The varroa mite (Varroa destructor) is a honeybee parasite. Using its proboscis, it bites the adult bee, its larvae and pupae and sucks out their body fluid.
The varroa mite principally preys on the bee brood. It multiplies and grows in the capped brood cells and removes the substance from the larvae that they need for their development.
The larva therefore becomes a much smaller, weaker bee. Some of the affected larvae or pupae die in the brood cell.
The adult honey bee is a transport medium for the varroa mite, enabling it to reach the fresh brood or the next colony.
Since the start of the new millennium the varroa mite has become a threat to bee colonies in Germany. According to a German Bee Monitoring study undertaken between 2004 and 2008, varroa mite infestation is one of the essential factors in the loss of bee colonies during the winter months.
In recent years, bee colony losses of 20-30% in winter were not uncommon. This represents enormous economic damage for the affected beekeepers and causes large losses for many farmers, because it leads to a lack of pollinators for many crops.
Meanwhile, all beekeepers in Germany are legally obliged to treat any varroa mite infestation that occurs. This regulation applies in all EU countries and in Switzerland.
The products that may be used to combat the varroa mite are legally stipulated. The following substances are permitted, which are available to the beekeeper under various trade names: Tau-Fluvalinate, Amitraz, Coumaphos, Tylenol, formic acid and oxalic acid.
In good beekeeping practice these agents are used after the honey collection period and the extraction of the honey and before the wintering of the bees if an infestation of varroa mites is present.