Conclusion on the peer review of the pesticide risk assessment for bees for the active substance clothianidin considering all uses other than seed treatments and granules

Flupyradifurone negatively affects survival, physical condition and mobility in the two-spotted lady beetle (Adalia bipunctata)

Lady beetles play a crucial role in natural ecosystems and agricultural settings. Unfortunately, these insects and more specifically the two-spotted lady beetle (Adalia bipunctata) are currently facing a severe decline in populations due to various stressors, with pesticide exposure being a significant threat. Flupyradifurone is a relatively newly introduced insecticide and as existing research is mainly elucidating its effects on bees there remains a limited understanding of its effects on non-hymenopteran insects, including lady beetles. In this study we investigated the impact of acute orally applied flupyradifurone doses on survival and sublethal parameters such as physical condition and mobility on A. bipunctata. Our findings revealed a significant increase in mortality among individuals subjected to flupyradifurone doses of 19 ng/individual (corresponding to >1.5-2.0 ng active substance (a.s.)/mg body weight (bw). The calculated LD50 of flupyradifurone at 48 h was 2.11 ng a.s./mg bw corresponding to an amount of 26.38 ng/individual. Sublethal consequences were observable immediately after pesticide application. Even at doses as low as 2 ng/individual (corresponding to >0.0-0.5 ng a.s./mg bw), flupyradifurone induced trembling and temporary immobility in treated animals. Furthermore, pesticide intoxication led to hypoactivity, with less distance covered and a decline in straightness of locomotion. In conclusion, our study underscores the harmful effects of flupyradifurone on the two-spotted lady beetle at doses notably lower than those affecting bees. These findings stress the importance of additional research to attain a more holistic understanding of pesticide impacts not only on a broader range of non-target arthropods species, but also on various exposure routes as well as lethal and sublethal effects.

Potential Risk of Residues From Neonicotinoid-Treated Sugar Beet Flowering Weeds to Honey Bees (Apis mellifera L.)

In 2018 the European Union (EU) banned the three neonicotinoid insecticides imidacloprid, clothianidin (CLO), and thiamethoxam (TMX), but they can still be used if an EU Member State issues an emergency approval. Such an approval went into effect in 2021 for TMX-coated sugar beet seeds in Germany. Usually, this crop is harvested before flowering without exposing non-target organisms to the active ingredient or its metabolites. In addition to the approval, strict mitigation measures were imposed by the EU and the German federal states. One of the measures was to monitor the drilling of sugar beet and its impact on the environment. Hence we took residue samples from different bee and plant matrices and at different dates to fully map beet growth in the German states of Lower Saxony, Bavaria, and Baden-Württemberg. A total of four treated and three untreated plots were surveyed, resulting in 189 samples. Residue data were evaluated using the US Environmental Protection Agency BeeREX model to assess acute and chronic risk to honey bees from the samples, because oral toxicity data are widely available for both TMX and CLO. Within treated plots, we found no residues either in pools of nectar and honey crop samples (n = 24) or dead bee samples (n = 21). Although 13% of beebread and pollen samples and 88% of weed and sugar beet shoot samples were positive, the BeeREX model found no evidence of acute or chronic risk. We also detected neonicotinoid residues in the nesting material of the solitary bee Osmia bicornis, probably from contaminated soil of a treated plot. All control plots were free of residues. Currently, there are insufficient data on wild bee species to allow for an individual risk assessment. In terms of the future use of these highly potent insecticides, therefore, it must be ensured that all regulatory requirements are complied with to mitigate any unintentional exposure. Environ Toxicol Chem 2023;42:1167-1177. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A global study of pesticides in bees: QuEChERS as a sample preparation methodology for their analysis - Critical review and perspective

To this day, it remains unknown what the cause of decline of honey bee populations is and how to prevent this phenomenon efficiently. Poisonings with pesticides are assumed to be among the main causes for the decline of the honey bee population. Despite the significant progress observed in analytics over recent years, research aimed at improving methods applied in diagnostics of bee poisoning is still in progress. This is no easy task, since determination of the content of trace amounts (often equal to sublethal doses) of a wide range of compounds with diverse physico-chemical properties in honey bee samples with a complex matrix composition poses a serious challenge to modern analytics. This overview is the first to include a comprehensive critical assessment of analytical methods proposed for quantification of pesticides in honey bees over the last decade. Since the QuEChERS method is currently of great significance to ensuring accurate and reliable results of pesticide quantification in honey bees, the present overview focuses on the major aspects of this method, which will provide a comprehensive reference for scientists. The review focuses on the limitations of methods and on potential future prospects. It also contains information on the detection of pesticides in honey bees between 2010 and 2020 and characterizes the pesticide classes which are most toxic to these insects. This is extremely important, not just in the context of understanding the potential adverse impact of pesticides, manifesting as losses in bee colonies; it is also intended to facilitate decision-making in future research related to this difficult yet very important subject.

