Induced brood breaks by refrigerated bee storage in spring: an effective strategy for Varroa destructor (Mesostigmata: Varroidae) control in honey bee colonies.

During winter months, a significant portion of commercial honey bee (Apis mellifera L.) colonies are stored indoors to overwinter in climate-controlled conditions. However, refrigerated bee storage facilities could be a useful tool at other times of the year in an integrated pest management approach to control the infamous Varroa destructor Anderson and Trueman. Here, we investigated the efficacy of using refrigerated bee storage in the spring to temporarily disrupt honey bee brood production, followed by treating colonies with miticides that perform best in times of low brood production. Immediately following commercial spring pollination in California almonds, colonies were moved to refrigerated bee storage or an apiary as a control. After 18 d, colonies in refrigerated bee storage were relocated to the apiary, and all colonies were treated with a miticide. Bee samples, frames of bees, and hive weights were recorded at the time of miticide application and 37 d later. While there were no statistically significant differences in hive weight or number of frames of bees, colonies that experienced an induced brood break had significantly lower Varroa loads (mites per 100 bees) than colonies that did not experience a brood break. This study demonstrates a viable large-scale method to increase the efficacy of and decrease the need for reapplication of miticides for Varroa control.