The Experts below are selected from a list of 459 Experts worldwide ranked by ideXlab platform
Mark E. Whalon - One of the best experts on this subject based on the ideXlab platform.
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transovarial transmission of Novaluron in choristoneura rosaceana lepidoptera tortricidae
Canadian Entomologist, 2014Co-Authors: S H Kim, Christine Vandervoort, Mark E. Whalon, John C. WiseAbstract:The obliquebanded leafroller (OBLR), Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), has become a significant pest of tree fruit production in North America within the past 25 years. Control of the OBLR has historically relied upon broad-spectrum insecticides like organophosphates, carbamates, and pyrethroids. However, with evidence of resistance development, newer chemistries have been developed to combat this pest. The effects of Novaluron, a chitin synthesis inhibitor, were studied to determine if reduced egg hatch occurs after exposure to adults. The transovarial effects of this compound were tested through laboratory bioassays, looking at decreased egg hatch and also presence of Novaluron in egg masses following adult exposure. Results from the study demonstrated a decrease in egg hatch after adult exposure. Analysis of egg mass using HPLC also demonstrated Novaluron present in the eggs laid by treated adults. Along with the direct ovicidal and larvicidal properties of Novaluron, this transovarial activity provides an important contribution to the overall control seen in the field.
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reduced egg viability in codling moth cydia pomonella l lepidoptera tortricidae following adult exposure to Novaluron
Pest Management Science, 2009Co-Authors: Ayhan Gokce, John C. Wise, S H Kim, Mark E. WhalonAbstract:BACKGROUND: The codling moth, Cydia pomonella (L.), is one of the principal pests of pome fruits in the world. The effects of Novaluron, a benzoylurea chitin synthesis inhibitor insecticide registered for use on apples in the USA, on fecundity and egg viability in codling moth were studied under laboratory conditions. Three different exposure methods were investigated: ingestion, contact and topical spray. Additionally, the duration of Novaluron sublethal effects was measured subsequent to the three modes of exposure. RESULTS: The fecundity of codling moth adults was not significantly affected by Novaluron with any of the exposure methods. However, Novaluron did cause significant reductions in the proportion of egg hatch with all three exposure methods. The duration of sublethal effects was 9 days or more for all modes of exposure, but with the topical spray these effects began to diminish after 6 days. CONCLUSION: Novaluron does not affect fecundity in codling moth, but has significant sublethal activity by reducing egg viability subsequent to adult exposure. The topical, contact and ingestion exposures all induce sublethal effects after exposure, and these persist to various degrees throughout codling moth oviposition. A more complete understanding of Novaluron's lethal and sublethal activities will help IPM practitioners optimize its use for management of the codling moth. Copyright © 2008 Society of Chemical Industry
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novel life stage targets against plum curculio conotrachelus nenuphar herbst in apple integrated pest management
Pest Management Science, 2007Co-Authors: John C. Wise, Eric J. Hoffmann, Ki Duk Kim, Christine Vandervoort, Ayhan Gokce, Mark E. WhalonAbstract:In this study the authors employed the plant-insect-chemistry (PIC) triad to investigate two novel life stage targets against the plum curculio (PC), Conotrachelus nenuphar (Herbst), in apple integrated pest management (IPM). Laboratory treated apple bioassays were used to determine if the insect growth regulator (IGR) insecticides Novaluron and tebufenozide have physiological effects on PC larvae following adult exposure. Curative activity bioassays were conducted for IGR, neonicotinoid, oxidiazine and organophosphate insecticides on PC larvae post-infestation, and fruit penetration profiles of insecticides were developed. The results revealed that Novaluron exhibits activity on PC larvae via vertical transmission following exposure of mated females to treated substrate. Surface treatments of azinphos-methyl, thiacloprid and thiamethoxam to preinfested fruit resulted in significant reductions in larval emergence. For all compounds, 50% or more of the total recovered active ingredient was from apple skin, and for azinphos-methyl, indoxacarb and thiamethoxam it was greater than 80%. For azinphos-methyl, Novaluron, methoxyfenozide and thiacloprid, however, active ingredient was recovered from every section of the apple, from skin to core. Implications for twenty-first century IPM are discussed.
