We are studying Varroa destructor as an immunosuppressant and viral vector in honey bees, by examining the changes in prevalence of viral infections during a field season. We investigated the impact of three spring mite control treatments – coumaphos, formic acid pads, West Virginia fume board – for effects on the endemic honey bee viruses (Deformed Wing Virus (DWV) and Black Queen Cell Virus (BQCV).  The viral prevalence rates in colonies varied over the season in response to the mite treatments, with each virus having a significantly different response.  Some treatments caused amplification of viruses, suggesting that sub-lethal toxin exposure can exacerbate viral infections.