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Robert S. Vernon - One of the best experts on this subject based on the ideXlab platform.
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efficacy of diamide neonicotinoid pyrethroid and phenyl pyrazole insecticide seed treatments for controlling the sugar beet Wireworm limonius californicus coleoptera elateridae in spring wheat
Journal of the Entomological Society of British Columbia, 2019Co-Authors: W G Van Herk, T J Labun, Robert S. VernonAbstract:Four classes of insecticide applied on seed were evaluated for managing high populations of the sugar beet Wireworm, Limonius californicus (Coleoptera: Elateridae), in spring wheat in southern Alberta, Canada. Three separate field trials were conducted, and assessments made for stand protection, yield, and Wireworm survival. Imidacloprid and thiamethoxam applied at 10–30 g AI and cyantraniliprole applied at 10–40 g AI provided initial stand protection, but did not protect seedlings until harvest and did not decrease Wireworm populations. λ-cyhalothrin applied at 30 g AI provided stand protection that persisted until harvest, but yields were considerably lower than observed in fipronil treatments and there was little (23%) decrease in populations relative to controls. Fipronil applied at 0.6, 1.0, and 5.0 g AI, either singly or in blend with thiamethoxam at 10 g AI, provided stand protection until harvest and significantly reduced numbers of Wireworms larger than 10 mm (range: 74–96%). Very low numbers of small (<11 mm) Wireworms were observed in all trials. These results are compared to data from laboratory and field studies for this and other Wireworm species. The relation between crop stand protection and Wireworm mortality, the potential of insecticide blends, and the importance of seed type, Wireworm species, and activity periods for managing Wireworms with seed treatments are discussed.
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Wireworm in Quebec Field Crops: Specific Community Composition in North America.
Environmental Entomology, 2017Co-Authors: J. Saguez, Robert S. Vernon, W G Van Herk, A. Latraverse, J. De Almeida, J-p. Légaré, J. Moisan-de Serres, M. Fréchette, G. LabrieAbstract:Wireworms are important economic pests that attack the seeds and roots of numerous vegetable and field crops worldwide. A 5-yr study was conducted in the main agricultural regions of the province of Quebec (Canada), to identify and characterize the Wireworm communities (Coleoptera: Elateridae) that occur in fields planted with economically important crops (maize, soybean, cereals, canola, and grasslands). Bait traps were used to collect Wireworms each spring from 2011 to 2015. More than 600 sites were sampled in total, involving ca. 14,000 traps. Wireworms were found in 69% of the sites and 73% of the traps. A total of 6,014 Wireworms were collected and identified to genus, or to species when possible. The results show that nine genera occur in Quebec and that Hypnoidus abbreviatus (Say) is currently the most abundant species in arable land in Quebec, representing 72% of all collected Wireworms. The other genera collected were Melanotus (8% of all Wireworms collected), Ampedus (7%), Limonius (6%), and Agriotes (4%). Wireworms from the genera Aeolus, Dalopius, Hemicrepidius, and Oestodes constituted ca. 3% together. The predominance of H. abbreviatus appeared to be specific to Quebec compared with the other Canadian provinces and the rest of North America. We observed differences in the relative abundance of Wireworm genera among the agricultural regions sampled. However, no effect of current and preceding crops was observed in this study. Our results suggest that integrated pest management strategies for managing Wireworms in Quebec fields should take into consideration the species present in each agronomical region.
