Mustard cover crop effects on honey bee (Apis mellifera) colony size

Honey bee colonies can experience stress and slow growth during periods of dearth during summer and fall when floral resources are scarce in Ohio agricultural landscapes, particularly those dominated by field corn and soybeans. The practice of using cover crops has become increasingly common among growers to aid in overall soil health but also has the potential to provide additional floral resource to relieve honey bee colony stress if those cover crops flower during the dearth periods. To assess this hypothesis, a mustard cover crop strip (0.166 ha) was planted in the spring and fall in a landscape dominated by corn and soybeans so that flowering would occur during these periods of scarcity to measure the impact on colony growth. Two hives were placed adjacent to the mustard cover crop (MCC) strip to evaluate if the flowering cover crop can boost colony growth and two hives were placed approximately one mile away in a similar landscape but without the MCC as the control group. Pollen and honey samples collected from the colonies were analyzed to determine what floral resources were foraged by honey bees prior to and after the peak mustard cover crop bloom. A Broodminder under-hive weight scale was installed on each colony to measure weight as a proxy for colony growth. Colonies were inspected to evaluate colony health, brood production, and food stored before and after cover crop blooms. Observations of the mustard crop areas during flowering were also taken to measure honey bee abundance in that area.