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Following the deregistration of lindane, several neonicotinoid insecticides have been registered as seed treatments for controlling wireworms in cereal crops. Unlike lindane, which did both, neonicotinoids provide crop protection but do not reduce wireworm populations. Hence populations of various economic species are growing in key wheat production areas of the United States and Canada, and there is a need for novel seed treatments that match the efficacy of lindane. Herein we evaluated broflanilide, a novel GABA-gated Cl- channel allosteric modulator that differs from the cyclodienes (e.g. lindane) in that it binds to a unique site in the GABA receptor. As such, broflanilide confers a new mode of insecticidal action (Group 30 MOA), and is the first meta-diamide insecticide developed. When evaluated in field trials over 7 yr at various rates, broflanilide at 5.0 g [AI]/100 kg wheat seed was as effective at protecting wheat stand from wireworm (Agriotes obscurus) injury as the current industry standard thiamethoxam at 20–30 g [AI]/100 kg seed. In addition, broflanilide at 5.0 g reduced neonate wireworms (produced from eggs laid in established wheat during the growing season) and resident wireworms (in the field at time of planting) by 73.1 and 81.1%, respectively, which is comparable to that reported for the previous industry standard lindane (75.3 and 57.6%, respectively). These studies show that broflanilide at 5.0 g [AI] will provide consistent wheat stand protection (equal to thiamethoxam at 20–30 g [AI]), and A. obscurus wireworm population reduction (equal to lindane at 59 g [AI]), and will do so at far lower dosages per hectare. [ABSTRACT FROM AUTHOR]

The use of neonicotinoids in agriculture is a critical environmental protection issue. Although there has been considerable research on pollinator exposure and aquatic toxicological effects, few studies have investigated the chronic impacts on soil‐dwelling species. Given the application of neonicotinoids into soil systems, there is the potential for risk to soil invertebrates. The toxicity of 2 commercial formulations containing the active ingredients (a.i.) thiamethoxam (Actara® 240SC) or clothianidin (Titan™) was investigated using 3 soil invertebrate species: Oppia nitens, Eisenia andrei, and Folsomia candida. No adverse effects were observed for O. nitens at the highest tested concentrations (≥92 mg a.i./kg dry soil) after a 28‐d exposure. Exposure to clothianidin resulted in a 28‐d median inhibitory concentration (IC50) of 0.069 (95% confidence limits: 0.039–0.12) mg/kg dry soil for F. candida, and a 56‐d IC50 of 0.26 (0.22–3.2) mg a.i./kg dry soil for E. andrei. Exposure to thiamethoxam was less toxic, with IC50s of 0.36 (0.19–0.66) and 3.0 (2.2–4.0) mg a.i./kg dry soil for F. candida and E. andrei reproduction, respectively. The observed toxicity for F. candida adult survival and reproduction and for E. andrei reproduction occurred at environmentally relevant concentrations. However, because clothianidin is a degradation product of thiamethoxam, and detection of clothianidin rose to levels of concern in the thiamethoxam‐amended soils over time, the observed toxicity may be partly attributed to the presence of clothianidin. Environ Toxicol Chem 2019;38:2111–2120. © 2019 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC. [ABSTRACT FROM AUTHOR]

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The article offers information on the effects of six selected orchard insecticides on neoseiulus fallacies, tetranychid mites' key predator, as evaluation for integrated pest management (IPM) in Canada. It says that Methoxyfenozide is harmless to neoseiulus and would be included on IPM programs. It adds that imidacloprid and thiamethoxam were moderately toxic to adult neoseiulus, while Acetamoprid, spinosad and thiacloprid had varying degree of toxicity and will be subject to field evaluation.

The article presents a study which examines the effect of orchard pesticides in predacious mites known as Galendromus occidentalis in Canada. It notes that imidacloprid and acetamicloprid are incompatible with integrated pest management (IPM) programs due to their toxic effect on adult predacious mites. Thiamethoxam and spirodeclofen can reduce fertility but were non-toxic to adult predacious mites. Further, it mentions the pesticides which are not harmful to predacious mites such as thiacloprid, spinosad, and methoxyfenoxide.

