Reinfestation rates of Varroatosis after treatments in brood-free honeybee colonies

The trial was conducted during the active season of 1984 on 80 colonies. Every month, in a set of 10 colonies the queens were confined in cages and four treatments with Folbex VA were carried out in absence of brood. The number of mites that survived the treatment was related to the number of mites found in October. The effect on the entity of reinfestation of a varying rate of the mite reproduction and mortality throughout the active season was studied. The trial enabled to ascertain a remarkable rate of reinfestation in the treated hives so as to recommend annual treatment, even when the fumigations are carried out in the complete absence of brood.