An obligate ectoparasitic mite, Varroa destructor, is the most important problem facing beekeepers, having surpassed American Foulbrood as the leading cause of honey bee colony collapse by 1996. We are studying the emerging problem of V. destructor as an immunosuppressant and vector of honey bee viruses. The 18 or more endemic viral pathogens of the honey bee, Apis mellifera, usually were not highly virulent but V. destructor changed this situation. The introduction of V. destructor into European honey bee from the Asian honey bee, Apis cerana, has provided a vector for some of the endemic viruses of our honey bee. Various mite control tactics have never been investigated as to their effect on viral prevalence. We investigated the impact of four spring and fall mite control treatments – coumaphos, formic acid pads, flash formic and water – on viral type and quantity.