Sugar dusting represents a cheap and chemical-free technique for managing Varroa mite populations in honeybee colonies. As its name implies, this method involves applying powdered sugar to the hive, which helps reduce mite numbers through three potential mechanisms:

• Physical dislodgment of mites from bees
• Increased grooming behaviour by bees which removes attached mites
• Possible direct stress on the mites.

Previous research has shown sugar dusting can reduce phoretic mite populations (mites attached to adult bees) by up to 80% in controlled trials. However, long-term control strategies using this method have not been created.

We are currently trialing sugar dusting effectiveness at both individual and colony levels. In our laboratory experiments, individual worker bees are placed in Petri dishes and dusted with a small amount of powdered sugar (0.02g), enough to cover the whole bee. We then measure the frequency, efficiency and duration of grooming events to remove mites compared to non-dusted bees. We then examine dislodged mites in a microscope to look for physical damage that might impair their ability to reproduce or reinfest other bees.

Using these insights, we plan to develop and test efficient sugar dusting protocols for commercial and hobbyist apiaries. Our planned research will determine whether individual-level mechanisms translate to colony-level effects and identify the most efficient application methods. We are particularly interested in understanding if the mechanisms observed at the individual bee level are similar to those within the hive.

While sugar dusting shows promise, its current application can be labour-intensive and time-consuming for beekeepers. A goal of ours is to create practical solutions that help beekeepers protect their colonies from Varroa mite infestations without excessive time or resource investments.