A field monitoring study to explore the European honey bee exposure to pesticide residues in orchards

Aim of study: The European honey bee (Apis mellifera L.) is threatened due to diverse pressures, including the habitat fragmentation, the pests or diseases which affect them and the misuse of plant protection products (PPPs). This work aimed to evaluate and compare the degree of exposure of A. mellifera to PPPs residues in orchards, in both conventional and organic production. Area of study: Region of Murcia (Spain). Material and methods: During a three-year period, field monitoring campaigns were organised in peach and apricot orchards under both conventional and organic managements and coinciding with the flowering period. The evaluation of exposure relied on chemical characterisation of pesticide residues using a non-targeted screening by high resolution accurate mass (HRAM) spectrometry. Main results: The findings of this study reveal that pesticide residues were detected in honey bees captured in both conventional and organic orchards. Pesticide residues tentatively identified were carbetamide, flufenacet, iprovalicarb, isoprocarb and spiromesifen. Since honey bees, particularly the forager bees, fly up to several km away from the hive to collect pollen and nectar, they may visit conventionally managed plots where crops are treated with PPPs. Research highlights: This study evinces that, in orchards, the forager bees are exposed to agrochemicals during their foraging activity on the flowers of treated fruit trees, either in contiguous or distant plots. The exposure of bees to pesticide residues in organic orchards can be due to the high persistence of some of these substances in the environment, or to the proximity of other orchards where PPPs are applied.