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European Foulbrood: what it looks like on the frame

May · built up fast, then stalled. A faint sour smell.

Drawn illustration. The gold circles mark what to look at.
WHAT YOU'RE SEEING

Larvae dying in OPEN cells — twisted off their neat coil, going yellow-tan and slumped, some melted into the cell bottom. That timing is the tell: EFB kills larvae before they're capped, while AFB kills after, under sunken cappings.

WHAT TO DO

Requeen or give a brood break, and get it confirmed

EFB often clears once a strong flow and a laying break break the cycle, so requeening buys both. Get it confirmed, though — the reason to be sure is that AFB looks similar and is the one that means fire. And in the US antibiotics for bees are prescription-only through a vet, so 'buy some online' isn't a legal option.

Easy to mistake for

Could you spot this with the lid off?

Read the Frame deals you 8 random frames. Say what you see, say what you'd do, and find out why. It's free and runs on your phone.

Drill disease → Mixed round (all 32 frames) →

More disease

These frames are drawn to teach the pattern, and real frames vary. If you suspect foulbrood or a pesticide kill, contact your state apiarist. In Pennsylvania that's the PA Department of Agriculture apiary program. Samples to the USDA Beltsville Bee Lab are free. From The Alleman Apiary in Middletown, PA.