The Use of Formic Acid

This is from a work made by Ingemar Fries in 1989. Sixty-four honey bee colonies infected vith Varroa in six different apiaries were exposed to seven different treatments in accordance with the table. IMP= Illertisser Milbenplatten containing 14,2 g waterfree FA. 20 g, 30 g,= dosage of free FA applied on fibre material in an 85% water solution. Intervals in days, and number of treatments. TreatmentNumber of coloniesAgentDose, gramsInterval and number of treatmentPlace of applicationDistance form combs, mmA20IMP56,81×4Under combs70B9IMP56,84×4Under combs70C7IMP56,81×4Above combs10D10IMP42,61×3Under combs10E520 ml81,31×4Under combs70F530 ml121,91×4Under combs70G820 ml81,31×4Under combs10The colonies were treated, with brood present, early in the morning in late August with temps varying from +14 to +18 C. The results from treatment were estimated by counting the mite downfall within 12 days after treatment. 12 days were used since sealed brood will hatch within that peroid and the effect of FA on mites inside the brood cells will be included. In late October, in broodless condition, all colonies were treated with Perizin and the mite downfall counted. The total mite population was estimated after a 95% efficiency of Perizin treatment. TreatmentDownfall FADownfall PerizinEffect %A965.8±201,7463.6±130.363.9±6.1B596.9±111.3421.2±125.661.4±6.9C2149.1±440.9217.9±57.790.2±3.0D392.8±43.322.4±4.794.5±1.0E364.2±190.643.2±21.184.7±5.6F1098.0±592.011.0±4.196.6±1.6G2028.4±491.064.1±17.496.3±1.1Treatment A and B did not differ significantly, but both were less effective than all other treatments. No significant differences were seen between treating from above (C) or from below (D), or between treating colonies every day (A) or every fourth day (B) using the same doses and distance in both comparisons. A simple analysis shows that both the doses and the distance of application from the combs significantly influenced the results. Possible effects from treatment on queen losses were studied in 91 separate colonies that were on a long time experiment with FA. In the 91 colonies where the presence of the queen was investigated after 4 treatments with IMP, 5 colonies had lost their queen (5,5%), probably due to the treatment. 1599