Formic Acid 85%
Behandlungsmittel
Formic acid in an 85% preparation contains the same active substance as the 60% solution but is considerably more concentrated.
Formic acid in an 85% preparation contains the same active substance as the 60% solution but is considerably more concentrated. The mode of action and the form of application are the same: the acid evaporates within the colony, the vapor damages the mites and also penetrates through the cell cappings into the capped brood. Because of the higher concentration, more active substance is released per unit of time at the same evaporation surface, so the treatment acts faster and more sharply.
For use in Germany, the legal framework is decisive and is often overlooked. As a veterinary medicinal product, only the 60% preparation is available here. An 85% formic acid is not approved as a bee medicine in Germany and could only be prescribed within the scope of a veterinarian-established therapeutic emergency. Since sufficient treatment options exist with the approved products, such an emergency generally does not apply. In Austria, by contrast, an 85% formic acid ad us. vet. is available as a veterinary medicinal product, and there the information in the respective package leaflet applies.
In practice, the higher concentration means a considerably narrower window between effect and harm. If too much acid evaporates too quickly, unrest within the colony, brood damage, and the risk of queen losses increase. The Austrian authorization names daytime temperatures outside the range of 14 to 30 °C as a contraindication and staggers the start of treatment: at 14 to 20 °C during the day, above 20 °C in the morning or evening, above 25 °C in the early morning. There, queen losses are listed as an occasional side effect and colony losses as rare, occurring more frequently with short-term treatments or improper handling. The manufacturer assigns the 85% preparation, because of its higher vapor pressure, to larger hives and lower temperatures, and the 60% preparation to smaller hives and higher temperatures.
The same principles apply to honey and the withdrawal period as for the 60% acid. Treatment with organic acids is only permitted after the last honey harvest of the season; it is excluded during the nectar flow. Formic acid is water-soluble and does not accumulate in the wax, but treatment at the wrong time leads to honey with a noticeably altered taste. When handling the highly concentrated acid, the Austrian authorization requires protective clothing, acid-resistant gloves, safety goggles, and a half or full mask with a type B or E filter. The vapors must under no circumstances be inhaled.
Quellen (4)
- Die Honigmacher (Landwirtschaftskammer NRW): Ameisensäure in der Varroabehandlung
- BASG Österreich: Fachinformation Formivar 85 % ad us. vet., Zulassungsnummer 838625
- EU Union Product Database: Formivar 85 % ad us. vet. (Zulassung nur Österreich)
- Übersichtsartikel Varroatosetherapie von Honigbienen in Deutschland (Open Access)