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Contact behaviour and mortality of Wireworms exposed to six classes of insecticide applied to wheat seed
Journal of Pest Science, 2015Co-Authors: Willem Van Herk, Robert S. Vernon, Bobbi Vojtko, Shelby Snow, Jacqueline Fortier, Chantelle FortinAbstract:Insecticide-treated seed is commonly used to manage Wireworms, with insecticide toxicity generally being deduced from crop stand protection rather than from directly observed Wireworm responses. We observed the behaviour of larvae of two economic elaterids exposed to wheat seeds treated with 11 insecticides at various rates or combinations in a soil environment. Wireworms were exposed for 3 or 24 h, and the post-contact health and mobility of 1030 larvae that contacted seeds were assessed (bi)weekly for 12–42 weeks. Considerable repellency was observed when Wireworms were exposed to bifenthrin, tefluthrin, λ-cyhalothrin, and some repellency was also observed at high rates of various other insecticides. A high proportion of Wireworms were moribund after 24 h when exposed to treatments containing thiamethoxam, fipronil, or high rates of ethiprole, cyazypyr, chlorpyrifos, and spinosad, but not after exposure to bifenthrin, tefluthrin, chlorantraniliprole, spirotetramat, or low rates of ethiprole, cyazypyr, and chlorpyrifos. High mortality was observed in all treatments containing fipronil, but none after exposure to bifenthrin, tefluthrin, λ-cyhalothrin, chlorantraniliprole, spirotetramat, spinosad, or low rates of cyazypyr. Combining thiamethoxam with fipronil or a high rate of chlorpyrifos decreased the toxicity of the second compound. These findings largely explain why we observe stand protection without Wireworm population reduction in efficacy studies with wheat seed treated with various pyrethroid and neonicotinoid insecticides, and suggest a similar result for other insecticides that only induce temporary morbidity. This bioassay allows for rapid screening of insecticides proposed for Wireworm management before these are evaluated in labour-intensive and costly field trials.
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Further Studies on Wireworm Management in Canada: Damage Protection Versus Wireworm Mortality in Potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (
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further studies on Wireworm management in canada damage protection versus Wireworm mortality in potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (<9 mm long = ‘neonate‘) Wireworms were also observed. Neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) tested as seed piece treatments at ≈12.5 g active ingredient/100 kg potato seed reduced blemishes by, respectively, 19.1, 71.6, and...
Chantelle Harding - One of the best experts on this subject based on the ideXlab platform.
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further studies on Wireworm management in canada damage protection versus Wireworm mortality in potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (<9 mm long = ‘neonate‘) Wireworms were also observed. Neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) tested as seed piece treatments at ≈12.5 g active ingredient/100 kg potato seed reduced blemishes by, respectively, 19.1, 71.6, and...
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Further Studies on Wireworm Management in Canada: Damage Protection Versus Wireworm Mortality in Potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (
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Crop protection and mortality of Agriotes obscurus Wireworms with blended insecticidal wheat seed treatments
Journal of Pest Science, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Herk, Chantelle HardingAbstract:In Canada, as in much of the northern hemisphere, insecticidal seed treatments for cereals that both protect crops from damage by Wireworms (Coleoptera: Elateridae) and actually reduce Wireworm populations to sub-economic levels are lacking. Thiamethoxam and fipronil applied alone or in combination as wheat seed treatments were evaluated in field studies between 2006 and 2008 in protecting wheat from damage and reducing populations of resident and neonate Wireworms. Thiamethoxam alone applied at 5 or 10 g a.i./100 kg seed provided adequate wheat stand and yield protection, but did not significantly reduce Agriotes obscurus Wireworm populations. Fipronil alone at 5–50 g a.i./100 kg seed provided adequate wheat stand and yield protection, and also killed significant numbers of both resident and neonate Wireworms. Thiamethoxam (10 g a.i.) was initially combined with fipronil at 50, 5, 0.5, 0.05, and 0.005 g a.i./100 kg seed, and subsequently with a delimiting range of fipronil at 50, 5, 1, 0.5, and 0.1 g a.i. Blends of thiamethoxam (10 g a.i.) + fipronil at rates of 50, 5, or 1 g a.i. provided stand and yield as good or better than the former industry standard Vitavax Dual (containing lindane). Combinations of thiamethoxam (10 g a.i.) + fipronil at rates of 50, 5, 1, and 0.5 g a.i. had very low numbers of resident or neonate Wireworms relative to the untreated check and were comparable to the Vitavax Dual standard. The benefit of combined thiamethoxam + fipronil seed treatments at these rates, is that crop stand and yield are improved over the individual chemicals applied alone, and resident and neonate Wireworm mortality is high. The large reductions in resident and neonate Wireworms observed with these combined seed treatments would remove the economic threat of Wireworms in fields for 3+ years with rates of insecticides much lower than the formerly used Vitavax Dual.
