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

Abstract

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.

Keywords:

• formic acid
• Apis mellifera
• Varroa destructor
• evaporators
• efficacy
• tolerability

Acknowledgements

The authors wish to thank the Bologna beekeepers’ association “Le nostre api” for providing the colonies; the National Union of Italian Beekeepers (UNAAPI) for providing the evaporators and probes; Chemicals laif spa for providing formic acid.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

The authors are also very grateful to Micol Baracani for the mites count and Fabio Silvestre for his precious suggestions.