Do you recognise this problem on the brood? Explain what you see.
- European foulbrood, with flaccid larvae and patchy brood.
- Healthy colony, with regular brood and no suspicious sign.
- Banded brood.
- American foulbrood, with dark cappings and a stringy mass.
- Deformed Wing Virus: DWV, a viral disease.
- Nosemosis affecting mainly adult bees.
- Chalkbrood alone, a fungal brood disease.
Show answer
Correct answer: 3.
Banded brood associated with wax moth, with possible chalkbrood.
Why?
Banded brood, or bald brood, is recognised by brood cells that are open, raised, or irregularly capped. The pupa may be visible in the cell, sometimes surrounded by a small rim of wax.
This picture is generally linked to galleries dug by wax moth larvae under the cells. These galleries disrupt normal capping and can give the impression of cells opened in a series.
If the image also shows dried-out, hard larvae that are whitish, greyish, or black, there may be an appearance of chalkbrood. This point must remain cautious if the mummies are not clearly visible.
What to understand
Banded brood and chalkbrood do not arise from the same mechanism. The first is often linked to a pest, the wax moth, whereas the second is a fungal brood disease due to Ascosphaera apis.
The wax moth develops above all in areas poorly occupied by the bees, in weak colonies, or on combs stored under poor conditions. Wax moth droppings, webbing, and galleries are then useful clues.
Chalkbrood, for its part, manifests through dry larval mummies that detach quite easily. It is favoured by humidity, chilling of the brood, stress, and a colony too weak to cover its brood nest properly.
Key takeaways
The main sign here is banded brood: open or domed cells, often neighbouring, which may indicate a wax moth gallery.
Chalkbrood is only to be kept as a possibility if dry larval mummies that are white, grey, or black are visible.
Prevention relies on strong colonies, few unoccupied combs, regular renewal of old combs, and storage of combs in a cool, ventilated, and controlled place.
Further reading
► Practical Guide: 2.6 Wax moth
► Practical Guide: 2.4 Chalkbrood