested. Differential responses were observed between these receptors regarding their sensitivity to dopamine agonists and antagonists, level of maximal stimulation, and constitutive activity. Subsequently, a chemical library screen was implemented to discover lead chemistries active at AaDOP2. Fifty-one compounds were identified as "hits," and follow-up validation assays confirmed the antagonistic effect of selected compounds at AaDOP2. In vitro comparison studies between AaDOP2 and the human D(1 dopamine receptor (hD(1 revealed markedly different pharmacological profiles and identified amitriptyline and doxepin as AaDOP2

Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV): Natural occurrence and efficacy as a biological insecticide on young banana plants in greenhouse and open-field conditions on the Canary Islands.

Science.gov (United States)

Fuentes, Ernesto Gabriel; Hernández-Suárez, Estrella; Simón, Oihane; Williams, Trevor; Caballero, Primitivo

2017-01-01

Chrysodeixis chalcites, an important pest of banana crops on the Canary Islands, is usually controlled by chemical insecticides. The present study aimed to evaluate the efficacy of the most prevalent isolate of the Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV, Baculoviridae) as a biological insecticide. Overall the prevalence of ChchNPV infection in C. chalcites populations was 2.3% (103 infected larvae out of 4,438 sampled), but varied from 0-4.8% on Tenerife and was usually low (0-2%) on the other islands. On Tenerife, infected larvae were present at 11 out of 17 plantations sampled. The prevalence of infection in larvae on bananas grown under greenhouse structures was significantly higher (3%) than in open-field sites (1.4%). The ChchNPV-TF1 isolate was the most abundant and widespread of four genetic variants of the virus. Application of 1.0x109 viral occlusion bodies (OBs)/l of ChchNPV-TF1 significantly reduced C. chalcites foliar damage in young banana plants as did commonly used pesticides, both in greenhouse and open-field sites. The insecticidal efficacy of ChchNPV-TF1 was similar to that of indoxacarb and a Bacillus thuringiensis (Bt)-based insecticide in one year of trials and similar to Bt in the following year of trails in greenhouse and field crops. However, larvae collected at different time intervals following virus treatments and reared in the laboratory experienced 2-7 fold more mortality than insects from conventional insecticide treatments. This suggests that the acquisition of lethal dose occurred over an extended period (up to 7 days) compared to a brief peak in larvae on plants treated with conventional insecticides. These results should prove useful for the registration of a ChchNPV-based insecticide for integrated management of this pest in banana crops on the Canary Islands.

Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV: Natural occurrence and efficacy as a biological insecticide on young banana plants in greenhouse and open-field conditions on the Canary Islands.

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Ernesto Gabriel Fuentes

Full Text Available Chrysodeixis chalcites, an important pest of banana crops on the Canary Islands, is usually controlled by chemical insecticides. The present study aimed to evaluate the efficacy of the most prevalent isolate of the Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV, Baculoviridae as a biological insecticide. Overall the prevalence of ChchNPV infection in C. chalcites populations was 2.3% (103 infected larvae out of 4,438 sampled, but varied from 0-4.8% on Tenerife and was usually low (0-2% on the other islands. On Tenerife, infected larvae were present at 11 out of 17 plantations sampled. The prevalence of infection in larvae on bananas grown under greenhouse structures was significantly higher (3% than in open-field sites (1.4%. The ChchNPV-TF1 isolate was the most abundant and widespread of four genetic variants of the virus. Application of 1.0x109 viral occlusion bodies (OBs/l of ChchNPV-TF1 significantly reduced C. chalcites foliar damage in young banana plants as did commonly used pesticides, both in greenhouse and open-field sites. The insecticidal efficacy of ChchNPV-TF1 was similar to that of indoxacarb and a Bacillus thuringiensis (Bt-based insecticide in one year of trials and similar to Bt in the following year of trails in greenhouse and field crops. However, larvae collected at different time intervals following virus treatments and reared in the laboratory experienced 2-7 fold more mortality than insects from conventional insecticide treatments. This suggests that the acquisition of lethal dose occurred over an extended period (up to 7 days compared to a brief peak in larvae on plants treated with conventional insecticides. These results should prove useful for the registration of a ChchNPV-based insecticide for integrated management of this pest in banana crops on the Canary Islands.

Determination of insecticides malathion and lambda-cyhalothrin residues in zucchini by gas chromatography

OpenAIRE

Lofty, Hayam M.; Abd El-Aleem, Abd El-Aziz A.; Monir, Hany H.

2013-01-01

A sensitive gas chromatographic method has been developed for the determination of malathion and lambda-cyhalothrin (λ-cyhalothrin) insecticide residues in zucchini. The developed method consists of extraction with acetone, purification and partitioning with methylene chloride, column chromatographic clean-up, and finally capillary gas chromatographic determination of the insecticides. The recoveries of method were greater than 90% and limit of determination was 0.001 ppm for both insecticide...

Efficacy of insecticides in fruit borer control and residues on sugar apple fruit

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Alessandro da Silva Oliveira

Full Text Available ABSTRACT Bahia is the Brazilian state with the largest production of sugar apple fruits (Annona squamosa L., and fruit borer (Cerconota anonella, Sepp. 1830 is a key crop pest. Insecticides are the main strategy for pest control even though there are no pesticides registered for this crop. This study aimed to assess the efficacy of insecticides to control fruit borer and determine the levels of insecticide residues in sugar apple fruits aiming at requesting the extension of authorization to use insecticide products in this crop. The experiment was conducted in an eight-year-old irrigated orchard (2 × 4 m located in Anagé, Bahia, Brazil. The experimental design was a randomized block design with 10 treatments (three insecticides with three doses and a control with water and 5 replications. Each plot was composed of four plants but only the two central ones were assessed. Insecticides and doses (g a.i. 100 L−1 water were Bacillus thuringiensis: 0.8, 1.7, and 2.5; triflumuron: 2.4, 3.6, and 4.8; and imidacloprid: 4.0, 10.0, and 16.0. Nine sprayings were carried out at fortnightly intervals with a costal sprayer with constant pressure, JA-2 nozzle, and with jet directed to the fruits. Ten assessments were performed in order to observe fruit borer presence in 30 previously marked fruits per plot. Imidacloprid, at the highest studied dose, was the only effective treatment. Analyses of imidacloprid residues, at 21 and 30 days after the highest dose application, indicated levels higher than the maximum limit allowed. Insecticides under the conditions tested do not meet the norms for requesting the extension of authorization to use insecticides for citrus in sugar apple fruits.

Insecticidal Constituents of Essential Oil Derived from Zanthoxylum armatum against Two Stored-Product Insects.

Science.gov (United States)

Wang, Cheng-Fang; Zhang, Wen-Juan; You, Chun-Xue; Guo, Shan-Shan; Geng, Zhu-Feng; Fan, Li; Du, Shu-Shan; Deng, Zhi-Wei; Wang, Yong-Yan

2015-01-01

In the course of our search for natural bioactive chemicals and investigations on their insecticidal activities from some medicinal plants growing in China, the essential oil derived from the twigs of Zanthoxylum armatum (Rutaceae) was found to possess strong insecticidal activities against two stored-product insects, Lasioderma serricorne and Tribolium castaneum. A total of 32 constituents of the essential oil were identified by GC and GC-MS analysis, and it revealed (E)-anethole (20.5%), 1,8-cineole (14.0%), 2-tridecanone (12.5%), limonene (9.0%) and piperitone (8.0%) as major components, followed by β-phellandrene (6.3%), β-pinene (5.1%) and 4-terpineol (4.4%). From the essential oil, five compounds were isolated and identified as (E)-anethole, 1,8-cineole, 2-tridecanone, limonene and piperitone. The results of insecticidal bioassays showed that the essential oil of Z. armatum exhibited strong fumigant toxicity towards L. serricorne and T. castaneum with LC50 values of 13.83 and 4.28 mg/L air, respectively, and also possessed contact toxicity against two insect species with LD50 values of 18.74 and 32.16 μg/adult, respectively. Among the active compounds, piperitone performed the strongest fumigant toxicity against L. serricorne (LC50 = 1.21 mg/L air) and contact toxicity against T. castaneum (LD50 = 3.16 μg/adult). 1,8-Cineole, limonene and piperitone showed similar fumigant toxicity against T. castaneum with LC50 values of 5.47, 6.21 and 7.12 mg/L air, respectively. Meanwhile, L. serricorne was the most sensitive to 2-tridecanone (LD50 = 5.74 μg/adult) in the progress of contact toxicity assay.

Pheromone-assisted techniques to improve the efficacy of insecticide sprays against Linepithema humile (Hymenoptera: Formicidae).

Science.gov (United States)

Choe, Dong-Hwan; Tsai, Kasumi; Lopez, Carlos M; Campbell, Kathleen

2014-02-01

Outdoor residual sprays are among the most common methods for targeting pestiferous ants in urban pest management programs. If impervious surfaces such as concrete are treated with these insecticides, the active ingredients can be washed from the surface by rain or irrigation. As a result, residual sprays with fipronil and pyrethroids are found in urban waterways and aquatic sediments. Given the amount of insecticides applied to urban settings for ant control and their possible impact on urban waterways, the development of alternative strategies is critical to decrease the overall amounts of insecticides applied, while still achieving effective control of target ant species. Herein we report a "pheromone-assisted technique" as an economically viable approach to maximize the efficacy of conventional sprays targeting the Argentine ant. By applying insecticide sprays supplemented with an attractive pheromone compound, (Z)-9-hexadecenal, Argentine ants were diverted from nearby trails and nest entrances and subsequently exposed to insecticide residues. Laboratory experiments with fipronil and bifenthrin sprays indicated that the overall kill of the insecticides on Argentine ant colonies was significantly improved (57-142% increase) by incorporating (Z)-9-hexadecenal in the insecticide sprays. This technique, once it is successfully implemented in practical pest management programs, has the potential of providing maximum control efficacy with reduced amount of insecticides applied in the environment.

Neonicotinoid insecticides can serve as inadvertent insect contraceptives

Science.gov (United States)

Villamar-Bouza, Laura; Bruckner, Selina; Chantawannakul, Panuwan; Gauthier, Laurent; Khongphinitbunjong, Kitiphong; Retschnig, Gina; Troxler, Aline; Vidondo, Beatriz; Neumann, Peter; Williams, Geoffrey R.

2016-01-01

There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera. Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. PMID:27466446

Dermal insecticide residues from birds inhabiting an orchard

Science.gov (United States)

Vyas, N.B.; Spann, J.W.; Hulse, C.S.; Gentry, S.; Borges, S.L.

2007-01-01

The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and the feet of brown-headed cowbirds (Molothrus ater) in order to quantify dermal exposure to songbirds that entered and inhabited an apple (Malus x domestica) orchard following an insecticide application. Exposure to azinphos-methyl was measured by sampling birds from an aviary that was built around an apple tree. Birds sampled at 36 h and 7-day post-application were placed in the aviary within 1 h after the application whereas birds exposed for 3 days were released into the aviary 4-day post-application. Residues on vegetation and soil were also measured. Azinphos-methyl residues were detected from the skin plus feathers and the feet from all exposure periods. Our results underscore the importance of incorporating dermal exposure into avian pesticide risk assessments.

Differences between organophosphorus insecticides in human self-poisoning: a prospective cohort study.