John C. Wise - One of the best experts on this subject based on the ideXlab platform.
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transovarial transmission of Novaluron in choristoneura rosaceana lepidoptera tortricidae
Canadian Entomologist, 2014Co-Authors: S H Kim, Christine Vandervoort, Mark E. Whalon, John C. WiseAbstract:The obliquebanded leafroller (OBLR), Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), has become a significant pest of tree fruit production in North America within the past 25 years. Control of the OBLR has historically relied upon broad-spectrum insecticides like organophosphates, carbamates, and pyrethroids. However, with evidence of resistance development, newer chemistries have been developed to combat this pest. The effects of Novaluron, a chitin synthesis inhibitor, were studied to determine if reduced egg hatch occurs after exposure to adults. The transovarial effects of this compound were tested through laboratory bioassays, looking at decreased egg hatch and also presence of Novaluron in egg masses following adult exposure. Results from the study demonstrated a decrease in egg hatch after adult exposure. Analysis of egg mass using HPLC also demonstrated Novaluron present in the eggs laid by treated adults. Along with the direct ovicidal and larvicidal properties of Novaluron, this transovarial activity provides an important contribution to the overall control seen in the field.
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activity of broad spectrum and reduced risk insecticides on various life stages of cranberry fruitworm lepidoptera pyralidae in highbush blueberry
Journal of Economic Entomology, 2010Co-Authors: John C. Wise, Ryan Vander Poppen, Paul E Jenkins, Rufus IsaacsAbstract:ABSTRACT Laboratory and semifield bioassays were conducted to determine the life-stage activity of insecticides for controlling cranberry fruitworm, Acrobasis vaccinii Riley (Lepidoptera: Pyralidae), a key lepidopteran pest of highbush blueberry, Vaccinium corymbosum L. The organophosphates azinphosmethyl and phosmet, the pyrethroid esfenvalerate, and the carbamate methomyl were lethal to all life stages. The neonicotinoids thiacloprid and acetamiprid demonstrated strong larvicidal and ovicidal activity but were somewhat weaker adulticides than the conventional broad-spectrum compounds. Bacillus thuringiensis, indoxacarb, and emamectin benzoate were shown to control A. vacinii primarily through their larvicidal activity. Spinosad was toxic to all life stages, including eggs laid on top of residues and those that were treated topically, but larvicidal activity was short lived. The growth regulators pyriproxyfen and Novaluron had strong ovicidal activity when eggs were laid on top of residues but had limite...
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curative activity of insecticides against plum curculio coleoptera curculionidae in tart cherries
Journal of Economic Entomology, 2009Co-Authors: Eric J. Hoffmann, Christine Vandervoort, John C. WiseAbstract:Tart cherry, Prunus cerasus L. variety Montmorency, fruit were infested with plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), and treated with insecticides to target late instars, neonates, and eggs. The organophosphates azinphos-methyl and phosmet and the neonicotinoid thiamethoxam reduced larval emergence rates by >90% for all life stage targets; after >30 d, few surviving larvae were found inside fruit. Acetamiprid and thiacloprid also had curative activity and yielded >75% reductions in emergence and few surviving larvae in the fruit after >30 d. The juvenile hormone analog pyriproxyfen reduced larval emergence, but 66% of fruit that was treated to target late-instars still had live larvae inside of them after >30 d. Novaluron, chlorantraniliprole, and esfenvalerate had no curative activity. Indoxacarb had limited curative activity, and all targeted life stages had larval emergence. Internal and external residues were analyzed and are discussed in relation to their penetration and curative potential. The curative activity of azinphos-methyl has played an important role in meeting federal standards for infestation-free tart cherries at processing. Regulatory changes are eliminating the use of this compound, and new integrated pest management programs for plum curculio will need to address the loss of azinphos-methyl's curative activity.
