Oxuvar
Behandlungsmittel
Oxuvar is an oxalic-acid-based veterinary medicinal product available in two variants.
Oxuvar is an oxalic-acid-based veterinary medicinal product available in two variants. The 3.5% solution corresponds to the standard authorization and is intended for trickling only. The 5.7% variant is a concentrate that is diluted differently depending on the intended use and is approved for both trickling and spraying. This makes it, alongside lactic acid, a second acid available for spray application.
For trickling, the ready-to-use, approximately 3.5% solution is made from the concentrate with household sugar. It is applied lukewarm to the bees in the occupied comb spaces. The amount depends on the frame size: for smaller frames such as German Normal, Zander, or Simplex, about 3 to 4 milliliters per comb space; for large frames such as Dadant, 5 to 6 milliliters, up to a maximum of 50 milliliters per colony. For two-box colonies, the lower box is treated first, then the upper one. A broodless colony is a precondition, since oxalic acid acts through contact and does not penetrate into capped brood cells. The classic timing is the final mite treatment in late autumn or winter.
For spraying, by contrast, the concentrate is diluted only with drinking water to about a 3% solution, without added sugar. 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 hive. The combs are sprayed at an angle of about 45 degrees, so that as little solution as possible reaches open cells. Broodless nucleus colonies, artificial swarms, and broodless colony parts are treated, outside flight activity, i.e. in the evening or early morning.
A practical difference between the two applications concerns the shelf life of the ready-to-use solution. The sugar-containing trickle solution is intended for immediate use and must be discarded, because the sugar forms hydroxymethylfurfural, which is toxic to bees and larvae. The spray solution, diluted only with tap water and therefore sugar-free, remains usable for considerably longer.
The two variants differ in withdrawal period. For products under standard authorization, honey may only be harvested the following spring. For the 5.7% variant, the withdrawal period is zero days for correctly treated colonies, and treatment is to be carried out without honey supers in place. For nucleus colonies and young colonies, the bee institutes additionally recommend not using medically treated young colonies for honey production in the current season. For trickling, acid-resistant gloves and safety goggles are required; for spraying, also a respiratory mask, because an aerosol is produced.
Quellen (5)
- Emmerich, I.: Zugelassene Arzneimittel für Honigbienen in Deutschland, Berliner und Münchener Tierärztliche Wochenschrift 2018
- Gebrauchsinformation Oxuvar 5,7 % Konzentrat zur Herstellung einer Lösung für Honigbienen (Andermatt BioVet)
- LLH Bieneninstitut Kirchhain: Infoblatt Varroazide (Übersicht zugelassener organischer Varroazide)
- LWG Veitshöchheim: Merkblatt Varroa 3, Medikamentöse Standardverfahren
- LWG Veitshöchheim, Institut für Bienenkunde und Imkerei: Träufelbehandlung mit Oxalsäure