Varroacidal Efficiency of Treatment with Amitraz in Honey Bee Colonies with Brood

Field trials were conducted to evaluate the effectiveness of amitraz fumigation against Varroa destructor in honey bee colonies with brood. Within this project the following aspects were taken into consideration: strength of colony, the number of treatments, time intervals between treatments and way of its performance. Honey bee colonies with brood were fumigated four times with one tablet of Apiwarol® per each treatment every four, six, eight and ten days. The tablets with amitraz were burned in the electrical device Wakont or directly in hives. In case of amitraz fumigation with Wakont even four treatments reduced infestations of V. destructor to a limited extent, on average from 40 to 61% of mite populations. A similar effectiveness among the treatments has been ascertained regardless of intervals between them. The efficacy of amitraz combustion in hives was slightly higher and statistically significant only after four treatments. Moreover, beyond brood area, the population of worker bees turned out to determine treatment efficacy with amitraz in this form and modes of administration. In honey bee colonies with brood, even four amitraz fumigations do not decrease the level V. destructor infestation to the extent that it is safe for wintered bees.