Management of Varroa destructor by essential oils and formic acid in Apis Mellifera Linn. Colonies
Noor Islam, Muhammad Amjad, Ehsan-ul-Haq, Elizabeth Stephen and Falak Naz
Four essential oils of Thyme (Thymus linearis), Lemon grass (Cymbopogon citratus), Rosemary (Rosmarinus officinalis), Mint (Mentha longifolia) and Formic Acid (65%) used at three concentrations (25, 50 and 100%) against Varroa destructor damaging honey bee Apis mellifera colonies in Honeybee Research Institute, National Agricultural Research Centre, Islamabad, Pakistan. The percentage of infestation by V. destructor on worker brood and adult workers, number of dead fallen Varroa on the sheet, per cent mite mortality and their honey yield (kg) was determined before and after the treatments in the experimental colonies. The results revealed that formic acid and the highest concentrations (100%) of tested essential oils caused effective control of Varroa mites, whereas the infestation reduction percentage with formic acid, lemon grass, thyme, mint and rosemary oils was recorded more than 96% after the end of treatments on both worker brood and adult workers. The highest total number of dead Varroa mites (323) fallen on the sheet was recorded by formic acid followed by lemon grass (306), thyme (263), mint (204) and rosemary (188) respectively. The hives treated with essential oils and formic acid also showed good persistence with mite mortality ranging from 46.97 to 63.41% up to fourth treatment. High mean value for honey yield (14.2 kg) was recorded by formic acid, followed by thyme (13.7 kg), lemon grass, mint (13.0 kg) and rosemary (12.4 kg) per colony as compared with control colonies (6.5 kg) per colony.