(2nd Place) Pesticide risk to honey bees and native bees across four crops in Oregon: Can the honey bee accurately represent the risk to all?

Food and seed production relies on the pollinating force of European honey bee, Apis mellifera L., colonies to facilitate fruit and seed set in a diverse range of crops. Yet, colonies in agricultural environments may stray from the crop and forage on wild plants and other nearby food sources. This leads to a complex pesticide risk profile that includes the products applied to the crop and the potential for honey bees to be exposed to chemicals applied to other attractive plants within their foraging radius.

When pollen a diverse pollen sample is tested for pesticides, it is difficult to ascertain where the chemicals originated in the landscape. Pollen samples collected from honey bee colonies are a composite of plant species. Therefore, while a test of the composite sample provides a wholistic view of the honey bee’s pesticide exposure over a given period, it does not allow scientists and land managers to identify high-risk areas of the landscape.

In this study, we investigate pesticide hazard to honey bees and native bees sweet cherry production of Oregon. Twelve fields were monitored for pesticides via pollen trapping and pollen identification through acetolysis. Pollen samples, collected at early and peak bloom, were sorted into colors and analyzed for over 250 pesticide residues as both individual colors and composite samples. Pesticide residues were then sorted into those found on crop (cherry) pollen, understory weeds, and surrounding native vegetation. This allows the formation and comparison of distinct pesticide hazard profiles throughout the growing season.