Hive debris counts in honeybee colonies: a method to estimate the size of small populations and rate of growth of the miteVarroa jacobsoni Oud. (Mesostigmata: Varroidae)

Fifteen honeybee colonies (Apis mellifera L.) infested with the ectoparasiteVarroa jacobsoni Oud. were monitored for the number of mites falling to the bottom of the hive. Mites in the debris were counted periodically on the plastic sheet on which they were collected. Two months later, colonies were treated with an acaricide to determine mite population. A high positive correlation was found between the number of mites collected in the hive debris over different periods and the final population size. Based on this correlation, it was possible to use hive debris counts to predict the degree of infestation. Furthermore, counting fallen mites over a period of two months, followed by an acaricide treatment, might be a useful method of estimating the rate of growth ofV. jacobsoni in honeybee colonies.