Hydrex Pest Control - The Cluster Fly

The Cluster Fly

Cluster flies are named for thier strange hibernation behavior where they sometimes form in clusters. Adults are around 3/8" long, dark colored, with no metallic sheen. Cluster flies are generally slower and clumsier than other types of similar flies. And if they are crushed, will leave a greasy stain. When it starts to get cold out, these flies seek shelter in homes to overwinter. They only need a very small hole to get in, so even well sealed homes can be infested. They can be in various types of voids, or in attics, or even in plain view. Since they are attracted to light, you may see them by windowsills as well. At this point they have their food stored, and won't be active feeders. As for the larvae, they're another story. You won't see cluster fly larvae like you do other types of maggots. This is because they live inside earthworms. The adult lays her eggs in the soil, and then they hatch out and find an earthworm to host on and develop. This makes control at the larval stage almost impossible.

Treatments for Flies