Revised guidance on the risk assessment of plant protection products on bees (Apis mellifera, Bombus spp. and solitary bees)

Development of a test design for a semi-field, colony-feeding study for the common eastern bumble bee (Hymenoptera: Apidae)

Ecological risk assessment is a key component of the regulatory process required for registration of crop protection products around the world. The western honey bee (Apis mellifera) is the model organism for pesticide risk assessments for bees, but there are uncertainties over whether it is predictive of risks to other bees. Consequently, efforts are underway to develop test methodologies for other non-Apis bees. We conducted a semi-field colony-feeding study with Bombus impatiens colonies to develop a colony-level methodology for bumble bees. We exposed commercially available bumble bee colonies to diets consisting of 4 concentration treatments of dimethoate insecticide (0.05, 0.19, 0.75, and 3.0 mg a.i./L) via supplemental sugar solution for 6 wk and compared exposed colonies to untreated controls. Each treatment group had 10 replicate colonies, with 1 replicate per treatment group represented at each of the 10 study rural locations. We collected data on various colony-level endpoints including production of female reproductive (gyne) offspring, colony weight, foraging activity, and consumption of provisioned sugar solution. Our results indicated that the test design could be used to derive concentration-response relationships for several endpoints including the most sensitive, colony mass (No Observed Adverse Effect Concentration = 0.05 mg a.i./L). Overall, our study provides the foundation for a semi-field, colony-feeding study test design for bumble bees, thus adding to the growing body of studies that may be used to assess the protectiveness of the honey bee risk assessment framework for non-Apis bees exposed to pesticides.

Ecofriendly control of Drosophila suzukii via the photoinsecticide chlorophyllin

BACKGROUND

Drosophila suzukii is an invasive pest causing high losses of agricultural crops. Conventional treatment strategies are considered problematic for their high risk of inducing resistance and environmental harm. Photodynamic Inactivation (PDI) is based on the photosensitizer-mediated and light-dependent generation of reactive oxygen species. Natural and food-grade photosensitizers, such as the food additive sodium magnesium chlorophyllin (Chl, E140), have been proven effective against microbial pathogens and several agricultural pests. The aim of this study is to assess whether the principle of Chl-based PDI of D. suzukii could be transferred from laboratory towards practical conditions.

RESULTS

We prove that D. suzukii is photokilled after feeding on 5 mM Chl with 3% sucrose (98.4% median moribundity, 9 h drug to light interval, 78.9 J/cm2 radiant exposure). Therefore, aspects of environmental safety and practical feasibility were assessed, using streamlined variations of the same assay: the required photosensitizer concentration could be reduced to 0.5 mM Chl (90.1% median moribundity 6 days after 315.6 J/cm2 illumination with LEDs). Chl was photoactivable with sunlight (92.5% median moribundity, 6 days after 294.5 J/cm2 and 1 mM Chl). Offering alternative food lures did not impair this effect. Photobleaching rendered Chl non-toxic (2.5% median moribundity after bleaching Chl with 78.9 J/cm2 with subsequent illumination using 157.8 J/cm2). Furthermore, fluorescence microscopy of Chl-fed flies confirmed Chl accumulation in the flies' intestines.

CONCLUSION

Our findings demonstrate that Chl-based PDI could be harnessed as a safe and effective alternative for the management of D. suzukii pests. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Acute and repeated exposure toxicity of the insecticide sulfoxaflor on hymenopteran pollinators; sulfoxaflor environmental science review part III

To support regulatory risk assessment, standardized laboratory tests of toxicity to representative species including honeybees (Apis mellifera L.), orchard bees (Osmia spp.), and bumblebees (Bombus spp.) provide the benchmark toxicity values for use in preliminary Tier 1 assessments and more detailed and realistic higher-tier assessments. In this analysis, we summarize the results of studies of toxicity of SFX to pollinators conducted by the registrant as well as results published in the literature. The geometric mean of 48-hr adult acute oral LD50 values for SFX for honeybees was 0.0740 μg SFX bee-1 (n = 5). Toxicity values for technical grade SFX (SFX-T) and formulated products were not significantly different. The geometric mean 48 hr adult acute contact LD50 values for SFX-T and several formulated products were 0.432 (n = 2) and 0.202 (n = 3) μg SFX bee-1, respectively. Exposures sprayed foliage was not significant after the spray had dried did not cause significant toxicity. Transformation products were not significantly toxic to adult or larval honeybees or other representative bee species. Results showed that, to complete the risk assessment, higher-tier studies were required. Differences in results between standard test methods and the nonstandard methods used in published work affect the outcome of the risk assessment. An understanding of these differences reconciled the differences in the reported findings.

