Varroa control: comparison of three queen-caging methods

Apis mellifera has suffered from the synergistic effects of Varroa destructor and pesticides such as neonicotinoids. Reduced or avoided acaricide use has caused many beekeepers to search for alternative ways to contain the mite without harming to the bee. Queen caging is one method that can be employed, in summer after the main honey production, and in which the resultant block of brood seems useful against V. destructor and allows colony resumption for the winter. Sadly, caging methods differ widely and generally are not scientifically validated. Four groups, five hives each, were treated as follows: 1) Treatment with Apilife Var only (control), 2) two-frame cage, 3) single-frame cage, and 4) “Scalvini” queen excluder cage. Each treatment was maintained for 22 days; the hives were then treated drop-wise with a sugar solution containing an oxalic acid (OA) based formulation, API-Bioxal®. Tests periodically considered colony development (adult bees, brood), and the number of mites dropped during the trial as well as after the winter OA treatment. Treatments 2 and 3 showed quicker queen egg-laying recoveries than did the others. No significant differences were found relative to the considered parameters.