Thiamethoxam is a neonicotinoid insecticide widely applied in the Canadian Prairies. It has been detected in surface waters of agro-ecosystems, including wetlands, but the potential effects on non-target invertebrate communities in these wetlands have not been well characterized. In an effort to understand better the fate of thiamethoxam in wetlands and the response of invertebrates (zooplankton and emergent insects), model systems were used to mimic wetland flooding into planted fields. Outdoor mesocosms were treated with a single application of thiamethoxam-treated canola seeds at three treatment levels based on a recommended seeding rate (i.e., 6 kg/ha; 1×, 10×, and 100× seeding rate) and monitored over ten weeks. The mean half-life of thiamethoxam in the water column was 6.2 d. There was no ecologically meaningful impact on zooplankton abundances or community structure among treatments. Statistically significant differences were observed in aquatic insect abundance between control mesocosms and the two greatest thiamethoxam treatments (10× and 100× seeding rate). The observed results indicate exposure to thiamethoxam at environmentally relevant concentrations likely does not represent a significant ecological risk to abundance and community structure of wetland zooplankton and emergent insects., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Neonicotinoid and fungicide exposure has been linked to immunosuppression and increased susceptibility to disease in honeybees (Apis mellifera). European foulbrood, caused by the bacterium Melissococcus plutonius, is a disease of honeybee larvae which causes economic hardship for commercial beekeepers, in particular those whose colonies pollinate blueberries. We report for the first time in Canada, an atypical variant of M. plutonius isolated from a blueberry-pollinating colony. With this isolate, we used an in vitro larval infection system to study the effects of pesticide exposure on the development of European foulbrood disease. Pesticide doses tested were excessive (thiamethoxam and pyrimethanil) or maximal field-relevant (propiconazole and boscalid). We found that chronic exposure to the combination of thiamethoxam and propiconazole significantly decreased the survival of larvae infected with M. plutonius, while larvae chronically exposed to thiamethoxam and/or boscalid or pyrimethanil did not experience significant increases in mortality from M. plutonius infection in vitro. Based on these results, individual, calculated field-realistic residues of thiamethoxam and/or boscalid or pyrimethanil are unlikely to increase mortality from European foulbrood disease in honeybee worker brood, while the effects of field-relevant exposure to thiamethoxam and propiconazole on larval mortality from European foulbrood warrant further study. [ABSTRACT FROM AUTHOR]

Overwinter colony mortality is an ongoing challenge for North American beekeepers. During winter, honey bee colonies rely on stored honey and beebread, which is frequently contaminated with the neonicotinoid insecticides clothianidin and thiamethoxam. To determine whether neonicotinoid exposure affects overwinter survival of Apis mellifera L., we chronically exposed overwintering field colonies and winter workers in the laboratory to thiamethoxam or clothianidin at different concentrations and monitored survival and feed consumption. We also investigated the sublethal effects of chronic thiamethoxam exposure on colony pathogen load, queen quality, and colony temperature regulation. Under field conditions, high doses of thiamethoxam significantly increased overwinter mortality compared to controls, with field-realistic doses of thiamethoxam showing no significant effect on colony overwinter survival. Under laboratory conditions, chronic neonicotinoid exposure significantly decreased survival of winter workers relative to negative control at all doses tested. Chronic high-dose thiamethoxam exposure was not shown to impact pathogen load or queen quality, and field-realistic concentrations of thiamethoxam did not affect colony temperature homeostasis. Taken together, these results demonstrate that chronic environmental neonicotinoid exposure significantly decreases survival of winter workers in the laboratory, but only chronic high-dose thiamethoxam significantly decreases overwinter survival of colonies in the field. [ABSTRACT FROM AUTHOR]

Neonicotinoids are water-soluble neurotoxic insecticides widely used in agriculture that are being detected in nontarget aquatic environments. Nontarget aquatic wildlife, such as amphibians, may be at risk of exposure. Studies using larval stages suggest neonicotinoids are a minor concern to amphibians; however, behavioral effects manifesting later in life are not often considered. Behavioral endpoints could further our understanding of potential sublethal neurotoxic effects after exposure has ended. Using juvenile wood frogs (Lithobates sylvaticus), we investigated the effects of chronic larval exposure to 3 concentrations (1, 10, and 100 μg/L) of formulations containing imidacloprid or thiamethoxam on the putative escape response to a simulated heron attack. We found that control frogs actively responded (i.e., moved or jumped) to the simulated predator attack but frogs exposed to imidacloprid at 10 and 100 μg/L were less likely to respond. The exposed frogs, specifically from the imidacloprid treatment at 10 μg/L (tendency at 100 μg/L) were less likely to leave the attack area compared with controls. However, frogs used refuge similarly among all treatments. Finally, there were no differences in locomotor performance, as measured by total number of jumps and distance traveled during a trial among treatments. In conclusion, our study suggests that exposure to neonicotinoids during amphibian larval development may affect a juvenile frog's ability to perceive or respond to a predator, potentially increasing their vulnerability to predation. Future studies should validate and explore this potential effect further. Environ Toxicol Chem 2018;37:3115-3123. © 2018 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC., (© 2018 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC.)