Do you recognise this brood disease? Explain what you see.
- Chalkbrood, a fungal brood disease.
- American foulbrood, a bacterial brood disease.
- Healthy colony with regular brood.
- Banded brood associated with wax moth.
- Nosemosis affecting mainly adult bees.
- Deformed Wing Virus: DWV.
- European foulbrood, a bacterial brood disease.
Show answer
Correct answer: 7.
European foulbrood, a bacterial brood disease.
Why?
European foulbrood is a bacterial brood disease caused by Melissococcus plutonius. It mainly affects the larvae, often before capping.
In the expected image, the suggestive signs are patchy brood, flaccid larvae that are yellowish to brownish, and dead larvae placed in abnormal positions in the cells.
The larval mass may be viscous, but it is generally little or not stringy in the ropiness test, unlike what is often observed in American foulbrood.
What to understand
European foulbrood can remain barely visible as long as the colony quickly removes the diseased larvae. The symptoms become more obvious when infection pressure increases or when cleaning behaviour is no longer sufficient.
Differential diagnosis is important. Dead larvae or patchy brood are not enough on their own: European foulbrood must be distinguished from American foulbrood, from chalkbrood, and from other brood disorders.
In case of suspicion, the beekeeper should not move any suspect combs, colonies, or equipment. The apiary inspector should be contacted to assess the situation.
Key takeaways
European foulbrood is a contagious bacterial brood disease. It must be taken seriously from the suspicion stage onward.
The important signs are patchy brood, flaccid and discoloured larvae, abnormal larval positions, sometimes a sour odour, and residues that detach more easily than in American foulbrood.
The right response is to limit handling, move nothing, and quickly seek competent advice.
Further reading
► Practical Guide: 2.2 European foulbrood
► Practical Guide: 2 Diseases and pests