Chalkbrood

Causal agent		Ascosphaera apis - Fungus
Other names		Chalk
Age group
Egg	Larvae		Pupae		Adult - worker	Drone	Queen
No	Yes
Clinical signs
Season		Commonly occurs in wet springs
Outside		The chalk mummies are often deposited on the landing board or on the ground surrounding the hive
Odour		None
Brood		Examination of the brood nest reveals chalk brood mainly at the bottom
Cappings		Almost no torn caps. May be sealed and unsealed cells.
Larvae appearance		The larvae die and become hard and white or black. Occurs after capping. Larvae are upright in cell. The mucelia grow to fill the cell.
Scales (larvae)		White-grey and hard, rattle in cell. Does not adhere to cell wall.
Other		Problems tend to occur in older colonies – 3^rd season plus Hive tend to raise less Drone bees which may affect fertility Often seen in association with Sacbrood.
Chalkbrood mummies are removed from the hive by the house bees and found on the ground by the hive				The chalkbrood in the brood nest. They will rattle when you move the frame. If the “chalk” has black spots this indicates spores being produced.
Infectivity
		Fungus is in the honey and fed to the larvae. Spores resistant for 15 years.
Transmission
		Drifting and robbing moves the fungus between hives
Post-mortem Lesions
		Appearance of larvae
Diagnosis
		Appearance of larvae – become covered by fluffy cotton-like mycelia.
		Culture
Treatment
		Increase ventilation though the hive
		Clean frames
		Enhance biosecurity
		Spontaneous recovering in warm weather
Control		Do not move infected frames
Common differentials
Zoonosis		None