Spatial and temporal distribution, degradation, and metabolism of three neonicotinoid insecticides on different parts, especially pests' target feeding parts of apple tree

BACKGROUND

Neonicotinoid insecticides (NIs) have been recently banned in some countries because of increased pest resistance and deleterious risks to non-target organisms. Recent studies considered all parts of crops as a whole part in plant protection. However, there are few reports focused on the distribution and metabolic trends of NIs on target feeding sites of different pests in apple orchards.

RESULTS

The spatial and temporal distribution, absorption, degradation, and metabolism of three NIs, imidacloprid, acetamiprid, and thiamethoxam, on different parts of apple trees were studied under foliar spray and root irrigation treatments. In the spray treatment, the initial average concentration ratios (TCRs) were 31.6% for lower shoots, 23.3% for upper leaves, 23.2% for upper shoots, 21.0% for lower leaves, and 0.5% and 0.4% for upper and lower fruits, respectively. The average half-lives of the three NIs were 2.9 days for shoots, 7.4 days for leaves, and 10.8 days for fruits. The degradation rate of shoots was 2.5 times that of leaves, and 3.6 times that of fruits. Imidacloprid olefin and N-methyl acetamiprid were two of the main metabolites. In the root treatment, both roots and soils had high TCRs during the whole sampling period. Only imidacloprid was transmitted to above-ground parts of the plants, with TCRs of 0.38-50.94%.

CONCLUSION

This study found significant differences in spatial and temporal distribution, degradation, metabolism, and trends of NIs on different pest target sites of apple trees. The data obtained may help promote scientific control of target pests and evaluation of safety for non-target species in orchards. © 2020 Society of Chemical Industry.

The minimally effective dosages of nitenpyram and thiamethoxam seed treatments against aphids (Aphis gossypii Glover) and their potential exposure risks to honeybees (Apis mellifera)

Neonicotinoid seed coatings have been used as a major method to control seedling pests, especially the cotton aphid (Aphis gossypii Glover), around the world. However, their negative influence on natural enemies and pollinators has been criticized for decades. The present study was designed to compare the efficacy of nitenpyram and thiamethoxam for A. gossypii control, impacts on natural enemies and their potential risks to honeybees. Investigations in two locations in China revealed that the seed treatment with nitenpyram at a dosage of 3 g a.i. kg^-1 seed could effectively control A. gossypii throughout the seedling stage. In addition, Nitenpyram at the dosage of 2 g a.i. kg^-1 seed did not significantly change present number of the 7-spot ladybeetles in fields, compared with thiamethoxam treatments and blank control. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS) was utilized to identify and quantify the residue dynamics and transformation of parental and metabolite products in pollen and leaves. On the basis of residue data, the first-tier risk assessment disclosed that nitenpyram applied at doses of 2, 3 and 4 g a.i. kg^-1 seed might result in relative lower potential exposure risks to honeybees when compared with thiamethoxam. These results enable us to better understand the performance of nitenpyram seed treatments against A. gossypii during the seedling stage, indicating that nitenpyram may be safer than thiamethoxam for natural enemies and honeybees.

Role of Tillage, Thiamethoxam Seed Treatment, and Foliar Insecticide Application for Management of Thrips (Thysanoptera: Thripidae) in Seedling Cotton

Thrips are early-season pests of cotton and can cause yield and stand losses if not managed. Strip tillage into a winter cover crop, use of a neonicotinoid seed treatment, and foliar insecticide applications are all reliable pest management tactics, but how these methods interact with each other in a thrip-cotton agroecosystem needs to be further understood. A 2-yr field study was conducted to compare thrip counts and thrip-induced plant injury as a function of tillage practice (conventional vs strip tillage with heavy rolled rye), thiamethoxam seed treatment, and foliar insecticide application for managing thrips in cotton. Adult and nymph density, seedling biomass, true leaf formation, stand count, and lint yield were assessed. Results indicate that heavy rolled rye was effective for mitigating thrips on seedling cotton. On conventionally tilled fields, the neonicotinoid seed treatment and a foliar insecticide application were necessary for maximizing yield. Spinetoram was more efficacious than either acephate or cyantraniliprole for management of immature thrips; however, there were no yield effects attributed to foliar insecticide application. These data suggest that growers can mitigate early-season thrips using both cultural and chemically based management tactics.

