Using safe materials to control Varroa mites with studying grooming behavior of honey bees and morphology of Varroa over winter

Extracts of drone larvae and propolis as safe materials are anticipated to boost the grooming behavior of honey bees against Varroa mites. It is also expected that grooming behavior of bees and morphology of Varroa are stable during the least active period of the year to bee colonies (i.e winter). Sugar syrup alone or mixed with drone larvae extract or propolis extract were examined as potential Varroa control materials to test these hypothesizes. Moreover, percentages of groomed mites along with body lengths and widths of Varroa were studied on weekly basis during winter. The results showed that propolis extract was able to increase the number of fallen mites under field conditions but with lethal impacts on bee workers in the laboratory than extract of drone larvae or sugar syrup. All the treatments were not able to boost the grooming behavior of bees. The results proved that grooming behavior was stable during winter. Therefore, it is better to select colonies with grooming potential against Varroa during winter in selection programs. December was significantly the minimal month in percentage of groomed mites based on the overall means. Means of measured characteristics of Varroa declined significantly over the study period. For beekeepers, using sugar syrup as spray on bees during regularly colony inspection can help managing Varroa populations without harming the bees.