Evaluation of two methods for applying Apiguard® in an area with continuous nectar flows and brood rearing

The results of a trial conducted in Southern Italy to evaluate the effectiveness of Apiguard® treatments against Varroa destructorAnderson and Trueman are reported. Twenty one colonies of Apis mellifera L. in Dadant-Blatt hives were used. Two groups of sevencolonies each were treated and one group was left as untreated controls. Two aluminium trays of Apiguard® were installed in thehives with a two week interval between treatments. The trays of one of the treatments (group 1) were covered with a plasticmesh which only allowed the bees’ legs and mouthparts to contact the product. The plastic mesh allowed evaporation but reducedbee contact and product removal. The other Apiguard® treated group (group 2) received uncovered trays as recommended by themanufacturer. Apiguard® trays were present in the hives for 30 days. Two methods were used to evaluate the treatment efficacy:the percent effectiveness (E%) and the degree of efficacy (DE%). Mean E% (± s.e.) was significantly higher in the uncovered trays(93.34 ± 1.18%) than in the covered trays (87.23 ± 1.80%) (F= 8.80, d.f.= 1, P= 0.012). Similarly DE% also was significantly differentbetween the 2 groups (Covered trays = 84.24 ± 2.23%; Uncovered trays = 91.78 ± 1.45%) (F= 8.781, d.f.= 1, P= 0.012).