Volume 22, Number 2, 1991
|135 - 145
Effective control of varroatosis using powdered thymolF. Chiesa and M. D'Agaro
Istituto di Difesa delle Piante, Università degli Studi, Piazzale M Kolbe 4, 33100 Udine, Italy
Abstract - In order to provide a consistent control of varroatosis without harmful effects such as the occurrence of toxic residues in the hive products, treatment with powdered thymol was tested during a 2-yr research trial. Treatment consisted of 4 identical applications carried out at 2-day intervals on honeybee colonies with little or no brood. In all hives during both years, mite populations were drastically reduced as a consequence of treatment (96.77% on average) indicating that thymol is worth further study. The rate of mite fall was highest in the hours immediately following each application and was positively influenced by outdoor temperatures. The addition of confectioner's sugar to thymol seemed to enhance both effectiveness and rate of mite fall though significant effects were not achieved. Modified Gary's traps installed on treated and untreated colonies showed that bee mortality was generally affected by treatment.
Key words: Apis mellifera / varroatosis / chemical control / thymol