Search

The efficacy of formic acid in a gel matrix was evaluated in two groups of honeybee colonies. In Group 1, a dispenser with 120 g of formic acid (70%) in gel was placed on the brood combs and another dispenser with the same dose was located on the hive bottom (total dose, 240 g). Group 2 received two doses of 240 g of formic acid (70%) in gel and each application was applied in two dispensers containing 120 g of the formic acid solution each and they were located over the brood chamber (total dose, 480 g). In Group 2, the period between both applications was 15 days, and the efficacies after the first and both applications were calculated. Significant differences were registered for final efficacy between both groups. When final efficacy of Group 1 was compared with efficacy after first application of Group 2, significant differences were found (P=0.0005). Same doses in different positions within the hive have different final efficacy. The higher efficacy was registered when the dispensers were placed over brood combs and on the hive bottom. It is suggested that efficacy is related to dispenser position within the hive.

An organic product based on formic acid in a gel matrix was evaluated for use in Varroa control under autumnal climatic conditions in Argentina. Twenty colonies each received two gel packets with formic acid in two applications and numbers of falling mites were registered. After this treatment colonies received two other acaricides in order to compare efficacy. Average final efficacy in colonies treated with the organic product was 92% with a low variability. The gel matrix kept an adequate formic acid concentration inside the colonies with only two applications. This product is, therefore, a good alternative for Varroa control because it is organic, easy to use and presents a low variability in final efficacy between colonies. No queen, brood, or adult honeybee mortality was registered.