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Dong Wang - One of the best experts on this subject based on the ideXlab platform.
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Lethal and Sublethal Effects of Spinosad on Spodoptera exigua (Lepidoptera: Noctuidae)
Journal of economic entomology, 2013Co-Authors: Dong Wang, Yongming Wang, Huiyuan Liu, Zheng Xin, Ming XueAbstract:As a selective biological insecticide, spinosad has been used widely for the control of pests including beet armyworm, Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae). To form effective pest control strategies, lethal and Sublethal Effects should be considered for a complete analysis of spinosad impact. However, few studies have been reported to investigate Sublethal Effects of spinosad on S. exigua. This study attempts to evaluate the lethal and Sublethal Effects of spinosad on this pest by recording and analyzing various toxicological and physiological parameters. The toxicity of spinosad against S. exigua was determined under laboratory conditions by oral exposure of late second-instar larvae to the compound. The LC50 values of spinosad to S. exigua at 48 and 72 h after treatment were 0.317 and 0.293 mg x kg(-1), respectively. Spinosad at Sublethal concentrations significantly extended the developmental period of survivor larvae, and reduced larval wet weight. Postexposure Effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults. The net replacement rate (Ro) tended to be lower in the exposed spinosad groups than those in the unexposed spinosad group. Intrinsic rate of population increase (r(m)) for the high-dose group (0.365) was significantly lower than the control (0.521) and the low-dose group (0.521), but the latter two were not significantly difference. These results suggest that the combination of lethal and Sublethal Effects of spinosad might affect S. exigua population dynamics significantly by decreasing its survival and reproduction, and by delaying its development.
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Sublethal Effects of spinosad on survival growth and reproduction of helicoverpa armigera lepidoptera noctuidae
Pest Management Science, 2009Co-Authors: Dong Wang, Peiyu Gong, Xinghui Qiu, Kaiyun WangAbstract:BACKGROUND:Helicoverpa armigera (Hubner) is one of the most important pests in many countries. Spinosad is used widely for the control of pests, but there is sparse information available regarding its Sublethal Effects on H. armigera. Here, the authors attempt to investigate the Sublethal Effects of spinosad on H. armigera in order to reveal the negative, non-lethal impact of insecticides on this pest. RESULTS: The toxicity of spinosad against H. armigera was determined under laboratory conditions by oral exposure of late second-instar larvae to the compound. The 48 h LC50 and 72 h LC50 values of spinosad to this pest were found to be 0.41 mg kg−1 and 0.35 mg kg−1 respectively. Spinosad at Sublethal concentrations significantly extended the developmental time of survivor larvae, and reduced larval wet weight. Post-exposure Effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults. CONCLUSION: These results suggest that the combination of lethal and Sublethal Effects of spinosad might affect pest population dynamics significantly by decreasing its survival and reproduction, and by delaying its development. Copyright © 2008 Society of Chemical Industry
Wagner Faria Barbosa - One of the best experts on this subject based on the ideXlab platform.
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lethal and Sublethal Effects of azadirachtin on the bumblebee bombus terrestris hymenoptera apidae
Julius-Kühn-Archiv, 2015Co-Authors: Wagner Faria Barbosa, Laurens De Meyer, R N C Guedes, Guy SmaggheAbstract:Background: Lethal and Sublethal Effects of azadirachtin were studied on Bombus terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. Results: Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg litre -1 . No reproduction was scored at concentrations higher than 3.2 mg litre -1 . At 3.2 mg litre -1 , azadirachtin significantly inhibited the egg laying and, consequently, the production of drones during 6 weeks. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the Sublethal Effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg litre -1 . Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. Conclusion: Azadirachtin can affect B. terrestris with a range of Sublethal Effects. This study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. Keywords: chronic oral exposure, insect growth regulator (IGR), neem, repellence effect, reproduction
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lethal and Sublethal Effects of azadirachtin on the bumblebee bombus terrestris hymenoptera apidae
Ecotoxicology, 2015Co-Authors: Wagner Faria Barbosa, Laurens De Meyer, R N C Guedes, Guy SmaggheAbstract:Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and Sublethal Effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the Sublethal Effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of Sublethal Effects. Taking into account that Sublethal Effects are as important as lethal Effects for the development and survival of the colonies of B. terrestris, this study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. The latter agrees with the recent European Food Safety Authority guidelines to assess 'potentially deleterious' compounds for Sublethal Effects on behavior.