Weight of evidence assessment from field studies on effects of the insecticide sulfoxaflor on hymenopteran pollinators: sulfoxaflor environmental science review part V

Field studies involve combinations of exposure, natural dynamics, and effects in natural and agricultural environments. To be more realistic, field studies focussed on pollinating insects must consider the details of biology, life history, behavior, and pollination ecology of the test species. While expensive and time-consuming, these tests provide the most realistic information, especially for social insects, but are valuable for solitary bee species as well. They are more realistic than laboratory studies because they determine the combined effects of natural stressors including weather, food availability, parasites, and pathogens with anthropogenic stressors, such as the pesticide treatment itself, within agroecosystem landscapes. Twenty-four field studies conducted with bees to support the registration of sulfoxaflor and published work are included, and a standardized rating system for the quality and relevance of the studies was used. The studies included Apis mellifera L., Bombus terrestris L., and Osmia bicornis L. The results show that, when SFX products are applied at the highest labeled application rate with bees actively foraging or fed in syrup at equivalent rates, the effects are minor and temporary. Sublethal effects included lethargy, disorientation, and reduced body mass at emergence. No new modes of action and no treatment-related effects on brood rearing were found.

Acute and chronic pesticide exposure trigger fundamentally different molecular responses in bumble bee brains

BACKGROUND

Beneficial insects, including pollinators, encounter various pesticide exposure conditions, from brief high-concentration acute exposure to continuous low-level chronic exposure. To effectively assess the environmental risks of pesticides, it is critical to understand how different exposure schemes influence their effects. Unfortunately, this knowledge remains limited. To clarify whether different exposure schemes disrupt the physiology of pollinators in a similar manner, we exposed bumble bees to acute or chronic treatments of three different pesticides: acetamiprid, clothianidin, or sulfoxaflor. Genome-wide gene expression profiling enabled us to compare the effects of these treatments on the brain in a high-resolution manner.

RESULTS

There were two main findings: First, acute and chronic exposure schemes largely affected non-overlapping sets of genes. Second, different pesticides under the same exposure scheme showed more comparable effects than the same pesticide under different exposure schemes. Each exposure scheme induced a distinct gene expression profile. Acute exposure mainly caused upregulation of genes linked to the stress response mechanisms, like peroxidase and detoxification genes, while chronic exposure predominantly affected immunity and energy metabolism.

CONCLUSIONS

Our findings show that the mode of exposure is critical in determining the molecular effects of pesticides. These results signal the need for safety testing practices to better consider mode-of-exposure dependent effects and suggest that transcriptomics can support such improvements.

Peer review of the pesticide risk assessment of the active substance maltodextrin

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Ireland, and co-rapporteur Member State, France, for the pesticide active substance maltodextrin and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2020/103. The conclusions were reached on the basis of the evaluation of the representative uses of maltodextrin as an insecticide and acaricide on all edible and non-edible crops. The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Peer review of the pesticide risk assessment of the active substance pyraclostrobin

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Germany and co-rapporteur Member State Hungary for the pesticide active substance pyraclostrobin and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of pyraclostrobin as a fungicide and plant growth regulator on cereals (wheat, barley, oats, rye, triticale), maize (forage and grain) and potatoes. MRLs were assessed in sweet corn and fish. The reliable end points, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Impacts of neonicotinoids on biodiversity: a critical review

Neonicotinoids are the most widely used class of insecticides in the world, but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air. They have only been recently monitored in coastal and marine environments, but some studies already reported the presence of imidacloprid and thiamethoxam in transitional or semi-enclosed ecosystems (lagoons, bays, and estuaries). The contamination of the environment leads to the exposure and to the contamination of non-target organisms and to negative effects on biodiversity. Direct impacts of neonicotinoids are mainly reported on terrestrial invertebrates (e.g., pollinators, natural enemies, earthworms) and vertebrates (e.g., birds) and on aquatic invertebrates (e.g., arthropods). Impacts on aquatic vertebrate populations and communities, as well as on microorganisms, are less documented. In addition to their toxicity to directly exposed organisms, neonicotinoid induce indirect effects via trophic cascades as demonstrated in several species (terrestrial and aquatic invertebrates). However, more data are needed to reach firmer conclusions and to get a clearer picture of such indirect effects. Finally, we identified specific knowledge gaps that need to be filled to better understand the effects of neonicotinoids on terrestrial, freshwater, and marine organisms, as well as on ecosystem services associated with these biotas.

