Preliminary Researches Regarding the Effectiveness of the Formic Acid Treatment on Varroa (Varroa destructor) Found in the Artificially Decapped Bee Brood

Abstract

The objective of the study was to establish the effect of formic acid on varroa (Varroa destructor), inside the capped brood cells, artificially decapped. The experiments were carried out in 2017-2018 on honeybee colonies infested with varroa (V. destructor), in a research apiary belonging to the Institute for Beekeeping Research and Development in Bucharest. The decapping method in the present researches used the decapping fork to scrape the capped comb, without affecting the brood, in order to open it for an effective treatment. The combined treatment method was applied on honeybee colonies as a whole, as well as on brood combs, without bees, put in a special treatment box. The researches were focused on establishing the mortality level of various stages of varroa in artificially decapped brood, in normal colony and separately, as well as to make observations on the effect of formic acid on viability of capped bee brood, artificially decapped. The results show a high mortality of varroa, especially the protonymphs and deutonymphs stages (over 80%). The main conclusion is that the brood decapping method combined with formic acid treatment could be a useful technique to control varroa infestation, both in brood and honeybees, shortening strongly the treatment duration as compared to the usual treatments, increasing the efficacy of treatment by cutting the life cycle of varroa in brood.