The European honey bee (Apis mellifera L.) is an essential crop pollinator and is frequently exposed to pesticide residues that may compromise bee health. Mechanisms underlying chemical adaptation and detoxification in honey bees remain incompletely understood, particularly those involving glutathione S-transferases (GSTs). Here, we structurally and functionally characterized omega-class GST AmGSTO1. AmGSTO1 was highly expressed in the fat bodies of nurse and forager bees. X-ray crystallography resolved the glutathione (GSH)-bound AmGSTO1 structure, revealing an active-site cysteine characteristic of omega GSTs. Enzyme assays showed greater catalytic efficiency toward the thioltransferase substrate HED than toward CDNB or PNA. Disc diffusion and bacterial survival assays demonstrated antioxidant activity against cumene hydroperoxide, hydrogen peroxide, and paraquat. Fluorescence binding assays indicated agrochemical binding, while HPLC detected no significant substrate depletion, suggesting a sequestration rather than catalytic role. Overall, AmGSTO1 may contribute to the protection against agrochemical toxicity and oxidative stress in honey bees.

Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) is an effective endoparasitoid of the woolly apple aphid, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae), a globally important pest of apple orchards. Reliable monitoring of A. mali populations is essential for evaluating its establishment and effectiveness as a biological control agent within integrated pest management systems. This 3-yr field study evaluated the efficacy of yellow, blue, and white pan traps for capturing adult A. mali in 9 commercial apple orchards in Pennsylvania, representing both conventional and reduced-risk pesticide programs. Weekly sampling was conducted from April through October, and data were analyzed using a generalized linear mixed-effects model with a negative binomial distribution to account for over-dispersed count data. A total of 526 A. mali adults were captured over the study period. Trap color had a significant effect on capture rates, with yellow traps collecting over 6 times more parasitoids than either blue or white traps, which did not differ significantly. Capture rates were not significantly affected by the pesticide management program, and no interaction between trap color and management regime was detected. Analysis of seasonal dynamics revealed significant differences in monthly capture rates, with peak activity occurring during July and August for this region. These findings demonstrate that yellow pan traps provide a simple, standardized, and cost-effective tool for monitoring A. mali populations, supporting improved decision-making and reduced reliance on chemical inputs in sustainable apple orchard management.

Apple and peach tree growers in the eastern United States face unique pest management challenges. To maintain fruit quality and yield, integrated pest management (IPM) strategies can address weather-related and invasive species pests. However, adoption of IPM has been inconsistent among eastern US tree fruit growers, with many using both chemical and biological approaches. The purpose of this study was to identify evolving pest problems among eastern US tree fruit growers, document the IPM strategies the growers are currently using, and develop a communication plan for introducing new or improved IPM strategies to encourage adoption. Using a qualitative research design, 7 focus groups were conducted with 82 growers across the eastern United States. Results indicated that the participants had numerous pest challenges, which were dependent on their location and the fruit they grow. Participants reported challenges with insecticide resistance, cross-regional pest pressure, and difficulty managing both native and invasive species. They felt that these challenges threaten production and economic viability and make integration of IPM tactics challenging. Moreover, research on existing tactics such as alternative management strategies, mating disruption, monitoring traps, and entomopathogenic fungi is needed. Dissemination of research findings should be through diverse communication channels, including e-mail newsletters, YouTube videos, blogs, podcasts, and at conferences. Participants felt that future IPM research should prioritize refining and validating pest management models that are more accurate and adaptable across orchard systems. Recommendations include increased collaboration among researchers, extension specialists, crop consultants, and growers in the eastern United States to address adoption of effective IPM practices.

Wild bees are crucial crop pollinators, but our ability to manage this ecosystem service is limited by lack of attention to which wild bee species are key pollinators of which crops. Flower visitation to a given crop is typically dominated by just a few bee species, and this information could be used to develop targeted, crop-specific management. To identify the dominant wild bees visiting crops in northeastern North America, we compiled 29 datasets of wild bee visits to crop flowers. We summarized the identities and traits of dominant wild bees in each dataset and evaluated how the taxonomic and functional composition of wild bee visitors shifted with the season in which a crop bloomed. Of 265 wild bee species observed on crops, we identified 52 dominant species, defined as species providing ≥5% of visits to at least one crop. On average across datasets, dominant visitors comprised only 16% of the observed bee species yet performed 71% of crop visitation. Critically, the dominant bee species differed between crop species, and much of the variation in dominant species identities and functional traits was explained by phenology. In our study region, wild bee crop visitation broadly shifted from a spring suite of solitary, soil-nesting species with short flight seasons, to a summer suite of social species with long flight seasons. Thus, targeted pollinator management strategies should differ between spring- and summer-blooming crops to meet the resource needs of these distinct sets of species, with particular attention to conserving and restoring habitats that provide floral resources throughout the flight seasons of the dominant visitors. While our particular findings are specific to our study region, phenological turnover of wild bee communities is a general phenomenon that is likely to be useful for informing targeted pollinator management in other regions as well.

