Neonicotinoid impacts on pollinators in apple orchards

Neonicotinoids are pesticides commonly used in integrated pest management in tree fruit production, but there is increasing suspicion of harm to pollinators. Neonicotinoid use can be continued for pest management while avoiding harm to beneficial insects if knowledge-based adjustments are made. Knowledge of pollinator exposure to toxins in nectar and pollen is key given the pesticides’ systemic properties. Adult Osmia cornifrons, an effective tree fruit pollinator, and honey bees were fed four commercial formulations of neonicotinoids and a dimethoate standard to test oral toxicity. Adult morbidity and mortality were calculated. A pesticide analysis of pollen balls collected from nesting Osmia cornifrons, was compared with orchard spray records to document larval exposure. This study illuminates the relationship between standard toxicity testing and the actual exposure that bees experience. This type of information can be used to adjust IPM recommendations to avoid harm to pollinators as well as influence regulatory policy affecting bee exposure to pesticides.