Detection of resistance in US Varroa jacobsoni oud. (Mesostigmata: Varroidae) to the acaricide fluvalinate

Abstract

Populations of Varroa jacobsoni Oud. from three geographic regions of the United States were assayed for resistance to fluvalinate. A bioassay using a discriminating concentration estimated to cause approximately 80-90% mortality in a fluvalinate-susceptible strain of V. jacobsoni was used to compare percent mortalities between locations. An average of 73.3 % mortality was seen in two additional operations in Texas, not significantly less than the susceptible strain. An average of 23.7 % mortality was found for mites tested in Florida that had originated from field control failures; Florida test mortality was significantly less than that of the susceptible strain. An average of 65.1% mortality was found for mites tested in California, also significantly less than mortality of susceptible mites. However, no field control failures were reported for the mites tested in California.