Chalkbrood

Chalkbrood is a common and widespread bee disease affecting honey bee larvae. It is caused by the fungus Ascosphaera apis. The disease is characterized by the mummification of infected larvae, which turn chalky white or gray. These mummified larvae are often found lying on their sides, or curled into a "C" shape, within the honeycomb.

The disease is spread when healthy larvae ingest spores of the fungus, typically from contaminated food or equipment. The spores germinate within the larva's gut, and the fungus then grows throughout the larval body. As the larva dies, it hardens into a mummy. The mummies can be easily dislodged from the cells and are often found on the bottom board of the hive.

Chalkbrood can range in severity from mild infections with few symptoms to severe outbreaks that can significantly weaken or even destroy a colony. Symptoms are most visible when the larvae are still in their cells, appearing as hardened, discolored lumps. Adult bees will attempt to remove the mummies from the hive.

There is no cure for chalkbrood, but management strategies can help control its spread and impact. Good apiary hygiene, including regular inspection and cleaning of equipment, is important. Beekeepers may also select for more hygienic bee strains that are better at detecting and removing diseased larvae. Providing colonies with good nutrition and preventing overcrowding can also help them resist infection. In severe cases, beekeepers may need to requeen their colonies or even destroy infected hives to prevent the disease from spreading to other colonies.