Chalkbrood is fairly common in Europe and can cause serious damage to hives if left unchecked. It is caused by a fungus Ascosphaera apis and affects honey bee brood. The fungus can forms spores when reproducing and infection by spores occurs in young larvae of around three days old and enter the body by ingestion or absorption.
How Do I Spot it?
Swelling of the dead brood is covered in a white coated in covering as a result of the fungus. The dead brood shrink and appear, chalklike resulting in a mummified appearance. The colour of the dead brood varies with time of exposure from white, to grey and finally, black. If the infestation is heavy, most of the sealed brood dries out and dies within the cells.
In the early stages, encouraging good bee hygiene, as the bees remove the affected brood quite effectively. Although in heavier infestations once spores are produced bees can carry the spores throughout the hive whilst cleaning.
Removing the white mummies as soon as possible, so that the spores of the fungus are not propagated throughout the hive, by bees and air currents.
Stimulate bee hygiene behaviour by changing the hive conditions. Reduce the size of the hive to the strength of the colony so the bees have a manageable cleaning task.
Reduce hive humidity by providing suitable ventilation.
In the early stages of the disease, ensuring there are lots of young adult workers and hatching brood, combined with feeding sugar-syrup, often proves to be helpful.