Peer review of the pesticide risk assessment of the active substance cyprodinil

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State France and co-rapporteur Member State Bulgaria for the pesticide active substance cyprodinil are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of cyprodinil as a fungicide on apples and barley. The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Comparative temporal response of toxicity for the neonicotinoid clothianidin and organophosphate dimethoate insecticides in two species of solitary bee (Osmia bicornis and Osmia cornuta)

Solitary bees provide essential pollination services. Concerns for the decline of these wild bee species have led to calls for their inclusion in pesticide risk assessment. Solitary bees differ from honey bees in their physiology and ecology and this may affect how they respond to pesticide exposure. Here we investigate the life-time toxicity of two insecticides, the organophosphate dimethoate and neonicotinoid clothianidin, for two mason bee species, Osmia bicornis and O. cornuta using a toxicokinetic/toxicodynamic stochastic death model taken from Dynamic Energy Budget (DEBtox) theory. Both species showed concentration and exposure duration dependent effects for each chemical. LC50 values estimated from the model parameters at 48 h were ≥ 14 fold and 6 fold those at 480 h for dimethoate and clothianidin respectively. Survival modelling indicated greater sensitivity in O. bicornis than for O. cornuta to dimethoate, whilst for clothianidin, O. cornuta females but not males, were more sensitive than both sexes of O. bicornis. These sensitivity differences were not related to body size. Toxicokinetic and toxicodynamic traits derived from modelling indicated lower elimination rates in O. bicornis and higher killing rates for O. cornuta females for dimethoate and lower elimination rates for clothianidin in O. cornuta females that were related to sensitivity. This study shows the near life-time testing is possible for solitary bees and that combining adult life-time toxicity tests with toxicokinetic/toxicodynamic modelling provides a more mechanistic understanding of pesticide effects in solitary bee species.

Exposure of insects to current use pesticide residues in soil and vegetation along spatial and temporal distribution in agricultural sites

Current use pesticides (CUPs) are recognised as the largest deliberate input of bioactive substances into terrestrial ecosystems and one of the main factors responsible for the current decline in insects in agricultural areas. To quantify seasonal insect exposure in the landscape at a regional scale (Rhineland-Palatine in Germany), we analysed the presence of multiple (93) active ingredients in CUPs across three different agricultural cultivation types (with each three fields: arable, vegetable, viticulture) and neighbouring meadows. We collected monthly soil and vegetation samples over a year. A total of 71 CUP residues in different mixtures was detected, with up to 28 CUPs in soil and 25 in vegetation in single samples. The concentrations and numbers of CUPs in vegetation fluctuated over the sampling period, peaking in the summer months in the vegetation but remaining almost constant in topsoil. We calculated in-field additive risks for earthworms, collembola, and soil-living wild bees using the measured soil concentrations of CUPs. Our results call for the need to assess CUP mixture risks at low concentrations, as multiple residues are chronically present in agricultural areas. Since this risk is not addressed in regulation, we emphasise the urgent need to implement global pesticide reduction targets.

ApisTox: a new benchmark dataset for the classification of small molecules toxicity on honey bees

The global decline in bee populations poses significant risks to agriculture, biodiversity, and environmental stability. To bridge the gap in existing data, we introduce ApisTox, a comprehensive dataset focusing on the toxicity of pesticides to honey bees (Apis mellifera). This dataset combines and leverages data from existing sources such as ECOTOX and PPDB, providing an extensive, consistent, and curated collection that surpasses the previous datasets. ApisTox incorporates a wide array of data, including toxicity levels for chemicals, details such as time of their publication in literature, and identifiers linking them to external chemical databases. This dataset may serve as an important tool for environmental and agricultural research, but also can support the development of policies and practices aimed at minimizing harm to bee populations. Finally, ApisTox offers a unique resource for benchmarking molecular property prediction methods on agrochemical compounds, facilitating advancements in both environmental science and chemoinformatics. This makes it a valuable tool for both academic research and practical applications in bee conservation.

