Honeybees are exposed to an astonishing range of chemical pesticides, not just the neonicotinoids often tabbed as the cause of population declines, says a Purdue study. The research suggests honeybees in the Corn Belt are exposed to considerably higher overall level of pesticide exposure than previously thought.
In the study, Purdue scientists collected pollen from honeybee hives at three sites in Indiana for 16 weeks from May through September. The overwhelming majority of their pollen from uncultivated plants, particularly the plant family that includes clover and alfalfa. Some 30 plant families were represented in the samples, which contained residues from nine classes of pesticides, including so-called neonics. The highest concentrations were from pyrethroid insecticides, used against mosquitoes and other pests.
“Homeowners and urban landscapes are big contributors, even when hives are directly adjacent to crop fields,” said entomology professor Christian Krupke. While neonics and pyrethroids were the most common insecticides found in the pollen, the most common chemicals were fungicides and weedkillers, said Purdue.