Selection and Surface Modification of Materials by Non-thermal Plasma to Improve Impregnation with Essential Oils for the Control of Honeybee Mites

Abstract

Tropilaelaps mites are a serious ectoparasite of honeybees, Apis mellifera, in Thailand and Asia. In this research, the absorption and release properties of essential oils (EOs) of porous media were analyzed. The brown ceramic bar showed the highest clove oil absorption capacity, 0.0050±0.0002 µl/mg, followed by carbon at 0.0036±0.0002 µl/mg of oil absorption capacity. The highest cinnamon oil absorption was observed in carbon and brown ceramic bar materials (0.0067±0.0002 and 0.0065±0.0002 µl/mg, respectively). A slight decrease in clove oil absorption was observed in carbon after plasma treatment generated by argon and helium gases, but there were no significant differences (0.0036± 0.0002 and 0.0035±0.0001 µl/mg, respectively). Although, argon- and helium-water vapour mixtures were applied for carbon surface modification, the absorption of clove oil did not significantly change. The clove oil slowly evaporated from the carbon material during the first 8 hours of incubation. Then, the quantification of evaporation increased on day 3 (40-50%) and reached 50-60% by day 14 of incubation. Lastly, the evaporation of clove oil from carbon was not significantly affected by plasma treatments. Therefore, the conditions of non-thermal plasma should be further investigated to improve the surface of materials for the application of essential oils or other materials to control honeybee mites.