A test method for assessing chronic oral toxicity of a pesticide to solitary nesting orchard bees, Osmia spp. (Hymenoptera: Megachilidae)

Orchard bees of the genus Osmia Panzer are important pollinators of fruit trees in various regions of the world, with some species commercially available in the United States and Europe. In addition to their pollination services, Osmia lignaria, Osmia cornifrons, Osmia bicornis, and Osmia cornuta have been identified as potential model species for solitary bees in pesticide risk assessment and have been used for the development of new methods to test acute lethal effects via contact and oral routes of exposure. Our goal was to expand the available methodology to characterize the toxicity of pesticides for these solitary bees through a chronic oral test for adult bees. Chronic oral toxicity of pesticides to orchard bees has been reported, but methods differ among research groups. In our study, O. lignaria, O. cornifrons, O. bicornis, and O. cornuta female bees had access to sucrose solution ad libitum in separate, species-specific 10-day tests. Mean body mass, mean daily consumption, and survival differed among the studied bee species. The dose-response test design was validated with dimethoate, a reference toxic compound, and chronic toxicity endpoints were estimated for the 4 Osmia species. The median lethal daily doses normalized by weight for O. lignaria, O. bicornis, O. cornuta, and O. cornifrons were within the same order of magnitude at 0.23, 0.26, 0.49, and 0.61 µg dimethoate/g bee/day, respectively. The methodology described here was aligned as much as possible with the available honey bee and bumble bee standard methods to facilitate the comparison of chronic toxicity profiles among bee species.

SolBeePopecotox: A Population Model for Pesticide Risk Assessments of Solitary Bees

In agricultural landscapes, solitary bees occur in a large diversity of species and are important for crop and wildflower pollination. They are distinguished from honey bees and bumble bees by their solitary lifestyle as well as different nesting strategies, phenologies, and floral preferences. Their ecological traits and presence in agricultural landscapes imply potential exposure to pesticides and suggest a need to conduct ecological risk assessments for solitary bees. However, assessing risks to the large diversity of managed and wild bees across landscapes and regions poses a formidable challenge. Population models provide tools to estimate potential population-level effects of pesticide exposures, can support field study design and interpretation, and can be applied to expand study data to untested conditions. We present a population model for solitary bees, SolBeePopecotox, developed for use in the context of ecological risk assessments. The trait-based model extends a previous version with the explicit representation of exposures to pesticides from relevant routes. Effects are implemented in the model using a simplified toxicokinetic-toxicodynamic model, BeeGUTS (GUTS = generalized unified threshold model for survival), adapted specifically for bees. We evaluated the model with data from semifield studies conducted with the red mason bee, Osmia bicornis, in which bees were foraging in tunnels over control and insecticide-treated oilseed rape fields. We extended the simulations to capture hypothetical semifield studies with two soil-nesting species, Nomia melanderi and Eucera pruinosa, which are difficult to test in empirical studies. The model provides a versatile tool for higher-tier risk assessments, for instance, to estimate effects of potential exposures, expanding available study data to untested species, environmental conditions, or exposure scenarios. Environ Toxicol Chem 2024;43:2645-2661. © 2024 SETAC.

Peer review of the pesticide risk assessment of the active substance fludioxonil

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State France and co-rapporteur Member State Spain for the pesticide active substance fludioxonil are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative use of fludioxonil as a fungicide on wheat, oats, grapes, pome fruit and strawberry. The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

The impact of landscape structure on pesticide exposure to honey bees

Pesticides may have serious negative impacts on bee populations. The pesticide exposure of bees could depend on the surrounding landscapes in which they forage. In this study, we assess pesticide exposure across various land-use categories, while targeting the Japanese honey bee, Apis cerana japonica, a native subspecies of the eastern honey bee. In a project involving public participation, we measured the concentrations of major pesticides in honey and beeswax collected from 175 Japanese honey bee colonies across Japan and quantitatively analyzed the relationships between pesticide presence/absence or pesticide concentration and land-use categories around the colonies. Our findings revealed that the surrounding environment in which bees live strongly influences pesticide residues in beehive materials, whether the pesticides are systemic or not, with a clear trend for each land-use category. Agricultural lands, particularly paddy fields and orchards, and urban areas resulted in higher pesticide exposure, whereas forests presented a lower risk of exposure. To effectively control pesticide exposure levels in bees, it is essential to understand pesticide usage patterns and to develop appropriate regulatory systems in non-agricultural lands, similar to those in agricultural lands.