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Eddleston, Michael; Eyer, Peter; Worek, Franz; Mohamed, Fahim; Senarathna, Lalith; von Meyer, Ludwig; Juszczak, Edmund; Hittarage, Ariyasena; Azhar, Shifa; Dissanayake, Wasantha; Sheriff, M H Rezvi; Szinicz, Ladislaus; Dawson, Andrew H; Buckley, Nick A

Although more than 100 organophosphorus insecticides exist, organophosphorus poisoning is usually regarded as a single entity, distinguished only by the compound's lethal dose in animals. We aimed to determine whether the three most common organophosphorus insecticides used for self-poisoning in Sri Lanka differ in the clinical features and severity of poisoning they cause. We prospectively studied 802 patients with chlorpyrifos, dimethoate, or fenthion self-poisoning admitted to three hospitals. Blood cholinesterase activity and insecticide concentration were measured to determine the compound and the patients' response to insecticide and therapy. We recorded clinical outcomes for each patient. Compared with chlorpyrifos (35 of 439, 8.0%), the proportion dying was significantly higher with dimethoate (61 of 264, 23.1%, odds ratio [OR] 3.5, 95% CI 2.2-5.4) or fenthion (16 of 99, 16.2%, OR 2.2, 1.2-4.2), as was the proportion requiring endotracheal intubation (66 of 439 for chlorpyrifos, 15.0%; 93 of 264 for dimethoate, 35.2%, OR 3.1, 2.1-4.4; 31 of 99 for fenthion, 31.3%, 2.6, 1.6-4.2). Dimethoate-poisoned patients died sooner than those ingesting other pesticides and often from hypotensive shock. Fenthion poisoning initially caused few symptoms but many patients subsequently required intubation. Acetylcholinesterase inhibited by fenthion or dimethoate responded poorly to pralidoxime treatment compared with chlorpyrifos-inhibited acetylcholinesterase. Organophosphorus insecticide poisoning is not a single entity, with substantial variability in clinical course, response to oximes, and outcome. Animal toxicity does not predict human toxicity since, although chlorpyrifos is generally the most toxic in rats, it is least toxic in people. Each organophosphorus insecticide should be considered as an individual poison and, consequently, patients might benefit from management protocols developed for particular organophosphorus insecticides.

Concentration-mortality responses of Myzus persicae and natural enemies to selected insecticides.

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Bacci, Leandro; Rosado, Jander F; Picanço, Marcelo C; Pereira, Eliseu J G; Silva, Gerson A; Martins, Júlio C

2012-01-01

The toxicity of six insecticides was determined for the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae), and some of its natural enemies - the predatory beetles Cycloneda sanguinea (Coccinellidae) and Acanthinus sp. (Anthicidae), and the wasp parasitoid Diaeretiella rapae (Aphidiidae). Natural enemies from these groups are important natural biological control agents in a number of agroecosystems, and insecticides potentially safe to these non-target organisms should be identified using standardized tests. Thus, concentration-mortality bioassays were carried out with both the aphid and its natural enemies to assess the toxicity and selectivity of acephate, deltamethrin, dimethoate, methamidophos, methyl parathion, and pirimicarb. The latter insecticide was highly selective to all natural enemies tested, and its LC(90) for M. persicae was 14-fold lower than the field rate recommended for control of the aphid in brassica crops. Methyl parathion also showed selectivity to C. sanguinea and Acanthinus sp., but not to D. rapae. Acephate was the least potent insecticide against M. persicae and was equally or more toxic to the natural enemies relative to the aphid. Pirimicarb and methyl parathion were efficient against M. persicae and selective in favor of two of the natural enemies tested. Acanthinus sp. and C. sanguinea were more tolerant to the insecticides than was the parasitoid D. rapae. This study shows that there are selective insecticides that may be compatible with conservation of natural enemies in brassica crops, which is important practical information to improve integrated pest management systems in these crops.

Influence of Pyrethroid Insecticides on Sodium and Calcium Influx in Neocortical Neurons

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Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Using murine neocortical neurons in primary culture, we have compared the ability of 11 structurally diverse pyrethroid insecticides to evoke Na+ ...

Design, Synthesis, and Insecticidal Activity of Some Novel Diacylhydrazine and Acylhydrazone Derivatives

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Jialong Sun

2015-03-01

Full Text Available 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.

Resistance: a threat to the insecticidal crystal proteins of Bacillus thuringiensis

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Leah S. Bauer

1995-01-01

Insecticidal crystal proteins (also known as d-endotoxins) synthesized by the bacterium Bacillus thuringiensis Berliner (Bt) are the active ingredient of various environmentally friendly insecticides that are 1) highly compatible with natural enemies and other nontarget organisms due to narrow host specificity, 2) harmless to vertebrates, 3) biodegradable in the...

Selectivity of diacylhydrazine insecticides to the predatory bug Orius laevigatus: in vivo and modelling/docking experiments.

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Amor, Fermín; Christiaens, Olivier; Bengochea, Paloma; Medina, Pilar; Rougé, Pierre; Viñuela, Elisa; Smagghe, Guy

2012-12-01

Knowledge of pesticide selectivity to natural enemies is necessary for a successful implementation of biological and chemical control methods in integrated pest management (IPM) programmes. Diacylhydrazine (DAH)-based ecdysone agonists, also known as moulting-accelerating compounds (MACs), are considered to be a selective group of insecticides, and their compatibility with predatory Heteroptera, which are used as biological control agents, is known. However, their molecular mode of action has not been explored in beneficial insects such as Orius laevigatus (Fieber) (Hemiptera: Anthocoridae). In this project, in vivo toxicity assays demonstrated that the DAH-based RH-5849, tebufenozide and methoxyfenozide have no toxic effect against O. laevigatus. The ligand-binding domain (LBD) of the ecdysone receptor (EcR) of O. laevigatus was sequenced, and a homology protein model was constructed that confirmed a cavity structure with 12 α-helices, harbouring the natural insect moulting hormone 20-hydroxyecdysone. However, docking studies showed that a steric clash occurred for the DAH-based insecticides owing to a restricted extent of the ligand-binding cavity of the EcR of O. laevigatus. The insect toxicity assays demonstrated that MACs are selective for O. laevigatus. The modelling/docking experiments are indications that these pesticides do not bind with the LBD-EcR of O. laevigatus and support the supposition that they show no biological effects in the predatory bug. These data help in explaining the compatible use of MACs together with predatory bugs in IPM programmes. Copyright © 2012 Society of Chemical Industry.

Discovery of the aryl heterocyclic amine insecticides: synthesis, insecticidal activity, field results, mode of action and bioavailability of a leading field candidate.

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Dent, William H; Pobanz, Mark A; Geng, Chaoxian; Sparks, Thomas C; Watson, Gerald B; Letherer, Theodore J; Beavers, Kenneth W; Young, Cathy D; Adelfinskaya, Yelena A; Ross, Ronald R; Whiteker, Greg; Renga, James

2017-04-01

γ-Amino butyric acid (GABA) antagonists are proven targets for control of lepidopteran and other pests. New heterocyclic compounds with high insecticidal activity were discovered using a competitive-intelligence-inspired scaffold-hopping approach to generate analogs of fipronil, a known GABA antagonist. These novel aryl heterocyclic amines (AHAs) displayed broad-spectrum activity on a number of chewing insect pests. Through >370 modifications of the core AHA structure, a 7-pyrazolopyridine lead molecule was found to exhibit much improved activity on a number of insect pests. In field trial studies, its performance was 2-4 times lower than commercial standards and also appeared to be species dependent, with good activity seen for larvae of Spodoptera exigua, but inactivity on larvae of Trichoplusia ni. An extensive investigational biology effort demonstrated that these AHA analogs appear to have multiple modes of action, including GABA receptor antagonism and mitopotential or uncoupler activity. The limited capability in larvae of T. ni to convert the lead molecule to its associated open form correlates with the low toxicity of the lead molecule in this species. This work has provided information that could aid investigations of novel GABA antagonists. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Mechanistic modeling of insecticide risks to breeding birds in North American agroecosystems

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Insecticide usage in the United States is ubiquitous in urban, suburban, and rural environments. In evaluating data for an insecticide registration application and for registration review, scientists at the United States Environmental Protection Agency (USEPA) assess the fate of ...

Organochlorine insecticide poisoning in Golden Langurs Trachypithecus geei

OpenAIRE

D.C. Pathak

2011-01-01

Organochlorine insecticide poisoning was recorded in three Golden Langurs (Trachypithecus geei) in Chakrashila Wildlife Sanctuary (CWS) in Kokrajhar district of Assam during the month of December, 2008. The poisoning was due to prolonged ingestion of rubber plant leaves sprayed with the insecticide in a rubber plantation adjacent to the sanctuary. Though no specific gross lesions were observed, histopathologically, centilobular hepatic necrosis, mild renal degeneration, necrotic enteritis, pu...

Chemical constituents and insecticidal activities of the essential oil from Amomum tsaoko against two stored-product insects.

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Wang, Ying; You, Chun-Xue; Wang, Cheng-Fang; Yang, Kai; Chen, Ran; Zhang, Wen-Juan; Du, Shu-Shan; Geng, Zhu-Feng; Deng, Zhi-Wei

2014-01-01

The aim of this research was to determine the chemical constituents and toxicities of the essential oil derived from Amomum tsaoko Crevost et Lemarie fruits against Tribolium castaneum (Herbst) and Lasioderma serricorne (Fabricius). Essential oil of A. tsaoko was obtained from hydrodistillation and was investigated by gas chromatography-mass spectrometry (GC-MS). GC-MS analysis of the essential oil resulted in the identification of 43 components, of which eucalyptol (23.87%), limonene (22.77%), 2-isopropyltoluene (6.66%) and undecane (5.74%) were the major components. With a further isolation, two active constituents were obtained from the essential oil and identified as eucalyptol and limonene. The essential oil and the two isolated compounds exhibited potential insecticidal activities against two storedproduct insects. Limonene showed pronounced contact toxicity against both insect species (LD50 = 14.97 μg/adult for T. castaneum; 13.66 μg/adult for L. serricorne) and was more toxic than eucalyptol (LD50 = 18.83 μg/adult for T. castaneum; 15.58 μg/adult for L. serricorne). The essential oil acting against the two species of insects showed LD50 values of 16.52 and 6.14 μg/adult, respectively. Eucalyptol also possessed strong fumigant toxicity against both insect species (LC50 = 5.47 mg/L air for T. castaneum; 5.18 mg/L air for L. serricorne) and was more toxic than limonene (LC50 = 6.21 mg/L air for T. castaneum; 14.07 mg/L air for L. serricorne), while the crude essential oil acting against the two species of insects showed LC50 values of 5.85 and 8.70 mg/L air, respectively. These results suggested that the essential oil of A. tsaoko and the two compounds may be used in grain storage to combat insect pests.

Willingness to pay for insecticide-treated nets in Berehet District, Amhara Region, Northern Ethiopia: implication of social marketing.

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Aleme, Adisu; Girma, Eshetu; Fentahun, Netsanet

2014-01-01

Understanding the feasibility of achieving widespread coverage with Insecticide-Treated Nets has to be preceded by learning how people value the Insecticide-Treated Nets and estimating the potential demand and willingness to pay so that sustainability of the intervention can be assured. The objective of this study was to determine willingness to pay for Insecticide-Treated Nets among households in Berehet District, Northern Ethiopia. A community-based cross-sectional study was conducted using both quantitative and qualitative methods in five randomly selected Kebeles from January-February 2012. Open ended contingent valuation technique with follow-up method was used. Qualitative data were collected through focus group discussions and observation methods. Binary logistic regression was used to determine the association between dependent and independent variables. The average number of individuals per Insecticide-Treated Nets was 3.83. Nearly 68.5% persons had willingness to buy Insecticide-Treated Nets if they have access to these Nets. The median maximum price a person is willingness to pay for blue rectangular Insecticide-Treated Net was 20 ETB. People had willingness to pay 30 ETB for blue and white conical insecticide-treated nets. Working on knowledge of malaria (OR=0.68, CI (0.47, 0.98; ppay Insecticide-Treated Nets. Respondents who prefer Kebele/place/ to buy Insecticide-Treated Net for rectangular shape had a significant association with a willingness to pay for Insecticide-Treated Nets (OR=1.92, CI= 1.07-3.92). Promotions, products, price and place had significant association with willingness to pay for Insecticide-Treated Nets. Designing a social marketing strategy helps ensure sustainable supply of Insecticide-Treated Nets and proper use of Insecticide-Treated Nets.

Evolutionary changes in gene expression, coding sequence and copy-number at the Cyp6g1 locus contribute to resistance to multiple insecticides in Drosophila.

