Chalkbrood
Chalkbrood is a fungal disease of honey bee larvae caused by Ascosphaera apis. It affects bee brood, particularly during periods of stress or in damp hive conditions. Infected larvae become mummified and hardened, resembling chalk pieces, hence the name. Chalkbrood is generally considered a less severe disease than AFB or EFB, but it can weaken colonies, reduce brood viability, and impact colony buildup. Chalkbrood thrives in cool, damp conditions and is often more prevalent in spring or during prolonged wet weather. Management focuses on improving hive ventilation, reducing moisture, and promoting strong colony health. Chalkbrood is typically diagnosed by visual inspection of brood combs for chalk-like mummies. While treatments exist, improving hive conditions is often sufficient for milder cases.
- Requeen with hygienic stock3
Replace the existing queen with one bred from a hygienic genetic line to strengthen the colony's natural defense against chalkbrood. Hygienic bees detect diseased or dead larvae by scent, uncap infected cells, and remove the mummified brood before spores can spread further. Purchase a mated queen…
📌 commercial📌 best practice4/16/2025, 9:22:01 PM
🛠️ Queen cage, hive tool, queen from hygienic stock breeder
- Increase sunlight exposure2
Relocate hives to a position that receives direct morning sunlight for at least several hours each day. A south- or southeast-facing location (in the Northern Hemisphere) warms the hive early, prompting bees to become active sooner and helping evaporate overnight condensation. Ensure the site is…
📌 diy📌 free4/16/2025, 9:22:01 PM
🛠️ Hive stand (optional)
- Improve hive ventilation3
Reduce moisture inside the hive by improving airflow, since the chalkbrood fungus (Ascosphaera apis) thrives in cool, damp conditions. Install a screened bottom board to allow air circulation from below, and drill a small upper entrance (about 25 mm / 1 inch) near the top of the hive body to…
📌 diy📌 low cost4/16/2025, 9:22:01 PM
🛠️ Screened bottom board, drill with 25 mm bit