The link between popular pesticides and declining bee populations has been the subject of controversy and the target of research for some time; but the soaring use of fungicides hasn’t received much attention as they were accepted to be harmless to the pollinators—until now. Two recent studies found fungicides to be the potential cause for deteriorating health in bumblebee and wild bee populations.
Researchers in one study focused on bumblebees and revealed some startling evidence: bumblebees who visited fungicide-laden blossoms had smaller workers, feeble queens, and overall reduced colony size. In the second study, areas predominantly devoted to agriculture saw an overall reduction in wild bee populations, partly due to widespread fungicide use. Though neither study revealed incontrovertible proof, both found enough correlation between the popular chemicals and worsening bee health to warrant concern.
University of Wisconsin entomologist Hannah Gaines-Day and her team of researchers were asked by local farmers if fungicides were safe to use while crops were in bloom and bees were actively foraging. “It’s a group of pesticides that hasn’t been looked at too closely. Insecticides are meant to kill insects, so people have been really interested in how insecticides kill beneficial insects. But fungicides are not meant to kill insects, so they’ve been passed over,” she explained. Though spraying insect-killing pesticides may be intuitively harmful to bees, the application of fungicides to blossom-heavy crops is common practice.
Previous studies had found fungicides to be safe but had been limited to honeybees; and, even then, only investigated more drastic effects—such as dropping dead within days. Other important species of wild bees and bumblebees as well as critical, lasting effects—like the impact of fungicides on behavior, immunity, and reproduction on long-term health—had not been examined until now.