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Thomas W R Harrop

Full Text Available Widespread use of insecticides has led to insecticide resistance in many populations of insects. In some populations, resistance has evolved to multiple pesticides. In Drosophila melanogaster, resistance to multiple classes of insecticide is due to the overexpression of a single cytochrome P450 gene, Cyp6g1. Overexpression of Cyp6g1 appears to have evolved in parallel in Drosophila simulans, a sibling species of D. melanogaster, where it is also associated with insecticide resistance. However, it is not known whether the ability of the CYP6G1 enzyme to provide resistance to multiple insecticides evolved recently in D. melanogaster or if this function is present in all Drosophila species. Here we show that duplication of the Cyp6g1 gene occurred at least four times during the evolution of different Drosophila species, and the ability of CYP6G1 to confer resistance to multiple insecticides exists in D. melanogaster and D. simulans but not in Drosophila willistoni or Drosophila virilis. In D. virilis, which has multiple copies of Cyp6g1, one copy confers resistance to DDT and another to nitenpyram, suggesting that the divergence of protein sequence between copies subsequent to the duplication affected the activity of the enzyme. All orthologs tested conferred resistance to one or more insecticides, suggesting that CYP6G1 had the capacity to provide resistance to anthropogenic chemicals before they existed. Finally, we show that expression of Cyp6g1 in the Malpighian tubules, which contributes to DDT resistance in D. melanogaster, is specific to the D. melanogaster-D. simulans lineage. Our results suggest that a combination of gene duplication, regulatory changes and protein coding changes has taken place at the Cyp6g1 locus during evolution and this locus may play a role in providing resistance to different environmental toxins in different Drosophila species.

A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

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Charreton, Mercédès; Decourtye, Axel; Henry, Mickaël; Rodet, Guy; Sandoz, Jean-Christophe; Charnet, Pierre; Collet, Claude

2015-01-01

The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…), before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence) since (i) few studies are available on locomotion at this stage and (ii) in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h), three pyrethroids, namely cypermethrin (2.5 ng/bee), tetramethrin (70 ng/bee), tau-fluvalinate (33 ng/bee) and the neonicotinoid thiamethoxam (3.8 ng/bee) caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee) had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field, the case of

A Locomotor Deficit Induced by Sublethal Doses of Pyrethroid and Neonicotinoid Insecticides in the Honeybee Apis mellifera.

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Mercédès Charreton

Full Text Available The toxicity of pesticides used in agriculture towards non-targeted organisms and especially pollinators has recently drawn the attention from a broad scientific community. Increased honeybee mortality observed worldwide certainly contributes to this interest. The potential role of several neurotoxic insecticides in triggering or potentiating honeybee mortality was considered, in particular phenylpyrazoles and neonicotinoids, given that they are widely used and highly toxic for insects. Along with their ability to kill insects at lethal doses, they can compromise survival at sublethal doses by producing subtle deleterious effects. In this study, we compared the bee's locomotor ability, which is crucial for many tasks within the hive (e.g. cleaning brood cells, feeding larvae…, before and after an acute sublethal exposure to one insecticide belonging to the two insecticide classes, fipronil and thiamethoxam. Additionally, we examined the locomotor ability after exposure to pyrethroids, an older chemical insecticide class still widely used and known to be highly toxic to bees as well. Our study focused on young bees (day 1 after emergence since (i few studies are available on locomotion at this stage and (ii in recent years, pesticides have been reported to accumulate in different hive matrices, where young bees undergo their early development. At sublethal doses (SLD48h, i.e. causing no mortality at 48 h, three pyrethroids, namely cypermethrin (2.5 ng/bee, tetramethrin (70 ng/bee, tau-fluvalinate (33 ng/bee and the neonicotinoid thiamethoxam (3.8 ng/bee caused a locomotor deficit in honeybees. While the SLD48h of fipronil (a phenylpyrazole, 0.5 ng/bee had no measurable effect on locomotion, we observed high mortality several days after exposure, an effect that was not observed with the other insecticides. Although locomotor deficits observed in the sublethal range of pyrethroids and thiamethoxam would suggest deleterious effects in the field

Interactive effects of an insecticide and a fungicide on different organism groups and ecosystem functioning in a stream detrital food web.

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Dawoud, Mohab; Bundschuh, Mirco; Goedkoop, Willem; McKie, Brendan G

2017-05-01

Freshwater ecosystems are often affected by cocktails of multiple pesticides targeting different organism groups. Prediction and evaluation of the ecosystem-level effects of these mixtures is complicated by the potential not only for interactions among the pesticides themselves, but also for the pesticides to alter biotic interactions across trophic levels. In a stream microcosm experiment, we investigated the effects of two pesticides targeting two organism groups (the insecticide lindane and fungicide azoxystrobin) on the functioning of a model stream detrital food web consisting of a detritivore (Ispoda: Asellus aquaticus) and microbes (an assemblage of fungal hyphomycetes) consuming leaf litter. We assessed how these pesticides interacted with the presence and absence of the detritivore to affect three indicators of ecosystem functioning - leaf decomposition, fungal biomass, fungal sporulation - as well as detritivore mortality. Leaf decomposition rates were more strongly impacted by the fungicide than the insecticide, reflecting especially negative effects on leaf processing by detritivores. This result most like reflects reduced fungal biomass and increased detritivore mortality under the fungicide treatment. Fungal sporulation was elevated by exposure to both the insecticide and fungicide, possibly representing a stress-induced increase in investment in propagule dispersal. Stressor interactions were apparent in the impacts of the combined pesticide treatment on fungal sporulation and detritivore mortality, which were reduced and elevated relative to the single stressor treatments, respectively. These results demonstrate the potential of trophic and multiple stressor interactions to modulate the ecosystem-level impacts of chemicals, highlighting important challenges in predicting, understanding and evaluating the impacts of multiple chemical stressors on more complex food webs in situ. Copyright © 2017 Elsevier B.V. All rights reserved.

Temporo-spatial distribution of insecticide-resistance in Indian malaria vectors in the last quarter-century: Need for regular resistance monitoring and management.

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Raghavendra, Kamaraju; Velamuri, Poonam Sharma; Verma, Vaishali; Elamathi, Natarajan; Barik, Tapan Kumar; Bhatt, Rajendra Mohan; Dash, Aditya Prasad

2017-01-01

The Indian vector control programme similar to other programmes in the world is still reliant on chemical insecticides. Anopheles culicifacies is the major vector out of six primary malaria vectors in India and alone contributes about 2/3 malaria cases annually; and per se its control is actually control of malaria in India. For effective management of vectors, current information on their susceptibility status to different insecticides is essential. In this review, an attempt was made to compile and present the available data on the susceptibility status of different malaria vector species in India from the last 2.5 decades. Literature search was conducted by different means mainly web and library search; susceptibility data was collated from 62 sources for the nine malaria vector species from 145 districts in 21 states and two union territories between 1991 and 2016. Interpretation of the susceptibility/resistance status was made on basis of the recent WHO criteria. Comprehensive analysis of the data indicated that An. culicifacies, a major vector species was resistant to at least one insecticide in 70% (101/145) of the districts. It was reported mostly resistant to DDT and malathion whereas, its resistant status against deltamethrin varied across the districts. The major threat for the malaria control programmes is multiple-insecticide-resistance in An. culicifacies which needs immediate attention for resistance management in order to sustain the gains achieved so far, as the programmes have targeted malaria elimination by 2030.

Effects of a naturally occurring and a synthetic synergist on toxicity of three insecticides and a phytochemical to navel orangeworm (Lepidoptera: Pyralidae).

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Niu, Guodong; Pollock, Henry S; Lawrance, Allen; Siegel, Joel P; Berenbaum, May R

2012-04-01

The navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), is the most destructive lepidopteran pest of almonds [Prunus dulcis (Mill.) D.A.Webb] and pistachios (Pistacia vera L.) in California and is a serious problem in figs (Ficus carica L.) and walnuts (Juglans spp.). In addition to direct damage, larval feeding leaves nuts vulnerable to infection by Aspergillus spp., fungi that produce toxic aflatoxins. A potentially safe and sustainable approach for managing navel orangeworm in orchards may be to use natural essential oil synergists to interfere with this insect's ability to detoxify insecticides and phytochemicals. We tested the effects of a naturally occurring plant-derived chemical, myristicin, and a synthetic inhibitor of cytochrome P450 monooxygenases (P450s), piperonyl butoxide, on the toxicity of three insecticides (alpha-cypermethrin, tau-fluvalinate, and methoxyfenozide [Intrepid]) and a phytochemical (xanthotoxin) to A. transitella. Piperonyl butoxide significantly synergized alpha-cypermethrin and tau-fluvalinate, whereas myristicin synergized only alpha-cypermethrin. Piperonyl butoxide synergized the toxicity of xanthotoxin as early as 72 h after exposure, whereas myristicin synergized xanthotoxin after 120 h. In view of these findings and the limited availability of environmentally safe synthetic insecticides for sustainable management, particularly in organic orchards, myristicin is a potential field treatment in combination with insecticides to reduce both navel orangeworm survival and aflatoxin contamination of nuts. In addition, this study demonstrates that in A. transitella the insect growth regulator methoxyfenozide is not detoxified by P450s.

Effects of various insecticides on the development of the egg parasitoid Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae).

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Takada, Y; Kawamura, S; Tanaka, T

2001-12-01

The toxicity of six insecticides, acephate, methomyl, ethofenprox, cartap, chlorfluazuron, and Bacillus thuringiensis (Bt) was tested on different developmental stages of the egg parasitoid, Trichogramma dendrolimi (Matsumura). Each of the insecticides tested showed different degrees of toxicity to the parasitoid, Ethofenprox showed the highest toxicity and cartap showed relatively higher toxicity compared with the other insecticides. The development of the parasitoids treated with these two insecticides was normal, similar to that of the control group. Only the emergence of adult wasps from host eggs was disturbed. Emergence of the host, Mamestra brassicae larva was reduced following treatment with ethofenprox, cartap and methomyl. However, adult female wasps, which emerged from host eggs treated with the insecticides had the ability to oviposit normally.

Genetic variation associated with increased insecticide resistance in the malaria mosquito, Anopheles coluzzii.

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Main, Bradley J; Everitt, Amanda; Cornel, Anthony J; Hormozdiari, Fereydoun; Lanzaro, Gregory C

2018-04-04

Malaria mortality rates in sub-Saharan Africa have declined significantly in recent years as a result of increased insecticide-treated bed net (ITN) usage. A major challenge to further progress is the emergence and spread of insecticide resistance alleles in the Anopheles mosquito vectors, like An. coluzzii. A non-synonymous mutation in the para voltage-gated sodium channel gene reduces pyrethroid-binding affinity, resulting in knockdown resistance (kdr). Metabolic mechanisms of insecticide resistance involving detoxification genes like cytochrome P450 genes, carboxylesterases, and glutathione S-transferases are also important. As some gene activity is tissue-specific and/or environmentally induced, gene regulatory variation may be overlooked when comparing expression from whole mosquito bodies under standard rearing conditions. We detected complex insecticide resistance in a 2014 An. coluzzii colony from southern Mali using bottle bioassays. Additional bioassays involving recombinant genotypes from a cross with a relatively susceptible 1995 An. coluzzii colony from Mali confirmed the importance of kdr and associated increased permethrin resistance to the CYP9K1 locus on the X chromosome. Significant differential expression of CYP9K1 was not observed among these colonies in Malpighian tubules. However, the P450 gene CYP6Z1 was overexpressed in resistant individuals following sublethal permethrin exposure and the carboxylesterase gene COEAE5G was constitutively overexpressed. The significant P450-related insecticide resistance observed in the 2014 An. coluzzii colony indicates that ITNs treated with the P450 inhibitor piperonyl butoxide (PBO) would be more effective in this region. The known insecticide resistance gene CYP6Z1 was differentially expressed exclusively in the context of sublethal permethrin exposure, highlighting the importance of tissue-specificity and environmental conditions in gene expression studies. The increased activity of the carboxylesterase

Synergistic Combinations of a Pyrethroid Insecticide and an Emulsifiable Oil Formulation of Beauveria bassiana to Overcome Insecticide Resistance in Listronotus maculicollis (Coleoptera: Curculionidae).

