Effect of different concentrations of formic acid and oxalic acid on the control of Varroa mite (Varroa destructor) in Iranian honey bee (Apis mellifera meda) colonies

The effect of different concentrations of formic acid (25, 35 and 45%) and oxalic acid (2.5, 3.5 and 4.5%) and control treatment on Varroa mite and honey bee mortality, as well as the percentage of residual mite infestation in the colony, were evaluated in a completely randomized design with7 treatments and 5 replications in the climatic conditions of Markazi province. Results showed that the highest percentage of mortality on mites was related to the concentrations of formic acid 45% (88.13%) and oxalic acid 4.5% (80.91%) respectively, and the lowest residual contamination of colonies after the experiment was observed in the treatment of formic acid 45% (0.66%) and oxalic acid 4.5% (2.06%). The highest percentage of bee mortality was related to formic acid 45% concentration, which was significantly different from other treatments. Based on the results, the most favorable effect based on the percentage of mortality on mites and the lowest residual contamination in colonies between different concentrations of these two acids in the present study was related to the concentration of formic acid 45% and oxalic acid 4.5%. There was no significant difference between these two superior treatments in terms of mite mortality and residual infection. Due to the significant difference in bee mortality in these two treatments and less bee mortality in the oxalic acid treatment of 4.5% and having economic benefits, the use of oxalic acid 4.5% is suggested to control Varroa mite in apiaries with similar climatic and ecological conditions to present study.