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reduced egg viability in codling moth cydia pomonella l lepidoptera tortricidae following adult exposure to Novaluron
Pest Management Science, 2009Co-Authors: Ayhan Gokce, John C. Wise, S H Kim, Mark E. WhalonAbstract:BACKGROUND: The codling moth, Cydia pomonella (L.), is one of the principal pests of pome fruits in the world. The effects of Novaluron, a benzoylurea chitin synthesis inhibitor insecticide registered for use on apples in the USA, on fecundity and egg viability in codling moth were studied under laboratory conditions. Three different exposure methods were investigated: ingestion, contact and topical spray. Additionally, the duration of Novaluron sublethal effects was measured subsequent to the three modes of exposure. RESULTS: The fecundity of codling moth adults was not significantly affected by Novaluron with any of the exposure methods. However, Novaluron did cause significant reductions in the proportion of egg hatch with all three exposure methods. The duration of sublethal effects was 9 days or more for all modes of exposure, but with the topical spray these effects began to diminish after 6 days. CONCLUSION: Novaluron does not affect fecundity in codling moth, but has significant sublethal activity by reducing egg viability subsequent to adult exposure. The topical, contact and ingestion exposures all induce sublethal effects after exposure, and these persist to various degrees throughout codling moth oviposition. A more complete understanding of Novaluron's lethal and sublethal activities will help IPM practitioners optimize its use for management of the codling moth. Copyright © 2008 Society of Chemical Industry
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Ovicidal Activity of Organophosphate, Oxadiazine, Neonicotinoid and Insect Growth Regulator Chemistries on Northern Strain Plum Curculio, Conotrachelus nenuphar
Journal of Insect Science, 2008Co-Authors: Eric J. Hoffmann, Samantha M. Middleton, John C. WiseAbstract:An in vitro method was developed for assessing ovicidal effects of the organophosphate azinphos-methyl, the neonicotioids thiacloprid, thiamethoxam and clothianidin, the oxadiazine indoxacarb and the insect growth regulators Novaluron and pyriproxifen on the plum curculio, Conotrachelus nenuphar (Herbst)(Coleoptera: Curculionidae). The baseline survivorship of this method was 88 percent. Plum curculio eggs were most sensitive to azinphos-methyl. Thiacloprid, clothianidin and the chitin synthesis inhibitor, Novaluron, had LC50 values below 100 ppm. Thiamethoxam, indoxacarb and pyriproxifen were not ovicidal at 100 ppm. Octanol-water partitioning coefficients, log Kow, appeared to be an important indicator of ovicidal activity within the neonicotinoids. This new bioassay method eliminates the confounding of the insect-chemical and plant-chemical interactions and the results highlight the utility of a post-infestation curative approach to plum curculio management.
Ayhan Gokce - One of the best experts on this subject based on the ideXlab platform.
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reduced egg viability in codling moth cydia pomonella l lepidoptera tortricidae following adult exposure to Novaluron
Pest Management Science, 2009Co-Authors: Ayhan Gokce, John C. Wise, S H Kim, Mark E. WhalonAbstract:BACKGROUND: The codling moth, Cydia pomonella (L.), is one of the principal pests of pome fruits in the world. The effects of Novaluron, a benzoylurea chitin synthesis inhibitor insecticide registered for use on apples in the USA, on fecundity and egg viability in codling moth were studied under laboratory conditions. Three different exposure methods were investigated: ingestion, contact and topical spray. Additionally, the duration of Novaluron sublethal effects was measured subsequent to the three modes of exposure. RESULTS: The fecundity of codling moth adults was not significantly affected by Novaluron with any of the exposure methods. However, Novaluron did cause significant reductions in the proportion of egg hatch with all three exposure methods. The duration of sublethal effects was 9 days or more for all modes of exposure, but with the topical spray these effects began to diminish after 6 days. CONCLUSION: Novaluron does not affect fecundity in codling moth, but has significant sublethal activity by reducing egg viability subsequent to adult exposure. The topical, contact and ingestion exposures all induce sublethal effects after exposure, and these persist to various degrees throughout codling moth oviposition. A more complete understanding of Novaluron's lethal and sublethal activities will help IPM practitioners optimize its use for management of the codling moth. Copyright © 2008 Society of Chemical Industry
