It’s smack in the middle of summer, so chances are you aren’t seeing too many cluster flies hanging around inside your home. However, as soon as the weather gets cool and the leaves begin to change, you may start to notice these annoying pests flying around and clustering near windows, in attics, or along doorways.
What’s up with these flies? Where do they come from and how can you get rid of them? More importantly, are they dangerous?
Cluster flies may be annoying and very common household pests, but the good news is that they are harmless to people and pets.
Still, they can “cluster”, as their name suggests, in very large numbers inside your home. No one wants a fly infestation, even if those flies are harmless.
So today, we are going to talk about how to prevent cluster flies before they become a problem and learn about other ways to manage a cluster fly infestation during the fall.
Let’s get started.
What Are Cluster Flies?
Cluster flies are slightly larger than common house flies.
Often confused for house flies, cluster flies are an outdoor fly in the family of Polleniidae. These flies are around 8 to 10 millimeters in length once mature, meaning they are a bit bigger than common houseflies, which is one of the ways you can tell them apart.
Another characteristic of cluster flies that is unique to them is that they’re not the most talented fliers. In fact, they fly quite slowly and are not as agile as their housefly counterparts. This means when they make it into your house they’re rather easy to swat and kill one by one.
Unfortunately, when cluster flies do make it into your house, they hardly do it without other fly companions.
The below video shows how cluster flies can become problematic once they enter your home and goes over a few professional methods you can use to get rid of them.
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But how else are cluster flies unique to other flies like common house flies? Cluster flies are indeed a bit larger, a bit darker, and they also have golden hair on the tops of their bodies.
Aside from moving sluggishly when they fly, cluster flies are also unique in that their larvae are considered parasitic. While adult cluster flies feed on the common food sources you would expect like fruit, plant sap, flower nectar, and decaying organic matter, their larvae rely solely on earthworm hosts to survive.
That’s right. Adult cluster flies lay their eggs in soil outside. Once the eggs hatch, the larvae find their way into the bodies of earthworms. They then feed on these earthworms for several days until they pupate and become adults.
This process generally takes between 13 to 22 days. Once adults, cluster flies can live for up to two years. This is a relatively long time in fly world, as many other fly species only live for around two weeks to a month.
The cluster flies’ long lifespan, the fact that they infiltrate our homes to hibernate over the winter, and the fact that they cluster in large numbers at exit points of homes once spring hits are some of the main reasons cluster flies are considered such nuisance pests.
That said, we should remind you again that cluster flies are not dangerous, they don’t bite, and they do not transmit any diseases to people or pets. In fact, while they can be a nuisance when they get into our homes to overwinter, they really prefer to be outdoors where an abundance of their food sources are available.
So then why do cluster flies come inside our homes and drive us bonkers? Let’s find out.
What Attracted Cluster Flies To Your Home?
Cluster flies prefer to live outdoors, but they are attracted to the warmth of your home when the weather gets cool.
Though it is true that cluster flies prefer to live outdoors, these insects are highly attracted to warmth and sunlight and they don’t do well in the cold. In regions where seasons change dramatically, cluster flies will find their way into houses in search of shelter and warmth.
They get into homes via any entry possible, whether it is through cracks and crevices along the perimeter, holes in window screens, or gaps along doorways and sidings. Once inside, cluster flies find small spaces to hide in like behind power outlets, in attics, or beneath baseboards where they overwinter.
Many people don’t even realize they have cluster flies boarding in their homes until the weather warms up again and these pests cluster around exit points like windows and doorways as they try to get outside.
While cluster flies are certainly annoying and definitely unnerving to suddenly come across inside your home, remember that they are harmless and that they do not lay eggs inside your home. Therefore, an infestation of cluster flies only occurs when they are inside your home for the winter months.
Once the winter passes and the weather warms up, they will attempt to make their way back outside again.
How To Identify Cluster Flies
Cluster flies move slower than house flies and have golden hairs on their backs.