Peer review of the pesticide risk assessment of the active substance bixlozone

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, The Netherlands for the pesticide active substance bixlozone are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of bixlozone as an herbicide on winter cereals (wheat and barley), winter oilseed rape and maize via soil broadcast spray application in field. The reliable endpoints, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

No impact of cyantraniliprole on the hibernation success of bumble bees (Bombus terrestris audax) in a soil-mediated laboratory exposure study

Increasing evidence shows that wild bees, including bumble bees, are in decline due to a range of stressors, including pesticides. Our knowledge of pesticide impacts has consequently grown to enable the design of increasingly realistic risk assessment methods. However, one area where knowledge gaps may still hinder our ability to assess the full range of bee-pesticide interactions is the field of exposure. Exposure has historically been linked to either direct contact with pesticides or the ingestion of contaminated pollen and nectar by bees. However, bumble bees, and other wild bees, may also be exposed to pesticides while using contaminated soil as an overwintering substrate. Yet knowledge of how soil-mediated exposure affects bumble bee health is lacking. Here we take one of the first steps towards addressing this knowledge gap by designing a method for testing the effects of soil-mediated pesticide exposure on bumble bee queen hibernation success. We measured hibernation survival, body weight change and abdominal fat content and found that none of these responses were affected by a field realistic soil exposure to the novel insecticide cyantraniliprole. Our study may help in developing a standardised method to test the effects of the soil-mediated pesticide exposure route in bumble bee queens.

Peer review of the pesticide risk assessment of the active substance pirimicarb

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Sweden for the pesticide active substance pirimicarb are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative use(s) of pirimicarb as an insecticide on winter and spring wheat and sugar beet via foliar spray application and on ornamental pot plants in permanent greenhouses. The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Leveraging In Silico Structure-Activity Models to Predict Acute Honey Bee (Apis mellifera) Toxicity for Agrochemicals

In the realm of crop protection products, ensuring the safety of pollinators stands as a pivotal aspect of advancing sustainable solutions. Extensive research has been dedicated to this crucial topic as well as new approach methodologies in toxicity testing. Hence, within the agricultural and chemical industries, prioritizing pollinator safety remains a constant objective during the development of predictive tools. One of these tools includes computational models like quantitative structure-activity relationships (QSARs) that are valuable in predicting the toxicity of chemicals. This research uses bee toxicity data to develop artificial neural network classification models for predicting honey bee acute toxicity. Bee toxicity data from 1542 compounds were used to develop models; the sensitivity and specificity of the best model were 0.90 and 0.91, respectively. These in silico models can aid in the discovery of next-generation crop protection products. These tools can guide the screening and selection of next-generation crop protection molecules with high margins of safety to pollinators, and candidates with favorable sustainability profiles can be identified at the early discovery stage as precursors to in vivo data generation.

Peer review of the pesticide risk assessment of the active substance bensulfuron-methyl

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Italy and co-rapporteur Member State Spain for the pesticide active substance bensulfuron-methyl are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of bensulfuron-methyl as an herbicide on rice and spring cereals (spring wheat, spring barley, oat, rye, triticale). The reliable end points, appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Mechanistic population models for ecological risk assessment and decision support: The importance of good conceptual model diagrams

The use of mechanistic population models as research and decision-support tools in ecology and ecological risk assessment (ERA) is increasing. This growth has been facilitated by advances in technology, allowing the simulation of more complex systems, as well as by standardized approaches for model development, documentation, and evaluation. Mechanistic population models are particularly useful for simulating complex systems, but the required model complexity can make them challenging to communicate. Conceptual diagrams that summarize key model elements, as well as elements that were considered but not included, can facilitate communication and understanding of models and increase their acceptance as decision-support tools. Currently, however, there are no consistent standards for creating or presenting conceptual model diagrams (CMDs), and both terminology and content vary widely. Here, we argue that greater consistency in CMD development and presentation is an important component of good modeling practice, and we provide recommendations, examples, and a free web app (pop-cmd.com) for achieving this for population models used for decision support in ERAs. Integr Environ Assess Manag 2024;20:1566-1574. © 2023 SETAC.

Using equivalence tests in higher tier studies of honey bees under the revised EFSA Bee Guidance-How?

The proposed use of equivalence tests instead of difference tests in the revised guidance on the risk assessment of plant protection products for bees is a reasonable approach given an adverse effect was observed in the lower tier studies, using the hypothesis that there is a risk as the null hypothesis places the burden to prove the opposite on the other side. However, some uncertainties regarding the application of equivalence tests in field studies are discussed in the present study. Here, we compare equivalence and difference testing methods using a control dataset of a honey bee field effect study conducted in northern Germany in 2014. Half of the 48 colonies were assigned to a hypothetical test item group, and the colony strength data were analyzed using t-tests, a generalized linear mixed model (GLMM), and the corresponding equivalence tests. The data reflected the natural variability of honey bee colonies, with initially approximately 12 000 adult bees. Although the t-test and GLMM confirmed that 24 + 24 colonies are sufficient to show "no adverse effect," the equivalence tests of the t-test and GLMM were not able to reject the null hypothesis and classified at least some of the assessments as "high risk," indicating a power that was too low. Based on this, different operating options to reduce the variability are discussed. One possible option, which may provide a more realistic application of equivalence to avoid false high risk, is to consider the lower confidence interval of the control as a baseline and use GLMMs. With this option, we demonstrate a relatively acceptable probability to prove that no high risk for initially similar groups can be achieved. Further studies with different numbers of colonies are still needed to develop and validate the suggested approach. Integr Environ Assess Manag 2024;20:1496-1503. © 2024 SETAC.

