Any type of fly is a menace to have around the house, and they will only get more irritating as time passes because flies breed so fast, their populations keep growing. Many people often cluster flies with house flies, because of their similarities, but they are different in some ways.
Getting rid of a cluster fly problem on time is important for preventing more problems.
What are cluster flies?
Cluster flies are large, black flies that start showing up in homes starting late fall to early spring. They are also known as attic flies, because of their tendency to cluster together in large groups inside attics.
Cluster flies tend to overwinter – that is, they enter homes and buildings when the temperature outside is very cold and unbearable. However, these flies will hide and avoid contact with humans.
Most often, they are seen in the spring, when the weather gets warmer, and they start leaving the building to look for food. You might also see them flying around the house on sunny winter days.
What is the life cycle of a cluster fly?
Per season, you’d get around 3 to 4 generations of cluster flies. A typical cycle begins as the adults leave their overwintering spots in the spring and lay eggs on soil containing earthworms.
These eggs are usually laid in the soil cracks. The eggs take about 3-4 days to hatch, and the maggots enter earthworm’s bodies and feed there for a few days.
This stage lasts about 13-22 days, after which they molt and become pupae in the soil. About two weeks later, the adult flies emerge, ready to start the cycle again. Some cluster flies can live up to 2 years.
Cluster flies’ feeding habits
Cluster flies are parasitic on earthworms only. When the larvae hatch from the eggs, they find an earthworm, whose body they burrow into and feed.
The worm soon dies from this. Cluster flies are otherwise not harmful in their feeding to your property or buildings.
They enter houses and buildings for hibernation purposes, and do not have mouthparts like some fly species, nor are they associated with animal carcasses or feces.
How did cluster flies enter your house?
These flies can enter your house by crawling through small openings in the walls or even electrical outlets and boards. They can usually be found buzzing around and collecting at windows, but usually, screens are not enough to keep them from getting in.
However, unlike other species of fly, cluster flies are not very dangerous since they are not disease carriers, and don’t cause damage to homes. However, they might darken the surfaces they gather on with their droppings, and if one dies inside the wall it lives in, it might attract other insects.
When these flies start collecting in large numbers, they will certainly become a nuisance to people.
How do I get rid of cluster flies?
While it is much better to have a careful prevention plan in mind to keep cluster flies from entering your home in the first place, if you do end up with a problem on your hands, there are some easy ways to get rid of them.
Natural methods
Vacuuming
Cluster flies don’t breed inside homes, nor do they lay eggs, so if they are unable to find a way back outside, they will simply die. They are also very slow and sluggish, unlike house flies, which makes it easy for you to simply vacuum them up, or even simply sweep them out of your house.
Cluster flies tend to gather at windows because they are looking for ways out. Many homeowners find that a vacuum is all they need to get rid of a cluster fly problem.
Breeding sites
Since cluster flies are so prominent during fall and winter because of the cold weather, an easy way to avoid larger populations of cluster flies is to make sure that you don’t have any old, abandoned buildings like sheds left standing. If they are not serving any use and are just eyesores, consider having them torn down.
Livestock
If you have livestock, they might be drawing flies towards them. One thing you can do is to keep predatory insects released around your animal barns so that they can get rid of the flies for you, and avoid dirty straw, manure and bedding getting piled up.
Having too much livestock in small spaces also allows cluster flies to thrive. If the farm animals are further away from your home, they are less likely to enter it.
However, cluster flies also bother the animals themselves, so you would want to get them away.
Take away sweets
Like many other species of fly, cluster flies love decaying food and are more attracted to food with high sugar composition. You should make sure to throw out all perishables before they start bringing flies into your house.
Seal your home
Cluster flies can enter your house through small cracks and crevices and live in the wall voids for their warmth. When the temperature gets warmer during the winter days, these flies will sometimes emerge from their wall voids and fly towards the window.
This is usually the time you would notice you have a problem since they would otherwise prefer to stay hidden. By sealing cracks, you can make sure the flies don’t enter your house at all.
Bottle traps
You can also trap the flies by luring them in. All you need is a Mason jar, sweetened water, and a lid that is perforated to lure them in and trap them.
A soda bottle can also make a good trap for these flies.
In fact, here’s a great video on how to make a trap using a regular water bottle:
Sticky fly traps
While these are unpleasant to look at, they can solve the problem in places where nobody goes often. You can hang a sticky trip at a high place where the flies will come and get stuck.
Drainage
Having a good drainage system helps prevent flies because they need surface water for survival. With lots of standing water around, you might be contributing to a larger insect problem.
You can also make your basement less moist to avoid giving the flies the ideal resting environment.
Swatters
Cluster flies are so slow that it is easy to simply swat them to get rid of them. This may not work for larger problems with many flies since you can’t swat all of them, but if there is only a small number of cluster flies in your house, a swatter is good enough.
Trash bins
Even if you’re very careful about your trash disposal, it is inevitable for some food or liquid to make its way around your trash bin. Smelly bins can be a wonderful atmosphere for cluster flies, so you should empty it out as often as possible, and keep insect repellents sprayed around them to make the atmosphere around them more unwelcoming.
Fly lights
Fly Lights are plugged into standard outlets and can be used in rooms that are not used very often. The flies get attracted to the light and then stuck on the glue board inside it. You would have to remember to replace the board regularly.
Chemical Methods
Of course, you can just get rid of the flies by spraying them with insect repellants. While some people may not like the use of chemical products within their homes, if the problem is too large, there is no other choice.
However, this does not usually pose a problem, and cluster fly infestations don’t last more than the winter months, so instead of using insect repellants and insecticides, you can simply use a spray around walls and windows where you suspect the flies will congregate.
By using residual sprays beforehand, you can get rid of them as soon as they start gathering.
Related questions
What do I do if there are suddenly lots of flies in my house?
A common reason for many flies swarming your house would be an infestation inside or nearby. A swarm of flies means that the eggs have already hatched and developed into adult flies, and this means that there could easily be more eggs. The source may be either inside your garden or even your house.
Do cluster flies return every year?
Cluster flies tend to return to the same property they took refuge in earlier, even if there are similar or better buildings nearby. The good news is that even though they are irritating, they are easy to control.
What smells do flies hate?
Flies usually hate the smells of essential oils like peppermint and eucalyptus. They also hate camphor, which you can easily buy online.