Whether you know it or not, your home or building could serve as a hotel for pests like cluster flies while they harbor for the winter. Cluster flies typically hide in the cracks and crevices of homes during the winter to avoid the cold, only emerging in the spring when temperatures warm. This is known as overwintering.
Once cluster flies are inside your home for the winter, they can be hard to control. Instead, the best way to eliminate a cluster fly infestation is to prevent the infestation before it begins.
Read below to learn how to stop cluster flies from entering your home. These steps should be taken before temperatures cool in the fall or else they will not prevent cluster flies from entering the home for the winter.
Treat Your Home for Cluster Flies
Choose an insecticide labeled for cluster flies, such as Onslaught, Tempo SC Ultra, or Suspend Polyzone. Ideally, the insecticide you choose is a residual. Residual insecticides last longer than non-residuals, allowing more cluster flies to come into contact with the product.
Treat the Outside of Your Home
Use an insecticide labeled for cluster flies to create a barrier around the perimeter of your home.
Read the label of your insecticide to determine how much insecticide and water you will need for your treatment. Then, while wearing gloves and long-sleeves, mix the insecticide of your choice with water in a hand pump sprayer. Replace the cap of the sprayer and shake the sprayer to thoroughly mix your solution.
Read our guide on how to mix and apply liquid insecticides for further mixing instructions.
Then, spray the following areas around the home:
- Spray 3 feet up and 3 feet out around the perimeter of your home's foundation
- Spray 3 feet up onto the sunniest side of the house or building. This is where cluster flies and other overwintering pests are most likely to be found.
- Around outdoor light fixtures
- Around door and window frames
- Where utility pipes enter your home
- Where caulking around windows and doors has cracked open
Treat the Inside of Your Home
As a second preventative measure, spray the insecticide-water mixture in the following areas around the inside of the home:
- Around door and window frames
- In cracks and crevices
- In crawlspaces and basements
- Where utility pipes enter the home
Use an Aerosol Spray Outdoors
Another way to prevent cluster flies from entering the home is to use a residual insecticide in an aerosol can, such as Cy-kick CS Aerosol. Spray the aerosol can in the following areas:
- On window and door screens
- Around light fixtures
- In the corners of garages and porches
- Around window and door frames
- Around soffits and eaves
- In cracks and crevices around the foundation of the home
Refer to the label of the can for instructions on how often to reapply. Do not apply where you have already applied liquid insecticides (step 1) as the two treatments in the same area will lessen the effects of the insecticide, essentially cancelling each other out.
Exclusion and General Pest Prevention
The easiest way to prevent cluster flies from entering your home or yard is to practice basic sanitation methods, known as general pest prevention.
Follow these simple steps to keep cluster flies away:
- Caulk or seal off any points of entry for cluster flies including cracks and crevices around door and window frames, soffits, vents, pipes, and where utilities enter the home
- Use door sweeps to block cluster flies from entering below exterior doors
- Use Xcluder cloth to seal up any gaps where pipes or utilities enter the home
- Maintain general cleanliness around the home by frequently vacuuming, sweeping crumbs from the kitchen, and emptying out trash cans
- Address drainage issues and other areas of moisture around the home. Yard waste, lawn clippings, wood mulch, and piles of wood can be breeding grounds for cluster flies as these areas attract earthworms, which themselves attract cluster flies.
We hope you have found this guide helpful. If you are not sure if you have cluster flies, read our guide on what cluster flies look like to be sure. Where cluster flies hide will help you find cluster flies inside or around your home or building. And how to get rid of cluster flies will review your treatment options.
If you have any additional questions about cluster flies or the products mentioned in this guide, give our customer service team a call at 866-581-7378 or email us at firstname.lastname@example.org.