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Wu, Shaohui; Kostromytska, Olga S; Koppenhöfer, Albrecht M

2017-08-01

The annual bluegrass weevil, Listronotus maculicollis (Kirby), is a major pest of golf course turf in eastern North America and has become particularly problematic owing to widespread development of insecticide resistance. As an alternative option to manage resistant adult L. maculicollis, we explored combinations of the pyrethroid insecticide bifenthrin with an emulsifiable oil formulation of the entomopathogenic fungus Beauveria bassiana strain GHA (Bb ES). Combinations synergistically enhanced mortality in both insecticide-susceptible and insecticide-resistant L. maculicollis adults in the laboratory when bifenthrin was used at LC50s for each population. To determine the component behind the synergism, technical spores of B. bassiana GHA and the emulsifiable oil carrier in the fungal formulation were tested separately or in combination with bifenthrin. In both separate and combined applications, the emulsifiable oil carrier was responsible for high mortality within 3 d after treatment and interacted synergistically with bifenthrin, whereas fungus-induced mortality started later. Strong synergism was also observed in three field experiments with a relatively resistant L. maculicollis population. Combinations of Bb ES and bifenthrin hold promise as an effective L. maculicollis management tool, particularly of pyrethroid-resistant populations. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

GC×GC-TOFMS Analysis of Essential Oils Composition from Leaves, Twigs and Seeds of Cinnamomum camphora L. Presl and Their Insecticidal and Repellent Activities.

Science.gov (United States)

Jiang, Hao; Wang, Jin; Song, Li; Cao, Xianshuang; Yao, Xi; Tang, Feng; Yue, Yongde

2016-03-28

Interest in essential oils with pesticidal activity against insects and pests is growing. In this study, essential oils from different parts (leaves, twigs and seeds) of Cinnamomum camphora L. Presl were investigated for their chemical composition, and insecticidal and repellent activities against the cotton aphid. The essential oils, obtained by hydrodistillation, were analyzed by GC×GC-TOFMS. A total of 96 components were identified in the essential oils and the main constituents found in the leaves and twigs were camphor, eucalyptol, linalool and 3,7-dimethyl-1,3,7-octatriene. The major components found in the seeds were eucalyptol (20.90%), methyleugenol (19.98%), linalool (14.66%) and camphor (5.5%). In the contact toxicity assay, the three essential oils of leaves, twigs and seeds exhibited a strong insecticidal activity against cotton aphids with LC50 values of 245.79, 274.99 and 146.78 mg/L (after 48 h of treatment), respectively. In the repellent assay, the highest repellent rate (89.86%) was found in the seed essential oil at the concentration of 20 μL/mL after 24 h of treatment. Linalool was found to be a significant contributor to the insecticidal and repellent activities. The results indicate that the essential oils of C. camphora might have the potential to be developed into a natural insecticide or repellent for controlling cotton aphids.

Blended Refuge and Insect Resistance Management for Insecticidal Corn

Science.gov (United States)

Crespo, Andre L B; Pan, Zaiqi; Crain, Philip R; Thompson, Stephen D; Pilcher, Clinton D; Sethi, Amit

2018-01-01

Abstract In this review, we evaluate the intentional mixing or blending of insecticidal seed with refuge seed for managing resistance by insects to insecticidal corn (Zea mays). We first describe the pest biology and farming practices that will contribute to weighing trade-offs between using block refuges and blended refuges. Case studies are presented to demonstrate how the trade-offs will differ in different systems. We compare biological aspects of several abstract models to guide the reader through the history of modeling, which has played a key role in the promotion or denigration of blending in various scientific debates about insect resistance management for insecticidal crops. We conclude that the use of blended refuge should be considered on a case-by-case basis after evaluation of insect biology, environment, and farmer behavior. For Diabrotica virgifera virgifera, Ostrinia nubilalis, and Helicoverpa zea in the United States, blended refuge provides similar, if not longer, delays in the evolution of resistance compared to separate block refuges. PMID:29220481

Rhodnius prolixus supergene families of enzymes potentially associated with insecticide resistance.

Science.gov (United States)

Schama, Renata; Pedrini, Nicolás; Juárez, M Patricia; Nelson, David R; Torres, André Q; Valle, Denise; Mesquita, Rafael D

2016-02-01

Chagas disease or American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi. Once known as an endemic health problem of poor rural populations in Latin American countries, it has now spread worldwide. The parasite is transmitted by triatomine bugs, of which Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae) is one of the vectors and a model organism. This species occurs mainly in Central and South American countries where the disease is endemic. Disease prevention focuses on vector control programs that, in general, rely intensely on insecticide use. However, the massive use of chemical insecticides can lead to resistance. One of the major mechanisms is known as metabolic resistance that is associated with an increase in the expression or activity of detoxification genes. Three of the enzyme families that are involved in this process - carboxylesterases (CCE), glutathione s-transferases (GST) and cytochrome P450s (CYP) - are analyzed in the R. prolixus genome. A similar set of detoxification genes to those of the Hemipteran Acyrthosiphon pisum but smaller than in most dipteran species was found in R. prolixus genome. All major CCE classes (43 genes found) are present but the pheromone/hormone processing class had fewer genes than usual. One main expansion was detected on the detoxification/dietary class. The phosphotriesterase family, recently associated with insecticide resistance, was also represented with one gene. One microsomal GST gene was found and the cytosolic GST gene count (14 genes) is extremely low when compared to the other hemipteran species with sequenced genomes. However, this is similar to Apis mellifera, a species known for its deficit in detoxification genes. In R. prolixus 88 CYP genes were found, with representatives in the four clans (CYP2, CYP3, CYP4 and mitochondrial) usually found in insects. R. prolixus seems to have smaller species-specific expansions of CYP genes than

Screening Test for Detection of Leptinotarsa decemlineata (Say Sensitivity to Insecticides

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Dušanka Inđić

2012-01-01

Full Text Available In 2009, the sensitivity of 15 field populations of Colorado potato beetle (Leptinotarsadecemlineata Say. - CPB was assessed to chlorpyrifos, cypermethrin, thiamethoxam and fipronil,four insecticides which are mostly used for its control in Serbia. Screening test that allows rapidassessment of sensitivity of overwintered adults to insecticides was performed. Insecticideswere applied at label rates, and two, five and 10 fold higher rates by soaking method (5 sec.Mortality was assessed after 72h. From 15 monitored populations of CPB, two were sensitiveto label rate of chlorpyrifos, one was slightly resistant, 11 were resistant and one populationwas highly resistant. Concerning cypermethrin, two populations were sensitive, two slightlyresistant, five were resistant and six highly resistant. Highly sensitive to thiamethoxam labelrate were 12 populations, while three were sensitive. In the case of fipronil applied at label rate,two populations were highly sensitive, six sensitive, one slightly resistant and six were resistant.The application of insecticides at higher rates (2, 5 and 10 fold, that is justified only in bioassays,provided a rapid insight into sensitivity of field populations of CPB to insecticides.

ASGDB: a specialised genomic resource for interpreting Anopheles sinensis insecticide resistance.

Science.gov (United States)

Zhou, Dan; Xu, Yang; Zhang, Cheng; Hu, Meng-Xue; Huang, Yun; Sun, Yan; Ma, Lei; Shen, Bo; Zhu, Chang-Liang

2018-01-10

Anopheles sinensis is an important malaria vector in Southeast Asia. The widespread emergence of insecticide resistance in this mosquito species poses a serious threat to the efficacy of malaria control measures, particularly in China. Recently, the whole-genome sequencing and de novo assembly of An. sinensis (China strain) has been finished. A series of insecticide-resistant studies in An. sinensis have also been reported. There is a growing need to integrate these valuable data to provide a comprehensive database for further studies on insecticide-resistant management of An. sinensis. A bioinformatics database named An. sinensis genome database (ASGDB) was built. In addition to being a searchable database of published An. sinensis genome sequences and annotation, ASGDB provides in-depth analytical platforms for further understanding of the genomic and genetic data, including visualization of genomic data, orthologous relationship analysis, GO analysis, pathway analysis, expression analysis and resistance-related gene analysis. Moreover, ASGDB provides a panoramic view of insecticide resistance studies in An. sinensis in China. In total, 551 insecticide-resistant phenotypic and genotypic reports on An. sinensis distributed in Chinese malaria-endemic areas since the mid-1980s have been collected, manually edited in the same format and integrated into OpenLayers map-based interface, which allows the international community to assess and exploit the high volume of scattered data much easier. The database has been given the URL: http://www.asgdb.org /. ASGDB was built to help users mine data from the genome sequence of An. sinensis easily and effectively, especially with its advantages in insecticide resistance surveillance and control.

Plant compounds insecticide activity against Coleoptera pests of stored products

OpenAIRE

MOREIRA, M.D.; PICANÇO, M.C.; BARBOSA, L.C. de A.; GUEDES, R.N.C.; CAMPOS, M.R. de; SILVA, G.A.; MARTINS, J.C.

2008-01-01

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed...

Development, oviposition, and mortality of Neoseiulus fallacis (Acari: Phytoseiidae) in response to reduced-risk insecticides.

Science.gov (United States)

Villanueva, Raul T; Walgenbach, James F

2005-12-01

Eight reduced-risk insecticides (acetamiprid, thiamethoxam, imidacloprid, thiacloprid, methoxyfenozide, pyriproxyfen, indoxacarb, and spinosad) and three conventional insecticides (azinphosmethyl, fenpropathrin, and esfenvalerate) were tested against Neoseiulus fallacis (Garman) (Acari: Phytoseiidae), the most abundant predacious mite in North Carolina apple (Malus spp.) orchards. To assess the effect of insecticides on development and mortality of N. fallacis immatures, 12-h-old eggs were individually placed on bean leaf disks previously dipped in insecticide solutions. Tetranychus urticae Koch (Acari: Tetranychidae) females were added as a food source. None of the reduced-risk insecticides significantly affected immature N. fallacis compared with the control; however, the pyrethroids esfenvalerate and fenpropathrin were highly toxic to immatures. To evaluate the effect of insecticides on mortality and oviposition of adult N. fallacis, 7- to 8-d-old females were confined on insecticide-treated bean leaves with Malephora crocea (Aizoaceae) pollen added as a food source. Spinosad resulted in the highest mortality, whereas azinphosmethyl, acetamiprid, fenpropathrin, and imidacloprid were moderately toxic, and mortality from esfenvalerate, indoxacarb, thiacloprid, methoxyfenozide, pyriproxyfen, and thiamethoxam did not differ significantly from the control. Oviposition was affected in a similar manner, with the exception of acetamiprid that did not affect oviposition, and thiamethoxam that reduced oviposition.

The effect of insecticide applications to melon crop on melon aphid and its natural enemies

International Nuclear Information System (INIS)

Guerra, J.; Gonzalez, J.E.; Ceballos, J.; Checa, B.

1999-01-01

Melons are an important export crop for Panama and are cultivated on more than 1000 ha of land. Long growing season, extending well into January, allows several generations and build up of heavy populations of an important insect pest, Aphis gossypii, the melon aphid. Growers find it difficult to cultivate melons without several applications of insecticides. Although the insecticide applications control the aphids, they may also have adverse effects on the natural enemies of the aphid, in particular the two predatory insects Cycloneda sanguinea and Chrysoperla carnea. The purpose of this research was to evaluate the impact of insecticide applications on these insects and on the yield of melons, and to estimate residues of the applied insecticides in soil. The insecticides were applied as four different type of treatments to melon crop. The treatments were (i) three periodic applications of endosulfan (Thiodan 35EC), each at 0.52 kg a.i./ha, (ii) three applications of fenitrothion (Sumithion 50WP), each at 0.35 kg a.i./ha, (iii) two applications of fenitrothion and one of endosulfan, and (iv) grower's treatment, which included applications of six different insecticides. The effect of the insecticide applications was evaluated by estimating numbers of each of the three type of insects before and within 72 hours after the applications and estimating yield of melons. All insecticide treatments reduced the populations of Aphis gossypii, but they also reduced the numbers of the benificial insects. Endosulfan was somewhat less toxic to C. carnea than the other insecticides were, since greater number of C. carnea were recorded from the plots treated with endosulfan than the other treated plots. The best yield of melons was recorded in the plots which were sprayed with fenitrothion, followed by the plots sprayed with endosulfan. and then those with grower's insecticides. Soon after the application of endosulfan the residue in the soil was 0.2 mg/kg, but it declined to less

Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

African Journals Online (AJOL)

HP

Original Research Article. Gas Chromatography-Mass Spectrometric Analysis and ... into a natural fumigant/insecticide for the control of stored product insects. Keywords: Mallotus ..... stability as well as reduce cost. ACKNOWLEDGEMENT.

