Varroxal
Behandlungsmittel
Varroxal is a powder for use in the hive containing 0.71 gram of oxalic acid per gram, corresponding to 1 gram of oxalic acid dihydrate per gram.
Varroxal is a powder for use in the hive containing 0.71 gram of oxalic acid per gram, corresponding to 1 gram of oxalic acid dihydrate per gram. A level measuring spoon contains 1 gram of oxalic acid dihydrate. The product can be applied in three ways: vaporized, trickled, or sprayed. It has become best known for vaporization.
The significance here lies in the legal area. Varroxal has been approved in Germany since September 2023 and is thus the first and so far only varroacide with which vaporizing oxalic acid is permitted at all in this country. This authorization does not, however, generally release the method. It applies to this product, at this dose, and with the two vaporizer models for which efficacy and safety data were submitted during the authorization process. The Federal Office of Consumer Protection and Food Safety has explicitly clarified that no data exist for other devices, even apparently identical ones, and that no efficacy can be guaranteed.
For vaporization, 2 grams per colony are placed in the crucible and the vaporizer is pushed through the entrance under the winter cluster. Treatment is carried out once in the broodless colony at outdoor temperatures of 2 to at most 10 °C. A second vaporization after two weeks is only provided for in cases of continued noticeable mite drop or small areas of capped brood. For trickling, the powder is mixed with lukewarm sugar syrup to make an approximately 4% solution and applied at about 0.25 milliliters per square decimeter of comb side. For spraying, it is diluted with drinking water only, to about 3%, and applied at 2 to 4 milliliters per occupied comb side, up to a maximum of 80 milliliters per colony and only above 8 °C.
The same basic condition applies to all three forms of application: the colony must be broodless. Oxalic acid acts through contact and is ineffective against mites in capped brood cells. Vaporization is physically delicate because oxalic acid sublimates at about 157 °C and already decomposes from just under 190 °C. Visible white mist, incidentally, is no proof of efficacy; it is essentially water vapor.
User protection is regularly underestimated. Long-sleeved protective clothing, chemical-resistant gloves, and safety goggles are required. For vaporizing and spraying, an FFP3 respiratory mask is provided for, and at least FFP2 for trickling. Work is carried out outdoors or in a well-ventilated space, with one's back to the wind. The withdrawal period for honey is zero days, but the product must not be applied during the nectar flow or with honey supers in place. Oxalic acid acts corrosively on the metal parts of beekeeping equipment, and the application must be documented as a veterinary treatment in the Colony Register.
Quellen (4)
- Produktblatt Varroxal 0,71 g/g Pulver für den Bienenstock (Andermatt BioVet)
- BVL: Hinweise zur Anwendung des Tierarzneimittels Varroxal 0,71 g/g Pulver für den Bienenstock in Bezug auf die geeigneten Verdampfer (15.03.2024)
- LAVES Institut für Bienenkunde Celle: Was man über Varroxal, das bislang einzige zugelassene Varroazid zum Verdampfen, wissen sollte
- LWG Veitshöchheim: Merkblatt Varroa 3, Medikamentöse Standardverfahren