Bees and other pollinators are exposed to co‐formulants and adjuvants at very high levels in agriculture. Thorough, targeted, assessment of the toxicity of co‐formulants and adjuvants is urgently ...required. Created with BioRender.com.
Pollinators, particularly wild bees, are suffering declines across the globe, and pesticides are thought to be drivers of these declines. Research into, and regulation of pesticides has focused on ...the active ingredients, and their impact on bee health. In contrast, the additional components in pesticide formulations have been overlooked as potential threats. By testing an acute oral dose of the fungicide product Amistar, and equivalent doses of each individual co-formulant, we were able to measure the toxicity of the formulation and identify the ingredient responsible. We found that a co-formulant, alcohol ethoxylates, caused a range of damage to bumble bee health. Exposure to alcohol ethoxylates caused 30% mortality and a range of sublethal effects. Alcohol ethoxylates treated bees consumed half as much sucrose as negative control bees over the course of the experiment and lost weight. Alcohol ethoxylates treated bees had significant melanisation of their midguts, evidence of gut damage. We suggest that this gut damage explains the reduction in appetite, weight loss and mortality, with bees dying from energy depletion. Our results demonstrate that sublethal impacts of pesticide formulations need to be considered during regulatory consideration, and that co-formulants can be more toxic than active ingredients.
Agrochemical formulations are composed of two broad groups of chemicals: active ingredients, which confer pest control action, and 'inert' ingredients, which facilitate the action of the active ...ingredient. Most research into the effects of agrochemicals focusses on the effects of active ingredients. This reflects the assumption that 'inert' ingredients are non-toxic. A review of relevant research shows that for bees, this assumption is without empirical foundation. After conducting a systematic literature search, we found just 19 studies that tested the effects of 'inert' ingredients on bee health. In these studies, 'inert' ingredients were found to cause mortality in bees through multiple exposure routes, act synergistically with other stressors and cause colony level effects. This lack of research is compounded by a lack of diversity in study organism used. We argue that 'inert' ingredients have distinct, and poorly understood, ecological persistency profiles and toxicities, making research into their individual effects necessary. We highlight the lack of mitigation in place to protect bees from 'inert' ingredients and argue that research efforts should be redistributed to address the knowledge gap identified here. If so-called 'inert' ingredients are, in fact, detrimental to bee health, their potential role in widespread bee declines needs urgent assessment.
Pollinators underpin global food production, but they are suffering significant declines across the world. Pesticides are thought to be important drivers of these declines. Herbicides are the most ...widely applied type of pesticides and are broadly considered ‘bee safe’ by regulatory bodies who explicitly allow their application directly onto foraging bees. We aimed to test the mortality effects of spraying the world's most popular herbicide brand (Roundup®) directly onto bumble bees Bombus terrestris audax.
We used three Roundup® products, the consumer products Roundup® Ready‐To‐Use and Roundup® No Glyphosate, the agricultural product Roundup® ProActive, as well as another herbicide with the same active ingredient (glyphosate), Weedol®. Label recommended pesticide concentrations were applied to the bees using a Roundup® Ready‐To‐Use spray bottle.
Bees exhibited 94% mortality with Roundup® Ready‐To‐Use® and 30% mortality with Roundup® ProActive®, over 24 hr. Weedol® did not cause significant mortality, demonstrating that the active ingredient, glyphosate, is not the cause of the mortality. The 96% mortality caused by Roundup® No Glyphosate supports this conclusion. Dose‐dependent mortality caused by Roundup® Ready‐To‐Use, further confirms its acute toxicity. Roundup® products caused comprehensive matting of bee body hair, suggesting that surfactants, or other co‐formulants in the Roundup® products, may cause death by incapacitating the gas exchange system.
These mortality results demonstrate that Roundup® products pose a significant hazard to bees, in both agricultural and urban systems, and that exposure of bees to them should be limited.