Environmental risk assessment of registered insecticides in Iran using Environmental Impact Quotient (EIQ index

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S. Moinoddini

2016-05-01

Full Text Available In the last decades, pesticides have been used extensively, in order to control pests and plant diseases, but negative impacts of pesticides caused several environmental problems and put human health in danger. In order to decrease environmental hazards of pesticide, risk of pesticide application should be measured briefly and precisely. In this study environmental impacts of registered insecticides in Iran which applied in 2001-2002, 2003-2004, 2004-2005, are considered using environmental impact quotient (EIQ index. Results showed that among considered insecticides, Imidacloprid, Fipronil and Tiodicarb, potentially (EIQ were the most hazardous insecticides, respectively. Taking rate of application and active ingredient of insecticide in to account, environmental impact (practical toxicity per cultivated hectare (EIQ Field of each provinces were investigated. In this regard, among different province of Iran, Kerman, Mazandaran and Golestan were in danger more than the others, respectively. Besides, considering the amount of agricultural production in provinces, environmental impact per ton of production were calculated for each provinces which three northern provinces of Mazandaran, Golestan and Guilan, respectively endure the most environmental impact per ton of production. Eventually based on environmental impact quotient, results demonstrated that majority of environmental impacts of insecticide in Iran were due to inadequate knowledge and also overuse of a few number of insecticides. Therefore, by improving knowledge about environmental impact of pesticides and also developing environmental friendly and ecological based methods, negative environmental impacts of insecticides will be reduced significantly.

Chemical Sensing Regulates Mastication/Swallowing.

Science.gov (United States)

Yamamura, Kensuke; Kurose, Masayuki; Okamoto, Keiichiro

2016-01-01

Mastication and swallowing are the first stage of digestion involving several motor processes such as food intake, intra-oral food transport, bolus formation and chewing and swallowing reflex. These complicated motor functions are accomplished by the well-coordinated activities in the jaw, hyoid, tongue, facial and pharyngeal muscles. Although the basic activity patterns of these movements are controlled by the brainstem pattern generators, these movements generate various peripheral sensory inputs. Among the sensory inputs, it is well-known that somatic sensory inputs play important roles in reflexively modulating the movements so that the final motor outputs fit the environmental demand. However, little is known about the effects of chemical sensory inputs such as taste and olfaction originating from the ingested foods by these movements. A possible reason could be raised that cognition of the chemical sensory inputs at the higher brain also influences the movements, so it is difficult to discuss the neural mechanisms underlying the observed effect. In this review, we focus on the effects of chemical sensory inputs on the masticatory movements and initiation of swallowing. We first summarize chemical sensory inputs occurring during mastication and swallowing, and their receptive mechanisms. In addition, we will introduce the effect of application of monosodium L-glutamate (MSG) solution as an umami taste to the oropharynx on the swallow initiation which is involuntary controlled and the possible neural mechanisms underlying this effect is discussed.

Identification of Insecticidal Constituents of the Essential Oil of Acorus calamus Rhizomes against Liposcelis bostrychophila Badonnel

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Shu Shan Du

2013-05-01

Full Text Available The aim of this research was to determine the chemical composition of the essential oil of Acorus calamus rhizomes, its insecticidal activity against the booklouse, (Liposcelis bostrychophila and to isolate any insecticidal constituents from the essential oil. The essential oil of A. calamus rhizomes was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. A total of 32 components of the essential oil of A. calamus rhizomes was identified and the principal compounds in the essential oil were determined to be α-asarone (50.09%, (E-methylisoeugenol (14.01%, and methyleugenol (8.59%, followed by β-asarone (3.51%, α-cedrene (3.09% and camphor (2.42%. Based on bioactivity-guided fractionation, the three active constituents were isolated from the essential oil and identified as methyleugenol, (E-methylisoeugenol and α-asarone. The essential oil exhibited contact toxicity against L. bostrychophila with an LD50 value of 100.21 µg/cm2 while three constituent compounds, α-asarone, methyleugenol, and (E-methylisoeugenol had LD50 values of 125.73 µg/cm2, 103.22 µg/cm2 and 55.32 µg/cm2, respectively. Methyleugenol and (E-methylisoeugenol possessed fumigant toxicity against L. bostrychophila adults with LC50 values of 92.21 μg/L air and 143.43 μg/L air, respectively, while the crude essential oil showed an LC50 value of 392.13 μg/L air. The results indicate that the essential oil of A. calamus rhizomes and its constituent compounds have potential for development into natural fumigants/insecticides for control of the booklice.

Environment polluting conventional chemical control compared to an environmentally friendly IPM approach for control of diamondback moth, Plutella xylostella (L.), in China: a review.

Science.gov (United States)

Shakeel, Muhammad; Farooq, Muhammad; Nasim, Wajid; Akram, Waseem; Khan, Fawad Zafar Ahmad; Jaleel, Waqar; Zhu, Xun; Yin, Haichen; Li, Shuzhong; Fahad, Shah; Hussain, Saddam; Chauhan, Bhagirath Singh; Jin, Fengliang

2017-06-01

The diamondback moth, Plutella xylostella, is recognized as a widely distributed destructive insect pest of Brassica worldwide. The management of this pest is a serious issue, and an estimated annual cost of its management has reached approximately US$4 billion. Despite the fact that chemicals are a serious threat to the environment, lots of chemicals are applied for controlling various insect pests especially P. xylostella. An overreliance on chemical control has not only led to the evolution of resistance to insecticides and to a reduction of natural enemies but also has polluted various components of water, air, and soil ecosystem. In the present scenario, there is a need to implement an environmentally friendly integrated pest management (IPM) approach with new management tactics (microbial control, biological control, cultural control, mating disruption, insecticide rotation strategies, and plant resistance) for an alternative to chemical control. The IPM approach is not only economically beneficial but also reduces the environmental and health risks. The present review synthesizes published information on the insecticide resistance against P. xylostella and emphasizes on adopting an alternative environmentally friendly IPM approach for controlling P. xylostella in China.

Calcium uptake by sarcoplasmic reticulum in the presence of organophosphorus insecticide methyl-parathion

International Nuclear Information System (INIS)

Blasiak, J.

1995-01-01

Using an isotope labelling technique it has been shown that an organophosphorus insecticide methyl parathion (0,0-diethyl 0-4-nitrophenyl phosphorothionate) depressed calcium uptake by sarcoplasmic reticulum isolated from rabbit hind leg muscle. The effect was significant for insecticide concentrations of 50 and 100 μM and was dose-dependent. The insecticide exerted a more pronounced effect on calcium uptake in the presence of ATP in the reticulum environment than in the absence of ATP. The inhibitory action of methyl parathion on Ca 2+ accumulation by sarcoplasmic reticulum can cause a rise in myoplasmic free Ca 2+ , the essential prerequisite for contracture activation. Because methyl parathion, as well as other organophosphorus insecticides, is primarily neurotoxic, evidence of non-specific effect could be important for assessing its environmental safety. (author). 20 refs, 2 figs

Aedes aegypti resistance development to commonly used insecticides in Jakarta, Indonesia.

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Penny Humaidah Hamid

Full Text Available Aedes aegypti is the primary vector of various relevant arthropod-borne viral infectious diseases worldwide. The mosquito control is still mainly performed by using insecticides but their effectiveness is increasingly questioned nowadays. We here conducted a study on Ae. aegypti resistance development towards several commonly used insecticides in the capital city of Jakarta, Indonesia. In order to achieve this goal, Ae. aegypti eggs from Jakarta were collected with ovitraps and hatched in the insectary of the Gadjah Mada University, Indonesia. The F0 generations were used for WHO resistance tests and knockdown resistance (kdr assays. Presented results clearly showed that there was resistance development of Ae. aegypti populations to the here tested pyrethroid insecticides (i. e. permethrin. Observed mortalities were less than 90% with highest resistance against 0.75% permethrin concentrations. Furthermore, a significant association of V1016G gene mutations with resistance phenotypes to 0.75% permethrin was observed. Nevertheless, the F1534C mutation did not show a significant correlation to resistance development. In conclusion, our results show that populations of Ae. aegypti mosquitoes within the city of Jakarta have developed resistance against several routinely used pyrethroid insecticides in local performed control programs. Thus, the regular verification/assessment of resistance development status will hopefully help in the future to assist local public health authorities in their mosquito control programs by recommending and managing the rotation of different routinely used insecticides with diverse effector mechanisms in order to delay Ae. aegypti resistance development.

Non-Hodgkin Lymphoma and Occupational Exposure to Agricultural Pesticide Chemical Groups and Active Ingredients: A Systematic Review and Meta-Analysis

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Leah Schinasi

2014-04-01

Full Text Available This paper describes results from a systematic review and a series of meta-analyses of nearly three decades worth of epidemiologic research on the relationship between non-Hodgkin lymphoma (NHL and occupational exposure to agricultural pesticide active ingredients and chemical groups. Estimates of associations of NHL with 21 pesticide chemical groups and 80 active ingredients were extracted from 44 papers, all of which reported results from analyses of studies conducted in high-income countries. Random effects meta-analyses showed that phenoxy herbicides, carbamate insecticides, organophosphorus insecticides and the active ingredient lindane, an organochlorine insecticide, were positively associated with NHL. In a handful of papers, associations between pesticides and NHL subtypes were reported; B cell lymphoma was positively associated with phenoxy herbicides and the organophosphorus herbicide glyphosate. Diffuse large B-cell lymphoma was positively associated with phenoxy herbicide exposure. Despite compelling evidence that NHL is associated with certain chemicals, this review indicates the need for investigations of a larger variety of pesticides in more geographic areas, especially in low- and middle-income countries, which, despite producing a large portion of the world’s agriculture, were missing in the literature that were reviewed.

Effects of irrigation levels on interactions among Lygus hesperus (Hemiptera: Miridae), insecticides, and predators in cotton.

Science.gov (United States)

Asiimwe, Peter; Naranjo, Steven E; Ellsworth, Peter C

2014-04-01

Variation in plant quality and natural enemy abundance plays an important role in insect population dynamics. In manipulative field studies, we evaluated the impact of varying irrigation levels and insecticide type on densities of Lygus hesperus Knight and the arthropod predator community in cotton. Three watering levels were established via irrigations timed according to three levels of percent soil water depletion (SWD): 20, 40, or 60, where 40% SWD is considered standard grower practice, 60% represents a deficit condition likely to impose plant productivity losses, and 20% represents surplus conditions with likely consequences on excessive vegetative plant production. The two key L. hesperus insecticides used were the broad-spectrum insecticide acephate and the selective insecticide flonicamid, along with an untreated check. We hypothesized that densities of L. hesperus and its associated predators would be elevated at higher irrigation levels and that insecticides would differentially impact L. hesperus and predator dynamics depending on their selectivity. L. hesperus were more abundant at the higher irrigation level (20% SWD) but the predator densities were unaffected by irrigation levels. Both L. hesperus and its predators were affected by the selectivity of the insecticide with highest L. hesperus densities and lowest predator abundance where the broad spectrum insecticide (acephate) was used. There were no direct interactions between irrigation level and insecticides, indicating that insecticide effects on L. hesperus and its predators were not influenced by the irrigation levels used here. The implications of these findings on the overall ecology of insect-plant dynamics and yield in cotton are discussed.

Relative toxicity and residual activity of insecticides used in blueberry pest management: mortality of natural enemies.

Science.gov (United States)

Roubos, Craig R; Rodriguez-Saona, Cesar; Holdcraft, Robert; Mason, Keith S; Isaacs, Rufus

2014-02-01

A series of bioassays were conducted to determine the relative toxicities and residual activities of insecticides labeled for use in blueberry (Vaccinium corymbosum L.) on natural enemies, to identify products with low toxicity or short duration effects on biological control agents. In total, 14 insecticides were evaluated using treated petri dishes and four commercially available natural enemies (Aphidius colemani Viereck, Orius insidiosus [Say], Chrysoperla rufilabris [Burmeister], and Hippodamia convergens [Guérin-Menéville]). Dishes were aged under greenhouse conditions for 0, 3, 7, or 14 d before introducing insects to test residual activity. Acute effects (combined mortality and knockdown) varied by insecticide, residue age, and natural enemy species. Broad-spectrum insecticides caused high mortality to all biocontrol agents, whereas products approved for use in organic agriculture had little effect. The reduced-risk insecticide acetamiprid consistently caused significant acute effects, even after aging for 14 d. Methoxyfenozide, novaluron, and chlorantraniliprole, which also are classified as reduced-risk insecticides, had low toxicity, and along with the organic products could be compatible with biological control. This study provides information to guide blueberry growers in their selection of insecticides. Further research will be needed to determine whether adoption of a pest management program based on the use of more selective insecticides will result in higher levels of biological control in blueberry.