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novel life stage targets against plum curculio conotrachelus nenuphar herbst in apple integrated pest management
Pest Management Science, 2007Co-Authors: John C. Wise, Eric J. Hoffmann, Ki Duk Kim, Christine Vandervoort, Ayhan Gokce, Mark E. WhalonAbstract:In this study the authors employed the plant-insect-chemistry (PIC) triad to investigate two novel life stage targets against the plum curculio (PC), Conotrachelus nenuphar (Herbst), in apple integrated pest management (IPM). Laboratory treated apple bioassays were used to determine if the insect growth regulator (IGR) insecticides Novaluron and tebufenozide have physiological effects on PC larvae following adult exposure. Curative activity bioassays were conducted for IGR, neonicotinoid, oxidiazine and organophosphate insecticides on PC larvae post-infestation, and fruit penetration profiles of insecticides were developed. The results revealed that Novaluron exhibits activity on PC larvae via vertical transmission following exposure of mated females to treated substrate. Surface treatments of azinphos-methyl, thiacloprid and thiamethoxam to preinfested fruit resulted in significant reductions in larval emergence. For all compounds, 50% or more of the total recovered active ingredient was from apple skin, and for azinphos-methyl, indoxacarb and thiamethoxam it was greater than 80%. For azinphos-methyl, Novaluron, methoxyfenozide and thiacloprid, however, active ingredient was recovered from every section of the apple, from skin to core. Implications for twenty-first century IPM are discussed.
Guy Smagghe - One of the best experts on this subject based on the ideXlab platform.
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comparative effects of insecticides with different mechanisms of action on chrysoperla externa neuroptera chrysopidae lethal sublethal and dose response effects
Insect Science, 2013Co-Authors: Moises Joao Zotti, Anderson Dionel Grutzmacher, Isac Heres Lopes, Guy SmaggheAbstract:The comprehensive knowledge that the delayed systemic and reproduction side effects can be even more deleterious than acute toxicity, has caused a shift in focus toward sublethal effects assessment on physiology and behavior of beneficial insects. In this study, we assessed the risks posed by some insecticides with different mode of action through lethal and delayed systemic sublethal effects on the pupation, adult emergence, and reproduction of the chrysopid Chrysoperla externa (Hagen, 1861; Neuroptera: Chrysopidae), an important predator in pest biological control. The maximum field recommended dose (MFRD) and twice (2×MFRD) for chlorantraniliprole, tebufenozide, and pyriproxyfen were harmless to C. externa. In contrast, all the tested chitin synthesis inhibitors (CSIs) were highly detrimental to the predator, despite of their lack of acute lethal toxicity. Therefore, the safety assumed by using IGRs toward beneficial insects is not valid for chrysopids. Dose–response data showed that although all CSIs have a similar mechanism of action, the relative extent of toxicity may differ (Novaluron > lufenuron > teflubenzuron). For CSIs, the delayed systemic effects became obvious at adult emergence, where the predicted no observable effect dose (NOED) was 1/2 048 of the MFRD for Novaluron (0.085 ng/insect), and 1/256 of the MFRD for both lufenuron (0.25 ng/insect) and teflubenzuron (0.6 ng/insect). Finally, this work emphasized the significance of performing toxicity risk assessments with an adequate posttreatment period to avoid underestimating the toxicities of insecticides, as the acute lethal toxicity assays may not provide accurate information regarding the long-range effects of hazardous compounds.
