Monoterpenoids as possible control agents for Varroa destructor

The use of plant-derived monoterpenoids for control of Varroa destructor, a destructive ectoparasite of the honey bee, Apis mellifera, was investigated in laboratory bioassays and autumn field treatments. Twelve monoterpene derivatives were analysed through fumigation bioassays. Linalyl acetate, (R)-myrtenyl acetate, (S)-perillyl acetate, and thymyl acetate exhibited high toxicities toward V. destructor (mean LC₅₀ = 0.05) and significantly lower toxicities toward A. mellifera (mean LC₅₀ = 0.95). Due to their demonstration of species-selective toxicity, these four acetates were chosen for field trials. In the field trials, all four monoterpenoid-treated groups were statistically significantly different from the control group in reduction of V. destructor infestation, yielding a 51-64% reduction of V. destructor when compared with the control group.