Identifying cluster flies in your home is important because they look so similar to common house flies, but they require different methods of control to get rid of. Therefore, if you think you’re dealing with houseflies and you instead have cluster flies, you may use resources to get rid of them in vain.
So, how do you know if you have cluster flies in your home as opposed to common house flies?
Aside from their appearance, which remember is larger and darker than a common house fly, cluster flies also “cluster” around warm surfaces like sunlit windows and doorways.
Cluster flies also choose specific areas in the home to overwinter, including attics and inside of walls. This is one of the reasons that cluster flies are sometimes referred to as attic flies.
These pests may also cluster and die around light fixtures in the ceiling and along walls, leaving numerous dark fly carcasses for owners to clean up come summer. And while cluster flies are not dangerous or damaging to homes, they can attract other insects who feed on them due to their large numbers.
This is why it’s so important to work on remedies for how to get rid of cluster flies properly.
How To Get Rid Of Cluster Flies – Most Popular Methods
Cluster flies can hide behind our walls via power outlets, so using specific methods like dusts may be required to get rid of them.
As with most pest control, you have a few different options for how you choose to manage and control a cluster fly infestation. Some of these methods include the use of natural repellents, home remedies, insecticides or professionals.
Natural repellents are becoming a more and more popular method of pest control these days, especially for those with children or pets in the home or for those who are very environmentally conscious.
What we like best about using natural repellents is that these methods are safe, effective, and harm-free to people, pets and the environment and can often be used both indoors and out.
Some natural repellents you might come across for cluster fly control include sprays, ultrasonic pest repellents, dusts, and even fly light traps.
If you’re into using natural repellents for pest control then you may also like the idea of using home remedies. What many people don’t know is that you can execute do it yourself pest control methods by using ingredients you already have in your home pantry, medicine cabinet or refrigerator.
Like many pests, cluster flies are repelled by a number of everyday household ingredients commonly used, which is great news for anyone looking to get creative or save a few dollars on pest control.
While we are fans of natural pest control methods and home remedies, sometimes a very large infestation of cluster flies can require more extensive and intensive treatments. While insecticides can be dangerous if not used correctly, the truth is that they are an effective form of pest control many people find works well for them.
That said, any use of insecticides should be done carefully, as these products often contain harsh chemical ingredients that can be harmful to people, pets and the environment.
A cluster fly infestation in your home rarely requires the help from professionals, although in some cases a very large infestation of these insects can result in other pest problems in your home. If you notice you are constantly struggling with cluster flies and other pests inside your home, there may be a bigger issue that needs to be addressed.
We will go over more about when to contact a professional regarding cluster fly control in your home, but before we do let’s talk about some of our favorite products you can use for how to get rid of cluster flies naturally.
How To Get Rid Of Cluster Flies Using Natural Repellents
Diatomaceous Earth is a natural dust insecticide made of fossilized algae that can get rid of cluster flies.
Cluster flies are certainly annoying, but the great news is that they are harmless when they invade our homes. This gives you the luxury of trying your hand at natural repellents to get rid of them.
However, before you go out and buy just any old natural pest repellent on the market, remember that cluster flies often congregate in large numbers and overwinter in areas inside your home that can be difficult to reach.
Some natural repellents, sprays and products used to get rid of cluster flies may need to be used alongside other methods as well in order to completely get rid of them effectively.
If you’re not sure which products would be right for you to begin with when it comes to getting rid of cluster flies inside your home, don’t worry. We have listed some of our favorite products specifically designed to get rid of and control cluster flies below.
Faicuk Fly LIght
Fly lights are a popular form of natural pest control because they are silent, harmless to people, pets and the environment, and work well to attract and kill pesky flying insects like cluster flies, gnats, mosquitoes, and moths.
The fly light above works by luring the cluster flies in with an attractive light, then trapping them behind the light with a sticky glue trap you cannot see. This product is ideal for using inside homes during winter when cluster flies enter, and can be used all year around to kill and control a number of home invading pests who are attracted to light.
