Effectiveness evaluation of different concentrations of Satureja khuzistanica Jamzad and S. spicigera (C. koch) Boiss. essential oils on the control of hive tick (Varroa destructor)

Varroa destructor (VD) tick is one of the most important pests of honey bee colonies around the world, causing a lot of economic damage to the beekeeping industry in the world by feeding on bee larva and transferring some viruses. The use of chemical pesticides against this tick creates resistant populations and infects hive products. In this study, the level of repellent toxicity of different essential oil (EO) concentrations of Satureja khuzistanica Jamzad and S. spicigera (C. koch) Boiss., on the mortality of VD tick and honey bee (HB) was evaluated under laboratory conditions. Mature female ticks were treated with different EO concentrations including 0, 50, 75, 100, 150 and 200 ppm (at 32 °C, 50% relative humidity and darkness) for 5 and 10 hours, in four replicates, and after determining the equation of concentration vs. VD mortality, LC50 was calculated for concentrations of 20 to 1000 ppm. According to the results, the amount of LC50 at 5 and 10 hours after EO treatment was respectively determined as: for S. khuzistanica EO, 149.8 and 78.6 ppm for VD tick and 750.5 and 435.8 ppm for HB, and for S. Spicigera EO, 255.7 and 153.6 ppm for VD tick and 737.6 and 573 ppm for HB, indicating the more sensitivity of ticks in comparison with honey bees to applied EOs. The results showed that the EO of both species, especially S. khuzistanica, with the least mortality on HB, has a high potential for controlling VD tick. The main component(s) of essential oils was obtained as carvacrol (93%) in S. khuzistanica and carvacrol and thymol (43% and 29%, respectively) in S. spicigera based on qualitative analysis.