Use of essential oils for controlling the Varroa destructor acarus in Apis mellifera

Abstract

The Varroa destructor (Acari: Varroidae) acarus is considered a major bee pest worldwide. The contamination risk of honey and wax, as well as the development of resistance by this pest, have led to the need of alternative ways for replacing conventional acaricides. This study aimed at evaluating the effects of different essential oils on the mortality of the Apis mellifera honey bee and its parasite, the Varroa destructor acarus. The methodology consisted in maintaining separately groups formed by honey bees and acarus, in cages with essential oils at the concentrations of 10 µL, 50 µL and 200 µL, being each concentration an essay. Treatments with water, anise, rosemary, cinnamon, eucalyptus, clove and mint were performed. The experiment was conducted in randomized blocks, with six treatments and four replications. Bee and acarus specimens were observed for six hours, in order to quantify the mortality rate caused by treatments. The essential oils did not affect significantly the honey bees, however, the anise, cinnamon, eucalyptus and clove oils caused a significant mortality rate for the acarus. Concerning the 10 µL concentration, there was a mortality rate of 70% for anise and cinnamon, 77.5% for eucalyptus and 75% for clove. At the 50 µL concentration, a rate of 75% was observed for clove and cinnamon, 90% for anise and 92.5% for eucalyptus. For the 200 µL concentration, the mortality rates reached 92.5% for anise and eucalyptus, 52.5% for cinnamon and 87.5% for clove. Based on the mortality rates observed in the study, it is suggested that these substances can replace conventional acaricides.