A conceptual framework for landscape-based environmental risk assessment (ERA) of pesticides

While pesticide use is subject to strict regulatory oversight worldwide, it remains a main concern for environmental protection, including biodiversity conservation. This is partly due to the current regulatory approach that relies on separate assessments for each single pesticide, crop use, and non-target organism group at local scales. Such assessments tend to overlook the combined effects of overall pesticide usage at larger spatial scales. Integrative landscape-based approaches are emerging, enabling the consideration of agricultural management, the environmental characteristics, and the combined effects of pesticides applied in a same or in different crops within an area. These developments offer the opportunity to deliver informative risk predictions relevant for different decision contexts including their connection to larger spatial scales and to combine environmental risks of pesticides, with those from other environmental stressors. We discuss the needs, challenges, opportunities and available tools for implementing landscape-based approaches for prospective and retrospective pesticide Environmental Risk Assessments (ERA). A set of "building blocks" that emerged from the discussions have been integrated into a conceptual framework. The framework includes elements to facilitate its implementation, in particular: flexibility to address the needs of relevant users and stakeholders; means to address the inherent complexity of environmental systems; connections to make use of and integrate data derived from monitoring programs; and options for validation and approaches to facilitate future use in a regulatory context. The conceptual model can be applied to existing ERA methodologies, facilitating its comparability, and highlighting interoperability drivers at landscape level. The benefits of landscape-based pesticide ERA extend beyond regulation. Linking and validating risk predictions with relevant environmental impacts under a solid science-based approach will support the setting of protection goals and the formulation of sustainable agricultural strategies. Moreover, landscape ERA offers a communication tool on realistic pesticide impacts in a multistressors environment for stakeholders and citizens.

Peer review of the pesticide risk assessment of the active substance flufenacet

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Poland and co-rapporteur Member State France for the pesticide active substance flufenacet are reported. In addition, the assessment of the confirmatory data following the Article 12 maximum residue limit (MRL) review of Regulation (EC) No 396/2005 is also reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative use of flufenacet as a herbicide on winter cereals. Confirmatory data following the Article 12 MRL review were assessed. The reliable end points, appropriate for use in regulatory risk assessment and the assessment of confirmatory data following the Article 12 MRL review, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

A new exposure protocol adapted for wild bees reveals species-specific impacts of the sulfoximine insecticide sulfoxaflor

Wild bees are crucial pollinators of flowering plants and concerns are rising about their decline associated with pesticide use. Interspecific variation in wild bee response to pesticide exposure is expected to be related to variation in their morphology, physiology, and ecology, though there are still important knowledge gaps in its understanding. Pesticide risk assessments have largely focussed on the Western honey bee sensitivity considering it protective enough for wild bees. Recently, guidelines for Bombus terrestris and Osmia bicornis testing have been developed but are not yet implemented at a global scale in pesticide risk assessments. Here, we developed and tested a new simplified method of pesticide exposure on wild bee species collected from the field in Belgium. Enough specimens of nine species survived in a laboratory setting and were exposed to oral and topical acute doses of a sulfoximine insecticide. Our results confirm significant variability among wild bee species. We show that Osmia cornuta is more sensitive to sulfoxaflor than B. terrestris, whereas Bombus hypnorum is less sensitive. We propose hypotheses on the mechanisms explaining interspecific variations in sensitivity to pesticides. Future pesticide risk assessments of wild bees will require further refinement of protocols for their controlled housing and exposure.