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Possible aversion learning in the Pacific Coast Wireworm
Physiological Entomology, 2010Co-Authors: Willem G. Van Herk, Chantelle Harding, Robert S. Vernon, Bernard D. Roitberg, Gerhard GriesAbstract:The effects of carbon dioxide and the induction of morbidity on aversion learning in larvae of the Pacific Coast Wireworm Limonius canus LeConte (Coleoptera: Elateridae) are discussed. Wireworms preconditioned by exposing them one or four times to odour of Tefluthrin 20SC and Dividend XLRTA [Syngenta Crop Protection (Canada), Inc., Canada] during the induction of temporary morbidity subsequently contact tefluthrin-treated wheat seeds in soil bioassays for as long as naive (i.e. not preconditioned) larvae but are repelled four to five-fold more frequently by Dividend-treated seeds in soil bioassays than naive Wireworms, suggesting that Wireworms are capable of associating a novel odour (i.e. Dividend) with morbidity but require a minimum of 10–15 min subsequent contact time with treated seeds before being repelled. Wireworms preconditioned by exposure to peppermint odour during the induction of morbidity are not subsequently repelled by peppermint odour in soil bioassays, suggesting that Wireworms are either not capable of aversion learning or that the presence of a CO2 source and/or a suitable host plant may override a negative cue (i.e. peppermint odour). In studies conducted in the absence of soil, a host plant and CO2 production, Wireworms are repelled slightly by droplets of 1.0% but not 0.1% peppermint oil. Previous exposure to peppermint odour or contact with peppermint oil-treated filter paper during one induction of morbidity does not increase the repellency of Wireworms to 1.0% peppermint oil significantly. Repellency to 1.0% peppermint oil is almost eliminated when morbidity is induced five times in the absence of peppermint odour but is restored when peppermint odour is present during preconditioning. These findings suggest that Wireworm sensitivity to repellent compounds decreases when repeatedly made moribund, although the results are not sufficient to conclude that Wireworms are capable of associative learning.
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Wireworm management I: stand protection versus Wireworm mortality with wheat seed treatments.
Journal of Economic Entomology, 2009Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:The efficacy of various insecticidal seed treatments in protecting wheat, Triticum aestivum L., from Wireworm damage as well as reducing Wireworm (Coleoptera: Elateridae) populations was studied over 3 yr. Protection from Wireworm damage was measured by postplanting stand counts, and effects on Wireworm populations were measured by within-row core samples and by bait traps placed in plots the following spring. The effects of treatments on populations of larger Wireworms already present at planting were distinguished from their effects on neonate Wireworms produced that growing season. Neonicotinoid seed treatments (imidacloprid, clothianidin, and thiamethoxam) provided excellent wheat stand protection, likely through prolonged Wireworm intoxication, but populations of larger and neonate Wireworms were not significantly reduced in bait traps the following spring. The pyrethroid tefluthrin, applied to seed with and without a neonicotinoid insecticide (thiamethoxam), provided excellent crop protection, but populations of Wireworms also were not significantly reduced. This and additional laboratory data suggest that wheat stand establishment provided by tefluthrin is due to a combination of repulsion and short term morbidity events. The phenyl pyrazole fipronil provided excellent crop protection, and populations of both larger and neonate Wireworms could not be detected in plots the following spring. The previously registered organochlorine lindane, although reducing Wireworm feeding, was phytotoxic in 2 of 3 yr. Next to fipronil, lindane was the most consistent seed treatment in reducing populations of larger and neonate Wireworms. These studies indicate that stand and yield protection provided by contemporary wheat seed treatments cannot automatically be equated with Wireworm population mortality. This is an important consideration when choosing a suitable seed treatment to replace lindane, which historically provided both stand protection and Wireworm reduction, and did not have to be applied every year.
Verheggen François - One of the best experts on this subject based on the ideXlab platform.
