Evaluation of the effectiveness of oxalic acid strips (Calistrip® Biox) against Varroa destructor under conditions of presence and absence of brood

This study was conducted to evaluate the effectiveness of a new organic medication formulated with oxalic acid in the form of strips for hives (Calistrip® Biox, Laboratorios Calier, S.A.) for the treatment of Varroa destructor. The effectiveness and safety of the treatment were evaluated under conditions of presence and absence of brood (spring) and under conditions of low brood presence (late autumn/early winter). The treatment consisted of 2 applications of 2 strips per hive separated by an interval of 21 days (6.44 g of oxalic acid/strip) over a total treatment period of 6 weeks. Under conditions of absence of brood, very high effectiveness values were recorded, close to 90%, while in the presence of brood, the effectiveness was around 70-75%. The effectiveness results obtained in the presence of brood are considered very satisfactory compared to other treatments, considering that these are not the optimal conditions for treatments against Varroa.