PLANT-EXTRACTS USED FOR CONTROL OF THE PARASITIC MITES VARROA-JACOBSONI (ACARI, VARROIDAE) AND ACARAPIS-WOODI (ACARI, TARSONEMIDAE) IN COLONIES OF APIS-MELLIFERA (HYMENOPTERA, APIDAE)

Natural products were evaluated as control agents for the tracheal mit e Acarapis woodi (Rennie) and the Varroa mite Varroa jacobsoni (Oudema ns) in colonies of the honey bee, Apis mellifera L. Test materials con sisted of 1:1 (wt:wt) blends of thymol with cineole, citronellal, or l inalool. Two, 25.0-g applications (rate 1) of each blend were applied to colonies infested with Varroa. A 2nd group of Varroa infested colon ies received 2 x 12.5 g applications (rate 2). Each application was le ft in place for 14 d, during which time Varroa mites were collected on sticky boards placed on the bottom boards of the colonies. At the end of the 28-d treatment period, remaining mites were killed with fluval inate and collected on sticky boards. Mite mortality in the colonies r eceiving thymol and cineole was 56.4 and 49.1% for rates 1 and 2, resp ectively, compared with a natural mite fall of 28.0% in control coloni es. Two applications of each blend (rate 1) were applied to colonies i nfested with A. woodi in September. Mite prevalence values increased 2 8.3% in control colonies by the following May, but decreased 22.4% in colonies receiving thymol and citronellal. Our results suggest that th e presence of brood seriously limits the efficacy of thymol-based cont rol measures when they are applied as fumigants against Varroa. Howeve r, these products may be useful against the tracheal mite and may be a n important component of an integrated pest management program for Var roa if used when brood levels are low.