D3111: The potential for indoor storage to improve control of Varroa mites in honey bee colonies

It has become increasingly common for beekeepers to overwinter their hives inside cold storage facilities. However, indoor storage may also be a useful tool at other times of the year. Here we tested the use of spring indoor storage as a method of forcing a break in brood production to improve control of Varroa destructor. Immediately following almond pollination, 72 colonies were placed in a cold storage facility and 39 hives were left outside. After 18 days, the colonies were removed from cold storage and transferred to another outdoor location near the 39 colonies. At that time the stored colonies had an average of 4.78 mites per 100 bees. At the same time, the colonies left outdoors had significantly lower infestations at 2.98 mites per 100 bees. All colonies were treated for varroa mites at that time. Approximately 1 month later, the opposite was true. The colonies previously placed in cold storage had an average of 1.83 mites per 100 bees, significantly fewer than the 3.85 mites per 100 bees found in the colonies that were not placed in storage. The colonies placed in cold storage started out with 1 frame of bees less than the outdoor colonies on average, but by the end of the study there was no longer a significant difference between groups. These results demonstrate the strong potential of spring cold storage of honey bee colonies as a valuable tool in the fight against varroa mites.