Colony environment and absence of brood enhance tolerance to a neonicotinoid in winter honey bee workers, Apis mellifera

In eusocial insects, worker longevity is essential to ensure colony survival in brood-free periods. Trade-offs between longevity and other traits may render long-living workers in brood-free periods more susceptible to pesticides compared to short-lived ones. Further, colony environment (e.g., adequate nutrition) may enable workers to better cope with pesticides, yet data comparing long vs. short-living workers and the role of the colony environment for pesticide tolerance are scarce. Here, we show that long-living honey bee workers, Apis mellifera, are less susceptible to the neonicotinoid thiamethoxam than short-lived workers, and that susceptibility was further reduced when workers were acclimatized under colony compared to laboratory conditions. Following an OECD protocol, freshly-emerged workers were exposed to thiamethoxam in summer and winter and either acclimatized within their colony or in the laboratory. Mortality and sucrose consumption were measured daily and revealed that winter workers were significantly less susceptible than summer workers, despite being exposed to higher thiamethoxam dosages due to increased food consumption. Disparencies in fat body activity, which is key for detoxification, may explain why winter bees were less susceptible. Furthermore, colony acclimatization significantly reduced susceptibility towards thiamethoxam in winter workers likely due to enhanced protein nutrition. Brood absence and colony environment seem to govern workers' ability to cope with pesticides, which should be considered in risk assessments. Since honey bee colony losses occur mostly over winter, long-term studies assessing the effects of pesticide exposure on winter bees are required to better understand the underlying mechanisms.

Peer review of the pesticide risk assessment of the active substance triclopyr (variant triclopyr-butotyl)

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State Poland and co-rapporteur Member State Hungary for the pesticide active substance triclopyr (variant triclopyr-butotyl) and the assessment of applications for maximum residue levels (MRLs) are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of triclopyr (variant triclopyr-butotyl) as a herbicide on established pasture and non-recreational amenity grassland (field use). MRLs were assessed in rice. The reliable end points, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Peer review of the pesticide risk assessment of the active substance mepiquat (evaluated variant mepiquat chloride)

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Finland, and co-rapporteur Member State, Estonia, for the pesticide active substance mepiquat (evaluated variant mepiquat chloride) are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of mepiquat chloride as a plant growth regulator on cereals and grass (field uses). The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are identified.

Identifying and Predicting Delayed Mortality with Toxicokinetic-Toxicodynamic Models

The prevalence of standardized toxicity testing in ecotoxicology has largely obscured the notion that toxicity is a function of time as well. The necessity of considering time is vividly demonstrated by observations of delayed mortality, that is, deaths continue to occur even when animals are no longer exposed to a toxicant. In this contribution, I explore to what extent toxicokinetic-toxicodynamic (TKTD) models from the framework of the General Unified Threshold model for Survival (GUTS) can capture delayed mortality, and to what extent this phenomenon can be predicted from short-term standard tests. I use a previously published data set for fluoroquinolones in Daphnia magna that shows strongly delayed mortality (using immobilization as a proxy for death). The model analysis shows that the GUTS stochastic death models can capture delayed mortality in the complete data set with a long recovery phase, but that the delayed effects would not have been predicted from a 2-day standard test. The study underlines the limited information content of standard acute test designs. Toxicokinetic-toxicodynamic modeling offers a handle on the time aspects of toxicity but cannot always be relied on to provide accurate extrapolations based on severely limited standard tests. The phenomenon of delayed toxicity requires more structured study to clarify its prevalence and impact; I discuss several avenues for further investigation. Environ Toxicol Chem 2024;43:1030-1035. © 2024 SETAC.

A novel insecticide impairs bumblebee memory and sucrose responsiveness across high and low nutrition

Wild bees are important pollinators of crops and wildflowers but are exposed to a myriad of different anthropogenic stressors, such as pesticides and poor nutrition, as a consequence of intensive agriculture. These stressors do not act in isolation, but interact, and may exacerbate one another. Here, we assessed whether a field-realistic concentration of flupyradifurone, a novel pesticide that has been labelled as 'bee safe' by regulators, influenced bumblebee sucrose responsiveness and long-term memory. In a fully crossed experimental design, we exposed individual bumblebees (Bombus impatiens) to flupyradifurone at high (50% (w/w)) or low (15% (w/w)) sucrose concentrations, replicating diets that are either carbohydrate rich or poor, respectively. We found that flupyradifurone impaired sucrose responsiveness and long-term memory at both sucrose concentrations, indicating that better nutrition did not buffer the negative impact of flupyradifurone. We found no individual impact of sugar deficiency on bee behaviour and no significant interactions between pesticide exposure and poor nutrition. Our results add to a growing body of evidence demonstrating that flupyradifurone has significant negative impacts on pollinators, indicating that this pesticide is not 'bee safe'. This suggests that agrochemical risk assessments are not protecting pollinators from the unintended consequences of pesticide use.