Agricultural pesticides have historically been a critical tool in controlling pests and diseases, preventing widespread suffering and crop losses that led to catastrophes such as the Great Irish Famine (1845-1852) and the Cotton Boll Weevil Infestation (1915-1916). However, their usage has brought challenges, including resistance development, secondary pest outbreaks, harm to non-target organisms like pollinators, and environmental contamination. In response to these concerns, integrated pest management (IPM) has emerged as a comprehensive approach, emphasizing non-chemical pest control methods such as cultural practices, biological control, and crop rotation, with pesticides as the last resort. IPM has evolved, influenced by regulations like the Food Quality Protection Act (FQPA), which prioritizes human health protection, especially for children. The development of systemic pesticides, particularly neonicotinoids, introduced a more efficient and targeted pest control method within the IPM framework. However, they have also raised concerns due to their potential adverse effects on pollinators. In recent years, integrated pest and pollinator management (IPPM) has emerged as an enhanced approach, integrating pollinator health considerations into pest management strategies. In this article, we discuss this new approach, and briefly present an example of a modifying pesticide program in Pennsylvania apple orchards to illustrate the application of IPPM, in order to highlight the importance of IPPM in sustaining agriculture, protecting vital pollinators, and maintaining effective pest control practices. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Solitary bees are often exposed to various pesticides applied for pest control on farmland while providing pollination services to food crops. Increasing evidence suggests that sublethal toxicity of agricultural pesticides affects solitary bees differently than the social bees used to determine regulatory thresholds, such as honey bees and bumblebees. Studies on solitary bees are challenging because of the difficulties in obtaining large numbers of eggs or young larvae for bioassays. Here we show the toxic and sublethal developmental effects of four widely used plant systemic pesticides on the Japanese orchard bee (Osmia cornifrons). Pollen food stores of this solitary bee were treated with different concentrations of three insecticides (acetamiprid, flonicamid, and sulfoxaflor) and a fungicide (dodine). Eggs were transplanted to the treated pollen and larvae were allowed to feed on the pollen stores after egg hatch. The effects of chronic ingestion of contaminated pollen were measured until adult eclosion. This year-long study revealed that chronic exposure to all tested pesticides delayed larval development and lowered larval and adult body weights. Additionally, exposure to the systemic fungicide resulted in abnormal larval defecation and increased mortality at the pupal stage, indicating potential risk to bees from fungicide exposure. These findings demonstrate potential threats to solitary bees from systemic insecticides and fungicides and will help in making policy decisions to mitigate these effects.

In recent years, there has been an increase in the adventive establishment and spread of parasitoid wasps outside of their native range. However, lack of taxonomic tools can hinder the efficient screening of field-collected samples to document the establishment and range expansion of parasitoids on continent-wide geographic scales. Here we report that Leptopilina japonica (Hymenoptera, Figitidae), a parasitoid of the globally invasive fruit pest Drosophila suzukii (Diptera, Drosophilidae), is now widespread in much of North America despite not having been intentionally introduced. Surveys in 2022 using a variety of methods detected L. japonica in 10 of 11 surveyed USA States and one Canadian Province where it was not previously known to occur. In most surveys, L. japonica was the most common species of D. suzukii parasitoid found. The surveys also resulted in the detection of Ganaspis cf. brasiliensis (Hymenoptera, Figitidae), the recently-released biological control agent of D. suzukii, in six USA States where it had not previously been found. These new detections are likely a result of intentional biological control introductions rather than spread of adventive populations. A species-specific multiplex PCR assay was developed as a rapid, accurate and cost-effective method to distinguish L. japonica, G. cf. brasiliensis, the closely-related cosmopolitan parasitoid Leptopilina heterotoma (Hymenoptera, Figitidae) and other native parasitoid species. This dataset and the associated molecular tools will facilitate future studies of the spread and ecological impacts of these introduced parasitoids on multiple continents.