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The law of attraction: identification of Volatiles Organic Compound emitted by potatoes as Wireworm attractants
2017Co-Authors: La Forgia Diana, Verheggen FrançoisAbstract:Wireworms (Coleoptera: Elateridae) are common polyphagous soil pests of various crops, including maize and potatoes, inflicting severe economic damage (Parker and Howard 2001). Their management with pesticides is often not successful or sustainable and more research on biological alternatives is required. One of these alternatives could be the use of traps baited with attractive volatile organic compounds (VOCs) in association with a microbial control agent. In this paper, we describe the methodology followed to identify volatile organic molecules with potential as Wireworms attractants. We previously observed that cut potato tubers place on the soil surface were highly attractive for Wireworms. To identify the attractive cues released by potato tubers, we defined three specific objectives: 1) developing a behavioral assay suitable for the study of Wireworm orientation behavior; 2) profiling VOCs released by potato tubers; 3) evaluating the role of the identified VOCs on Wireworms foraging behavior.Peer reviewe
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The law of attraction: identification of Volatiles Organic Compound emitted by potatoes as Wireworm attractants
Universiteit Gent (UGent), 2017Co-Authors: La Forgia Diana, Verheggen FrançoisAbstract:peer reviewedaudience: researcherWireworms (Coleoptera: Elateridae) are common polyphagous soil pests of various crops, including maize and potatoes, inflicting severe economic damage (Parker and Howard 2001). Their management with pesticides is often not successful or sustainable and more research on biological alternatives is required. One of these alternatives could be the use of traps baited with attractive volatile organic compounds (VOCs) in association with a microbial control agent. In this paper, we describe the methodology followed to identify volatile organic molecules with potential as Wireworms attractants. We previously observed that cut potato tubers place on the soil surface were highly attractive for Wireworms. To identify the attractive cues released by potato tubers, we defined three specific objectives: 1) developing a behavioral assay suitable for the study of Wireworm orientation behavior; 2) profiling VOCs released by potato tubers; 3) evaluating the role of the identified VOCs on Wireworms foraging behavior
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Le rôle de l'olfaction chez les larves de taupin: une synthèse sur leur recherche de nourriture et appareil sensoriel
Presses Agronomiques de Gembloux, 2014Co-Authors: Barsics Fanny, Haubruge Eric, Francis Frédéric, Verheggen FrançoisAbstract:peer reviewedaudience: researcher, professional, studentIntroduction Integrated management of Wireworms (Coleoptera: Elateridae) depends upon approaches applied both above- and belowground, and over several spatial scales. While foraging, these soil pests use biotic and abiotic signals to orientate towards target plant organs. Development of efficient techniques for implementation in integrated strategies relies upon improved knowledge of this process. In particular, an important step consists of elucidating the role of volatile organic compounds (VOC), emitted by belowground plant organs, in Wireworm chemical ecology. This would have a positive impact on push-pull strategies and varietal selection developed against these insects. Literature In this work, we summarized the available data regarding Wireworm foraging behavior as well as variables that should be considered when studying the potential role of plant-produced volatile semiochemicals. This includes CO2 gradients and other host-related cues, temperature, relative humidity and soil moisture, and Wireworm physiological stage. We also review what is known of the sensory apparatus of Wireworms, since this is involved in every step of the foraging process. Conclusion Some baseline data for studying VOC related Wireworm foraging behavior exists. Using it as a tool in applied entomology should result in discovery of the semiochemicals that underpin trophic interactions involving these pests. However, most of the key pest species are not fully described with regards to the parameters detailed here. Obtaining accurate information to fill the current knowledge gaps will be needed in order to devise new integrated management strategies
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Le rôle de l'olfaction chez les larves de taupin: une synthèse sur leur recherche de nourriture et appareil sensoriel
2014Co-Authors: Barsics Fanny, Haubruge Eric, Francis Frédéric, Verheggen FrançoisAbstract:Introduction Integrated management of Wireworms (Coleoptera: Elateridae) depends upon approaches applied both above- and belowground, and over several spatial scales. While foraging, these soil pests use biotic and abiotic signals to orientate towards target plant organs. Development of efficient techniques for implementation in integrated strategies relies upon improved knowledge of this process. In particular, an important step consists of elucidating the role of volatile organic compounds (VOC), emitted by belowground plant organs, in Wireworm chemical ecology. This would have a positive impact on push-pull strategies and varietal selection developed against these insects. Literature In this work, we summarized the available data regarding Wireworm foraging behavior as well as variables that should be considered when studying the potential role of plant-produced volatile semiochemicals. This includes CO2 gradients and other host-related cues, temperature, relative humidity and soil moisture, and Wireworm physiological stage. We also review what is known of the sensory apparatus of Wireworms, since this is involved in every step of the foraging process. Conclusion Some baseline data for studying VOC related Wireworm foraging behavior exists. Using it as a tool in applied entomology should result in discovery of the semiochemicals that underpin trophic interactions involving these pests. However, most of the key pest species are not fully described with regards to the parameters detailed here. Obtaining accurate information to fill the current knowledge gaps will be needed in order to devise new integrated management strategies.Peer reviewe
W G Van Herk - One of the best experts on this subject based on the ideXlab platform.
