Which disease (A1)?

Why?

Banded brood, also sometimes called bald brood, is recognised by brood cells whose capping is absent, open, or raised. The pupa can be seen in the cell, often with an irregular rim of wax around the opening.

This picture is typically linked to the galleries dug by wax moth larvae under or between the cells. The bee larvae are then displaced or compressed, which hinders normal capping.

So it is neither a foulbrood nor a viral disease: it is above all a sign of the presence of wax moth, often favoured by old, poorly occupied, or poorly stored combs, or by a colony too weak to defend its combs properly.

What to understand

The wax moth is an opportunistic pest. Its larvae develop above all where they find brood residues, pollen, cocoons, or combs insufficiently protected by the bees.

In the field, you should look for additional clues: black droppings, silken webbing, galleries, several neighbouring cells that are open or domed, and sometimes small greyish rods on the extracted pupae.

Differential diagnosis is important. Unlike the foulbroods, banded brood does not first manifest through a stringy larval mass, a suspicious odour, or adherent scales. In case of doubt with a regulated brood disease, expert advice should be sought before any handling or moving of equipment.

Key takeaways

Banded brood generally indicates a wax moth gallery under brood cells. It is a pest and management problem, not a primary infectious disease.

Prevention relies above all on strong colonies, few unoccupied combs, regular comb renewal, and correct storage of combs outside the colony.

Old combs, combs that have contained brood, and combs with pollen are particularly attractive to the wax moth. They should not be kept for long without suitable protection.

Further reading

► Practical Guide: 2.6 Wax moth

► Practical Guide: 4.4.2 Comb storage

► Practical Guide: 2 Diseases and pests

► Practical Guide: 4.7.3 Recognising healthy colonies