Flies are one of the most common pests that UK households have to deal with. While the common housefly can cause serious problems due to the diseases they carry, cluster flies are a completely different issue altogether.
Cluster flies don’t carry the diseases that regular house flies do, nor do they have the same tendency to lay their eggs in human food as other flies do. However, they will create a nuisance, and their corpses can attract other pests and insects to your home. They can also discolour your walls and windows with their droppings.
If you suspect you have a problem with cluster flies, here’s what you need to know to confirm and address the issue.
Identifying Cluster Flies
There are numerous species of fly in the UK; each one has its own biology and habits. At a glance, most flies look the same. However, if you have a fly infestation, identifying what type of fly you are dealing with is essential to dealing with the issue. Identifying the type of fly that is in your home will tell you what the underlying problem that bought them there is likely to be.
Cluster flies are green, unlike other common types of fly, which are grey or metallic blue. If you crush a cluster fly, they will release a distinct honey-like odour. They can resemble houseflies, but they tend to be larger, between ¼ and ⅜ of an inch in size. Their thoraxes also have a yellowish sheen not seen on houseflies.
Cluster flies take their name from their habit of gathering in clusters. Individual cluster flies move more slowly than houseflies and bluebottle flies. Cluster fly clusters also tend to gather around windows, which other flies don’t.
Why do Cluster Flies Invade?
Cluster flies are parasites of earthworms. As a result, they will thrive in areas with fertile soil. If cluster flies attempt to invade your home unsuccessfully, you may come home one day to discover fly corpses littered around your windowsill. However, if they make it into your home, you will most likely find them still alive.
When the temperature drops in the winter months, cluster flies will seek out warmth and shelter. This is what draws them to peoples’ homes initially. If they can find any small gaps or openings through which to make an entry, they will establish themselves inside the home. While they are larger than houseflies, cluster flies are still small enough to enter homes through the tiniest of cracks.
Despite their tendency to swarm around windows looking for a point of entry, window screens are generally ineffective at preventing cluster flies from finding a way into your home.
Preventing Cluster Flies
As with any pest, prevention is the best cure. If you take the right steps before an infestation takes hold, you can prevent cluster flies from ever making their way into your home. Cluster flies are most active during the winter when the weather is colder.
There are sprays you can use to deter them from picking your home when they’re looking for somewhere warm to shelter themselves. Spraying the outside walls of your house, as well as any surfaces they are likely to land on will keep them away. If cluster flies aren’t able to find a point of entry immediately, they will look for somewhere to rest before trying again. If you cover all the available surfaces in repellant, it will force the flies to look elsewhere.
Make sure that you use the spray correctly. You need to cover all the necessary surfaces; door and window frames and any adjacent surfaces cluster flies could land on to rest. You should apply your sprays in late summer or early fall for maximum effectiveness.
Dealing With Active Cluster Fly Infestations
You can confirm a cluster fly infestation from the presence of flies, either alive or dead. If they are in your home, you will usually find them around windows. If they manage to enter your home, they will try to seek out dar voids where they will be difficult to spot. Sealing these voids will usually lead to a pile of fly corpses in your wall, which will attract other insects. It can also be tempting to spray insecticide into these voids, but this will leave you with the same problem.
If you already have cluster flies in your home, it’s too late for preventative measures and sprays will have little to no effect. The best option at this point is to call in a professional pest control technician to remove the infestation for you. The best tool for doing this is a ‘mini-vac’, which you can use to hoover up the flies before either releasing them outside or disposing of them.
There are several insecticides on the market that are effective at killing cluster flies. However, not everyone is comfortable spraying insecticides in their home. These insecticides are also ineffective against cluster fly eggs. You can get rid of every live fly in your home, but if there are eggs left behind, you will have a resurgent infestation the moment they hatch.
If you have cluster fly corpses littering your floors or spaces behind your walls, you can be sure there will also be live specimens nearby. If you leave them to their own devices, cluster fly infestations will reproduce at a prodigious rate. As long as they can rely on your home to provide them with warmth and shelter, they aren’t going to leave voluntarily.
Cluster flies can invade any home during the winter; they will usually attempt to enter whichever property is closest when the temperature gets too cold for them. Ensuring that there are no gaps or cracks they can use to enter your home will keep them out, but they are adept at finding entry points that most people would miss.
If you have an active cluster fly infestation in your home, contact Bon Accord today. We will arrange a time for one of our pest control technicians to come and evaluate the problem before suggesting an appropriate treatment plan.