Garsum Non-Toxic Window Fly Traps
Because cluster flies are often found clustering around windows to get to the sunlight, clear window fly traps are highly effective. The above order includes 48 strips of non-toxic fly traps that use sticky glue and come on a clear piece of material you can stick to your windows.
This product includes no chemicals or toxins either so it is perfectly safe to use indoors and even in areas where food is stored and prepared like kitchens. It is also easy to apply and simpel to remove, and even includes a subtle scent that attracts cluster flies in order to get them to stick to the glue.
Wondercide Indoor Pest Spray
Wondercide Indoor Pest Control spray uses essential oils to kill and repel pests like cluster flies, spiders, gnats, fleas, and even bed bugs. The essential oils used include lemongrass, rosemary oil, and peppermint oil.
The spray can be used to kill cluster flies on contact but will also work to repel them and keep them from coming around your home when sprayed along the perimeter and at entry and exit points.
Natures Good Guys Beneficial Nematodes
One of the reasons cluster flies become so problematic in homes is because they lay their eggs outside of homes in nearby gardens or along the perimeter in soil rich with earthworms. This is a problem, not only because cluster flies become a nuisance when they come into our homes as adults, but also because they kill off earthworms, which are beneficial to our garden soil.
Releasing beneficial nematodes into your garden will help kill off parasitic larvae and eggs from cluster flies and other pests. Best of all, these nematodes are harmless to the environment and will not hurt earthworms or other beneficial garden insects.
Colton’s Naturals Peppermint Oil Spray
Cluster flies, along with many other pests, are repelled by the overwhelming scent of peppermint oil. This is one of the reasons we like Colton’s Naturals Peppermint Oil spray so much for indoor use.
We also like that it is safe to use around people and pets and that it can be used in kitchens and anywhere else food is prepared or stored. Simply spray this solution wherever you have noticed cluster fly activity to repel them or spray it directly on cluster flies to kill them on contact.
Once cluster flies enter your home, they will often hide inside your walls or in your attic to overwinter. This can make getting rid of them difficult and is one of the reasons we recommend using a dust insecticide like Diatomaceous Earth.
What we like about Diatomaceous Earth is that it is a natural insecticide that kills pests like cluster flies without causing harm to people, pets or the environment. The above product includes a duster, making it much easier for you to spray this dust behind electrical outlets and along baseboards or other hard-to-reach areas in your home where cluster flies hide.
Best Home Remedies For How To Get Rid Of Cluster Flies
Cluster flies are attracted to chardonnay wine and this can be used to your advantage.
We love swapping tips on do it yourself pest control, and we have some good ones when it comes to how to get rid of cluster flies. These pests may be excellent hiders and difficult to spot when they’re sleeping behind electrical outlets or inside of our walls, but there are a few ways you can lure them out and stop them in their tracks.
Let’s take a look at some of the best home remedies you can use to get rid of cluster flies inside your home.
Chardonnay Wine and Detergent Cluster Fly Trap
Yes, you read that correctly. Cluster flies are suckers for chardonnay. You can fill a bowl with some leftover chardonnay wine and mix it with a bit of liquid dishwashing detergent, then leave this bowl around your house, in your attic, or in your kitchen where you think you have noticed cluster fly activity.
The cluster flies will be attracted to the wine, but when they drink it they will get poisoned by the dish soap. They may also drown in the bowl, as the dish soap can coat their bodies and wings and makes it impossible for them to fly.
Of course, if you have curious children or pets in the house, use this method with caution. Dish detergent can be toxic to children and pets if ingested.
DIY Fly Paper Trap
If wasting a good bottle of chardonnay on annoying cluster flies doesn’t sound like your jam, don’t worry. This paper bag fly trap you can make at home requires no alcohol and works like a charm.
Simply boil some water and mix equal parts sugar and corn syrup into the pan. Mix until the solution is sticky and slather it over a paper bag. Then you can hang this bag in your attic or near walls or outlets where you think the cluster flies are hiding.
The sugar will luer the flies out and the sticky corn syrup concoction will get them stuck to the bag. This is a completely safe and natural fly trap you can make right there at home. Brillant!
