Submitted to: American Bee Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Interpretive Summary: Beekeepers in the United States have used a single compound, fluvalinate, to control the mite parasite Varroa within honey bee colonies for over ten years. The constant use of one compound has lead to resistance to fluvalinate being detected in the Varroa mites in the U.S. in the fall of of 1997. Thus, U.S. beekeepers need a simple screening device to decide if fluvalinate will work to control Varoa in their colonies. We report the the development of a field assay that is easy to use and will detect fluvalinate-resistant Varroa. The field assay allows the beekeeper to determine if fluvalinate will work in advance of treating the colonies thus saving both time and money on treatments that may be ineffective.
An assay was developed to screen the parasitic honey bee mite Varroa jacobsoni for resistance to fluvalinate (Apistan(r). The assay is based on a comparison in mite mortality between 2.5% and 10% fluvalinate using paired samples of live adult honey bees from the same colony. Two samples of live bees with mites were collected per colony and bees were held in jars for 24 hours at 75-95F. After 24 hours, mite fall was recorded, number of mites remaining on bees was determined and a percent mortality calculated for each concentration. Results revealed that when mites were susceptible to fluvalinate (controlled with Apistan(r) in 3-4 weeks) they had nearly equal mite fall and percent mortality was above 85% for both concentrations. However, mites deemed resistant (from colonies where Apistan did not provide control) exhibited large concentration-dependant differences in mite fall, with percent mortality less than 30% and 50 % for the 2.5 and 10% concentrations respectively. The assay was designed to enable beekeepers to assess Varroa populations for resistance to fluvalinate and is useful in predicting anticipated control.