Neonicotinoid Can Harm Bees

The neonicotinoid insecticide imidacloprid has negative effects on bees and other pollinators at residue levels above 25 ppb, according to preliminary assessments released last week by EPA and Canada’s Pest Management Regulatory Agency. These effects include reducing both honey production and the numbers of pollinators. EPA’s study finds that pollen and nectar of citrus and cotton flowers can harbor residues of imidacloprid above the safety threshold. Corn and leafy vegetables, however, have residue levels below the threshold, the agency notes. The assessment is the first of four that EPA plans to release this year evaluating the risks of neonicotinoid pesticides for bees attracted to various crops. EPA expects to release assessments on three more—clothianidin, thiamethoxam, and dinotefuran—in December. EPA is working closely with California’s Department of Pesticide Regulation to complete the assessments. Once finalized, they could trigger regulatory action to restrict use of the pesticides.