Distribution of coumaphos in beeswax after treatment of honeybee colonies with CheckMite® against the parasitical mite Varroa destructor

We studied the distribution of coumaphos in beeswax after a single application of CheckMite® to 15 bee colonies in the fall according to the manufacturer’s instruction. Immediately after the treatment, residue levels were especially elevated in the wax that came into contact with the CheckMite® strips. During the following spring season, coumaphos levels ranged from 36 to 159 mg/kg in the wax of the brood frames next to the CheckMite® strips, and residue levels were about 10 times lower in the wax of frames that did not come into contact with the strips. Beeswax that was newly constructed 5 months after removing the treatment strips contained up to 7.3 mg/kg of coumaphos, and up to 0.5 and 2.3 mg/kg was detected in the honeycomb and capping wax, respectively. These results suggest that beeswax exposed to CheckMite® should not be recycled in order to prevent elevated concentrations of coumaphos in new foundations and hence to prevent honeybee larvae from being exposed to detrimental residue levels.