Effectiveness and residue levels of 3 methods of menthol application to honey bee colonies for the control of tracheal mites

Abstract - Menthol foam-strips, vegetable shortening-menthol paste containing 30 and 60 g menthol and melted vegetable shortening-menthol-dipped cardboard (30 g) were applied to tracheal mite-infested colonies and compared to untreated control colonies. Honey and wax samples from brood frames, honey super frames and from bulk extracted honey were analyzed for menthol residues. The prevalence of mite-infested bees was reduced in all menthol treatments (applied 17 May) to < 1% by the end of August. The controls increased in tracheal mite prevalence to a 25% level by the end of August. Sealed brood production was not significantly different among the treatments, although brood mortality was observed in most treatments for a few d after application. Honey production was generally lower in treated colonies and significant differences were evident. Menthol was not detectable in extracted honey or from honey frames in honey supers. Residue levels in brood nest honey were highest in the 60-g foam-strip treatments at 6.2 ppm and were lowest in the 30 g cardboard treatment at 0.8 ppm.