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efficacy of diamide neonicotinoid pyrethroid and phenyl pyrazole insecticide seed treatments for controlling the sugar beet Wireworm limonius californicus coleoptera elateridae in spring wheat
Journal of the Entomological Society of British Columbia, 2019Co-Authors: W G Van Herk, T J Labun, Robert S. VernonAbstract:Four classes of insecticide applied on seed were evaluated for managing high populations of the sugar beet Wireworm, Limonius californicus (Coleoptera: Elateridae), in spring wheat in southern Alberta, Canada. Three separate field trials were conducted, and assessments made for stand protection, yield, and Wireworm survival. Imidacloprid and thiamethoxam applied at 10–30 g AI and cyantraniliprole applied at 10–40 g AI provided initial stand protection, but did not protect seedlings until harvest and did not decrease Wireworm populations. λ-cyhalothrin applied at 30 g AI provided stand protection that persisted until harvest, but yields were considerably lower than observed in fipronil treatments and there was little (23%) decrease in populations relative to controls. Fipronil applied at 0.6, 1.0, and 5.0 g AI, either singly or in blend with thiamethoxam at 10 g AI, provided stand protection until harvest and significantly reduced numbers of Wireworms larger than 10 mm (range: 74–96%). Very low numbers of small (<11 mm) Wireworms were observed in all trials. These results are compared to data from laboratory and field studies for this and other Wireworm species. The relation between crop stand protection and Wireworm mortality, the potential of insecticide blends, and the importance of seed type, Wireworm species, and activity periods for managing Wireworms with seed treatments are discussed.
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Wireworm in Quebec Field Crops: Specific Community Composition in North America.
Environmental Entomology, 2017Co-Authors: J. Saguez, Robert S. Vernon, W G Van Herk, A. Latraverse, J. De Almeida, J-p. Légaré, J. Moisan-de Serres, M. Fréchette, G. LabrieAbstract:Wireworms are important economic pests that attack the seeds and roots of numerous vegetable and field crops worldwide. A 5-yr study was conducted in the main agricultural regions of the province of Quebec (Canada), to identify and characterize the Wireworm communities (Coleoptera: Elateridae) that occur in fields planted with economically important crops (maize, soybean, cereals, canola, and grasslands). Bait traps were used to collect Wireworms each spring from 2011 to 2015. More than 600 sites were sampled in total, involving ca. 14,000 traps. Wireworms were found in 69% of the sites and 73% of the traps. A total of 6,014 Wireworms were collected and identified to genus, or to species when possible. The results show that nine genera occur in Quebec and that Hypnoidus abbreviatus (Say) is currently the most abundant species in arable land in Quebec, representing 72% of all collected Wireworms. The other genera collected were Melanotus (8% of all Wireworms collected), Ampedus (7%), Limonius (6%), and Agriotes (4%). Wireworms from the genera Aeolus, Dalopius, Hemicrepidius, and Oestodes constituted ca. 3% together. The predominance of H. abbreviatus appeared to be specific to Quebec compared with the other Canadian provinces and the rest of North America. We observed differences in the relative abundance of Wireworm genera among the agricultural regions sampled. However, no effect of current and preceding crops was observed in this study. Our results suggest that integrated pest management strategies for managing Wireworms in Quebec fields should take into consideration the species present in each agronomical region.
