Cluster Flies and How to treat them
What are Cluster Flies
Cluster Fly is unlike other blow flies like bluebottle they do not present a health hazard because they do not lay eggs in human food, they are strictly parasitic on earthworms.
The females lay their eggs near earthworm burrows and the larvae then infest the worms.
These flies are a nuisance when the adults emerge in the late summer or autumn and they enter houses to hibernate often in large number and are difficult to eradicate because they favour inaccessible spaces such as roof and wall cavities.