Cluster Fly Prevention Guide

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.

Choose an insecticide labeled for cluster flies, such as Onslaught 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.

Another way to prevent cluster flies from entering the home is to use a residual insecticide in an aerosol can, such as D-Force Insecticide. 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.

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.