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the molecular identification and genetic diversity of economically important Wireworm species coleoptera elateridae in canada
Journal of Pest Science, 2013Co-Authors: Carly M. Benefer, Robert S. Vernon, W G Van Herk, R. P. Blackshaw, Jonathan Ellis, M. E. KnightAbstract:Click beetle larvae (Wireworms) are significant crop pests in Europe and North America. In Canada, there are ~30 economically important species which are morphologically difficult to identify, but for which sequence data are lacking. Accurate knowledge of damage-causing species and the population genetics and phylogeography of elaterids will provide insight into their sustainable management. Here, we use interspecific variation in mitochondrial 16S rRNA as a robust method of identification, consider the intra- and interspecific genetic variation of some important Canadian Wireworm pests and assess the genetic structure and isolation by distance for a re-emerging major pest species, Hypnoidus bicolor Eschscholtz. Wireworms were sampled from Canada and the USA, identified as morphospecies, and sequenced at the 16S rRNA region (294–442 bp). Within some species unusually high intraspecific genetic distances between samples suggested the possibility of cryptic Wireworm species or misidentifications, though this was <1 % for most species. Phylogenetic analyses gave some indication of the likely identity of these ambiguous samples. There was a significant correlation between genetic and geographic distance and significant genetic structuring within and between H. bicolor populations, which appeared to be composed of two species comprising several haplotypes. These data provide a starting point for determining the distribution of damage-causing species throughout Canada. The inclusion of data from other nuclear and mitochondrial loci, and use of sequence data from known adult samples, would further aid identification and relationships of Wireworm species.
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repellency of a Wireworm agriotes obscurus coleoptera elateridae on exposure to synthetic insecticides in a soil less bioassay
Environmental Entomology, 2008Co-Authors: W G Van Herk, Robert S. Vernon, Bernard D. RoitbergAbstract:A soil-less bioassay arena to test repellency of Wireworms (A. obscurus) to insecticides and carrier solvents is described. The bioassay and variables measured distinguish between shorter-range (contact and/or volatile) and longer-range (volatile) repellency. Wireworm positions are recorded every 3 s for 20 min, and average speed, rate of slowing, and longer- and shorter-range repellent behaviors calculated. Shorter-range repellency is determined with a Wireworm Repellency Score (WRS, range 0-100), calculated before contact and after contact with test chemicals. Of two carrier solvents tested, Wireworms were strongly repelled by acetone (WRS = 57) but not by water (WRS = 1) when introduced to the bioassay arenas immediately after chemical inoculation. When bioassay arenas were assembled/sealed 2 min after inoculation, acetone elicited no repellency (WRS = 2). When dissolved in acetone in bioassays assembled with a 2-min delay, imidacloprid, chlorpyrifos, lindane, and tefluthrin elicited slight to moderate repellency at the highest concentrations tested (WRS = 30, 48, 42, and 49, respectively). Both longer- and shorter-range repellency increased over the duration of the observation period for lindane and tefluthrin, and shorter-range repellency also increased over the duration of the observation period for chlorpyrifos. Removal of volatiles in the bioassay arena by vacuum considerably affected Wireworm movement in the arena, with the repellency elicited by acetone and lindane being significantly reduced. Clothianidin elicited no longer- or shorter-range repellency.
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effect of temperature on the morbidity and recovery of the pacific coast Wireworm limonius canus following contact with tefluthrin treated wheat seeds
Entomologia Experimentalis Et Applicata, 2008Co-Authors: W G Van Herk, Robert S. VernonAbstract:Late instars of the Pacific Coast Wireworm, Limonius canus (LeConte) (Coleoptera: Elateridae), were exposed to wheat seeds treated with tefluthrin at 10 g active ingredient/100 kg wheat seed, for 2 min, at 10,15,20, and 25 °C. All Wireworms were moribund within 20 min of first exposure and recovered fully within 7 h. Morbidity induction time (i) decreased considerably as the temperature (t) was increased from 10 to 15 °C, but did not decrease further when the temperature was increased from 15 to 25 °C. For each temperature, induction time decreased as Wireworm weight (w) increased, -0.126 lt +√0.003lt +0.013lw so that i = 21.9452* e -126lt + √0.003lt + 0.013lw . A strong negative temperature coefficient was observed in Wireworm recovery, the time required for recovery (r) after exposure decreasing as both temperature (t) and Wireworm weight (w) increased, so that r = 1102.47(w) -0.1848 * e- 0.1012t . The temperature at which Wireworms contact insecticides in the field may significantly affect the induction and duration of morbidity, and determine whether Wireworms will become moribund before they are repelled by tefluthrin. The ability of Wireworms to recover from tefluthrin-induced morbidity may seriously limit the efficacy of this insecticide in reducing Wireworm populations in the field.
