Agriculture Reference
In-Depth Information
like white mould on bread. The larvae are, at first, swollen inside their cells, but, later
on, dry out to become hard, white or grey/black, chalk-like mummies.
The fungus can affect larvae in unsealed (as in sacbrood) or sealed cells. The cell caps
are either light or dark, and are sunken with many with perforations like AFB, EFB
and sacbrood. Indeed, chalkbrood symptoms may be mistaken for other brood diseases
(such as AFB, EFB and sacbrood), and even, for white pollen. If you become at all
confused - and most of us do - ask for advice from your local bee-inspection officer or
from other beekeepers.
In a hygienic colony, if the bees detect dead larvae under the cell caps, they chew holes
in cappings and remove the mummies within ten days. The mummies are dropped onto
the hive floor and, later, outside the entrance, where they can usually be seen on the
alighting board.
Treating and preventing chalkbrood
There is no chemical cure or treatment for chalkbrood although, in recent years, many
patent liquids have been marketed as cure-alls. Management practices that reduce the
stress on the hives and, thus, that reduce the number of chalkbrood spores, are probably
the best way to prevent and manage the disease. Maintaining strong, healthy colonies is
also important in the management of chalkbrood.
Other management practices are as follows:
Provide good ventilation in your hives. Research has shown a possible link between
chalkbrood and CO
2
levels in hives.
Add young adult bees to your hives.
Do not force your bees to spend the winter in a hive that is over supered. This will
lead to chilling.
Avoid opening your hives in cold weather.
Try not to stress your colonies (for example, by moving them too much).