Distribution of infectious and parasitic agents among three sentinel bee species across European agricultural landscapes

Infectious and parasitic agents (IPAs) and their associated diseases are major environmental stressors that jeopardize bee health, both alone and in interaction with other stressors. Their impact on pollinator communities can be assessed by studying multiple sentinel bee species. Here, we analysed the field exposure of three sentinel managed bee species (Apis mellifera, Bombus terrestris and Osmia bicornis) to 11 IPAs (six RNA viruses, two bacteria, three microsporidia). The sentinel bees were deployed at 128 sites in eight European countries adjacent to either oilseed rape fields or apple orchards during crop bloom. Adult bees of each species were sampled before their placement and after crop bloom. The IPAs were detected and quantified using a harmonised, high-throughput and semi-automatized qPCR workflow. We describe differences among bee species in IPA profiles (richness, diversity, detection frequencies, loads and their change upon field exposure, and exposure risk), with no clear patterns related to the country or focal crop. Our results suggest that the most frequent IPAs in adult bees are more appropriate for assessing the bees' IPA exposure risk. We also report positive correlations of IPA loads supporting the potential IPA transmission among sentinels, suggesting careful consideration should be taken when introducing managed pollinators in ecologically sensitive environments.

Peer review of the pesticide risk assessment of the active substance dimoxystrobin

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Hungary, and co-rapporteur Member State, Ireland, for the pesticide active substance dimoxystrobin as well as the assessment of maximum residue levels (MRLs) and confirmatory data following the review of the existing MRLs of dimoxystrobin according to Article 12 of Regulation (EC) No 396/2005 are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. In June 2023, the European Commission sent a mandate confirming the need to adopt and publish a conclusion on the peer review of the pesticide risk assessment of the active substance dimoxystrobin excluding the full assessment of endocrine-disrupting properties, containing all the results of the peer review process related to the renewal of approval as well as the assessment of the application for MRL for oilseed rapeseed, poppy seed, mustard seed and gold of pleasure seed, and the MRL application addressing the confirmatory data identified during the MRL review under Article 12 of Regulation (EC) No 396/2005. The conclusions were reached on the basis of the evaluation of the representative uses of dimoxystrobin as a fungicide on oilseed rape and sunflower. MRLs were assessed in rapeseeds, poppy seed, mustard seed and Gold of pleasure seed. The reliable end points, appropriate for use in regulatory risk assessment and the proposed MRLs, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are presented where identified.

Peer review of the pesticide risk assessment of the active substance metconazole

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Belgium, and co-rapporteur Member State, the United Kingdom, for the pesticide active substance are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of metconazole as a fungicide on cereals and oilseed rape and as a plant growth regulator on oilseed rape. The reliable end points appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Peer review of the pesticide risk assessment of the active substance tritosulfuron

The conclusions of the European Food Safety Authority (EFSA) following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Slovenia, and co-rapporteur Member State, Austria, for the pesticide active substance tritosulfuron are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012, as amended by Commission Implementing Regulation (EU) No 2018/1659. The conclusions were reached on the basis of the evaluation of the representative uses of tritosulfuron as a herbicide on spring and winter cereals, spring cereals with undersown grasses and maize (field uses). The reliable end points, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Updated peer review of the pesticide risk assessment of the active substance mepanipyrim

The conclusions of the EFSA following the peer review of the initial risk assessments carried out by the competent authorities of the rapporteur Member State, Belgium, and co-rapporteur Member State, Greece, for the pesticide active substance mepanipyrim are reported. The context of the peer review was that required by Commission Implementing Regulation (EU) No 844/2012. The conclusions were reached on the basis of the evaluation of the representative uses of mepanipyrim as a fungicide on table and wine grapes and in field and protected strawberries and tomatoes. The conclusions were updated with regard to the endocrine-disrupting properties following a mandate received from the European Commission in January 2019. The reliable end points appropriate for use in regulatory risk assessment are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Revised guidance on the risk assessment of plant protection products on bees (Apis mellifera, Bombus spp. and solitary bees)

The European Commission asked EFSA to revise the risk assessment for honey bees, bumble bees and solitary bees. This guidance document describes how to perform risk assessment for bees from plant protection products, in accordance with Regulation (EU) 1107/2009. It is a review of EFSA's existing guidance document, which was published in 2013. The guidance document outlines a tiered approach for exposure estimation in different scenarios and tiers. It includes hazard characterisation and provides risk assessment methodology covering dietary and contact exposure. The document also provides recommendations for higher tier studies, risk from metabolites and plant protection products as mixture.