Guy Smagghe - One of the best experts on this subject based on the ideXlab platform.
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lethal and Sublethal Effects of azadirachtin on the bumblebee bombus terrestris hymenoptera apidae
Julius-Kühn-Archiv, 2015Co-Authors: Wagner Faria Barbosa, Laurens De Meyer, R N C Guedes, Guy SmaggheAbstract:Background: Lethal and Sublethal Effects of azadirachtin were studied on Bombus terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. Results: Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg litre -1 . No reproduction was scored at concentrations higher than 3.2 mg litre -1 . At 3.2 mg litre -1 , azadirachtin significantly inhibited the egg laying and, consequently, the production of drones during 6 weeks. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the Sublethal Effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg litre -1 . Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. Conclusion: Azadirachtin can affect B. terrestris with a range of Sublethal Effects. This study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. Keywords: chronic oral exposure, insect growth regulator (IGR), neem, repellence effect, reproduction
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lethal and Sublethal Effects of azadirachtin on the bumblebee bombus terrestris hymenoptera apidae
Ecotoxicology, 2015Co-Authors: Wagner Faria Barbosa, Laurens De Meyer, R N C Guedes, Guy SmaggheAbstract:Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and Sublethal Effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the Sublethal Effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of Sublethal Effects. Taking into account that Sublethal Effects are as important as lethal Effects for the development and survival of the colonies of B. terrestris, this study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. The latter agrees with the recent European Food Safety Authority guidelines to assess 'potentially deleterious' compounds for Sublethal Effects on behavior.
Helen M. Thompson - One of the best experts on this subject based on the ideXlab platform.
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colony impact of pesticide induced Sublethal Effects on honeybee workers a simulation study using beehave
Environmental Toxicology and Chemistry, 2017Co-Authors: Pernille Thorbek, Peter Campbell, Helen M. ThompsonAbstract:Research on neonicotinoids and honeybees have changed focus from direct mortality to Sublethal Effects. In the present study, a published honeybee model, BEEHAVE, is used to compare induced colony level impact of pesticides including direct mortality, poor brood care, disorientation, and increased handling time in oilseed rape and sunflower crops. Actual Effects on individual bees will depend on exposure concentrations, but in the present study large Effects were enforced. In oilseed rape, poor brood care had the largest colony impact, because it created a bottleneck for spring build-up of the workforce, and colony impact for all effect types peaked 1 mo after exposure ceased. In sunflower, the later exposure changed the response so colony impact peaked during exposure, and the bottleneck was honey store build-up. In all scenarios, good forage mitigated Effects substantially. It is concluded that field studies should continue at least 1 mo after exposure to ensure detection of ecologically relevant Sublethal Effects. The results indicated that even if a Sublethal effect is difficult to detect in the field, subsequent ecologically relevant colony level impacts would be clear if studies are continued for 1 mo after exposure. Guidance for regulatory studies recommends extended observation periods, and published field studies already use extended observation periods, so it is concluded that current methods are adequate for detecting ecologically relevant Sublethal Effects. Although published laboratory and semifield studies conducted under controlled exposure conditions suggest that Sublethal Effects may occur, published field studies with neonicotinoid seed treatments, naturally foraging bees, and extended observation periods do not report colony-level Effects, suggesting that in these studies no ecologically relevant Sublethal Effects occurred. Environ Toxicol Chem 2017;36:831-840. © 2016 SETAC.
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Colony impact of pesticide‐induced Sublethal Effects on honeybee workers: A simulation study using BEEHAVE
Environmental toxicology and chemistry, 2016Co-Authors: Pernille Thorbek, Peter Campbell, Helen M. ThompsonAbstract:Research on neonicotinoids and honeybees have changed focus from direct mortality to Sublethal Effects. In the present study, a published honeybee model, BEEHAVE, is used to compare induced colony level impact of pesticides including direct mortality, poor brood care, disorientation, and increased handling time in oilseed rape and sunflower crops. Actual Effects on individual bees will depend on exposure concentrations, but in the present study large Effects were enforced. In oilseed rape, poor brood care had the largest colony impact, because it created a bottleneck for spring build-up of the workforce, and colony impact for all effect types peaked 1 mo after exposure ceased. In sunflower, the later exposure changed the response so colony impact peaked during exposure, and the bottleneck was honey store build-up. In all scenarios, good forage mitigated Effects substantially. It is concluded that field studies should continue at least 1 mo after exposure to ensure detection of ecologically relevant Sublethal Effects. The results indicated that even if a Sublethal effect is difficult to detect in the field, subsequent ecologically relevant colony level impacts would be clear if studies are continued for 1 mo after exposure. Guidance for regulatory studies recommends extended observation periods, and published field studies already use extended observation periods, so it is concluded that current methods are adequate for detecting ecologically relevant Sublethal Effects. Although published laboratory and semifield studies conducted under controlled exposure conditions suggest that Sublethal Effects may occur, published field studies with neonicotinoid seed treatments, naturally foraging bees, and extended observation periods do not report colony-level Effects, suggesting that in these studies no ecologically relevant Sublethal Effects occurred. Environ Toxicol Chem 2017;36:831-840. © 2016 SETAC.
