Thymovar
Behandlungsmittel
Thymovar consists of impregnated cellulose strips, each containing 15 grams of thymol.
Thymovar consists of impregnated cellulose strips, each containing 15 grams of thymol. The strips are placed on the top bars of the uppermost brood box, at the brood nest, keeping a distance of at least four centimeters from the brood, because brood placed closer is removed by the bees. The active substance evaporates and acts through the thymol concentration in the hive air.
Dosage depends on the hive type: one strip for a single brood box, two strips for two brood boxes, one and a half strips for Dadant. A complete treatment consists of two applications. After three to four weeks the strips are removed and a second set is immediately inserted for a further three to four weeks, so about six to eight weeks in total. Increased mite drop continues for up to two weeks after the strips are removed.
The hive-air concentration is decisive for the effect, and it depends on two things. First, temperature: the best efficacy occurs at daily maximum temperatures of 20 to 25 °C; below 15 °C too little thymol evaporates, above 30 °C use is contraindicated. Second, the hive: open mesh floors must be closed during treatment and oversized entrances reduced to normal size, otherwise the vapors escape and no effective concentration builds up. This is one of the most common application errors of all.
Thymol does not act into the capped brood, which is why the long treatment duration spanning several brood cycles is necessary. A winter treatment with oxalic acid in the broodless state must additionally be carried out in every case. Opinions differ on the timing of treatment start: the manufacturer names late July to early August for the first and September for the second application, while the Hohenheim State Institute for Apiculture calls for a start by July 15 at the latest for thymol products in general. Assessments of propolization of the strips also differ: the manufacturer sees no discernible reduction in efficacy from it, while Hohenheim names heavy early propolization as a reason for insufficient efficacy.
Other known side effects are the moving of food away from underneath the strips and reduced food uptake with simultaneous feeding. The manufacturer recommends a distance of at least 20 centimeters from the feeding point; Hohenheim advises against feeding during thymol treatment altogether. Thymovar is approved as a veterinary medicinal product in Germany. The withdrawal period for honey is zero days; the product must not be used before or during the nectar flow, and combs that were in the brood chamber during treatment must not be extracted the following spring. When handling it, impermeable protective gloves should be worn; thymol can irritate skin and eyes and trigger contact eczema.
Quellen (4)
- Thymovar 15 g, Produkt- und Pflichttext (Andermatt BioVet GmbH, Zulassungsnummer 400966.00.00)
- Thymovar 15 g, EU Union Product Database (Zulassungsdatenbank für Tierarzneimittel)
- Landesanstalt für Bienenkunde Hohenheim: Hinweise zur Anwendung von Thymolpräparaten
- Emmerich, I.: Zugelassene Arzneimittel für Honigbienen in Deutschland, Berliner und Münchener Tierärztliche Wochenschrift 2018