Oxalic Acid Spray Method
Behandlungsmittel
In the spray method, a diluted, sugar-free oxalic acid solution is applied as a fine mist directly onto the bee-covered combs.
In the spray method, a diluted, sugar-free oxalic acid solution is applied as a fine mist directly onto the bee-covered combs. Because virtually every bee is wetted in the process, mite exposure is higher than with trickling. The bee institutes point out that spraying broodless nucleus colonies and colonies is often more successful than repeated trickling.
As with trickling, oxalic acid only acts through contact and does not reach mites in the capped brood. The method is therefore tailored to situations where no capped brood is present anyway: freshly formed nucleus colonies, once the brood given to them has hatched, artificial swarms and natural swarms, as well as broodless colony parts from the split-and-treat method. It is thus a summer and early-summer method that supplements the winter treatment but does not replace it.
For application, the concentrate is diluted with drinking water according to the instructions for use. For spray application with Oxuvar 5.7%, a 3% ready-to-use solution is prepared, of which, at temperatures above 8 °C, about 2 to 4 milliliters per fully bee-covered comb side are sprayed on, up to a maximum of about 80 milliliters per colony. For swarms and artificial swarms, the Bavarian State Institute states 20 to 25 milliliters per kilogram of bees. The combs are sprayed at an angle of about 45 degrees, so that as little solution as possible reaches open cells. Treatment is carried out outside flight activity, i.e. early in the morning or in the evening.
The most important application error is soaking the bees. A fine spray mist should form that only wets the bees, not drenches them. Equally critical is treating when capped brood is still present, because then a significant proportion of the mites remains out of reach. Another mistake is skipping a later final mite treatment, because the efficacy of the summer measures alone is generally not sufficient.
Legally, spray application only applies to products expressly approved for it. For Oxuvar 5.7%, the withdrawal period is zero days for correctly treated colonies, and treatment is to be carried out without honey supers in place. Spraying produces an aerosol, so in addition to acid-resistant gloves and safety goggles, an FFP2 respiratory mask is also required.
Quellen (3)
- Emmerich, I.: Zugelassene Arzneimittel für Honigbienen in Deutschland, Berliner und Münchener Tierärztliche Wochenschrift 2018
- LWG Veitshöchheim: Bayerisches Varroabehandlungskonzept, Medikamentöse Standardverfahren
- Varroose-Bekämpfungskonzept Baden-Württemberg, Landesanstalt für Bienenkunde Hohenheim, Stand 11/2024