Using powdered sugar to remove varroa mites from honey bees

The parasitic varroa mite, Varroa destructor, is a global threat to honey bee health and the leading cause
of honey bee (Apis mellifera) colony mortality. In the constant
battle against varroa, many apiarists turn to chemicals, such as formic
acid, oxalic acid, or synthetic compounds, to control mite populations
and save their colonies. However, each chemical treatment option
exhibits certain shortcomings and the development of new varroa mite
controls is key to combating varroa resistance and increasing safety to
beekeepers and bees. The objectives of this study were to a) assess the
effectiveness of powdered sugar as a means of varroa mite control, in
comparison to currently used chemical controls, and b) establish methods
of largescale live varroa mite collection for the use in laboratory
trials. In experiments using bees on single brood frames, powdered sugar
and oxalic acid were similarly effective in controlling phoretic varroa
(measured as mite drop after treatment). There was also no statistically
significant difference in effectiveness between powdered sugar
application methods (sifting or reverse vacuum). At the colony level,
powdered sugar treatments exhibited no significant differences in mite
infestations from control hives following the treatment period. While
powdered sugar did not show the ability to control varroa at the colony
level in this study, it could be incorporated into an IPM strategy and
used when the colony is broodless. Furthermore, sifting powdered sugar
over a brood box provides researchers with a technique to collect
hundreds of varroa mites to use in other control assays.