How do I identify and treat bee diseases?
Diagnose from the brood, not the adults. Sunken, perforated cappings over ropy brown larvae that smell foul indicate American foulbrood, which is notifiable in most countries and usually means destruction of the colony. Twisted grey larvae in open cells suggest European foulbrood. Chalkbrood and nosema respond to husbandry: dry sites, young queens, clean comb.
The full lesson
To protect your colony from varroa mites, which suck bees' blood and weaken the hive, you must take action every season before it's too late. Formic and oxalic acids leave no residue in honey, making them the most eco-friendly and effective methods to fight varroa.
This is the most dangerous bee disease. The larva collapses inside the cell, rots, and stretches like a brown thread. High humidity in chilled hives cause larvae to catch a fungus, hardening them into chalk-like dead mummies.
When bees are stressed or poorly fed during long winters, dark brown streaks on the hive walls indicate a nosema infection. To prevent diseases from spreading between colonies, empty wooden hives must be regularly sterilized using a propane torch.
This lesson is also in the app, along with the other twenty-nine.
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1:30Lessons and forum answers describe beekeeping practice and peer experience, not veterinary guidance. Treatment thresholds, inspection timing and disease management vary by climate, subspecies and local regulation. Diseases that are notifiable where you live must be reported to your national bee inspectorate.