cluster fly on wall

What are cluster flies?

As their name suggests cluster flies are a type of fly that when overwintering “cluster” together in large groups. Cluster flies look similar to the common house fly but are larger in size. They are gray with yellow hairs covering their body, giving them an almost golden sheen.

cluster fly on floor

Why do I have a problem with cluster flies?

Unlike house flies that are most problematic during the warm months of spring and summer, cluster flies are most problematic for people of Washington in the fall. As the weather turns cooler these flies gather on the warm, sunny sides of homes and other buildings. They move along the exterior looking for ways to move inside to overwinter.

Cluster flies often enter inside in large numbers and they don’t stay hidden away. On warm sunny winter days they will emerge from their hiding spots confused by the increase in temperature. In the spring when the temperatures do warm-up these flies move back outside to continue their lifecycle.

Are cluster flies dangerous?

Cluster flies are not a particularly dangerous species of fly and aren’t known for spreading diseases that make people ill. Instead of feeding on and laying their eggs in decaying animal or plant matter, cluster flies feed on plant pollen and lay their eggs in the bodies of earthworms.

The main issues associated with cluster flies are that they are difficult to prevent, invade in large numbers, and their droppings will stain surfaces where they have decided to overwinter.

Do cluster flies bite?

Being bitten by a cluster fly is not a worry, these flies do not bite people.

How do I get rid of cluster flies?

To prevent problems with cluster flies, contact a pest control company that specializes in fly control. At Prosite Pest Control, we offer onsite inspections to accurately identify the fly problems, evaluate the severity of the infestation, and develop a plan of action that will deliver results. Contact us today to learn more about our fly control solutions for homes and businesses or to schedule your inspection.

How do I prevent problems with cluster flies?

At Prosite, in addition to our professional services, we recommend implementing the following cluster fly prevention tips:

  • Take a close look at the exterior of your home sealing any openings around windows or doors or in exterior walls and foundation.

  • Repair holes along the roofline and replace damaged or missing roof tiles.

  • Take the time to place covers over vents, repair gaps in roof intersections, and chimney openings.

  • If you find cluster flies moving along walls or window sills do not swat or squish them, they may leave behind grease marks. Use a vacuum instead to suck them up.

  • The best way to avoid problems is to partner with Prosite. We can put into place the prevention measures needed to stop cluster flies from finding their way into your home.


Get Your Consultation Now!

Schedule Today! Please enter your contact information below and a pest control representative will contact you soon.

or call (509) 955-2456

Affiliations & Accreditations

quality pro schools iconbetter business bureau iconquality pro green logonational pest management logoquality pro logo

Prosite Pest Control Blog

View All Blog Articles

The cockroaches in Yakima County are enough to make your skin crawl. That alone should be a reason for you to eliminate roaches from your home, but there are plenty other reasons to evict these…

Read More

The housefly can be a real pain to deal with, but there are ways to alleviate this common issue. Get sensible advice from our knowledgeable technicians here.

Read More

When it comes to pests, there are various reasons why they invade homes and businesses. Examining some of the common causes can lead to a better understanding.

Read More