Effect of amitraz treatments on honey bees and on the honey bee tracheal mite

Abstract - Two formulations of the acaricide amitraz were tested for their effect on the honey bee tracheal mite, Acarapis woodi. An aerosol formulation of the acaricide was applied at 25 and 50 mg per colony. In 1 experiment, no difference in infestation rate was detected among treated and control colonies throughout the 8 wk of the experiment. In a 2nd experiment there was a significant decline in the infestation rate among treated colonies. Further testing of this formulation is warranted. An amitraz formulation in slow-release plastic strips was tested on infested worker bees in small mailing cages. Doses higher than ca 0.01 g amitraz/cage caused significant bee mortality. However, even at high doses (0.05 and 0.1 g amitraz/cage) living mites were observed after 4 d of continuous exposure to amitraz. This formulation is not suitable for treating bees within mailing cages.