بررسی تاثیر غلظت‌های مختلف اسید اگزالیک روی کنترل کنه واروآ (Varroa destractor) در کلنی‌های زنبورعسل (Apis mellifera meda)

Varroa mite is one of the most important pests of Apis mellifera L. all over the world. It causes great economic loss to the beekeeping industry by feeding on fat body of different developmental stages of honey bees and also by transmission of pathogenic viral agents. During the recent years, application of chemical acaricide has led to the occurrence of mite resistance and contamination of hive products. Due to adverse effects of chemical acaricide in controlling Varroa mite, researchers have been encouraged around the world to find alternative natural control methods that are both cheap and safe for human health, honey bees and the environment. Therefore, organic acids are considered as a suitable alternative to chemical acaricides for Varroa mite control. The aim of this study was to investigate effect of concentrations of 2.5, 3.5 and 4.5% oxalic acid to control Varroa mite in honey bee colonies in the climatic conditions of Gheshlagh region of Nobaran city of Markazi province in 2020 -2021. This study was carried out in a completely randomized design with 4 treatments and 5 replications on infested colonies with Varroa mite. The effect of different concentrations of oxalic acid was evaluated on Varroa mite and honey bee mortality as well as the percentage of residual contamination in the colonies after the experiment. Statistical analysis was performed via analysis of covariance (ANCOVA) method by SAS software. The results showed that the highest and lowest percentage of mortality on mites were observed to concentrations of 4.5% (80.91%) and 2.5% (44.32%) of oxalic acid, respectively. Also, there was a significant difference between the treatments in terms of mortality on mites. The highest percentage of losses on bees was related to the concentration of oxalic acid 4.5%, and the lowest was observed at the concentration of 2.5%. According to the results, the lowest and highest percentage of residual contamination in the colonies after the experiment were observed in concentrations 4.5% and 2.5%, respectively. Considering the highest percentage of mortality on mites and the lowest percentage of residual contamination in the colonies after the experiment observed in the oxalic acid treatment of 4.5% and also low mortality rate of bees in all treatments, oxalic acid 4.5% is recommended for controlling Varroa mites in honey bee colonies in areas with similar climatic conditions to the present study.