D3019: Powdered sugar and heat treatments for control of Varroa destructor infesting honey bees

The parasitic varroa mite, Varroa destructor, is a global threat to honey bee (Apis mellifera) health and the leading cause of honey bee hive mortality. In the constant battle against varroa, many apiarists turn to chemicals, such as formic and oxalic acids, to control mite populations and save their hives. However, each chemical treatment option exhibits certain shortcomings and developments of new varroa mite control options is key to preventing resistance and increasing safety to beekeepers and bees. Powdered sugar is an effective technique used for monitoring varroa mite infestation levels in hives because the sampling technique dislodges mites from a sample population of bees. The use of heat has also shown promise for control of varroa mites, yet further studies are needed to identify heat as an effective treatment option. Here we show that powdered sugar on brood frames and bees is an effective method of varroa control comparable to that of the widely popular oxalic acid. Our results further compare the efficacy of powdered sugar at two application rates (280 g and 560 g per deep super) and heat to that of negative control (no treatment) and positive control (Apivar and oxalic acid) in 25 uniform hives from May to November 2021. All honey bee hives will be assessed for colony strength and overwintering survival following the treatment period. Developments in varroa mite control are vital to combatting resistance, maintaining healthy honey bee populations, and creating safe, sustainable beekeeping practices.