Pesticide residues in corn: Impacts on non-target plants and pollinator interactions

The intensified use of pesticides in modern agriculture, while effective in protecting crops, poses significant ecological risks, particularly for non-target plants and pollinators. This study examines the off-target pesticide movement and residue accumulation, specifically for neonicotinoid, anthranilic diamide insecticides, and fungicides, from treated corn (Zea mays) to adjacent wild mustard (Rhamphospermum arvense) plants and evaluates the potential risk to pollinators. To assess this, we conducted in a controlled greenhouse at Cornell University, experiments involving planting field corn seeds pretreated with one of four treatments: 1) neonicotinoids combined with fungicides (Thiamethoxam, Fludioxonil, Mefenoxam), 2) fungicides only (Azoxystrobin, Fludioxonil, Mefenoxam, Thiabendazole, Sedaxane, Picorbutrazox), 3) anthranilic diamides only (Cyantraniliprole), and an untreated control, which had no pesticide seed treatment. In each six-inch planting pot we planted one corn seed alongside one R. arvense seed filled with an equal ratio of Lambert 111 potting substrate and field soil. We quantified pesticide residue levels in flower and pollen tissues using LC-MS to assess pesticide transfer between plants.
Preliminary findings reveal the presence of pesticide residues in mustard plant tissues, though concentrations remain below the limit of quantification (LOQ). These results suggest that off-target pesticide movement occurs between treated corn and neighboring plants, potentially exposing pollinators and other non-target organisms to low residue levels and sublethal doses. Further studies on the influence of these residue levels on pollinator behavior and development will help us to quantify the magnitude of the risk to pollinators and the ecosystem services they provide.