PLANT-EXTRACTS FOR CONTROL OF THE PARASITIC MITE VARROA-JACOBSONI (ACARI, VARROIDAE) IN COLONIES OF THE WESTERN HONEY-BEE (HYMENOPTERA, APIDAE)

Two natural product treatments were evaluated in field trials as control agents for the parasitic mite, Varroa jacobsoni (Oudemans), in colonies of the honey bee, Apis mellifera L. Eight colonies were treated with a blend of thymol, eucalyptus oil, menthol, and camphor. Eight colonies were treated with linalool: Each treatment was delivered using 4 pieces of florist block material, each 25 by 25 by 5 mm, saturated with test material and placed on the top bars of the upper hive body of each colony. Control colonies received the carrier without test material. Two applications of test materials were made to each colony during a treatment period that ran from 1 November 1993 through 19 November 1993. The Ist application was made on 1 November 1993. The 2nd application was made on 12 November and removed on 19 November. Each application consisted of a total of 17 g of test material. Mites killed during the treatment period were collected and counted. Mites remaining in each colony after the treatment period were killed with fluvalinate strips placed in each colony from 19 November through 17 December 1993 (the treatment-evaluation period), collected, and counted. Mite mortality during the treatment period was calculated by dividing the number of mites collected during the treatment period by the total number of mites collected during both the treatment and treatment-evaluation periods. Average mite mortality expressed as a percent, was 96.7% in the colonies receiving the thymol-based blend, 27.5% in the colonies receiving linalool, and 4.4% in the control colonies.