Varroa mites are a major threat to honeybee health in the US. Chemical applications have proved effective at controlling varroa mite populations in honey bee colonies, however, only to a point. The mites are developing resistance to these chemicals. Collaborative study between University of Valencia and UMD Entomology Bee Lab researchers, Grad Student Krisztina Christmon & Associate Professor Dennis vanEngelsdorp, demonstrate mutations related to tau-fluvalinate resistance in Varroa destructor are widely distributed in the US. Their research reveals an urgent need for pest management strategies based on treatment resistance. Knowing the frequency of resistant mites, the authors argue, would help beekeepers choose the right treatment for their colonies.