Vacuum The Flies Where They Cluster
Looking for a simpler way to get rid of cluster flies? Just grab your vacuum. This method does require that you wait until the cluster flies come out from their overwintering phase and congregate at windows or doors, but it’s simple to get rid of them once they are there.
Remember, cluster flies move slowly so you can simply turn on your vacuum and suck them up one by one where they’ve congregated. Just make sure you go outside and dump the bag if you don’t want a vacuum cleaner full of dead flies.
Essential Oils That Keep Cluster Flies Away
Along with making a wine trap and your own sticky traps for getting rid of cluster flies, you can also use essential oils. Many people use essential oils as a natural form of pest control to help them manage pests like bed bugs, rodents, spiders and more. So, it’s no surprise that you can also use essential oils to get rid of cluster flies.
The essential oils that work best for repelling cluster flies include:
- Peppermint Oil
- Garlic Oil
- Citronella Oil
- Eucalyptus Oil
- Lavender Oil
- Pennyroyal Oil
- Lemongrass OIl
To make your own essential oil cluster fly repellent, just add between five to ten drops of the essential oil of your choice in two cups of water. Mix the solution in a spray bottle and spray the solution around your home, the perimeter of your house, along entry and exit points, and anywhere else you think you have noticed cluster fly activity.
These essential oils have an overwhelming scent that repulses pests like cluster flies, and they can also help deter pests like brown recluses, mice, rats, bed bugs, and mosquitoes.
How To Get Rid Of Cluster Flies With Insecticides
Insecticides that contain the active ingredient pyrethrum are highly effective against cluster flies.
Sometimes cluster flies require a bit more intensive treatments that include the use of chemicals and insecticides. This is particularly true if you are dealing with a large number of cluster flies inside and outside of your home and if they have lured other pests inside your home as well.
Not all insecticides will work against cluster flies, but there are some that we recommend and that will work especially well against them both inside and outside of your home. We have listed some of our favorite products for how to get rid of cluster flies for you to consider below.
Permethrin SFR Insecticide
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Any insecticide with the active ingredient pyrethrum is going to work to kill and repel pests like cluster flies. The above order by Control Solutions includes a large container of Permethrin SFR which is designed to be used outside of the home.
This insecticide should be considered a preventive to keep cluster flies from entering your home and should therefore be used in late summer, before the weather turns cold and cluster flies are tempted to go inside your house seeking warmth.
To ensure you use Permethrin SFR properly to keep cluster flies at bay, we suggest using it along the perimeter of your home and applying it to doorways, windows, and other possible entry points around your house.
Of course, keep in mind that this is an insecticide and permethrin can be toxic to people, pets and the environment. With that in mind, only use this as directed and keep it out of reach of children.
BASF Pyrethrin Aerosol Spray
For killing cluster flies on contact, you may want to try using a pyrethrin aerosol spray like the one above by BASF. This spray is specifically designed to target and kill annoying flying pests like fruit flies, cluster flies, clover mites, clothes moths, indian meal moths, and more.
Of course, it can also kill and repel crawling insects like crickets, beetles, roaches, earwigs, and ants.
While this is a powerful and effective insecticide aerosol that works well to control and get rid of cluster flies, it does contain a chemical ingredient that can be dangerous for people and pets and should therefore be kept out of reach of children and animals.
Since cluster flies often invade hard to reach places inside our homes like inside our walls, in air vents and behind power outlets, you may need to rely on an insecticide dust like Delta Dust to get rid of them.
Delta Dust is a common pest control agent that uses Deltamethrin as an active ingredient. Deltamethrin is an insecticide chemical that is highly effective in getting rid of pests like cluster flies, termites, wasps, spiders, firebrats, bed bugs, roaches and more.
That said, it is a chemical insecticide that can be toxic to people and pets and should be used only as directed.
Pyrethrum Insecticide Dust
Another insecticide dust we recommend for getting rid of cluster flies in hard to reach places is pyrethrum insecticide dust by MGK. Because this dust uses the active ingredient pyrethrum, and we already know pyrethrum is a strong insecticide that works against cluster flies, we can confidently say this product will work.
