Evaluation of grapefruit essential oils for controlling Varroa jacobsoni and Acarapis woodi

Four essential oils found in citrus leaves - citral, limonene, citronellal, and linalool - were tested in the laboratory for effectiveness in knocking down Varroa jacobsoni mites from infested honey bees. Citral was the most effective, with 72.8% knockdown of mites from infested bees exposed to this compound. Only 7.9% initial knockdown of varroa mites was observed in the field test of citral, not significantly different from initial control mite drop. Total population change after 6 weeks of exposure between citral and control treatments was also not significantly different, with great increa ses in mite populations seen in the citral and control hives. Citral was mo re effective, however, in controlling the tracheal mite, Acarapis woodi, re sulting in a 66.8% reduction in populations after initial treatment. Discus sion is presented on the use of natural essential oils in the control of ho ney bee acarine pests.