Detection of the high risk pyrethroid resistant Varroa destructor mites in apiaries of the Warmia-Mazury province in Poland

Background. The aim of our current study was to investigate the possible occurence of pyrethroid (tau−fluvalinate) resistant Varroa mites infestations in 24 randomly chosen apiaries of Warmia−Mazury province of north−east Poland. Methods. The methodology used for the analysis of resistant Varroa strains strictly followed the protocol described by Milani [6, 14]. Results. We identified 3 apiaries that were infested with high risk pyrethroid resistance mites and a further 9 apiaries that were free from this resitance. The brood samples collected from the remaining apiaries did not contain sufficient numbers of parasites to enable us to properly perform the assay. Conclusions. Our finding that 25% of the tested brood samples showed a high risk of fully pyrethroid resistant Varroa mite contamination indicates that resistant Varroa may become wide spread in apiaries in Poland. Interestingly these high risk resistant mites were found in honeybee colonies with low levels of Varroa infestation, with an average rate of 2.16%. We also discuss the role of amitraz (amidine) in the phenomenon of Varroa resistance to pyrethroids.