Chalkbrood

Causative Agent:

Ascosphaera apis (fungus)                                                           IMAGE TO BE ADDED

Age of Brood Affected:

Larvae three or four days old are most susceptible - though both sealed and unsealed brood can become affected.

Chilling of susceptible larvae is required immediately after the cells have been capped for the disease to be come established. Death occurs about two days after the cell has been capped.

General Appearance of Brood Combs:

In a heavy infection, the brood pattern may appear scattered.

Method of Disease Infection:

The spores of the fungus are introduced to the larvae through contaminated food.

Chalkbrood spores are highly infectious and are carried in contaminated pollen, by infected foraging bees leaving spores at floral and water sites, by queens, drifting bees and drones.

The spores can remain viable for 15 or more years in contaminated equipment and soil.

Cell Position of Diseased Brood:

In the early stages of the infection, larva and pupa are fluffy (usually white in colour) and swollen to the full dimension of the cell.

Colour of Diseased Brood:

Infected larvae initially take on a white, fluffy appearance but gradually change to hard, flat lumps resembling chalk (these may also be grey or black).

It is the grey/black mummies that produce spores.

Ropiness of Moist Material:

Nil.

Scale Characteristics:

The hard "chalks" or "mummies" are removed by adult bees and may be found on the bottom board or on the ground near the hive entrance. Mummies will also be present in brood combs during inspection.

Treatment:

Hives usually recover from this disease by themselves. However, where a hive has been weakened, assistance in recovery may occur if the mummies deposited on the hive floor (or bottom board) are removed.

Cleaning hands and equipment between hives, keeping hives warm and dry, not subjecting bees to nutritional stress and re-queening if necessary can reduce outbreaks.

What Should be Sent for Diagnosis:

Mummies or comb containing suspect brood.

If comb is being sent please ensure that it is in within a waterproof container (eg jar).