Have you noticed an infestation of cluster flies in your house all of a sudden? There are some simple ways to get rid of these big fat black flies fast and naturally. The key is to keep them from coming back once you get rid of them.
Let’s start off by going over what a cluster fly is first so we know that you’re dealing with the right pest control, or you can skip ahead to the cluster fly removal parts of the post.
- What is a Cluster Fly?
- Identifying a Cluster Fly
- Cluster Flies Life Cycle
- Why Do They Fly Around the Windows?
- Do Cluster Flies Bite?
- Ways to Get Rid of Cluster Flies Naturally
- Cluster Fly Traps for Windows
- DIY Cluster Fly Trap
- Vacuum the Flies
- Indoor Bug Zapper
- Old School Fly Swatter
- Clean Up
- Get Rid of Cluster Flies with Chemicals
- How to Stop Cluster Flies from Returning
- Cluster Flies – Further Reading
What is a Cluster Fly?
Identifying a Cluster Fly
Cluster flies are small nuisance pests that are mostly found outdoors. They are about 1/4-1/2 inches which is a bit larger than a common housefly. You can identify them by their coloring of golden hairs on a non-metallic black/grayish body with dark splotches on the abdomen.
They are originally, and mainly from Europe, but have made their way to North America as well.
Other names for the cluster fly are pollenia rudis (scientific name), attic fly, loft fly, buckwheat fly, and pollenie du lombric for the French.

Cluster Flies Life Cycle
Cluster flies lay their eggs in the soil in late summer or early fall. The eggs hatch within a few days when the larvae seek out the cavities earthworms.
The lifespan of a cluster then fly varies slightly in Europe and North America. In Europe, depending on the weather, it takes about 10-12 months for an egg to mature fully into an adult. In North America, their lifespan is about 27-39 days from egg to adult.
Why Do They Fly Around the Windows?
Cluster flies are almost always in search for warmth during their lives. They’ll usually enter a building in the late autumn or early winter when it starts to get cooler outside and they need to find shelter to keep warm during the winter.
The heat from the sunlight hitting your window will attract these slow-moving black to the area, usually in a cluster…hence the name.
Do Cluster Flies Bite?
No, they do not bite humans or your pests. Their mouths are not equipped to bite.
Ways to Get Rid of Cluster Flies Naturally
There really is no need to use any chemicals, insecticides, or pesticides to get rid of cluster flies. You can easily treat the issue with one of these natural pest control solutions.
Cluster Fly Traps for Windows
Some of the best fly traps for cluster flies are these window traps. They are the most effective as they are located where the flies congregate the most, but not the most discreet if you have a large fly problem. This trap works decently as well, but it much more discrete as it won’t show a window full of dead flies attached to it.

DIY Cluster Fly Trap
There are many versions of these do-it-yourself fly traps that you can make at home. There are really 3 elements to all of these traps. (1) a container to catch the flies (2) a bait to draw in the flies and (3) a cover that they can’t escape once they fly in.
The easiest and a very good working trap uses a soda bottle.
- Leave a two-liter soda bottle open (the container)
- Make sure it is about 2-4 inches full of any sweet sugary soda (the bait)
- Place a rolled-up piece of paper into the top of the bottle to resemble a funnel that is large enough for a fly to enter (the trap)
Cluster flies will be able to enter the funnel trap, but can’t escape. They’ll have a delicious drink of soda but will drown in the liquid. Another easy option:https://www.youtube.com/watch?v=_1kAyn-IO5I
Vacuum the Flies
Luckily cluster flies are really slow-moving and fairly easy to catch. If you have a Shop-Vac or a vacuum on hand with a handheld attachment, you can suck up these flies even in groups. There are even small handheld insect catching portable vacuums you can by like this one for under $20. Make sure you empty your vacuum out immediately though in case the flies have eggs that can hatch in your vacuum bag.

Indoor Bug Zapper
Place a bug zapper like this one in your attic during the winter and you won’t likely have a problem with these cluster flies when the weather warms up. Cluster flies are attracted to heat and light so the light-up bug zappers are perfect for catching them.

Old School Fly Swatter
This is the tried and true way to get rid of flies of any type. It’s cheap and efficient, but it ends up being messy and ends up being more work than it is worth.
Clean Up
Like any pest control, it is a good idea to make sure your home is as clean as possible to keep these pests away. Clean up clutter so the flies have nowhere to hide. Make sure you don’t leave food out that the cluster flies eat as well. Also, make sure you have a clean and working drainage system. You don’t want to leave a moist area that gives a hospitable environment for cluster flies or any other pests.
Get Rid of Cluster Flies with Chemicals
If you have a small infestation of these insects, I recommend the natural repellents and traps. However, if you have a large infestation of cluster flies and you’re OK with chemicals you can use these options. You can leave residual dust insecticide around heavily trafficked areas like windows. You can also a pyrethrum spray as needed for contact kills.
Again, I don’t recommend using any chemical products to kill cluster flies.
How to Stop Cluster Flies from Returning
After one cluster fly infestation, I’m sure you want to make sure you don’t have to deal with that again. Make sure to follow these steps for preventing cluster flies from coming back next winter.
Seal Entrances
While you have a cluster fly infestation, make a note of any places you see them coming from. There is a good chance there is an opening that they are entering. Find that and seal/caulk it shut for the obvious entrances. After that check to make sure that all window/door trims, exhaust fans, and lights are sealed as well.
Fly Meshes
In addition to sealing openings, you’ll want to make sure the flies cannot enter your home through openings you do want. Install fly meshes in all vents and windows to make sure they don’t use these as welcoming entrances.
Plant Cluster Fly Repellents
Citronella plants can do wonders at repelling cluster flies and many other insects. If you can try planting citronella plans near the entrances to your home. The aroma of this plan is a deterrent to cluster flies and other bugs like mosquitoes.
Natural Repellents
There are other plants and herbs that give off “odors” that act as a cluster fly repellent. Mint, basil, and lavender are great for keeping cluster flies away. You can grow them near your home, use essential oils, or even grow them in your home.
Cluster Flies – Further Reading
How to Get Rid of Cluster Flies Naturally Today!
Have you noticed an infestation of cluster flies in your house all of a sudden? …
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