Sustainable varroa mite (Varroa destructor) control in field conditions

Anotace: Experiments assessed the comparative efficacy of oxalic acid solution (OA) and combination of formic acid (FA) evaporation and trickling OA to control the honey bee mite, Varroa destructor, at two apiary locations. Queen caging, consecutive OA treatments of broodless colonies, or combined treatments using OA and FA in colonies with brood increased mite mortality (P < 0.05) in comparison to the pre-treatment period. FA application in colonies with brood in September and October resulted in an average mite mortality of 18% in the first apiary and subsequent FA applications in the same period in the second apiary killed, on average, 73% and 71% of mites; respectively. OA treatment of broodless colonies after queen caging at two apiaries resulted in 18% and 47% mite mortality. Caging the queens and OA treatments in broodless colonies or subsequently use consecutive OA or FA treatments ensure adequate mite reduction before wintering the colonies. Synergistic control methods of Varroa mites using OA and FA along with queen caging is discussed.