Interested in other Waltham Pest Services blog content?

Cluster Flies

What Do Cluster Flies Look Like?

cluster fly control photo

Cluster flies are dark gray with a black checkered abdomen. They have a golden sheen from the tiny yellow hairs covering their bodies. About half of an inch long, these flies have wings that overlap when not in-flight. Their wedge-shaped maggots are cream-colored. However, only adults appear inside, as these pests breed in the soil.

How Can I Tell if I Have a Cluster Fly Problem?

Unable to withstand cold weather, cluster flies move indoors over the winter. Signs to look for include:

  • Sighting – When temperatures begin to drop, these insects seek out warmth. On a sunny day, you may notice large numbers of cluster flies gathering on the side of a building.
  • Noise – Sizeable groups of cluster flies may make audible sounds when living in attics, ceilings, or unused rooms.
  • Swarms – These pests may emerge on warm days, swarming overhead lights and sunlit areas.
  • Exits – During the spring, these pests want to return outdoors to lay eggs. They move to windows and doors in an effort to get back outside and breed.

How Do Cluster Flies Get Inside Homes and Businesses?

These insects prefer to live in fields and yards, feeding on nectar and fruit juices. However, they will come into homes and businesses to overwinter. Cluster flies get in through gaps under eaves and siding. They often stay in wall voids but may enter rooms through unsealed window frames or light fixtures.

Since they like to hide in crevices and holes, cluster flies may infest hotels or nursing facilities with uninhabited storage areas. Cracks or openings in roofs and windows offer easy access to these structures. Additionally, these pests can easily come in via open loading docks in warehouses.

Are Cluster Flies Dangerous?

Considered to be a nuisance pest, these insects don’t carry any diseases. Cluster flies don’t breed or nest in buildings, but they may appear indoors during the colder months. In the case of an infestation, you may find smudges of cluster fly waste on your windows or walls, which is harmless but unsightly.

Tenants in apartment complexes may lodge complaints about a cluster fly infestation. Residents can find the swarms and buzzing sounds annoying. While they don’t contaminate or eat human food, cluster flies in a restaurant can deter customers and make the establishment appear unclean.

How Can I Prevent Cluster Fly Infestations?

Sealing entry points, such as cracks around chimneys and spaces near utility pipes, can help keep cluster flies out. You should also repair gaps in windows and damaged screens. If you think you have a cluster fly problem, contact Waltham Pests Services and speak to a professional today.

Get rid of bugs fast.

* All fields are required