Apilife VAR(R), with thymol as its main active ingredient, is registered fo
r use against Varroa jacobsoni Oudemans in Switzerland. After Apilife VAR(R
) 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 res
idues 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 bt tween
1.1 and 1.6 mg.kg(-1). The brood comb in two apiaries, where Apilife VAR(R
) 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. (C) Inra/DIB/AGIB/Elsevi
er, Paris.