Determination of the Efficacy of Thymol, Eucalyptus and Oxalic Acid in the Control of Varroosis in Honey Bees

Objective: The subject of our study is to determine the efficacy and safety of non-chemical compounds thyme, eucalyptus, and oxalic acid against Varroa destructor ectoparasite, which is widely observed in honey bee (Apis mellifera L.) colonies both in our country and in the world. Materials and Methods: The study was designed of five groups and these groups were designed as group 1 (oxalic acid), group 2 (thymol), group 3 (eucalyptus), group 4 (positive control), group 5 (negative control). Seven honey bee colonies were included in each group. The first, second, and third groups were designed to form the treatment groups, and the last two groups to form the positive and negative control groups. Each group consisted of 7 hives. In the treatment groups, oxalic acid was dissolved in glycerin, thyme and eucalyptus were dissolved in ethyl alcohol, and they were absorbed into special towels. Two pieces per beehive were placed on the frames in the beehives. The treatments were applied weekly for 3 wk during the September. Treatment efficiencies were calculated with the Henderson-Tilton formula and the statistical difference between the oxalic acid, thyme, and eucalyptus treatment groups was determined by the General Linear Model procedure. Results: Treatment efficiencies were determined as 91.74%, 82.25%, and 79.2% in oxalic acid, thyme, and eucalyptus treatment groups, respectively. Conclusion: The findings revealed that completely natural herbal extracts and organic acids can be used instead of chemical drugs against Varroosis. Toxication and unnatural deaths were not observed in honey bees throughout the trials. Keywords: Varroosis, Oxalic acid, Thyme, Eucalyptus.