Cluster Flies (Pollenia rudis)

Dark greyish flies about 8mm long with overlapping wings and yellowish hairs on the back. Eggs are laid in cracks in the soil, the larvae emerge in 3 days to burrow into an earthworm where they feed and pupate. The adult fly bursts out after 12-14 days to feed on flowers. In Autumn, they congregate in large numbers to hibernate, often in the roof spaces or upper rooms of rural homes, where they cause a smell and nuisance.

Treatment for Cluster Flies
It is important to seal as many openings as possible, then control the infestation with an ultra-low volume insecticidal treatment supported by crack-and-crevice treatments.