EFFECTS ON VARROA-JACOBSONI FROM ACARICIDES IN BEESWAX

The effect from acaricide residues in beeswax on mortality and fertili ty of Varroa jacobsoni was investigated. Amitraz, coumaphos and fluval inate were added to acaricide-free wax at 0, 1, 10, 100 ppm each and t he wax subsequently was used to produce comb foundation. Amitraz could not be recovered from the foundation, but foundation where coumaphos and fluvalinate had been added to the wax contained approximately the added residue levels. When mites were allowed to enter brood in combs made from this foundation, the effect from coumaphos residues was dram atic. Almost all mother mites died in combs where 100 ppm coumaphos ha d been added to the foundation and increased mother mite mortality occ urred at the 10-ppm level. An effect from fluvalinate was only seen in combs drawn from foundation with 100 ppm fluvalinate. If one brood ge neration had been present prior to the brood attacked by the mites, no harmful effects to mites from wax contaminants were found;even at the highest contamination levels. This result is probably due to the hone y bee cocoon acting as a barrier for acaricide transfer from the wax t o the mites in the cells. It is concluded that studies of mite fertili ty probably do not need to consider if the wax is contaminated with up to 10 ppm of fluvalinate. At 100 ppm in the wax the effect from this acaricide on mite performance is detectable but not dramatic. However, comb drawn from foundation having 10 ppm or more coumaphos, and in wh ich no brood was reared, dramatically reduced mother mite survival. Si nce frozen combs are often used when mite fertility is investigated, c oumaphos in the wax may distort results at contamination levels found in European wax.