Soil Levels of Neonicotinoid Found Lethal to Ground-Nesting Bees

Researchers at the University of Guelph, in Canada, found that high numbers of ground-nesting bees are exposed to lethal doses of the neonicotinoid pesticide clothianidin in the soil of crop fields. Previous research has focused largely on the effect of neonicotinoids on honey bees, which do not nest in the ground. However, bee species that spend most of their lives in the soil are at particular risk from the 80% of neonicotinoid seed treatments that are not taken up by the plant but remain as residue in the soil. This study found that in commercial squash fields, 36% of the squash bee population is probably encountering lethal doses of clothianidin. Among bees near corn and soybean fields, 58% of ground-nesting bees would be exposed to a lethal dose of clothianidin while building their nests.