Fungicides are frequently used during tree fruit bloom and can threaten insect pollinators. However, little is known about how non-honey bee pollinators such as the solitary bee, Osmia cornifrons, respond to contact and systemic fungicides commonly used in apple production during bloom. This knowledge gap limits regulatory decisions that determine safe concentrations and timing for fungicide spraying. We evaluated the effects of two contact fungicides (captan and mancozeb) and four translaminar/plant systemic fungicides (cyprodinil, myclobutanil, penthiopyrad, and trifloxystrobin) on larval weight gain, survival, sex ratio, and bacterial diversity. This assessment was carried out using chronic oral ingestion bioassays where pollen provisions were treated with three doses based on the currently recommended field use dose (1X), half dose (0.5X), and low dose (0.1X). Mancozeb and penthiopyrad significantly reduced larval weight and survival at all doses. We then sequenced the 16S gene to characterize the larvae bacteriome of mancozeb, the fungicide that caused the highest mortality. We found that larvae fed on mancozeb-treated pollen carried significantly lower bacterial diversity and abundance. Our laboratory results suggest that some of these fungicides can be particularly harmful to the health of O. cornifrons when sprayed during bloom. This information is relevant for future management decisions about the sustainable use of fruit tree crop protection products and informing regulatory processes that aim to protect pollinators.

Bee monitoring, or widespread efforts to document bee community biodiversity, can involve data collection using lethal (specimen collections) or nonlethal methods (observations, photographs). Additionally, data can be collected by professional scientists or by volunteer participants from the general public. Collection-based methods presumably produce more reliable data with fewer biases against certain taxa, while photography-based approaches, such as data collected from public natural history platforms like iNaturalist, can involve more people and cover a broader geographic area. Few efforts have been made to quantify the pros and cons of these different approaches. We established a community science monitoring program to assess bee biodiversity across the state of Pennsylvania (USA) using specimen collections with nets, blue vane traps, and bowl traps. We recruited 26 participants, mostly Master Gardeners, from across the state to sample bees after receiving extensive training on bee monitoring topics and methods. The specimens they collected were identified to species, stored in museum collections, and the data added to public databases. Then, we compared the results from our collections to research-grade observations from iNaturalist during the same time period (2021 and 2022). At state and county levels we found collections data documented over twice as much biodiversity and novel baseline natural history data (state and county records) than data from iNaturalist. iNaturalist data showed strong biases towards large-bodied and nonnative species. This study demonstrates the value of highly trained community scientists for collections-based research that aims to document patterns of bee biodiversity over space and time.

Bees are important pollinators and are essential for the reproduction of many plants in natural and agricultural ecosystems. However, bees can have adverse ecological effects when introduced to areas outside of their native geographic ranges. Dozens of non-native bee species are currently found in North America and have raised concerns about their potential role in the decline of native bee populations. Osmia taurus Smith (Hymenoptera: Megachilidae) is a mason bee native to eastern Asia that was first reported in the United States in 2002. Since then, this species has rapidly expanded throughout the eastern part of North America. Here, we present a comprehensive review of the natural history of O. taurus, document its recent history of spread through the United States and Canada, and discuss the evidence suggesting its potential for invasiveness. In addition, we compare the biology and history of colonization of O. taurus to O. cornifrons (Radoszkowski), another non-native mason bee species now widespread in North America. We highlight gaps of knowledge and future research directions to better characterize the role of O. taurus in the decline of native Osmia spp. Panzer and the facilitation of invasive plant-pollinator mutualisms.

Abstract Characterizing the nutritional needs of wild bee species is an essential step to better understanding bee biology and providing suitable supplemental forage for at‐risk species. Here, we aim to characterize the nutritional needs of a model solitary bee species, Osmia cornifrons (Radoszkowski), by using dietary protein‐to‐lipid ratio (P:L ratio) as a proxy for nutritional niche and niche breadth. We first identified the mean target P:L ratio (~3.02:1) and P:L collection range (0.75–6.26:1) from pollen provisions collected across a variety of sites and time points. We then investigated the P:L tolerance range of larvae by rearing bees in vitro on a variety of diets. Multifloral and single‐source pollen diets with P:L ratios within the range of surveyed provisions did not always support larval development, indicating that other dietary components such as plant secondary compounds and micronutrients must also be considered in bee nutritional experiments. Finally, we used pollen metabarcoding to identify pollen from whole larval provisions to understand how much pollen bees used from plants outside of their host plant families to meet their nutritional needs, as well as pollen from individual forager bouts, to observe if bees maintained strict floral constancy or visited multiple plant genera per foraging bout. Whole larval provision surveys revealed a surprising range of host plant pollen use, ranging from ~5% to 70% of host plant pollen per provision. Samples from individual foraging trips contained pollen from multiple genera, suggesting that bees are using some form of foraging decision making. Overall, these results suggest that O. cornifrons have a wide nutritional niche breadth, but while pollen P:L ratio tolerance is broad, a tolerable P:L ratio alone is not enough to create a quality diet for O. cornifrons, and the plant species that make up these diets must also be carefully considered.