We especially like that it comes in this duster container that can be easily puffed into smaller spaces like below baseboards, behind power outlets, and more.
Of course, remember that pyrethrum is a chemical insecticide that can be dangerous if not used properly so keep it out of reach of children and pets, and make sure to read the directions.
How To Get Rid Of Cluster Flies – When To Call A Professional
Cluster flies are slow moving and easy to swat or vacuum up, but they may result in other pest problems which could require the help from a professional.
As we mentioned at the beginning of this article, not all cluster fly infestations will require the assistance from a professional pest control expert. That said, some infestations can be quite extensive and may even result in secondary pest issues in your home.
If you find you are dealing with an overwhelming infestation of cluster flies and other pests because of them, it may be time to contact a professional pest control expert.
Professional pest control experts typically charge around $100 to $500 depending on the severity of your infestation and your region. However, they should be able to help you pinpoint the problem at its core, which can further help you when working on coming up with preventative measures to avoid future cluster fly problems in your home.
How To Prevent Future Cluster Flies In Your Home
Prevent future cluster flies by keeping adult flies from laying eggs in the soil near your home.
One of the best ways to get rid of cluster flies is to be proactive. Remember, these pests prefer to live outdoors and typically don’t become active inside our homes until the weather gets cold and they need a place to overwinter.
In order to prevent cluster flies from choosing your home to hibernate in, we recommend following the below steps.
Remove Anything Around Your Home That May Attract Flies
Adult cluster flies are always responsible for cluster fly larvae, and an infestation of cluster flies in your home is generally a result of cluster flies laying their eggs around the perimeter of your house.
In order to keep cluster flies at bay, remove anything that might entice adult cluster flies including stagnant water sources, rotting fruits or vegetables from fruit trees or gardens, leaf litter, yard debris, and moist wood piles.
We also suggest keeping trash bins properly stored and sealed to keep cluster flies away, and avoid planting vegetation around the perimeter of your house, as vegetation requires soil and soil brings earthworms, which cluster fly larvae need in order to survive.
Grow Cluster Fly Repellent Plants
You can further help repel adult cluster flies by growing fly-repellent plants in your yard and garden. You can even grow some of the below plants in pots and keep them on your porch and window ledges to repel cluster flies in the fall and winter.
Some plants that cluster flies hate include:
- And Lemongrass
Keep Perishable Food Properly Stored Inside The Home
Just like common house flies or fruit flies, cluster flies are attracted to rotting fruits, meats and vegetables. Avoid leaving dirty dishes out in the sink overnight to reduce the chances of cluster flies being attracted to the smells inside your home.
We also recommend keeping perishable foods stored properly and refrigerated. Keep soda bottles and wine bottles sealed, and avoid letting fruit become overripe in fruit bowls on the counter.
Practice Routine Home Maintenance Around Your Home
Like most pests who enter your home, fruit flies do so on an opportunistic basis. You can keep them out by practicing routine home maintenance. Caulk and seal any cracks and crevices along the perimeter of your home that you find.
We also suggest making sure doors and windows shut securely and that you repair any ill-fitting or ripped screens.
Use A Perimeter Pest Control Spray Around Your Home In The Summer
Last but not least, use a pest repellent product around the perimeter of your home in late summer before the weather changes. Focus primarily on entry points around your home including doorways, windows, and even vents and air ducts along your siding.
Doing this will help prevent cluster flies from getting into your home come winter, and thus hopefully prevent you from having to deal with an infestation at all.
We hope this has been a helpful guide on how to get rid of and control cluster flies inside of your home and that you learned a little something about these interesting, (albeit annoying) flying insects.
Best of luck!
Jack founded our blog after two decades of working in the pest control industry. His vast experience dealing with a wide array of pests allows him to diagnose issues quickly and get to the heart of pest problems quickly and effectively. He has serviced more than 2,000 homes over his career and there is hardly any pest situation that he has not seen before.