Infestation of Honeybee (Apis Mellifera) Colonies by the Parasitic MitesVarroa JacobsoniandTropilaelaps Clareaein South Vietnam and Results of Chemical Treatment

SummaryIn honeybee (Apis mellifera) colonies examined in South Vietnam an average of 4·9% of brood cells were infested by Varroa jacobsoni and 46·2% by Tropilaelaps clareae. Average rates of infestation of adult workers were 6·3 per 100 for V. jacobsoni and 3·4 per 100 for T. clareae. Thus, despite a tenfold higher infestation of brood by T. clareae, infestation of adults by V. jacobsoni was twice as high. Amitraz was more effective than phenotiazine against both mite species, killing 95·7% of V. jacobsoni and 79·2% of T. clareae mites whereas phenotiazine killed only 57·7% of V. jacobsoni mites and 56·4% of T. clareae. Because of the low incidence of V. jacobsoni, mite treatment in Vietnam should be concentrated on T. clareae which can be controlled without medication.