The threats to colony health — from bacterial foulbrood to the varroa mite, wax moth, and the modern mystery of colony collapse disorder.
American Foulbrood (AFB)
Bacterial — larvae
Symptoms
•Irregular brood pattern
•Larvae change white → brown
•Foul odor
•Capped cells darken, sunken, moist
•Stringy taffy-like texture when pierced with a toothpick
Treatment
Terramycin (TM) as syrup, dust, or food patty. Never apply TM to colonies with active AFB or AFB scales — infected colonies must be killed and equipment burned or buried per local regulations.
European Foulbrood (EFB)
Bacterial — larvae
Symptoms
•Coiled larvae in cells
•Pale yellow to tan, sleek rather than moist
•Foul smell (not as strong as AFB)
Treatment
Terramycin (TM) as syrup, dust, or pellet. Preventive spring treatment common. Serious infections — send sample to agricultural extension; hive may need destruction.
Chalkbrood
Fungal — larvae
Symptoms
•White fluffy growth fills cell
•Dries to larval mummies — easily removed
•Mummies mottled black-and-white or completely black in spore form
•Mummies at entrance or in capped cells
Treatment
No approved medications — usually self-limiting. Remove mummified carcasses; replace heavily-infected frames. Ensure hives get plenty of spring sun.
Sacbrood
Viral — larvae
Symptoms
•Larvae turn pearly white → yellow → dark brown
•Cell fills with fluid
•Workers usually spot and remove infected larvae
Treatment
No approved medications — workers limit spread naturally.
Nosema
Protozoan — adult bees
Symptoms
•Bees stagger, extremely weakened
•Distended abdomens (midgut infection)
•Light-colored feces streaks in and on hive
•Can reduce honey production 40–50%
•Often infects the queen — requires requeening
Treatment
Fumagillin or fumidil. Prevent with adequate ventilation and clean fresh water access.