The alarming decline of pollinator populations has raised significant concerns worldwide and prompted the need for effective pesticide risk assessment within the Integrated Pest and Pollinator Management (IPPM) framework. This paper examines the diverse approaches to pollinator protection within the pesticide regulatory environments of the United States (US), the European Union (EU), and selected Asian countries. The US adopts a reactive approach, regulating pesticides only after evidence of harm emerges, while the EU embraces a proactive stance under the precautionary principle. The EU has implemented stringent regulations, including neonicotinoid bans, and conducts coordinated research on pesticide impacts. In contrast, some Asian countries face challenges with inadequate regulations, leading to adverse health and environmental consequences. This article highlights the need for comprehensive pesticide regulations across different regions to safeguard pollinators and mitigate the non-target risks associated with pesticide use.

The European honey bee, Apis mellifera , serves as the principle managed pollinator species globally. In recent decades, honey bee populations have been facing serious health threats from combined biotic and abiotic stressors, including diseases, limited nutrition, and agrochemical exposure. Understanding the molecular mechanisms underlying xenobiotic adaptation of A. mellifera is critical, considering its extensive exposure to phytochemicals and agrochemicals present in flowers, propolis, hives, and the environment. In this study, we conducted a comprehensive structural and functional characterization of AmGSTD1, a delta class glutathione S-transferase (GST) enzyme, to unravel its roles in agrochemical detoxification and antioxidative stress responses. Significantly, we determined the 3D structure of a honey bee GST using protein crystallography for the first time, providing new insights into its molecular structure. Our investigations revealed that AmGSTD1 efficiently metabolizes model substrates, including 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrophenyl acetate (PNA), phenylethyl isothiocyanate (PEITC), propyl isothiocyanate (PITC), and the oxidation byproduct 4-hydroxynonenal (4-HNE). Moreover, we discovered that AmGSTD1 exhibits binding affinity with the fluorophore 8-Anilinonaphthalene-1-sulfonic acid (ANS), which can be inhibited with various herbicides, fungicides, insecticides, and their metabolites. These findings highlight the potential contribution of AmGSTD1 in safeguarding honey bee health against various agrochemicals and their metabolites, while also mitigating oxidative stress resulting from exposure to these substances.

To manage spotted lanternfly (Lycorma delicatula (White)), an invasive planthopper recently introduced to the United States, governmental agencies, homeowners, and landscape professionals may treat its host plants with systemic neonicotinoid insecticides. Neonicotinoids can be harmful to non-target insect floral visitors collecting pollen or nectar. The insect floral visitors of red maple (Acer rubrum L.) or tree-of-heaven (Ailanthus altissima (Mill.), which are two of the preferred hosts of L. delicatula in Pennsylvania, are often targeted with neonicotinoid applications for control of this pest. To identify the floral visitors of these tree species, we conducted observations and collections of insects foraging on the flowers of these trees in Pennsylvania during the annual bloom period. In southeastern Pennsylvania, the margined leatherwing beetle (Chauliognathus marginatus (F.)). was the most dominant visitor of tree-of-heaven flowers, followed in abundance by bees, particularly Lasioglossum and Bombus spp., and flies. In central and southeastern Pennsylvania, bees were the most dominant group to visit red maple flowers, particularly Apis mellifera (L.), Andrena spp. and Osmia spp., followed by flies. These results contribute to our knowledge of the pool of bioindicator insects that may be at risk from exposure to neonicotinoid residues in flowers of trees treated for L. delicatula management.

Neonicotinoid insecticides are used to manage spotted lanternfly (Lycorma delicatula (White); hereafter SLF), a recently introduced pest in the United States. Neonicotinoids can harm nontargets, such as pollinators potentially exposed via floral resources of treated plants. We quantified neonicotinoid residues in whole flowers of two SLF host plant species, red maple (Acer rubrum L. [Sapindales: Sapindaceae]) and tree-of-heaven (Ailanthus altissima (Mill.) [Sapindales: Simaroubaceae]), treated with post-bloom imidacloprid or dinotefuran applications that differed in timing and method of application. In red maple flowers, dinotefuran residues from fall applications were significantly higher than summer applications, while imidacloprid residues from fall applications were significantly lower than summer applications. Residues did not differ between application methods or sites. In tree-of-heaven flowers, dinotefuran residues were only detected in one of 28 samples at a very low concentration. To assess acute mortality risk to bees from oral exposure to residues in these flowers, we calculated risk quotients (RQ) using mean and 95% prediction interval residue concentrations from treatments in this study and lethal concentrations obtained from acute oral bioassays for Apis mellifera (L. (Hymenoptera: Apidae)) and Osmia cornifrons (Radoszkowski (Hymenoptera: Megachilidae)), then compared these RQs to a level of concern. For A. mellifera, only one treatment group, applied at 2X maximum label rate, had an RQ that exceeded this level. However, several RQs for O. cornifrons exceeded the level of concern, suggesting potential acute risk to solitary bees. Further studies are recommended for more comprehensive risk assessments to nontargets from neonicotinoid use for SLF management.

