Posted on: November 25, 2008 Posted by: Nicole Harding Comments: 7

Cluster flies, also known as attic flies are about ½ up to ¾ of an inch in size. Slightly larger than the common house fly, they move in hundreds or even thousands, hence the name.

Unlike house flies, cluster flies are not associated with poor hygiene and poor sanitary conditions. These insects do not carry diseases and other hazards that may affect humans because they do not lay their eggs in human food. Though not pests and more of a nuisance, it is still a serious problem that must be get rid of.

The Cluster Fly

Cluster flies are generally outdoor flies. However, when the weather starts to get cold, they seek shelter and head towards homes and buildings to hibernate. They prefer inaccessible spots like attics, basements, cracks and crevices, as well as unused rooms. When the temperature gets warmer, they come out of hibernation and go back outdoors.

Unlike the common house fly, cluster flies do not deposit their eggs in human food. Instead, they prefer earthworms. A female cluster fly will deposit her eggs on rotting leaves or near an earthworm’s burrow. When the eggs hatch and turn into larvae, they will seek out nearby earthworms until they grow into adult flies.

These annoying insects don’t really pose a danger to humans since they don’t bite or carry diseases, so why do they have to be a problem? Try to ask someone who has experienced an infestation of cluster flies and they will surely tell you it is not a pleasant experience.

Common Places where Cluster Flies are Found

Cluster fly larvae can be found in the bodies of earthworms. Basically, they are parasites of the earthworm. Adults are found in several places, however. As long as the house or building is near an area where there are a lot of earthworms (turf, grass, gardens, cemeteries, and parks). In homes, they are commonly found in:

  • Between walls
  • Empty and unused rooms
  • Attics
  • Basements
  • Ceilings
  • Garages

Remember that these cluster flies number in hundreds to thousands, so imagine the horde of these insects as they go in or out of your home.

How a Cluster Fly Looks Like

A cluster fly looks almost the same like the common housefly, except for their larger size. Upon closer inspection, you will see that cluster flies have markings of yellow-gold hair in their thorax. On their abdomen, they have gray hairs all over. In flight, they don’t buzz around like the housefly. Their flight pattern is somehow “lazy” or jerky in comparison.

Getting Rid of Cluster Flies

As previously stated, these flies don’t really pose a threat to humans. However, they may be unsightly and disturbing considering their numbers. Aside from that, they may produce a slimy and disgusting smell. You don’t want to disturb them while they hibernate. They can be quite difficult to get rid of, but in this case, you don’t want these uninvited guests inside your home.

It is quite easy to get rid of the cluster flies inside your home once you find the places where they hide. They usually stay in undisturbed and inaccessible places in your home. Once you find those areas, you can easily kill them with a good can of insecticide.

The key in getting rid of these cluster flies from your home is to make sure that they don’t get inside your home. Even though they are slightly bigger than the housefly, they are known to be able to enter openings smaller than their body size by wriggling themselves through it.

Another way of getting rid of the cluster flies in your home is by using a vacuum cleaner. Aim the device at the hibernating flies and allow it to suck those insects. Swiftly move the vacuum and target the rest of the flies. If you don’t move it fast enough you might completely disturb the hibernating insects. When done, don’t open the bag indoors. Go outside and release them or dump them in a fire.

Of course you can always hire a professional exterminator to do the task for you, if you hate being around insects.

Cluster fly-proofing your Home

Cluster flies enter your home through some openings that even you don’t know. Here is how to make your home inaccessible to these cluster flies:

  1. The first place to start is the obvious entry points. Check your windows and doors for small openings. Cluster flies can squeeze through the sides of doors and windows, so make sure there isn’t enough space for them to pass through. Use quick-drying cement or some sealant to patch cracks and crevices. If you use a screen, make sure there aren’t any holes that the insect can go through.
  2. Check your cellar door for possible openings too. These are very possible entry points because your basement is an ideal undisturbed spot that cluster flies choose to hibernate in.
  3. If you have an attic, do the same. Windows, roofs, and walls are the places you should check in there.
  4. Basically, any room or area in your home that is not visited much by any of the people in your home are the ones you should check.

Cluster flies are known to return to the same home or building every year, even though there are other better places to stay in. The task of cluster fly-proofing your home may be tedious and tiring, it saves you a lot of trouble in getting rid of them every year. If you find this article interesting, you should read how to get rid of fruit flies too.

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7 People reacted on this

  1. I have a bajillion flies in my clean backyard/patio. This is the first year they have ever been this bad so I just wanted to post that I put out 2 ziplocks with the pennies tonight tomorrow is going to be a hot, humid sunny day here in Iowa so we will see if it does the trick! I have my fingers crossed….I always get a few who sneak in when I let the dog in. When that happens I zap them with hairspray, they are then “frozen” and I can pick them up with a tissue and give them a flush. I get a sick feeling a pleasure doing this to these little pests!

  2. Karen mentioned 2 ziplock bags with pennies I’m confused is this some magical trick to get rid of cluster flies. I have had pest control out here for the last four years and I still get them every year. I desperately need help in a good way to get rid of these horrible flies.

  3. How do I get rid of cluster flies outside ? We can’t enjoy our pool or eating outside without these things crawling all over us.

  4. I live in apartments and we have kids all over the place playing and i thought that the flies were attracted because of food dropped or drinks spilt but they are all over the dirt so i wonder if theyre cluster flies laying eggs and such, i have tried the penny and bag of water home remedy but it didnt work, and there are so many its crazy we cant sit on our porchs except for at night, does anyone know of anyother home remedies to get rid of these pesky critters?

  5. We sprayed SpiderEx out of desperation to get rid of the flies… we had the flies coming back year after year and had tried everything we could find so this was out of sheer frustration. It worked… SpiderEx was the only thing we have found to work.. It has changed our lives…

  6. I have them all over my tan camry-thousands. It started August2012. Every day that is 50 degrees plus I see them – no matter where my car is parked. It is really embarrassing at the supermarket parking lot. I don’t know what to use on the car that won’t damage it. Vinegar they don’t like. But it ruins the paint finish! They are not visible anywhere inside the car- yet! Any suggestions, please?

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