Stonebrood (Aspergillosis)
Krankheiten
Stonebrood is a rare but serious fungal disease in the honey bee colony.
Stonebrood is a rare but serious fungal disease in the honey bee colony. It is caused by mold fungi of the genus Aspergillus, mainly Aspergillus flavus, more rarely Aspergillus fumigatus. The spores of these fungi occur everywhere in soil and air. They enter the larva or the adult bee with the food, germinate in the gut, and grow through the body from the inside.
In the colony, a patchy brood nest and hard, stone-like mummies can be seen. Unlike chalkbrood, stonebrood mummies usually sit firmly in the cell and are difficult to remove. The fungal mycelium eventually grows out of the larva and covers it with a yellowish-green to brownish layer of spores. Adult bees can also become infected; they become unable to move and die, their abdomen hardening. Infestation occurs mainly in damp weather, at shaded locations, and in weak colonies.
There is no effective medicinal treatment. In practice, the only options are to remove and melt down or dispose of affected combs, reduce the space occupied by the colony, move the colony to a warm and dry location, and requeen with a young queen. Heavily affected colonies usually cannot be saved.
Personal protection is especially important. Aspergillus spores can infect the human respiratory tract, nasal mucosa, and eyes and cause serious inflammation there. Affected combs should therefore not be knocked out or scraped dry. A suitable respiratory mask, working outdoors, and avoiding dust are advisable. People with a weakened immune system or respiratory conditions should not carry out this work themselves.
There is no reporting requirement. Because of the risk of confusion with chalkbrood and with forms of foulbrood, a laboratory examination via a certified bee inspector or a bee institute is advisable in case of an unclear finding.