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The relevance of Sublethal Effects in honey bee testing for pesticide risk assessment.
Pest management science, 2007Co-Authors: Helen M. Thompson, Christian MausAbstract:The option of an evaluation and assessment of possible Sublethal Effects of pesticides on bees has been a subject of discussion by scientists and regulatory authorities. Effects considered included learning behaviour and orientation capacity. This discussion was enhanced by the French bee issue and allegations against systemic insecticides that were linked to the hypothesis that Sublethal intoxication might even have led to reported colony losses. This paper considers whether and, if so, how Sublethal Effects should be incorporated into risk assessment, by addressing a number of questions: What is meant by a Sublethal effect? Which Sublethal Effects should be measured, when and how? How are Sublethal Effects to be included in risk assessments? The authors conclude that Sublethal studies may be helpful as an optional test to address particular, compound-specific concerns, as a lower-tier alternative to semi-field or field testing, if the Effects are shown to be ecologically relevant. However, available higher-tier data (semi-field, field tests) should make any additional Sublethal testing unnecessary, and higher-tier data should always override data of lower-tier trials on Sublethal Effects.
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Perspective The relevance of Sublethal Effects in honey bee testing for pesticide risk assessment
2007Co-Authors: Helen M. Thompson, Christian MausAbstract:The option of an evaluation and assessment of possible Sublethal Effects of pesticides on bees has been a subject of discussion by scientists and regulatory authorities. Effects considered included learning behaviour and orientation capacity. This discussion was enhanced by the French bee issue and allegations against systemic insecticides that were linked to the hypothesis that Sublethal intoxication might even have led to reported colony losses. This paper considers whether and, if so, how Sublethal Effects should be incorporated into risk assessment, by addressing a number of questions: What is meant by a Sublethal effect? Which Sublethal Effects should be measured, when and how? How are Sublethal Effects to be included in risk assessments? The authors conclude that Sublethal studies may be helpful as an optional test to address particular, compound-specific concerns, as a lower-tier alternative to semi-field or field testing, if the Effects are shown to be ecologically relevant. However, available higher-tier data (semi-field, field tests) should make any additional Sublethal testing unnecessary, and higher-tier data should always override data of lower-tier trials on Sublethal Effects. Crown copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Kaiyun Wang - One of the best experts on this subject based on the ideXlab platform.
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Sublethal Effects of spinosad on survival growth and reproduction of helicoverpa armigera lepidoptera noctuidae
Pest Management Science, 2009Co-Authors: Dong Wang, Peiyu Gong, Xinghui Qiu, Kaiyun WangAbstract:BACKGROUND:Helicoverpa armigera (Hubner) is one of the most important pests in many countries. Spinosad is used widely for the control of pests, but there is sparse information available regarding its Sublethal Effects on H. armigera. Here, the authors attempt to investigate the Sublethal Effects of spinosad on H. armigera in order to reveal the negative, non-lethal impact of insecticides on this pest. RESULTS: The toxicity of spinosad against H. armigera was determined under laboratory conditions by oral exposure of late second-instar larvae to the compound. The 48 h LC50 and 72 h LC50 values of spinosad to this pest were found to be 0.41 mg kg−1 and 0.35 mg kg−1 respectively. Spinosad at Sublethal concentrations significantly extended the developmental time of survivor larvae, and reduced larval wet weight. Post-exposure Effects were indicated by decreased pupation ratio and pupal weight, by prolonged prepupal and pupal periods and by decreased emergence ratio, fecundity and longevity of adults. CONCLUSION: These results suggest that the combination of lethal and Sublethal Effects of spinosad might affect pest population dynamics significantly by decreasing its survival and reproduction, and by delaying its development. Copyright © 2008 Society of Chemical Industry
