Which disease (A1)?

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Correct answer: 1

Tubular brood, also known as “bald brood,” is characterized by the construction of a rim of wax at the upper part of the cell that remains unsealed. The pupa, of varying age, is visible inside. The condition is attributed to larvae of the lesser wax moth (Achroea grisella), a lepidopteran from the same family as the greater wax moth (Galleria mellonella), which infests combs during its larval stage. The larvae excavate galleries at the base of the cells, restricting the space available for the growth of bee larvae. As a result, these larvae are positioned higher and are not always capped.

Field symptoms and diagnosis:

• An infestation by wax moths is easily identified by the black droppings found on supports placed at the bottom of frame cabinets or in hive bodies. In addition, several domed or opened cappings of adjacent cells (tubular brood) indicate the presence of a gallery dug by the wax moth.
• Wax rims around cells that are not capped.
• When these pupae are removed from the cells, excreta from wax moth larvae (grayish rods) are often found on their bodies.

Prevention and control

Keep only honey frames without pollen that have never contained brood.

• Store food and honey frames separately. Melt down, rather than store, frames that have contained brood. Brood frames that have come into contact with chemically synthesized varroacides must be discarded or may be used for candle production.
• Frame storage: cool (below +12 °C), in a well-ventilated room, with light.
• Regularly melt down old frames.
• Avoid weak colonies.
• During storage, regularly check for wax moth droppings.

What can the beekeeper do?

It is recommended to strengthen bees’ natural defenses against disease by applying the principles of good beekeeping practice. Colonies are healthy when they develop well (adult bees and brood), display good hygienic behavior, and produce good yields. In practice, these are referred to as strong or vital colonies (see cover image). Colony vitality depends on many factors. Beekeepers mainly have the following levers of influence:

• Apiary locations with good nectar flows (continuous food supply) and a suitable local climate.
• Regular creation of young colonies and replacement of weak colonies.
• Selection of queens with sufficient vitality traits (colony development, hygienic behavior).
• Regular renewal of combs.
• Varroa mite control in accordance with regulations – hygiene in the apiary.
• Caution when taking over bees from other locations (diseases!).
• Avoid any importation of bees from regions outside Europe.

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