Testing a combination of control tactics to manage varroa destructor (acari: Varroidae) population levels in honey bee (hymenoptera: Apidae) colonies

Four combinations of strategies to reduce population growth of Varroa destructor Anderson and Trueman were tested in honey bee colonies located at two apiary sites. The strategies were combinations of mite tolerant queen stock, screen inserts, and T-02® strips (AI thymol). The effectiveness of the treatment combinations differed between the apiary sites. Site 1 apiary was in a cleared forest surrounded by secondary growth, while Site 2 was on the top of a hill, exposed to the wind. At Site 2, all but one colony survived the winter, while at Site 1, over-winter mortality of colonies was lowest in those colonies that combined hygienic queens and screen inserts. Mite populations at the end of the study did not differ among treatments or between sites. However, colony populations at Site 2 were significantly larger and overall colony survival was greater than at Site 1. The study demonstrates how the effectiveness of strategies to reduce the impact of Varroa on colony survival might ultimately depend upon the location of an apiary and how this affects the growth of colony populations.