Pest Management for Cluster Flies

Cluster flies, also known as grass flies and attic flies, are slightly larger than the common house fly, with a dark grey, non-metallic body covered with short golden hairs and wings that overlap, in contrast to the house fly. Named for clustering behaviours near light and heat sources, these parasites will infest their larvae inside earthworms in the wild, but have adapted to invade homes as a form of shelter from the cold as part of their natural hibernating behaviours.

While they do not reproduce inside invaded homes, their excrement and carcasses may attract other pests or stain curtains and walls. However, their mass hibernating behaviour means that indoor warmth and warm weather may prompt hidden swarms of cluster fly larvae and adults to reactivate, creating the appearance of sudden reproduction. They are natural omnivores and can be found around flowering plants, trees, wall voids, dark corners, under shelving, beneath curtains, and other concealed areas.

The best way to control cluster flies is to proactively reinforce the building before they enter buildings in large numbers. Sealing exterior cracks and holes requires a thorough inspection of a structure to pinpoint the entry points, and is most effective against cluster flies when done in midsummer. Once cluster flies have settled in wall voids and other secluded areas, control becomes difficult to achieve. Furthermore, the risk of additional infestations increases as pests such as beetles and rodents, which feed on dead flies, may cause a secondary infestation.

If you are facing an infestation of cluster flies in your home or office, then rely on Advantage Pest Control to provide effective solutions. We offer pest management services in Whitby, North York, Scarborough, Toronto, and surrounding areas.