Cluster Flies In House? Know What to Do!

Published on July 1, 2025 by Stella
Featured

Cluster Flies in house are not dangerous to your health, but their presence can be irritating for some. A little more information on cluster flies in house will help you to do a good job in getting rid of them and making your house clean and comfortable.

What are cluster flies and how to distinguish them?

Cluster flies, or attic flies, or grass flies, are of the genus Pollenia. They are a little bigger than the house flies, measuring 8-10 millimeters. They are the dark gray color with the golden-yellow hairs on the thorax and a chessboard-like pattern on the abdomen. Their wings are parallel to each other when they are resting unlike the house flies whose wings are spread.

As compared to the normal house flies cluster flies in house don’t reproduce indoors. On the other hand, the larval period of these flies takes place in the outdoors.

These flies decide to come inside homes during the late summer and fall. They prefer places such as rooms, attics, wall voids, etc. where they tend to invade in large numbers. This is why they are called Cluster Flies.

What-Do-Cluster-Flies-Eat

What Do Cluster Flies Eat?

The diet of cluster flies in a house is completely different from other flies. As larvae, they feed on earthworms. Adult cluster flies, on the other hand, have no appetite for garbage, decayed matter or human food, as house flies do. They only eat nectar and other plant-based liquids when they are outside.

What Are the Risks/Diseases Caused by Cluster Fly?

Cluster Flies are not a threat to the health of your family or the pets. However, these flies do not carry diseases that they can transfer either to humans or animals. They do not pollute the food and they do not bite or sting.  Although these flies are non-venomous, but their numbers could make them a nuisance to people.

Methods to Get Rid of Cluster Fly

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The cluster flies can be managed through prevention and elimination of the pests:

  • Seal cracks and gaps: Inspect the exterior of your house and seal any cracks or gaps with an appropriate material.Screen windows and vents: Properly screen windows, doors, and attic vents, leaving no gaps or holes and flies cannot enter.
  • Insulate attics: The reduction of hiding spots for cluster flies can be achieved by using proper insulation and sealing of attic spaces.
  • Clean up properly: Get rid of food and drink spills, stagnant water, open rubbish bins, and pet waste helps to eliminate the sources of attraction.
  • Use a vacuum cleaner: Vacuum is the ideal way of getting rid of flies because it removes them directly from the place where the fly is hiding without disturbing them.
  • If you have a certain area in your room where the flies love to go, put a trap over that spot. This way you will attract and capture all the flies there.
  • Long-lasting insecticide: Use a long-lasting insecticide on exterior cracks in your home. Never ignore the label instructions.
  • Professional pest control: If the infestation is chronic or very severe, call a licensed pest control service to receive special treatment. They will also help you in long-term prevention.

Conclusion

Cluster flies are a problem, mainly in rural and sub-urban regions. They do not transmit disease but there nature of invading in large groups can be an issue. You can prevent them in your home by knowing their habits and how to prevent and eliminate them. When you are overwhelmed with cluster flies in house, consider professional pest control services.