Residues in wax and honey after Apilife VAR® treatment

Abstract

Apilife VAR®, with thymol as its main active ingredient, is registered for use against Varroa jacobsoni Oudemans in Switzerland. After Apilife VAR® treatment in autumn of 1992, the residues in honey and comb were examined the following spring. Only thymol residues were found in honey, whereas in comb the residues consisted of 99 % thymol and 1 % menthol. The thymol residues in honey did not increase with an increasing number of treatments and varied between 0.02 to 0.48 mg·kg-1 with an average of 0.15 mg·kg-1 (n = 29). The taste threshold of thymol in acacia and rape honey was between 1.1 and 1.6 mg·kg-1. The brood comb in two apiaries, where Apilife VAR® was used for, on average, 4 consecutive years, had a mean content of 574 mg·kg-1 and this did not increase with an increasing number of treatments. The thymol residues in honey comb were on average 21.6 mg·kg-1. Thymol did not evaporate during comb melting, but decreased rapidly when comb and foundation were exposed to the air during storage.