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How to Prevent Cluster Flies

The cooling temperatures of fall warn pests that winter is approaching. Some pests, like cluster flies, search for places where they can overwinter. These pests often enter homes in large groups hoping to escape winter weather. We’ve gathered information to help you keep cluster flies out of your home

What Attracts Cluster Flies?

Cluster fly

When pests sneak into homes, there’s often a reason for their arrival. Knowing this reason can help you prevent an infestation. Here are a few things that may be luring cluster flies to your home.



One of the main reasons cluster flies end up in homes is due to a change in weather. As fall approaches, cluster flies need to find a safe place to hide during winter. Your home provides them with a warm place to stay. These pests gravitate to the sunny side of homes where it’s usually warmest. Since heat rises, cluster flies head towards attics or the upper floors of houses.



When searching for a warm spot, cluster flies also seek a dark and undisturbed location. Attics and wall voids make the perfect hiding spot for these pests. That’s why they are sometimes called attic flies. On a warm day, you may find them flying around your home, especially near doors and windows.


Light bulb

Like many pests, cluster flies are attracted to light. They cluster on and near windows that receive the most sunlight. They also are attracted to artificial lighting. Exterior porch lights can attract these flies. Lights in your home, like lamps and ceiling lights, can also act as an attractant. Cluster flies have been known to hide in light fixtures.

How to Prevent Cluster Flies

The best time to prepare for these overwintering pests is the end of summer and early fall. This will help ensure you’ve pest-proofed your house before cluster flies start seeking shelter. Here are a few tips to help prevent cluster flies.

Seal Entry Points

Sealing exterior of home

Sealing entry points will help prevent cluster flies from sneaking inside. These pests are small, so don’t overlook tiny holes. Make sure to pay attention to these areas:

  • Cracks & Gaps: Check the exterior and interior of your home for cracks and gaps. Seal them with caulk to keep cluster flies out of your house.
  • Weather Stripping: Make sure weather stripping is in good condition. You don’t want flies slipping in.
  • Door & Window Screens: If the screens on doors and windows have holes, you’ll need to repair or replace them.

Declutter Your Home

Cardboard boxes

Cluster flies prefer undisturbed locations. A messy and unorganized house provides them with extra hiding spots. Make sure to take the time to keep your home clean. Attics tend to be a spot where things accumulate, so make sure to keep this area as organized as possible. This will minimize the places where these flies can hide.

Create a Protective Barrier

Yard Bug Spray & Home Bug Spray

Spraying the perimeter of your home and yard with a plant-based insecticide spray can help to deter cluster flies. Not only does our Yard Bug Spray kill cluster flies, and other pests, on contact, it also has repellent properties. This will create a protective barrier that helps to keep cluster flies away. You can also spray common entry points, like doors and windows, with our Home Bug Spray. It will repel and kill cluster flies.

Your home is the perfect cozy spot for winter, but that doesn’t mean you have to share it with cluster flies. Before fall, make sure to pest-proof your home to keep these pests away. If pests are bugging you, we have your back! Check out our Maggie’s Farm Simply Effective™ Pest Control products for a more environmentally and family-friendly solution.

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