Laboratory Evaluation of Some Botanicals against the Honey Bee Ectoparasitic Mite Varroa Destructor (Acari: Varroidae) and its Impact on Honey Bees (Apis cerana indica)

Background: Honey bees are one of the most important and efficient insect pollinators of food crops on earth providing honey, bee wax, bee pollen, royal jelly, propolis, etc. Varroa destructor is the most obnoxious pest of honey bees infliciting damage to the colony vis-à-vis transmitting viral diseases. The repeated use of synthetic acaricidal treatment results in developing resistance against varroa mite followed by residue hazards in bee products. This leads to an urgent need to develop alternate eco-friendly methods to manage the pest. Methods: The experiment was designed to evaluate the relative efficiency of six botanical extracts viz. Sweet basil (Ocimum basilicum L.), Turmeric (Curcuma longa L.), Coleus (Coleus aromaticus), Sweet flag (Acorus calamus L.), Tulsi (Ocimum sanctum L.) and Goat weed (Ageratun conezoides L.) against Varroa mite (Varroa destructor) under laboratory conditions. After preliminary dose-setting experiments, mites and honeybees were exposed to 2% ethanol extracts of the plants, with 24 hours’ exposure time. Result: 2% concentration of Coleus, Sweet flag and Tulsi registered cent percent mortality of mites within 24 hours after treatment followed by Turmeric (93.33%), Sweet basil (86.67%) and Goat weed (80%). All the extracts exhibited less than 30% mortality of honey bees (Apis cerana indica) whereas turmeric showed the lowest efficiency (14.29%).