Synthesis and applications. Surfactants, or other co‐formulants, in herbicides and other pesticides may contribute to global bee declines. We recommend that, as a precautionary measure until co‐formulant identities are made public, label guidelines for all pesticides be altered to explicitly prohibit application to plants when bees are likely to be foraging on them. As current regulatory topical exposure toxicity testing inadequately assesses toxicity of herbicide products, we call for pesticide companies to release the full list of ingredients for each pesticide formulation, as lack of access to this information hampers research to determine safe exposure levels for beneficial insects in agro‐ecosystems.
Résumé
Les espèces pollinisatrices, essentielles à la production alimentaire mondiale, accusent un recul significatif en nombre au niveau planétaire. Les pesticides sont tenus comme l'une des causes majeures de ce déclin. Les herbicides sont la catégorie de pesticides la plus utilisée et sont généralement considérés par les organismes de réglementation, qui autorisent explicitement leur utilisation directement sur les abeilles, comme étant « non‐dangereux » pour ces dernières. Notre but était d'établir le taux de mortalité chez les bourdons (Bombus terrestris audax) suite à une mise en contact avec des produits de la marque d’herbicide la plus utilisée au monde (Roundup®).
Nous avons utilisé trois types de produits Roundup® : deux produits grand public ‐ Roundup® Ready‐To‐Use et Roundup® No Glyphosate ; un produit destiné à l’agriculture Roundup® ProActive et enfin l’herbicide Weedol® qui contient le même ingrédient actif que ce dernier (le glyphosate). Les bourdons ont été aspergés de pesticide à la concentration recommandée par la notice au moyen d'un vaporisateur Roundup® Ready‐To‐Use.
Sur une durée de 24 heures, le taux de mortalité chez les bourdons a été de 94% lors de l’exposition au Roundup® Ready‐To‐Use®, et de 30% pour le Roundup® ProActive®. Le taux de mortalité pour le Weedol® n’était pas statistiquement significative, démontrant que l’ingrédient actif, le glyphosate, n’est pas la cause de cette mortalité. Le taux de mortalité de 96% associé au produit Roundup® No Glyphosate conforte cette conclusion. Le taux de mortalité lié à la dose du Roundup® Ready‐To‐Use confirme sa toxicité aiguë. Les produits Roundup® provoquent un emmêlement important des poils recouvrant les bourdons, suggérant que des surfactants ou d’autres coformulants dans les produits Roundup® provoquent probablement une mort par asphyxie.
Ces résultats démontrent que les produits Roundup® constituent un danger non négligeable pour les bourdons tant en milieu rural qu’urbain, et que le contact entre les bourdons et ces produits se doit d’être limité.
Synthèse et applications. Les surfactants et autres coformulants présents dans les herbicides et autres pesticides pourraient contribuer aux pertes mondiales d’espèces pollinisatrices. Par mesure de précaution, jusqu’à ce que la nature des coformulants soit rendue publique, nous recommandons que les notices de tout pesticides soient modifiés pour interdire explicitement leur usage pendant des périodes où des pollinisateurs pourraient être en contact avec eux. Puisque les tests réglementaires actuels de toxicité par contact direct aux herbicides sont inadéquats, nous demandons que les compagnies produisant des pesticides donnent accès aux listes d’ingrédients de toutes leurs formules, car le manque d’accès à ces informations entrave la recherche visant à déterminer quels taux d’exposition sont tolérables pour les insectes qui bénéficient aux agrosystèmes.
Surfactants, or other co‐formulants, in herbicides and other pesticides may contribute to global bee declines. We recommend that, as a precautionary measure until co‐formulant identities are made public, label guidelines for all pesticides be altered to explicitly prohibit application to plants when bees are likely to be foraging on them. As current regulatory topical exposure toxicity testing inadequately assesses toxicity of herbicide products, we call for pesticide companies to release the full list of ingredients for each pesticide formulation, as lack of access to this information hampers research to determine safe exposure levels for beneficial insects in agro‐ecosystems.