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hazards and uptake of chitin synthesis inhibitors in bumblebees bombus terrestris
Pest Management Science, 2006Co-Authors: Veerle Mommaerts, Guy Smagghe, Guido SterkAbstract:This research project examined the potential hazards of a major class of insect growth regulators (IGRs) to survival, reproduction and larval growth in bumblebees Bombus terrestris L. Eight chitin synthesis inhibitors (CSIs) were tested: buprofezin, cyromazine, diflubenzuron, flucycloxuron, flufenoxuron, lufenuron, Novaluron and teflubenzuron. These different IGRs, which are important in the control of pest insects in greenhouses, were applied via three different routes of exposure under laboratory conditions: dermal contact, and orally via the drinking of sugar/water and via pollen. The compounds were tested at their respective maximum field recommended concentrations (MFRC) and also in dose-response assays to calculate LC50 values. In general, none of the CSIs showed acute worker toxicity. However, there was a dramatic reduction in brood production, especially after oral treatment with pollen and sugar/water. Conspicuously, egg fertility was reduced in all treatments with diflubenzuron and teflubenzuron. In addition to egg mortality, the worker bumblebees removed larvae from the treated nest, and in most cases these individuals were dead first-second instars. Under a binocular microscope, such larvae showed an abnormally formed cuticle leading to mechanical weakness and death. In another series of experiments using 14C-diflubenzuron and 14C-flufenoxuron, cuticular penetration in workers was studied for a better understanding of the differences in toxicity. With 14C-diflubenzuron, transovarial transport and accumulation in the deposited eggs supported the strong reproductive effects. Overall, the present results suggest that CSIs should be applied with caution in combination with bumblebees. The compatibility of each compound to be used in combination with B. terrestris is discussed in relation to calculated LC50 values, routes of uptake and effects. Copyright © 2006 Society of Chemical Industry
Marilucia Santorum - One of the best experts on this subject based on the ideXlab platform.
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reproductive toxicity of Novaluron in bombyx mori lepidoptera bombycidae and its impact on egg production
Chemosphere, 2021Co-Authors: Marilucia Santorum, Bertha Irina Gastelbondopastrana, Elton Luiz Scudeler, Rose Meire Costa, Daniela Carvalho Dos SantosAbstract:Abstract Bombyx mori was used as a model to evaluate the reproductive toxicity of Novaluron in insects. Morphological analyses of the testes and ovaries of B. mori throughout their life cycle revealed important alterations in the germ and somatic cells involved in spermatogenesis and oogenesis. We observed in all testicular developmental phases that Novaluron affected not only the organization, distribution and development of the cysts containing male germ cells, but also the morphological features of cell death. Similar cellular characteristics were found in the treated B. mori ovaries, suggesting the occurrence of cell death in both organs, in addition to a significant reduction in oviposition of eggs by female moths. We demonstrated reproductive toxicity of Novaluron to the nontarget beneficial insect silkworm, thus providing a theoretical basis for revealing the reproductive toxicity of this insecticide to other nontarget beneficial insects.
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Novaluron impairs the silk gland and productive performance of silkworm bombyx mori lepidoptera bombycidae larvae
Chemosphere, 2020Co-Authors: Marilucia Santorum, Rose Meire Costa, Gustavo Henrique Dos Reis, Daniela Carvalho Dos SantosAbstract:This study investigates the effects of the insect growth regulator Novaluron on the silk gland (SG) and silk cocoon production in a nontarget insect, the silkworm Bombyx mori, which is a model research insect among Lepidoptera and of great economic importance for the commercial production of silk threads. Larvae were segregated into experimental groups: the control group (CG) and the treatment group (TG), which was exposed to a Novaluron concentration of 0.15 mL/L. Following exposure, we analyzed the cytotoxic effects on the epithelial cells of the anterior, middle and posterior regions of the SG of B. mori larvae in the 3rd, 4th, and 5th instars, as well as the quality of the cocoons from larvae in the 5th instar. Cytotoxic effects were observed in the TG, such as the dilation of cells, emission of cytoplasmic protrusions, extreme rarefaction of the cytoplasm and nuclei, dilation of the endoplasmic reticulum, intracellular and intercellular spaces, spacing between the epithelial cells and the basal lamina and detachment of some cells towards the lumen of the SG, and decreased protein in the lumen, with faults in its composition. In addition, we verified ultrastructural changes in the production of fibers and silk cocoons, including a reduction in the weight of the cocoons constructed by both males and females in the TG and the construction of defective cocoons. Novaluron exposure impairs the SG and may affect the physiological functions of this organ; additionally, it compromises the quality of silk cocoons, potentially causing serious damage to sericulture.
