Oxalic Acid Dihydrate Solution 3.5% ad us. vet.
Behandlungsmittel
The oxalic acid dihydrate solution 3.5% ad us.
The oxalic acid dihydrate solution 3.5% ad us. vet. is the classic trickle solution for winter treatment and a veterinary medicinal product manufactured under standard authorization. It is supplied in two components: an aqueous oxalic acid solution and a sachet of sucrose. The sugar is only stirred in shortly before application, producing 500 milliliters of ready-to-use solution.
For preparation, the container is placed in a lukewarm water bath of 30 to 35 °C, the sucrose powder is added completely and shaken vigorously until fully dissolved. The solution is applied lukewarm. The added sugar increases viscosity, so the solution adheres better to the bees and the mites are exposed to the acid for longer. This is exactly why the finished mixture is intended for immediate use only: over time, the sugar forms hydroxymethylfurfural, which is toxic to bees and larvae. Leftovers must be discarded.
Depending on colony strength, 30 to 50 milliliters per colony are trickled, i.e. 30 milliliters for a small, 40 milliliters for a medium, and 50 milliliters for a strong colony. This corresponds to 5 to 6 milliliters per bee-occupied comb space. It is applied using a large-volume disposable syringe or an automatic pipette, in a meandering pattern along the occupied comb spaces directly onto the bees. The outdoor temperature should be at least 3 °C. Mite drop continues for about three weeks after treatment.
The authorization is clearly limited: application is carried out once, during the broodless period in late autumn; brood must not be present. Higher doses or repeated applications are explicitly prohibited. At concentrations of 5 percent or more, roughly double the bee mortality in autumn as well as poorer overwintering and spring development have been described. Repeated autumn treatments and summer application are also poorly tolerated by the bees even at low doses. If accidentally overdosed, an attempt can be made to dilute by trickling additional water.
The withdrawal period states that, after treatment in late autumn, honey may only be harvested the following spring. In practice this means treatment should be completed by December 31 if honey is to be harvested the following year. Application during the nectar flow is not permitted. The solution is hazardous to health and strongly caustic. Acid-resistant gloves and safety goggles are mandatory; eating, drinking, or smoking during application is prohibited, and pregnant women should have no contact with oxalic acid dihydrate. Corrosion-sensitive beekeeping equipment should also be protected.
Quellen (5)
- BfArM: Wortlaut der Standardzulassungen für Bienentherapeutika (Monographie Oxalsäuredihydrat-Lösung 3,5 % ad us. vet.)
- BVL: Standardzulassung Oxalsäuredihydrat-Lösung 3,5 % (m/V) ad us. vet., Zulassungsnummer 2669.99.99
- LWG Veitshöchheim, Institut für Bienenkunde und Imkerei: Träufelbehandlung mit Oxalsäure
- Emmerich, I.: Zugelassene Arzneimittel für Honigbienen in Deutschland, Berliner und Münchener Tierärztliche Wochenschrift 2018
- LAVES Institut für Bienenkunde Celle: Leitfaden Varroa-Bekämpfung in Öko-Imkereien