Willem G. Van Herk - One of the best experts on this subject based on the ideXlab platform.
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further studies on Wireworm management in canada damage protection versus Wireworm mortality in potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (<9 mm long = ‘neonate‘) Wireworms were also observed. Neonicotinoids (imidacloprid, clothianidin, and thiamethoxam) tested as seed piece treatments at ≈12.5 g active ingredient/100 kg potato seed reduced blemishes by, respectively, 19.1, 71.6, and...
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Further Studies on Wireworm Management in Canada: Damage Protection Versus Wireworm Mortality in Potatoes
Journal of Economic Entomology, 2013Co-Authors: Robert S. Vernon, Markus Clodius, Willem G. Van Herk, Chantelle HardingAbstract:ABSTRACT The efficacy of various insecticides and application methods in protecting potatoes from Wireworm (Agriotes obscurus L.) damage as well as reducing Wireworm populations was studied over 5 yr in Agassiz, British Columbia. Protection from Wireworm damage was measured by the number of blemishes to daughter tubers, and effects on Wireworm populations were measured by sampling soil around seed potatoes and/or by bait traps the following spring. Organophosphates registered for Wireworm control in the United States and/or Canada (phorate and chlorpyrifos), significantly reduced blemishes to tubers by, respectively, 92.2 and 90.2%, and populations of large (≥9 mm long = ‘resident’) Wireworms by 83.4 and 71.0% relative to controls. Similar reductions in smaller (
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Wireworms as Pests of Potato
Insect Pests of Potato, 2013Co-Authors: Robert S. Vernon, Willem G. Van HerkAbstract:Wireworms (Coleoptera: Elateridae) of several species cause severe cosmetic and economic injury to daughter tubers. Populations are expanding globally, due largely to the attrition of most organochlorine and organophosphate insecticides used since the 1950s. Where Wireworms could once be controlled for several years with organochlorine insecticides, contemporary management strategies for Wireworms are taking on more regional, species-specific and multi-tactical approaches. The requisite knowledge and expertise underlying these approaches involves taxonomy (traditional and molecular); biology and ecology (life history, behavior, distribution, habitat and host preferences, chemical ecology, phenology); surveillance (Wireworm and adult sampling and risk assessment); and species-specific response(s) to a variety of integrated pest management approaches (e.g. crop rotation, cultivation, tolerant varieties, soil amendments, biological and semiochemical controls and low-risk insecticides). These topics are reviewed in this chapter, along with suggestions as to the more likely and productive avenues of research to address now and in the future.
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Wireworm damage to wheat seedlings: effect of temperature and Wireworm state
Journal of Pest Science, 2012Co-Authors: Willem G. Van Herk, Robert S. VernonAbstract:We describe the results of four laboratory studies designed to measure the effect of temperature and Wireworm appetence, weight, and degree of Metarhizium infection on their ability to damage wheat seedlings. Wireworm activity, measured from Wireworm speed, increased linearly from 6 to 18 °C and leveled off thereafter. Plant emergence and growth increased exponentially from 6 to 22 °C for wheat cultivars AC Barrie and AC Unity VB. Plant root:shoot ratio at Zadoks 13 was highest at 14 °C and lowest at 22 °C for AC Barrie. Wireworm weight and degree of infection with Metarhizium did not affect their ability to kill wheat seedlings, but Wireworms in a feeding state caused significantly more damage than those in a non-feeding state when wheat was grown at 10, 14, 18, and 22 °C. Wireworms (ww) in a feeding state destroyed 1.8 seedlings/ww in 14 days at 22 °C if there were 1 or 2 Wireworms in a pot, and 1.5 seedlings/ww if there were 4 Wireworms in a pot. If 5 Wireworms were placed in a pot, Wireworms in a feeding state destroyed 0.3, 1.0, 0.9, 1.3, and 1.4 seedlings/ww in 46, 32, 25, 25, and 25 days at 6, 10, 14, 18, and 22 °C, respectively. Wireworm mortality from Metarhizium during 60 days of containment in pots in the study was higher in non-feeding than in feeding Wireworms, and higher if Wireworms were selected from a Metarhizium-infected colony than those selected from a non-infected colony. Some of the implications of these results for Wireworm management and laboratory trials are discussed.