Management to control the spotted lanternfly, Lycorma delicatula (White), would ideally achieve managers' goals while limiting impacts on nontarget organisms. In a large-scale field study with 45 plots at least 711 m2, we tested foliar applications of dinotefuran and 2 formulations of Beauveria bassiana (Balsamo) Vuillemin, each applied from the ground and separately by helicopter. Applications targeted early instar nymphs. For both application methods, a single treatment with dinotefuran significantly reduced L. delicatula numbers, as measured by catch on sticky bands (91% reduction by air and 84% reduction by ground 19 days after application) and by timed counts (89% reduction by air and 72% reduction by ground 17 days after application). None of the B. bassiana treatments significantly reduced L. delicatula numbers, even after 3 applications. Beauveria bassiana infection in field-collected nymphs ranged from 0.4% to 39.7%, with higher mortality and infection among nymphs collected from ground application plots. Beauveria bassiana conidia did not persist for long on foliage which probably contributed to low population reduction. Nontarget effects were not observed among arthropods captured in blue vane flight intercept traps, San Jose Scale pheromone sticky traps or pitfall traps, but power analysis revealed that small reductions of less than 40% may not be detected despite extensive sampling of 48,804 specimens. These results demonstrate that dinotefuran can markedly reduce local abundance of L. delicatula with little apparent effect on nontarget insects when applied shortly after hatch, and that aerial applications can match or exceed the effectiveness of applications from the ground.

Different species of bees provide essential ecosystem services by pollinating various agricultural crops, including tree fruits. Many fruits and nuts depend on insect pollination, primarily by wild and managed bees. In different geographical regions where orchard crops are grown, fruit growers rely on wild bees in the farmscape and use orchard bees as alternative pollinators. Orchard crops such as apples, pears, plums, apricots, etc., are mass-flowering crops and attract many different bee species during their bloom period. Many bee species found in orchards emerge from overwintering as the fruit trees start flowering in spring, and the active duration of these bees aligns very closely with the blooming time of fruit trees. In addition, most of the bees in orchards are short-range foragers and tend to stay close to the fruit crops. However, the importance of orchard bee communities is not well understood, and many challenges in maintaining their populations remain. This comprehensive review paper summarizes the different types of bees commonly found in tree fruit orchards in the fruit-growing regions of the United States, their bio-ecology, and genetic diversity. Additionally, recommendations for the management of orchard bees, different strategies for protecting them from multiple stressors, and providing suitable on-farm nesting and floral resource habitats for propagation and conservation are discussed.

Panonychus ulmi (Koch) (Acari: Tetranychidae), commonly known as European red mite, is a polyphagous pest of various tree and small fruit crops, including apples. A field study was conducted to evaluate different pesticide options available for the management of P. ulmi, and their impact on the population of non-target predatory mite species complex consisting of Neoseiulus fallacis, Typhlodromus pyri, and Zetzellia mali in apple orchards. Pesticides were applied using a commercial airblast sprayer at the 3–5 mite/leaf recommended economic Integrated Pest Management (IPM) threshold or prophylactically in the spring ignoring IPM practices such as monitoring, reliance on biological control and economic thresholds. Effects on the motile and egg stages of P. ulmi were evaluated as were effects on the populations of predatory mites through frequent leaf counts during the season. We also recorded the subsequent overwintering eggs of P. ulmi from each pesticide treatment. The two prophylactic treatments containing a mixture of zeta-cypermethrin + avermectin B1 + 1% horticultural oil and abamectin + 1% horticultural oil provided effective control of P. ulmi population throughout the season without reducing predatory mite populations. In contrast, eight treatments applied at the recommended economic threshold of 3–5 mites/leaf were not effective in suppressing P. ulmi populations and most reduced predatory mites. Etoxazole had significantly higher number of overwintering P. ulmi eggs compared to all other treatments.