EN
The study aimed at determining the efficacy of controlling Varroa destructor mites with Apitraz strips in honey-bee colonies. Moreover, the amount of an active ingredient (amitraz) freed from the strips during their 6-week-long exposure in colonies was examined. The efficacy of parasite control with Apitraz was high. On the average, 816.37 mites were killed when using Apitraz. The control application of Bayvarol resulted in a fall-off of 5.05 parasites. Assuming the total parasite fall-off as 100%, the efficacy of Apitraz against varroosis amounted to 99.38%. Up to the fourth week of drug administration, over 80% of the mites died in honey-bee colonies. Out of 453.6 mg of the amitraz contained in a micro-layer of two strips, 104 to 223 mg (162 mg on the average) had been freed during their exposure in honey-bee colonies. Regarding the efficacy of varroosis control in honey-bee colonies to the amount of active ingredient freed from the strips that it was determined that it was not conditioned by the amount of freed amitraz (within the range examined), as the calculated coefficient of the correlation was insignificant (r = - 0.77).