Concentrations of imidacloprid and thiamethoxam in pollen, nectar and leaves from seed-dressed cotton crops and their potential risk to honeybees (Apis mellifera L.)

Neonicotinoid insecticides (NIs) have recently been recognized as co-factors in the decline of honeybee colonies because most neonicotinoids are systemic and can transfer into the pollen and nectar of many pollinated crops. In this study, we collected pollen, nectar and leaves from a cotton crop treated with imidacloprid and thiamethoxam to measure the residue levels of these two NIs at different application doses during the flowering period. Then, the residual data were used to assess the risk posed by the systemic insecticides to honeybees following mandated methods published by the European Food Safety Authority (EFSA), and a highly toxic risk to honeybees was highlighted. Imidacloprid was found in both pollen and nectar samples, whereas thiamethoxam was found in 90% of pollen samples and over 60% of nectar samples. Analysis of the pollen and nectar revealed residual amounts of imidacloprid ranging from 1.61 to 64.58 ng g^-1 in the pollen and from not detected (ND) to 1.769 ng g^-1 in the nectar. By comparison, the thiamethoxam concentrations in pollen and nectar ranged from ND to 14.521 ng g^-1 and from ND to 4.285 ng g^-1, respectively. The results of this study provide information on the transfer of two NIs from seed treatment to areas of the plant and provides an understanding of the potential exposure of the bee and other pollinators to systemic insecticides.

Peer review of the pesticide risk assessment for bees for the active substance clothianidin considering the uses as seed treatments and granules

EFSA was asked by the European Commission to perform an updated risk assessment of neonicotinoids, including clothianidin, as regards the risk to bees, as a follow up of previous mandates received from the European Commission on neonicotinoids. The context of the evaluation was that required by the European Commission in accordance with Article 21 of Regulation (EC) No 1107/2009 to review the approval of active substances in light of new scientific and technical knowledge and monitoring data. In this context and in accordance with Article 31 of Regulation (EC) No 178/2002, EFSA has been previously asked by European Commission to organise an open call for data in order to collect new scientific information as regards the risk to bees from the neonicotinoid pesticide active substances clothianidin, thiamethoxam and imidacloprid applied as seed treatments and granules in the EU. The conclusions were reached on the basis of the evaluation of the supported uses as an insecticide of clothianidin applied as seed treatments and granules, on the new relevant data collected in the framework of the open call organised by EFSA and on the updated literature search performed by EFSA. The reliable endpoints, appropriate for use in regulatory risk assessment derived from the submitted studies and literature data as well as any other relevant data available at national level and made available to EFSA, are presented. Concerns are identified.

Peer review of the pesticide risk assessment for bees for the active substance imidacloprid considering the uses as seed treatments and granules

The EFSA was asked by the European Commission to perform an updated risk assessment of neonicotinoids, including imidacloprid, as regards the risk to bees, as a follow-up of previous mandates received from the European Commission on neonicotinoids. The context of the evaluation was that required by the European Commission in accordance with Article 21 of Regulation (EC) No 1107/2009 to review the approval of active substances in light of new scientific and technical knowledge and monitoring data. In this context and in accordance with Article 31 of Regulation (EC) No 178/2002, EFSA has been previously asked by the European Commission to organise an open call for data in order to collect new scientific information as regards the risk to bees from the neonicotinoid pesticide active substances clothianidin, thiamethoxam and imidacloprid applied as seed treatments and granules in the EU. The conclusions were reached on the basis of the evaluation of the supported uses as an insecticide of imidacloprid applied as seed treatments and granules, on the new relevant data collected in the framework of the open call organised by EFSA and on the updated literature search performed by EFSA. The reliable endpoints, appropriate for use in regulatory risk assessment derived from the submitted studies and literature data as well as any other relevant data available at national level and made available to EFSA, are presented. Concerns are identified.