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You are here: Public Pages » Bee Pests, Diseases & Maps » Other Brood Disorders
Cause
Sacbrood is a viral infection of the brood caused by the Iflavirus genus and occurs when a diseased larva fails to pupate after being sealed in its cell. Fluid then accumulates between the body of the larva and the unshed skin, forming a sac. It is a relatively common disease during the first half of the brood-rearing season and can often go unnoticed, affecting only a small percentage of the brood. It does not usually cause severe colony loss.
Symptoms
Initially during an infection, the virus particles replicate in the developing larva, which appear to develop normally until after being capped over. Typical symptoms include:
Cause
Chalkbrood is caused by the fungus Ascosphaera apis. When ingested by the larva it penetrates the gut wall to absorb nutrients. As the spores germinate and multiply, the larva eventually dies of starvation. After a few days of growth, the larva and fungus swells and fills the brood cell where it will eventually harden after a few days to its distinctive 'mummified' appearance. Here it adopts a mottled white and black colour and each chalkbrood mummy will produce millions of infective spores which stick to the cells, hive components and adult bees.
Symptoms
Typical symptoms will start to appear in early spring as the colony starts to build up its population. Conditions such as damp and cold weather will promote fungal spores. Symptoms of chalkbrood include:
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