How to Get Rid of Cluster Flies in House & Attic Naturally

fly paper with cluster flies entrapped to it
Fly paper that attract flies via pheromones and then get the flies stuck to an adhesive.

We will teach you how to get rid of cluster flies from your house or attic, including some natural methods. Cluster flies are similar to common house flies, but they are slightly larger up to 3/4 inches and do not buzz. These flies travel in packs and live in groups, hence the name. Their clusters can grow from hundreds to thousands flies.

Cluster flies generally stay outside during the warm months, but during the colder months, they will seek shelter in closed areas including homes and any undisturbed areas such as attics and basements.

These flies can find their way into your home, inside your walls, or chimney. Surprisingly, they can find their way into buildings through cracks and crevices as small as a dime’s thickness. Cluster flies can manage to push their way through these and nest until the spring.

There are steps to take to keep cluster flies away, but if you already have them you will need to take more drastic measures.

Video explaining cluster fly life cycle, cluster fly infestation entry points, and cluster fly infestations

How do Cluster Flies Reproduce and Spread?

A female cluster fly can drop her eggs onto rotting leaves or near an earthworm burrow. Her larvae stay with earthworms until adulthood. It takes around a month for cluster fly larvae transform into adults with wings.

Adult cluster flies often feed on flowers. Cluster flies are also prolific breeders. They can produce so many eggs that up to four generations can be hatched each summer. These flies do not cause any harm to any human since they don’t carry any diseases (as of yet).

But, they can reek over time. This tends to happen when they stick to an area for a while. Cluster flies can also leave behind a sticky mess. Overall, cluster flies can be very annoying and they spread fast. Due to how fast cluster fly infestations spread, it is best to get rid of them as soon as possible.

Help, I have an urgent cluster flies problem to solve!

Cluster Fly Removal

If you have cluster flies in your home you will need to take the steps in getting rid of them. You can either vacuum them up using a shop vac or use insecticide which will kill them immediately. You can use Lambda Star Ultra Cap 9.7 or Cyper WSP to help get rid of cluster flies.

The insecticide is odorless and doesn’t leave a stain. You can also use a pyrethrin aerosol; it’s just as effective when you spray it in the area where the flies are located. A dust method is another option. D Fense Dust can be placed into opened areas including crevices and holes before caulking or closing the openings.

The dust will fly throughout a short distance to kill off any flies around the area. It also prevent cluster flies from returning through any cracks or crevices where you applied the dust.

Cluster Fly Prevention Tips

In the Fall take measures to prevent cluster flies from coming around by closing up cracks and crevices that are unnecessary around your home. Check around your window and door frames to make sure there is no way any insect could get in.

Seal it up with caulking or make repairs where needed. Use protective screens over vents, the chimney opening, and the attic. This will prevent cluster flies from entering your home when all of the holes and cracks are repaired and screens are in place.

Spray the insecticide along the walls and roof of your home or building, particularly around doors and windows and any other entry place to help prevent cluster flies from entering.

They may choose to land on your home to see if there is an area to start nesting. You want to remove any debris that has been sitting around your home. Trash it or use it (depending on what it is), but clean it up.

If you have a pile of wood stacked for your fireplace, ensure it is at least 20 feet from your home to prevent insects that are attracted to wood from being too close to your home. Keep your lawn low along with your bushes and trees trimmed.

These are always the best methods to keep your home clean and free from predators, rodents, and insects from coming around. Be prepared to smell an odor if you squish a cluster fly. They give off an odor that is rather stinky.

Contact an expert at cluster fly control!

Steps for Cluster Fly Control

Follow these specific steps to get rid of cluster flies:

  • Identify where they are.
  • Spray insecticide where cluster flies are hibernating.
  • Place dust in cracks and crevices.
  • Place protective screens in attic and chimney openings.
  • Seal up all cracks and crevices and any holes.

Further Resources on Cluster Fly Control:

  1. Cluster Fly (Pollenia rudis) – Connecticut Agricultural Experiment Station
  2. Cluster Flies [fact sheet] – University of New Hamshire Extension
A deep dive into cluster fly control from the British Pest Control Association

By David Jackson

I enjoy learning about new pest control strategies and sharing what I learn at I aim to create a reliable resource for people dealing with all sorts of pest issues.

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