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Mortality of Metarhizium anisopliae -infected Wireworms (Coleoptera: Elateridae) and feeding on wheat seedlings are affected by Wireworm weight
Journal of the Entomological Society of British Columbia, 2011Co-Authors: Willem G. Van Herk, Robert S. VernonAbstract:As some Wireworm species are notorious pests of common wheat, Triticum aestivum (Vernon et al. 2009), a small study was conducted at the Pacific Agri-Food Research Centre (PARC) in Agassiz, BC in August 2009, to determine whether the number of germinating wheat seedlings (cv. AC Barrie) killed by the dusky Wireworm, Agriotes obscurus, is affected by the number and size of the Wireworms that seedlings are exposed to. An unexpected factor appeared at the end of the study in that many Wireworms were infected with Metarhizium anisopliae, resulting in considerable mortality. This factor precluded us from meeting some of the initial objectives of the experiment, but still allowed us to determine if mortality of seedlings was affected by Wireworm weight and number, and if mortality of the Wireworms from M. anisopliae infection was affected by their weight. We filled 160 500 ml circular (dia = 11 cm, height = 8 cm) plastic containers (Plastipak Industries, Inc., La Prairie, QC) with 500.0 (+/0.2) g of soil collected from a field at PARC, Agassiz in 2009. The soil was sieved through a 2 mm x 2 mm screen to remove rocks and organic material, made up to 20% moisture by weight, and homogenized. Containers with soil were placed in a walk-in cooler set at 15.0 +/-0.5°C to mimic soil temperature conditions in spring when wheat is normally planted. Wireworms were weighed individually on August 7, and 0-4 Wireworms were placed in each container (Table 1). All Wireworms were collected at PARC in April 2009 and stored in 40l Rubbermaid tubs without food, at 8-10°C, until 1 wk before the study, when tubs were brought up to room temperature and food baits (a cup of 100 ml moist vermiculite mixed with 10 ml wheat seed) placed inside. Only mobile Wireworms, appearing healthy (Vernon et al. 2008) and actively feeding 2 to 3 d prior to placement in the containers were used for this study. Wireworms selected ranged considerably in weight (range: 6.6 to 46.4 mg; Table 1), but all Wireworms in individual containers were similar in weight (within 5.0 mg), and an attempt was made to have an equal number of similar sized Wireworms for each of the 1, 2, and 3 or 4 Wireworm densities to determine the effect of Wireworm weight on the number of wheat seedlings killed. Two days after Wireworms were placed in containers, 21 untreated wheat seeds were planted 2 cm deep in small pre-made holes. Seeds were spaced at equal distance (1.75 cm) from each other, in a 3, 5, 5, 5, 3-grid pattern. After planting, groups of eight containers were placed in 26 cm x 47 cm x 6 cm deep nursery flats (Eddi’s Wholesale Garden Supplies, Ltd., Surrey, BC), 1.0l cold water added between the containers in the flat, and flats covered with 14 cm high transparent plastic domes (Eddi’s Wholesale) to prevent desiccation of the upper layer of soil. After planting, containers were subjected to a 12:12 light:dark regimen. Seedling emergence was first observed 5 d after planting, stand counts were conducted 8 d (when domes were permanently removed due to the length of plant shoots) and 15 d after planting. Wireworms were removed 25 d after planting and their health evaluated (Vernon et al. 2008). This revealed that only 123 of 255 larvae were alive, the rest having died from Metarhizium infection, most likely within the first two weeks of the study as evident from the extent of mould formation on the surface of the cadavers. Analysis of the proportion of Wireworms dead in each 38 J. ENTOMOL. SOC. BRIT. COLUMBIA 108, DECEMBER 2011
