Coumaphos residues in honey, bee brood, and beeswax after Varroa treatment

Abstract

Residues of acaricide coumaphos were assessed in honey, bee brood, and beeswax during a 2-year field experiment. Honey, bee brood, and beeswax samples were collected before and after routine use of coumaphos in the treatment of bee colonies against varroosis in two consecutive years. Determination of coumaphos in honey and bee brood was based on RP-HPLC with UV detection after a liquid-liquid extraction with hexane or ethyl acetate. Coumaphos in beeswax was identified and quantified by GC/MS. Results indicate the undetectable presence of coumaphos in honey. In bee brood, coumaphos was observed after the treatment. In beeswax, the accumulation of coumaphos was determined not only in hives where it was used but also in hives nearby in which coumaphos was not used. Results indicate the accumulation of coumaphos in bee brood and beeswax. Due to the coumaphos accumulation this drug should be used only in strongly affected bee colonies.