Insecticide toxicity to oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae) is influenced by environmental factors.

Science.gov (United States)

Lin, Yuying; Jin, Tao; Zeng, Ling; Lu, Yongyue

2013-02-01

In this study, we investigated the effects of environmental factors (temperature, dose, dietary source, and feeding density) on the insecticide tolerance of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae). The results indicated that the toxicities of trichlorphon and abamectin to B. dorsalis increased with an increase in temperature. At 15-35 degrees C, the toxicity of beta-cypermethrin decreased with an increase in temperature at low doses (0.82 and 1.86 mg/L), but was similar at a high dose (4.18 mg/L). These results demonstrated that the temperature coefficient of beta-cypermethrin was related to both temperature and dosage. The insecticide sensitivity of B. dorsalis reared on different dietary sources was significantly different. Trichlorphon sensitivity of B. dorsalis fed on banana was the highest with an LC50 of 1.61 mg/L, followed by on apple, carambola, semiartificial diet, pear, mango, guava, orange, and papaya. With an increasing feeding density, the sensitivity of B. dorsalis adults to trichlorphon increased, while the sensitivities of B. dorsalis adults to abamectin and beta-cypermethrin decreased. The differences between LC50 values of insects reared at densities of 10 and 13 eggs/g of semiartificial diet to trichlorphon, abamectin and beta-cypermethrin were not significant. This result suggested that representative toxicity could be obtained by using adults developed at a feeding density between 10-13 eggs/g of semiartificial diet. Adult body weight was positively correlated with the LC50 value of trichlorphon, but was negatively correlated with the toxicities of abamectin and beta-cypermethrin. These results suggested that the effects of adult body weight on the toxicity of insecticides were different among different chemicals.

Log bioassay of residual effectiveness of insecticides against bark beetles

Science.gov (United States)

Richard H. Smith

1982-01-01

Residual effectiveness of nine insecticides applied to bark was tested against western, mountain, and Jeffrey pine beetles. Ponderosa and Jeffrey pine trees were treated and logs cut from them 2 to 13 months later, and bioassayed with the three beetles. The insecticides were sprayed at the rate of 1 gal (3.8 l) per 40- or 80-ft² (3.6 or 7.2 m²) bark surface at varying...

Insecticidal activity of Trichilia claussenii (Meliaceae) fruits against Spodoptera frugiperda

International Nuclear Information System (INIS)

Nebo, Liliane; Matos, Andrea Pereira; Vieira, Paulo Cezar; Fernandes, Joao Batista; Silva, Maria Fatima das Gracas Fernandes da; Rodrigues, Ricardo Ribeiro

2010-01-01

An evaluation of the insecticidal activity of the fruits extracts of Trichilia claussenii was carried out and the methanol extract revealed to have strong insecticidal activity. The fractionation of methanol extract of T. claussenii seeds bioassay-guided against Spodoptera frugiperda has led to the identification of the ω-phenylalkyl and alkenyl fatty acids as active compounds in this extract. The structures of the compounds were proposed by spectroscopic analysis and comparison with literature data. (author)

Degradation analysis of some synthetic and bio-insecticides sprayed on okra crop using HPLC

International Nuclear Information System (INIS)

Abar, M.F.; Haq, M.A.; Yasmin, N.; Khan, M.F.U.

2012-01-01

This study aimed to find out the degradation of three conventional and two bio-insecticides sprayed on okra crop. Imidacloprid, Endosulfan and Profenofos were selected as convectional and biosal and spinosad as bioinsecticide. The insecticides were sprayed at the rates of 49.4, 642.2, 988, 35.5 and 158 g. a. i. ha/sup -1/ respectively. The insecticide residues were analyzed in the leaf and fruit after 0, 1, 3 and 7 days using high performance liquid chromatography. First order degradation kinetics was fitted on this data and degradation rate constants and half life were calculated. Conventional insecticides were found to be more persistent in the crop (Average half life: 1.95, 2.42 and 1.57 days for imidacloprid, endosulfan and profenofos respectively) than bioinsecticides (Average half life 1.25 and 0.27 days for spinosad and biosal respectively). Residues of all tested insecticides were compared with codex and EU MRLs and found both the bio-insecticides treated crops safe for human consumption even after few hours of spray. Endosulfan and profenofos treated crops were not found to be fit for consumption even after 7 days of application. Imidacloprid being biorational (low risk) was also safe for consumption on the next day of application. (author)

Impact of planting dates and insecticide strategies for managing crucifer flea beetles (Coleoptera: Chrysomelidae) in spring-planted canola.

Science.gov (United States)

Knodel, Janet J; Olson, Denise L; Hanson, Bryan K; Henson, Robert A

2008-06-01

Integration of cultural practices, such as planting date with insecticide-based strategies, was investigated to determine best management strategy for flea beetles (Phyllotreta spp.) (Coleoptera: Chrysomelidae) in canola (Brassica napus L.). We studied the effect of two spring planting dates of B. napus and different insecticide-based management strategies on the feeding injury caused by fleabeetles in North Dakota during 2002-2003. Adult beetle peak emergence usually coincided with the emergence of the early planted canola, and this resulted in greater feeding injury in the early planted canola than later planted canola. Use of late-planted canola may have limited potential for cultural control of flea beetle, because late-planted canola is at risk for yield loss due to heat stress during flowering. Flea beetle injury ratings declined when 1) the high rate of insecticide seed treatment plus a foliar insecticide applied 21 d after planting was used, 2) the high rate of insecticide seed treatment only was used, or 3) two foliar insecticide sprays were applied. These insecticide strategies provided better protection than the low rates of insecticide seed treatments or a single foliar spray, especially in areas with moderate-to-high flea beetle populations. The foliar spray on top of the seed treatment controlled later-emerging flea beetles as the seed treatment residual was diminishing and the crop became vulnerable to feeding injury. The best insecticide strategy for management of flea beetle was the high rate of insecticide seed treatment plus a foliar insecticide applied at 21 d after planting, regardless of planting date.

Pollution Of Insecticide Residues In PPTN Pasar Jumat Area

International Nuclear Information System (INIS)

Syahrir, Ulfa T.; Chairul, Sofnie M.

2000-01-01

Measurement of insecticide residue pollution from some organochlorin and organo-phosphat in soil and water samples were carried out 1999-2000 periode. The aim of the measurement was to get information about impact of laboratorium activity on insecticide contents in PPTN PASAR JUMAT. Gas chromatograph with electron capture and flame ionization detector were used to measure the pesticide content. Result of the measurement in PPTN area showed that organo-chlorin were alpha BHC, endosulfan band DDT and organo-phosphat were klorphyriphos and malation and were lower than tolerance level

Evidence of multiple/cross resistance to Bt and organophosphate insecticides in Puerto Rico population of the fall armyworm, Spodoptera frugiperda.

Science.gov (United States)

Zhu, Yu Cheng; Blanco, Carlos A; Portilla, Maribel; Adamczyk, John; Luttrell, Randall; Huang, Fangneng

2015-07-01

Fall armyworm (FAW) is a damaging pest of many economic crops. Long-term use of chemical control prompted resistance development to many insecticide classes. Many populations were found to be significantly less susceptible to major Bt toxins expressed in transgenic crops. In this study, a FAW strain collected from Puerto Rico (PR) with 7717-fold Cry1F-resistance was examined to determine if it had also developed multiple/cross resistance to non-Bt insecticides. Dose response assays showed that the PR strain developed 19-fold resistance to acephate. Besides having a slightly smaller larval body weight and length, PR also evolved a deep (2.8%) molecular divergence in mitochondrial oxidase subunit II. Further examination of enzyme activities in the midgut of PR larvae exhibited substantial decreases of alkaline phosphatase (ALP), aminopeptidase (APN), 1-NA- and 2-NA-specific esterase, trypsin, and chymotrypsin activities, and significant increases of PNPA-specific esterase and glutathione S-transferase (GST) activities. When enzyme preparations from the whole larval body were examined, all three esterase, GST, trypsin, and chymotrypsin activities were significantly elevated in the PR strain, while ALP and APN activities were not significantly different from those of susceptible strain. Data indicated that multiple/cross resistances may have developed in the PR strain to both Bt toxins and conventional insecticides. Consistently reduced ALP provided evidence to support an ALP-mediated Bt resistance mechanism. Esterases and GSTs may be associated with acephate resistance through elevated metabolic detoxification. Further studies are needed to clarify whether and how esterases, GSTs, and other enzymes (such as P450s) are involved in cross resistance development to Bt and other insecticide classes. Published by Elsevier Inc.

Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research ... apelta aerial parts was analyzed by gas chromatography/mass spectrometric (GC/MS) to determine its composition. ... into a natural fumigant/insecticide for the control of stored product insects.

Hormonal enhancement of insecticide efficacy in Tribolium castaneum: oxidative stress and metabolic aspects.

Science.gov (United States)

Plavšin, Ivana; Stašková, Tereza; Šerý, Michal; Smýkal, Vlastimil; Hackenberger, Branimir K; Kodrík, Dalibor

2015-04-01

Insect anti-stress responses, including those induced by insecticides, are controlled by adipokinetic hormones (AKHs). We examined the physiological consequences of Pyrap-AKH application on Tribolium castaneum adults (AKH-normal and AKH-deficient prepared by the RNAi technique) treated by two insecticides, pirimiphos-methyl and deltamethrin. Co-application of pirimiphos-methyl and/or deltamethrin with AKH significantly increased beetle mortality compared with application of the insecticides alone. This co-treatment was accompanied by substantial stimulation of general metabolism, as monitored by carbon dioxide production. Further, the insecticide treatment alone affected some basic markers of oxidative stress: it lowered total antioxidative capacity as well as the activity of superoxide dismutase in the beetle body; in addition, it enhanced the activity of catalase and glutathione-S-transferase. However, these discrepancies in oxidative stress markers were eliminated/reduced by co-application with Pyrap-AKH. We suggest that the elevation of metabolism, which is probably accompanied with faster turnover of toxins, might be responsible for the higher mortality that results after AKH and insecticide co-application. Changes in oxidative stress markers are probably not included in the mechanisms responsible for increased mortality. Copyright © 2015 Elsevier Inc. All rights reserved.

Gas Chromaotography-Mass Spectrometry Analysis of Insecticidal ...

African Journals Online (AJOL)

Insecticidal Essential Oil Derived from Chinese Ainsliaea fragrans Champ ex Benth ... Methods: The essential oil of A. fragrans aerial parts was obtained by hydrodistillation and analyzed by ..... toxicity than the crude oil. Caryophyllene showed.

Influence on sensitivity to insecticides: a case study of a settled area ...

African Journals Online (AJOL)

The close proximity of Liwonde National Park to Liwonde town creates a unique situation of a large human population adjacent to a natural undisturbed animal reserve. The closeness of the two ecosystems has an impact on biology of mosquitoes of the area, such as susceptibility to insecticides. Susceptibility to insecticide ...

Mode of Action of the Natural Insecticide, Decaleside Involves Sodium Pump Inhibition.

Science.gov (United States)

Rajashekar, Yallappa; Shivanandappa, Thimmappa

2017-01-01

Decalesides are a new class of natural insecticides which are toxic to insects by contact via the tarsal gustatory chemosensilla. The symptoms of their toxicity to insects and the rapid knockdown effect suggest neurotoxic action, but the precise mode of action and the molecular targets for decaleside action are not known. We have presented experimental evidence for the involvement of sodium pump inhibition in the insecticidal action of decaleside in the cockroach and housefly. The knockdown effect of decaleside is concomitant with the in vivo inhibition of Na+, K+ -ATPase in the head and thorax. The lack of insecticidal action by experimental ablation of tarsi or blocking the tarsal sites with paraffin correlated with lack of inhibition of Na+- K+ ATPase in vivo. Maltotriose, a trisaccharide, partially rescued the toxic action of decaleside as well as inhibition of the enzyme, suggesting the possible involvement of gustatory sugar receptors. In vitro studies with crude insect enzyme preparation and purified porcine Na+, K+ -ATPase showed that decaleside competitively inhibited the enzyme involving the ATP binding site. Our study shows that the insecticidal action of decaleside via the tarsal gustatory sites is causally linked to the inhibition of sodium pump which represents a unique mode of action. The precise target(s) for decaleside in the tarsal chemosensilla and the pathway linked to inhibition of sodium pump and the insecticidal action remain to be understood.

