Lessons Learned from Four Years of Research on Amitraz Resistance in Varroa Destructor
Studies on amitraz resistance in Varroa began in 2019 after reports of reduced amitraz efficacy from beekeepers. The initial phase of this ongoing project was to assess the presence of bona fide amitraz resistance in Varroa. Since the establishment of the connection of amitraz resistance in Varroa with the failure of colony-level treatments to reduce Varroa populations, annual resistance monitoring surveys have been conducted across the US with the help of cooperating beekeepers, extension agents, state apiarists, and scientific research colleagues. Approximately 1/3 of apiaries sampled over the past 4 years across the US showed high levels of amitraz resistance that should result in treatment failure at the colony level. The frequency of resistant populations has accelerated over the course of this survey as well as anecdotal reports of amitraz resistance in Varroa. Collaboration with scientists in Spain has verified the association of a mutation in the target site for amitraz in Varroa is associated with the amitraz resistance phenotype. This study also showed that the bioassay for amitraz may be influenced by environmental conditions. Following up on these results, experiments showed that temperature is important for collecting accurate and reproducible results with the amitraz resistance bioassay due to temperature-dependent toxicity of amitraz. Other research on amitraz resistance has led to a number of operational practices that beekeepers can implement immediately to reduce the development of amitraz resistance as well as how to manage amitraz-resistant Varroa populations.
Dr. Rinkevich is a Research Entomologist at the USDA-ARS Honey Bee Breeding, Genetics, and Physiology Laboratory. A major focus of his research is on the prevalence of amitraz resistance in Varroa, factors that affect amitraz toxicity, and development of effective miticide applications for amitraz resistant Varroa. Other research interests include breeding for bees with Varroa sensitive hygiene (VSH) and understanding how genetics, geography, and environment affect the expression of VSH, and the effects of pesticides on honey bee colony performance and physiology.
Guest/Non PAID Member Fee to attend is $10.00.
Apiary (Bee Yard) Time begins 5:30-5:45 p.m.
Speaker Presentation begins 7:00 p.m.
Please remember, there is a raffle with many items to try to win.
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