Article posted Thursday, August 27, 2015 2:35pm

When it comes to assessing the impact of their products on living things, do you believe scientists or the insecticide/herbicide industry? For example, are insecticides containing neonicotinoid chemicals really killing bees of all kinds? A number of lab studies say “yes,” but makers of the insecticides claim that lab studies do not represent what happens under field conditions. Recently scientists took their research from the lab to the field to study bees feeding on rapeseed flowers. Many farmers plant seeds coated with an insecticide or herbicide to ensure a relatively pest-free crop. The roots of such plants transfer the chemical to flowers and foliage. In field studies, scientists compared assays of bees feeding on the flowers of rapeseeds coated with the pesticide neonicotinoid to assays of bees in distant fields feeding on rapeseed flowers from untreated (uncoated) rapeseeds. They found that bee density diminished in fields grown from treated seeds and that nesting ability was impaired. In fields grown from untreated seeds, bees remained healthy. In general, the findings agree with other studies showing that bees ingesting neonicotinoids undergo changes in behavior and foraging ability, probably associated with the pesticide’s effect on the insects’ nervous system. (Science, 2006, Vol. 313, p. 351; Nature, Kessler et al, 2015, Vol. 521, p. 74; Nature, Rundlof et al, 2015, Vol. 521, p. 77)