Radiation fixation of vinyl chloride in an insecticide aerosol container

International Nuclear Information System (INIS)

Kagiya, V.T.; Takemoto, K.

1975-01-01

Recently, a large quantity of vinyl chloride has been used as spraying additive for insecticide aerosols. Since January 1974 when the Food and Drug Administration of the United States of America announced that vinyl chloride causes liver cancer, it has been forbidden in Japan and the United States of America to market insecticide aerosol containers containing vinyl chloride. In Japan, following a government order, about 20 million insecticide aerosol containers have been collected and put into storage. A report is given on the radiation fixation of vinyl chloride as polyvinylchloride powder by gamma-ray-induced polymerization in the aerosol container. Insecticide aerosol containers containing vinyl chloride were irradiated by gamma rays from 60 Co at room temperature. Vinyl chloride polymerized to form powdered polymer in the container. Polymerization conversion increased with the irradiation dose, and after 10 Mrad irradiation, vinyl chloride was not found in the sprayed gas. This establishes that vinyl chloride can be fixed by gamma-ray irradiation in the aerosol container. To accelerate the reaction rate, the effect of various additives on the reaction was investigated. It was found that halogenated hydrocarbons, such as chloroform and carbon tetrachloride, accelerated the initiation of the polymerization, and that a vinyl monomer such as vinyl acetate accelerated the reaction rate due to the promotion of the initiation and the high reactivity of the polyvinylacetate radical to vinyl chloride. Consequently, the required irradiation dose for the fixation of vinyl chloride was decreased to less than 5 Mrad by the addition of various kinds of additives. Following the request of the Ministry of Public Welfare, various technical problems for large-scale treatment are being studied with the co-operation of the Federation of Insecticide Aerosols. (author)

Tri-trophic insecticidal effects of African plants against cabbage pests.

Directory of Open Access Journals (Sweden)

Blankson W Amoabeng

Full Text Available Botanical insecticides are increasingly attracting research attention as they offer novel modes of action that may provide effective control of pests that have already developed resistance to conventional insecticides. They potentially offer cost-effective pest control to smallholder farmers in developing countries if highly active extracts can be prepared simply from readily available plants. Field cage and open field experiments were conducted to evaluate the insecticidal potential of nine common Ghanaian plants: goat weed, Ageratum conyzoides (Asteraceae, Siam weed, Chromolaena odorata (Asteraceae, Cinderella weed, Synedrella nodiflora (Asteraceae, chili pepper, Capsicum frutescens (Solanaceae, tobacco, Nicotiana tabacum (Solanaceae cassia, Cassia sophera (Leguminosae, physic nut, Jatropha curcas (Euphorbiaceae, castor oil plant, Ricinus communis (Euphorbiaceae and basil, Ocimum gratissimum (Lamiaceae. In field cage experiments, simple detergent and water extracts of all botanical treatments gave control of cabbage aphid, Brevicoryne brassicae and diamondback moth, Plutella xylostella, equivalent to the synthetic insecticide Attack® (emamectin benzoate and superior to water or detergent solution. In open field experiments in the major and minor rainy seasons using a sub-set of plant extracts (A. conyzoides, C. odorata, S. nodiflora, N. tabacum and R. communis, all controlled B. brassicae and P. xylostella more effectively than water control and comparably with or better than Attack®. Botanical and water control treatments were more benign to third trophic level predators than Attack®. Effects cascaded to the first trophic level with all botanical treatments giving cabbage head weights, comparable to Attack® in the minor season. In the major season, R. communis and A conyzoides treatment gave lower head yields than Attack® but the remaining botanicals were equivalent or superior to this synthetic insecticide. Simply-prepared extracts from

Tri-trophic insecticidal effects of African plants against cabbage pests.

Science.gov (United States)

Amoabeng, Blankson W; Gurr, Geoff M; Gitau, Catherine W; Nicol, Helen I; Munyakazi, Louis; Stevenson, Phil C

2013-01-01

Botanical insecticides are increasingly attracting research attention as they offer novel modes of action that may provide effective control of pests that have already developed resistance to conventional insecticides. They potentially offer cost-effective pest control to smallholder farmers in developing countries if highly active extracts can be prepared simply from readily available plants. Field cage and open field experiments were conducted to evaluate the insecticidal potential of nine common Ghanaian plants: goat weed, Ageratum conyzoides (Asteraceae), Siam weed, Chromolaena odorata (Asteraceae), Cinderella weed, Synedrella nodiflora (Asteraceae), chili pepper, Capsicum frutescens (Solanaceae), tobacco, Nicotiana tabacum (Solanaceae) cassia, Cassia sophera (Leguminosae), physic nut, Jatropha curcas (Euphorbiaceae), castor oil plant, Ricinus communis (Euphorbiaceae) and basil, Ocimum gratissimum (Lamiaceae). In field cage experiments, simple detergent and water extracts of all botanical treatments gave control of cabbage aphid, Brevicoryne brassicae and diamondback moth, Plutella xylostella, equivalent to the synthetic insecticide Attack® (emamectin benzoate) and superior to water or detergent solution. In open field experiments in the major and minor rainy seasons using a sub-set of plant extracts (A. conyzoides, C. odorata, S. nodiflora, N. tabacum and R. communis), all controlled B. brassicae and P. xylostella more effectively than water control and comparably with or better than Attack®. Botanical and water control treatments were more benign to third trophic level predators than Attack®. Effects cascaded to the first trophic level with all botanical treatments giving cabbage head weights, comparable to Attack® in the minor season. In the major season, R. communis and A conyzoides treatment gave lower head yields than Attack® but the remaining botanicals were equivalent or superior to this synthetic insecticide. Simply-prepared extracts from readily

Tri-Trophic Insecticidal Effects of African Plants against Cabbage Pests

Science.gov (United States)

Amoabeng, Blankson W.; Gurr, Geoff M.; Gitau, Catherine W.; Nicol, Helen I.; Stevenson, Phil C.

2013-01-01

Botanical insecticides are increasingly attracting research attention as they offer novel modes of action that may provide effective control of pests that have already developed resistance to conventional insecticides. They potentially offer cost-effective pest control to smallholder farmers in developing countries if highly active extracts can be prepared simply from readily available plants. Field cage and open field experiments were conducted to evaluate the insecticidal potential of nine common Ghanaian plants: goat weed, Ageratum conyzoides (Asteraceae), Siam weed, Chromolaena odorata (Asteraceae), Cinderella weed, Synedrella nodiflora (Asteraceae), chili pepper, Capsicum frutescens (Solanaceae), tobacco, Nicotiana tabacum (Solanaceae) cassia, Cassia sophera (Leguminosae), physic nut, Jatropha curcas (Euphorbiaceae), castor oil plant, Ricinus communis (Euphorbiaceae) and basil, Ocimum gratissimum (Lamiaceae). In field cage experiments, simple detergent and water extracts of all botanical treatments gave control of cabbage aphid, Brevicoryne brassicae and diamondback moth, Plutella xylostella, equivalent to the synthetic insecticide Attack® (emamectin benzoate) and superior to water or detergent solution. In open field experiments in the major and minor rainy seasons using a sub-set of plant extracts (A. conyzoides, C. odorata, S. nodiflora, N. tabacum and R. communis), all controlled B. brassicae and P. xylostella more effectively than water control and comparably with or better than Attack®. Botanical and water control treatments were more benign to third trophic level predators than Attack®. Effects cascaded to the first trophic level with all botanical treatments giving cabbage head weights, comparable to Attack® in the minor season. In the major season, R. communis and A conyzoides treatment gave lower head yields than Attack® but the remaining botanicals were equivalent or superior to this synthetic insecticide. Simply-prepared extracts from readily

Using Next-Generation Sequencing to Detect Differential Expression Genes in Bradysia odoriphaga after Exposure to Insecticides

Directory of Open Access Journals (Sweden)

Haoliang Chen

2017-11-01

Full Text Available Bradysia odoriphaga (Diptera: Sciaridae is the most important pest of Chinese chive. Insecticides are used widely and frequently to control B. odoriphaga in China. However, the performance of the insecticides chlorpyrifos and clothianidin in controlling the Chinese chive maggot is quite different. Using next generation sequencing technology, different expression unigenes (DEUs in B. odoriphaga were detected after treatment with chlorpyrifos and clothianidin for 6 and 48 h in comparison with control. The number of DEUs ranged between 703 and 1161 after insecticide treatment. In these DEUs, 370–863 unigenes can be classified into 41–46 categories of gene ontology (GO, and 354–658 DEUs can be mapped into 987–1623 Kyoto Encyclopedia of Genes and Genomes (KEGG pathways. The expressions of DEUs related to insecticide-metabolism-related genes were analyzed. The cytochrome P450-like unigene group was the largest group in DEUs. Most glutathione S-transferase-like unigenes were down-regulated and most sodium channel-like unigenes were up-regulated after insecticide treatment. Finally, 14 insecticide-metabolism-related unigenes were chosen to confirm the relative expression in each treatment by quantitative Real Time Polymerase Chain Reaction (qRT-PCR. The results of qRT-PCR and RNA Sequencing (RNA-Seq are fairly well-established. Our results demonstrate that a next-generation sequencing tool facilitates the identification of insecticide-metabolism-related genes and the illustration of the insecticide mechanisms of chlorpyrifos and clothianidin.

Greenhouse Gases Emission and Global Warming Potential as Affected by Chemical Inputs for Main Cultivated Crops in Kerman Province: - Horticultural Crops

OpenAIRE

Nasibe Pourghasemian; Rooholla Moradi

2017-01-01

Introduction The latest report of the IPCC states that future emissions of greenhouse gases (GHGs) will continue to increase and will be the main cause of global climatic changes, as well as Iran. The three greenhouse gases associated with agriculture are CO2, CH4, and N2O. Chemical inputs consumption in agriculture has increased annually, while more intensive use of energy led to some important human health and environmental problems such as greenhouse gas emissions and global warming. Th...

The Effects of Some Botanical Insecticides and Pymetrozine on Life Table Parameters of Silver Leaf Whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae

Directory of Open Access Journals (Sweden)

Reihaneh Barati

2013-01-01

Full Text Available The objective of this research was to assess the effects of extracts of two medicinalplant species: Allium sativum (Linn and Calotropis procera (Aiton, and a formulation containingazadirachtin on life table parameters of silver leaf whitefly (SLW, Bemisia tabaci biotypeB (Gennadius (Hemiptera: Aleyrodidae, grown on greenhouse tomato plants. Theeffects were compared to that of pymetrozine, a synthetic insecticide. Bioassays were carriedout in a greenhouse under controlled conditions of 27 ± 2°C, R.H. of 55 ± 5% and 16:8h (L:D photo period.All treatments significantly affected the survivorship and fertility of SLW female adults,reducing the net reproduction rate, mean generation time and intrinsic rate of increase ofthis insect.The net reproductive rate [R0] values for the populations treated with garlic extract,milkweed extract, pymetrozine, azadirachtin, control for extracts (ethanol + distilled waterand control for pesticides (distilled water were 23.58, 19.32, 10.78, 8.23, 49.66, 57.55; theintrinsic rate of increases [rm] were 0.134, 0.139, 0.110, 0.090, 0.177, 0.178; the mean generationtimes [T] were 23.49, 21.23, 21.66, 23.50, 22.06, 22.69; the doubling times [DT] were 5.14,4.95, 6.27, 7.56, 3.91, 3.87, and the finite rates of increase [λ] were 1.144, 1.149, 1.116, 1.094, 1.193,1.195, respectively. Azadirachtin had the highest effect on the life table parameters of SLW.Our findings indicated that, although herbal extracts were not effective as much asthe chemical insecticides, they can be effective in pest control. Therefore, they are suitablechoices for replacing chemical insecticides and for alternative use with azadirachtin inSLW IPM program.

Mesoionic Pyrido[1,2-a]pyrimidinone Insecticides: From Discovery to Triflumezopyrim and Dicloromezotiaz.

