The varroacidal action of propolis: A laboratory assay

Abstract

The action of propolis (bee glue) against the ectoparasitic mite Varroa destructor Anderson and Trueman has been investigated and showed narcotic and lethal effects. Length of narcosis and rate of mortality depended on the extraction procedure, concentration of propolis and contact time. Propolis extracted with 70% ethanol was found to be highly toxic, a 10% (w/v) propolis resulting in 100% mortality with a brief contact time of 5 s. In addition, the effect of propolis on the metabolic rate of the mites has been investigated calorimetrically. Even sublethal propolis concentrations without varroacidal effects and of only short lasting narcotic effects resulted in a significant reduction in the heat production rate, indicating weakening of the mites.