Varroa Mite (Varroa destructor)
Lexikon
The Varroa mite is the most significant parasite of the honey bee.
The Varroa mite is the most significant parasite of the honey bee. It originally comes from the Eastern honey bee and was introduced into Germany in the 1970s. It was not adapted to our honey bee, which is why untreated colonies usually die. The adult female mite is brown, oval and flattened, and clearly visible to the naked eye, for example when it sits between the abdominal segments of a bee or lies as a brown dot in the debris.
The reproductive cycle is key to understanding it. The foundress mite crawls into a brood cell shortly before capping and reproduces there, protected under the capping. In drone brood, which stays capped longer, more daughter mites can develop than in worker brood, which is why drone brood is much more heavily infested. The mites feed on the body tissue of larvae, pupae, and adult bees. Varroosis is therefore neither a pure brood disease nor a disease of the adult bee, but a parasitic infestation that affects both.
The damage is twofold. Even a single mite in the cell weakens the emerging bee, and several mites lead to deformities or death. In addition, the mite transmits viruses, above all deformed wing virus. Things become critical in late summer: when the amount of brood and the number of bees decline, the infestation rate rises sharply, and that is exactly when the winter bees are being raised. On top of this comes reinvasion, that is, mites being brought in from collapsing colonies in the surrounding area through drifting and robbing.
In practice several building blocks lead to success: regular monitoring of infestation through debris diagnosis or bee samples, biotechnical measures such as cutting out drone brood, making splits, or brood removal, and, coordinated with these, treatment with approved veterinary medicines. Every treatment must be followed by a check of its success. Legally, the Animal Disease Reporting Ordinance has applied in Germany since 11 March 2026: varroosis is listed there in Annex 2 and must be reported, but with considerably more limited consequences than the diseases in Annex 1, namely American foulbrood, infestation with the small hive beetle, and infestation with Tropilaelaps mites. At the same time, the Bee Disease Ordinance obliges the owner to treat all colonies in an infested apiary against varroosis every year.