Neonicotinoid impact on honey bees (Apis mellifera) in cantaloupe production

Apis mellifera (honey bees) provide pollination services to many agricultural crops, including cucurbits. The presence of neonicotinoid residues in the pollen and nectar of flowers threatens honey bee health. Neonicotinoid insecticides are generally safer, more selective, and often more effective for managing pests than other classes of insecticides. Many neonicotinoids are, however, highly toxic to honey bees. Neonicotinoid use may be one contributing factor to the alarming decline of honey bee populations occurring worldwide. This study aims to determine the impact that neonicotinoids have on honey bees in cantaloupe production, with two major objectives. First, we determined the residue concentrations of several recommended neonicotinoids in cantaloupe pollen. The delivery methods for the neonicotinoids included bedding tray applications, transplant soil drenches, foliar sprays, and seed treatments. Secondly, we coupled the field residue concentrations with known honey bee toxicological sensitivity to determine the health risk associated with such neonicotinoids and delivery methods. The neonicotinoids evaluated were imidacloprid, thiamethoxam, and acetamiprid and their corresponding metabolites imidacloprid olefin, 5-hydroxyimidacloprid, and clothianidin. The results enabled us to modify our neonicotinoid product and application method recommendations to growers to maximize insecticide efficacy while minimizing honey bee health risks.