How pesticides are used is very important in determining the risk they pose to both the user, and the environment. Given they can have toxic properties, if pesticides are misused they could cause ...serious harm to the users health as well as a range of environmental damage. Despite this, very little research has quantified whether agricultural use of pesticides is compliant with the legally binding obligations and associated guidance surrounding application. In this survey we used an online, fully anonymous, questionnaire to ask Irish farmers about how they use pesticides. We used a self-reporting methodology, directly asking farmers about their compliance levels. We had a total of 76 unique valid respondents. Our respondents covered the broad range of Irish agriculture, and we quantified how this relates to national demographics. Overall compliance regarding pesticide use was high, with the majority of respondents complying the majority of the time. However, we also found a sizable group who report low compliance levels for certain topics. Respondents reported the highest levels of non-compliance with the use of personal protective equipment, with nearly half of all respondents admitting to not wearing certain required protective equipment on a regular basis. In contrast, for some areas like application rate, very high compliance was reported. Moderate levels of non-compliance with bee protective mitigation measures were found, and some reported practices like not emptying or washing out the spray tank between sprays could have serious impacts on pollinators, soil organisms and other non-targets. Additionally, a minority of respondents admitted to actions which could cause serious water course pollution. As the first survey on a range of pesticide compliance topics within a developed nation, the compliance seen is very high compared to levels in developing nations. Our results demonstrate that the assumption that all legal obligations and guidance surrounding pesticide use are followed is unfounded, but that the majority of the respondents are mostly compliant. Education or enforcement should be targeted to certain areas where compliance is weakest to minimise harm from pesticide use. Reducing the non-compliance we report here could benefit both farmer and environmental health, and ensure that pesticides are used in a manner that risk assessment has deemed safe.
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•We surveyed Irish farmers about their compliance with pesticide regulations.•We had 76 responses from across Irish farming.•Overall compliance regarding pesticide use regulations was high.•Use of personal protective equipment had lowest compliance.•A minority of respondents reported practices that may be highly environmentally damaging.
Pesticides are recognised as a key threat to pollinators, impacting their health in many ways. One route through which pesticides can affect pollinators like bumblebees is through the gut microbiome, ...with knock-on effects on their immune system and parasite resistance. We tested the impacts of a high acute oral dose of glyphosate on the gut microbiome of the buff tailed bumblebee (Bombus terrestris), and glyphosate's interaction with the gut parasite (Crithidia bombi). We used a fully crossed design measuring bee mortality, parasite intensity and the bacterial composition in the gut microbiome estimated from the relative abundance of 16S rRNA amplicons. We found no impact of either glyphosate, C. bombi, or their combination on any metric, including bacterial composition. This result differs from studies on honeybees, which have consistently found an impact of glyphosate on gut bacterial composition. This is potentially explained by the use of an acute exposure, rather than a chronic exposure, and the difference in test species. Since A. mellifera is used as a model species to represent pollinators more broadly in risk assessment, our results highlight that caution is needed in extrapolating gut microbiome results from A. mellifera to other bee species.
Pesticides help produce food for humanity's growing population, yet they have negative impacts on the environment. Limiting these impacts, while maintaining food supply, is a crucial challenge for ...modern agriculture. Mitigation measures are actions taken by pesticide users, which modify the risk of the application to nontarget organisms, such as bees. Through these, the impacts of pesticides can be reduced, with minimal impacts on the efficacy of the pesticide. Here we collate the scientific evidence behind mitigation measures designed to reduce pesticide impacts on bees using a systematic review methodology. We included all publications which tested the effects of any pesticide mitigation measure (using a very loose definition) on bees, at any scale (from individual through to population level), so long as they presented evidence on the efficacy of the measure. We found 34 publications with direct evidence on the topic, covering a range of available mitigation measures. No currently used mitigation measures were thoroughly tested, and some entirely lacked empirical support, showing a weak evidence base for current recommendations and policy. We found mitigation measure research predominantly focuses on managed bees, potentially failing to protect wild bees. We also found that label-recommended mitigation measures, which are the mitigation measures most often applied, specifically are seldom tested empirically. Ultimately, we recommend that more, and stronger, scientific evidence is required to justify existing mitigation measures to help reduce the impacts of pesticides on bees while maintaining crop protection.
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