Science.gov (United States)

Zhang, Wenming

2017-09-19

One of the greatest global challenges is to feed the ever-increasing world population. The agrochemical tools growers currently utilize are also under continuous pressure, due to a number of factors that contribute to the loss of existing products. Mesoionic pyrido[1,2-a]pyrimidinones are an unusual yet very intriguing class of compounds. Known for several decades, this class of compounds had not been systemically studied until we started our insecticide discovery program. This Account provides an overview of the efforts on mesoionic pyrido[1,2-a]pyridinone insecticide discovery, beginning from the initial high throughput screen (HTS) discovery to ultimate identification of triflumezopyrim (4, DuPont Pyraxalt) and dicloromezotiaz (5) for commercialization as novel insecticides. Mesoionic pyrido[1,2-a]pyrimidinones with a n-propyl group at the 1-position, such as compound 1, were initially isolated as undesired byproducts from reactions for a fungicide discovery program at DuPont Crop Protection. Such compounds showed interesting insecticidal activity in a follow-up screen and against an expanded insect species list. The area became an insecticide hit for exploration and then a lead area for optimization. At the lead optimization stage, variations at three regions of compound 1, i.e., side-chain (n-propyl group), substituents on the 3-phenyl group, and substitutions on the pyrido- moiety, were explored with many analogues prepared and evaluated. Breakthrough discoveries included replacing the n-propyl group with a 2,2,2-trifluoroethyl group to generate compound 2, and then with a 2-chlorothiazol-5-ylmethyl group to form compound 3. 3 possesses potent insecticidal activity not only against a group of hopper species, including corn planthopper (Peregrinus maidis (Ashmead), CPH) and potato leafhopper (Empoasca fabae (Harris), PLH), as well as two key rice hopper species, namely, brown planthopper (Nilaparvata lugens (Stål), BPH) and rice green leafhopper (Nephotettix

Gene transcription in Daphnia magna: effects of acute exposure to a carbamate insecticide and an acetanilide herbicide.

Science.gov (United States)

Pereira, Joana Luísa; Hill, Christopher J; Sibly, Richard M; Bolshakov, Viacheslav N; Gonçalves, Fernando; Heckmann, Lars-Henrik; Callaghan, Amanda

2010-05-05

Daphnia magna is a key invertebrate in the freshwater environment and is used widely as a model in ecotoxicological measurements and risk assessment. Understanding the genomic responses of D. magna to chemical challenges will be of value to regulatory authorities worldwide. Here we exposed D. magna to the insecticide methomyl and the herbicide propanil to compare phenotypic effects with changes in mRNA expression levels. Both pesticides are found in drainage ditches and surface water bodies standing adjacent to crops. Methomyl, a carbamate insecticide widely used in agriculture, inhibits acetylcholinesterase, a key enzyme in nerve transmission. Propanil, an acetanilide herbicide, is used to control grass and broad-leaf weeds. The phenotypic effects of single doses of each chemical were evaluated using a standard immobilisation assay. Immobilisation was linked to global mRNA expression levels using the previously estimated 48h-EC(1)s, followed by hybridization to a cDNA microarray with more than 13,000 redundant cDNA clones representing >5000 unique genes. Following exposure to methomyl and propanil, differential expression was found for 624 and 551 cDNAs, respectively (one-way ANOVA with Bonferroni correction, Pchemicals. Both pesticides promoted transcriptional changes in energy metabolism (e.g., mitochondrial proteins, ATP synthesis-related proteins), moulting (e.g., chitin-binding proteins, cuticular proteins) and protein biosynthesis (e.g., ribosomal proteins, transcription factors). Methomyl induced the transcription of genes involved in specific processes such as ion homeostasis and xenobiotic metabolism. Propanil highly promoted haemoglobin synthesis and up-regulated genes specifically related to defence mechanisms (e.g., innate immunity response systems) and neuronal pathways. Pesticide-specific toxic responses were found but there is little evidence for transcriptional

Chloride channels as tools for developing selective insecticides.

Science.gov (United States)

Bloomquist, Jeffrey R

2003-12-01

Ligand-gated chloride channels underlie inhibition in excitable membranes and are proven target sites for insecticides. The gamma-aminobutyric acid (GABA(1)) receptor/chloride ionophore complex is the primary site of action for a number of currently used insecticides, such as lindane, endosulfan, and fipronil. These compounds act as antagonists by stabilizing nonconducting conformations of the chloride channel. Blockage of the GABA-gated chloride channel reduces neuronal inhibition, which leads to hyperexcitation of the central nervous system, convulsions, and death. We recently investigated the mode of action of the silphinenes, plant-derived natural compounds that structurally resemble picrotoxinin. These materials antagonize the action of GABA on insect neurons and block GABA-mediated chloride uptake into mouse brain synaptoneurosomes in a noncompetitive manner. In mammals, avermectins have a blocking action on the GABA-gated chloride channel consistent with a coarse tremor, whereas at longer times and higher concentrations, activation of the channel suppresses neuronal activity. Invertebrates display ataxia, paralysis, and death as the predominant signs of poisoning, with a glutamate-gated chloride channel playing a major role. Additional target sites for the avermectins or other chloride channel-directed compounds might include receptors gated by histamine, serotonin, or acetylcholine.The voltage-sensitive chloride channels form another large gene family of chloride channels. Voltage-dependent chloride channels are involved in a number of physiological processes including: maintenance of electrical excitability, chloride ion secretion and resorption, intravesicular acidification, and cell volume regulation. A subset of these channels is affected by convulsants and insecticides in mammals, although the role they play in acute lethality in insects is unclear. Given the wide range of functions that they mediate, these channels are also potential targets for

Susceptibility of Anopheles gambiae to insecticides used for malaria vector control in Rwanda.

Science.gov (United States)

Hakizimana, Emmanuel; Karema, Corine; Munyakanage, Dunia; Iranzi, Gad; Githure, John; Tongren, Jon Eric; Takken, Willem; Binagwaho, Agnes; Koenraadt, Constantianus J M

2016-12-01

The widespread emergence of resistance to pyrethroids is a major threat to the gains made in malaria control. To monitor the presence and possible emergence of resistance against a variety of insecticides used for malaria control in Rwanda, nationwide insecticide resistance surveys were conducted in 2011 and 2013. Larvae of Anopheles gambiae sensu lato mosquitoes were collected in 12 sentinel sites throughout Rwanda. These were reared to adults and analysed for knock-down and mortality using WHO insecticide test papers with standard diagnostic doses of the recommended insecticides. A sub-sample of tested specimens was analysed for the presence of knockdown resistance (kdr) mutations. A total of 14,311 mosquitoes were tested and from a sample of 1406 specimens, 1165 (82.9%) were identified as Anopheles arabiensis and 241 (17.1%) as Anopheles gambiae sensu stricto. Mortality results indicated a significant increase in resistance to lambda-cyhalothrin from 2011 to 2013 in 83% of the sites, permethrin in 25% of the sites, deltamethrin in 25% of the sites and DDT in 50% of the sites. Mosquitoes from 83% of the sites showed full susceptibility to bendiocarb and 17% of sites were suspected to harbour resistance that requires further confirmation. No resistance was observed to fenitrothion in all study sites during the entire survey. The kdr genotype results in An. gambiae s.s. showed that 67 (50%) possessed susceptibility (SS) alleles, while 35 (26.1%) and 32 (23.9%) mosquitoes had heterozygous (RS) and homozygous (RR) alleles, respectively. Of the 591 An. arabiensis genotyped, 425 (71.9%) possessed homozygous (SS) alleles while 158 (26.7%) and 8 (1.4%) had heterozygous (RS) and homozygous (RR) alleles, respectively. Metabolic resistance involving oxidase enzymes was also detected using the synergist PBO. This is the first nationwide study of insecticide resistance in malaria vectors in Rwanda. It shows the gradual increase of insecticide resistance to pyrethroids (lambda

Environmental insecticide residues from tsetse fly control measures in Uganda

International Nuclear Information System (INIS)

Sserunjoji-Sebalija, J.

1976-01-01

Up to June 1974 areas in Uganda totalling 8600km 2 have been successfully reclaimed from tsetse fly infestation by ground spray of 3% dieldrin water emulsions. A search for equally effective but less persistent and toxic compounds against tsetse flies has been unsuccessful. Fourteen insecticide formulations have been tested for their persistence on tree bark surfaces and, therefore, their availability and toxicity to the target tsetse flies. Only those compounds with a high immediate insecticidal activity (some higher than dieldrin) like endosulfan, Chlorfenvinphos and propoxur could merit further consideration in tsetse control. While some were toxic to tsetse as fresh deposits, they lacked sufficient persistence. A study of the environmental implication from the continued use of the highly persistent and toxic dieldrin has provided useful data on residues likely to be found both in terrestrial and aquatic fauna and flora. These are generally low. Moreover, there is evidence of degradation in some fish species (Protopterus aethiopicus and Clarias). Also, dilution factors and adsorption involving the muddy nature of water run-off, etc., and controlled burning of grasses after tsetse eradication would tend to inactivate the residual insecticide and protect aquatic systems. The general findings have indicated less risk than anticipated of the environmental contamination from tsetse control by application of persistent and toxic insecticides. (author)

Synergistic potential of dillapiole-rich essential oil with synthetic pyrethroid insecticides against fall armyworm

Directory of Open Access Journals (Sweden)

Murilo Fazolin

2016-03-01

Full Text Available ABSTRACT: The objective of this study was to evaluate the synergy and response homogeneity of the Spodoptera frugiperda larvae population to the Piper aduncum essential oil in combination with pyrethroid insecticides (alpha-cypermethrin, beta-cypermethrin, fenpropathrin, and gamma-cyhalothrin compared to piperonylbutoxide (PBO as positive control. Synergism (SF comparisons were obtained using lethal concentration (LC50 and lethal dose (LD50 ratios of insecticides individually and in their respective synergistic combinations with essential oil and PBO. Dose/concentration-mortality slope curves were used to establish relative toxicity increase promoted by synergism. They also determined homogeneity response. Residual contact revealed significant potentiation for commercial insecticides formulated with beta-cypermethrin (SF=9.05-0.5 and fenpropathrin (SF=34.05-49.77 when combined with the P. aduncum essential oil. For topical contact, significant potentiation occurred only for alpha-cypermethrin (SF=7.55-3.68, fenpropathrin (SF=3.37-1.21, and gamma-cyhalothrin (SF=5.79-10.48 insecticides when combined with essential oil. With the exception of fenpropathrin and gamma-cyhalothrin, insecticides synergistic combinations presented homogeneous response by topical as well as residual contact at least with essential oil. The SF significance values ​​of the P. aduncum essential oil combined with alpha-cypermethrin, beta-cypermethrin, fenpropathrin, and gamma-cyhalothrin insecticides indicated potential for this oil to be used as an alternative to PBO.

Occurrence and potential toxicity of pyrethroids and other insecticides in bed sediments of urban streams in central Texas

Energy Technology Data Exchange (ETDEWEB)

Hintzen, Emily P. [Department of Environmental Studies, Baylor University, Waco, TX 76798 (United States); Lydy, Michael J. [Fisheries and Illinois Aquaculture Center, and Department of Zoology, Southern Illinois University, Carbondale, IL 62091 (United States); Belden, Jason B. [Department of Zoology, Oklahoma State University, 430 Life Science West, Stillwater, OK 74078 (United States)], E-mail: jbelden@okstate.edu

2009-01-15

Despite heavy insecticide usage in urban areas, only a few studies have investigated the impact of current-use insecticides on benthic invertebrates in urban streams. The objective of this study was to measure the presence and concentration of current-use pesticides in sediments of residential streams in central Texas. Additionally, toxicity of these sediments to Hyalella azteca was evaluated. Sediment samples were collected from several sites in urban streams over the course of a year, of which, 66% had greater than one toxic unit (TU) of insecticide. Bifenthrin was the greatest contributor accounting for 65% of the TUs, and sediment toxicity to H. azteca correlated with the magnitude of total insecticides and bifenthrin TUs. The results of this study further raise concerns over the environmental consequences posed by many current-use insecticides, especially pyrethroids, in urban settings. - This study examined the presence of insecticides in Texas stream sediments as a model for evaluating the potential impact of urban insecticide use in the Southern United States.

Occurrence and potential toxicity of pyrethroids and other insecticides in bed sediments of urban streams in central Texas