Treatment based on formic acid for Varroa destructor control with two different evaporators: efficacy and tolerability comparison

Formic acid based treatments are active also against Varroas enclosed inside sealed brood. For its organic nature and the low risk of long-lasting residues in bee products, are very popular in Northern Europe, but could be problematic in Southern regions where summer temperatures are higher. In this study efficacy and tolerability of a 60% aqueous solution of formic acid administered via two different evaporators: (Aspro-Novar-Form® and Nassenheider professional®) were compared. Total efficacy was on average high (> 80%), but with high variability among the different colonies, without significant differences between the two evaporators. No significant differences in tolerability between the two approaches were observed, however, the number of bees after treatment in the AN group is on average higher than in the NH group. Further field comparisons should be conducted to explore the differences in tolerability that arose in this study.