What are Cluster Flies and How Can They Be Prevented?

With Utah’s hot summers, Utah residents are generally used to dealing with house flies throughout July and August. However, the cooler months of the year bring their challenges as cluster flies are more likely to be found inside homes.

What is a Cluster Fly?

There are a few easy ways to tell a cluster fly from a house fly. Cluster flies are larger than house flies and gray-colored with black markings or checks on the bottom. While the wings of house flies stay separate when they’re at rest, cluster flies’ overlap. These insects also fly more slowly than a house fly and can be easily swatted. The biggest sign that you’re dealing with cluster flies, however, is if they “cluster” or gather in a large group within your home, often on windows, windowsills, and walls.

Cluster flies generally live outdoors, but the colder months lead them to seek out warmth, which often can be found on or inside homes. These insects are attracted to warm, sunny parts of homes and may head inside through any cracks or gaps available to them. You’re most likely to see cluster flies in the fall when they’re searching for a place to overwinter, and in the spring, when they’re emerging again due to warmer weather.

Cluster flies are not dangerous to humans, do not bite, and do not result in damage to property. However, they can leave behind stains on walls from excrement. The primary reason why homeowners want to remove these insects from their homes is because of the frustration and annoyance that comes from dealing with large numbers of these flies indoors.

How to Prevent Cluster Flies From Infesting Your Home

The most important step to take in preventing cluster flies from infesting your home is to take away their entry points. Carefully inspect your home for cracks or gaps around windows, vents, chimneys, doors, and pipes, paying particular attention to the sunnier west- and south-facing sides of your home, and thoroughly seal any gaps with silicone caulk. Make sure any damaged screens or doors are promptly replaced.

You can also work with a professional pest control company to perform a preventative treatment. This generally occurs in the early autumn, before the insects start to congregate, and will keep cluster flies out of your home. It’s also worth taking extra steps to keep any foods and sweets in your home sealed and away. 

If the flies are already in your home, feel free to use a fly swatter, a vacuum, or fly traps like you would with houseflies. However, it’s generally not a good idea to attempt an insecticide treatment yourself, as dead insects may attract other pests such as carpet beetles or rodents. If the number of cluster flies in your home gets too much, reach out to a professional pest control provider for efficient and effective treatment.

Eco-Friendly Pest Control in Northern Utah

Whether you’re dealing with cluster flies or any other type of insect or rodent, Nature’s Balance can help. Our professional pest control technicians have extensive experience helping residential and commercial customers remove a wide variety of pests from their premises, and we take pride in providing each of our clients with fast, friendly, and effective pest control services.

Nature’s Balance serves all of Summit, Wasatch, Salt Lake, and Utah counties, and specializes in providing eco-friendly treatments that are safe for the environment, kids, and pets. Contact us today to learn more or request a free quote.