What Are Cluster Flies?
Cluster flies are medium-sized flies with a distinct appearance. They are usually a dull greyish-brown colour, with golden or blackish hairs on their thorax. Unlike common houseflies, cluster flies feed primarily on earthworms in their larval stage. They are known for forming large clusters as they attempt to enter homes and other buildings to hibernate during the colder months. Often found in attics, roof spaces, or window frames, where they huddle together to stay warm. These flies are not dangerous to humans, nor do they carry diseases like other types of flies, but their sheer numbers can make them a real nuisance, especially in older buildings.
Why Do Cluster Flies Enter Homes in Autumn?
They don’t typically live indoors throughout the year but instead emerge from the outdoors to find a suitable spot to hibernate; trying to keep dry and warm. Cluster flies are drawn to homes with sunny southern or western-facing walls, as these areas tend to warm up quickly during the day. Once inside, they will often find their way into attics, wall cavities, or under floorboards.
Signs of a Cluster Fly Infestation
While individual cluster flies are relatively easy to ignore, a significant infestation can be quite noticeable. Here are some signs that you may have cluster flies in your home:
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Large Groups of Flies: Cluster flies are known for gathering in large numbers. If you see swarms of flies around windows, in corners, or around light sources, it’s a good indication of an infestation.
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Dead Flies: Cluster flies tend to accumulate in dark areas such as attics or behind walls. If you find a lot of dead flies in these spaces, it could be a sign they’ve been nesting there for some time.
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Persistent Buzzing: You may hear a soft buzzing noise, especially in attic spaces, as the flies are trapped or trying to find a way out.
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Odour: In extreme cases, a build-up of dead flies can create a musty, unpleasant odour in the affected areas.
How to Prevent and Control Cluster Flies
The best way to handle a cluster fly problem is to take proactive measures before they invade your home. Here are some tips to prevent and manage a cluster fly infestation:
1. Seal Entry Points
The first step in prevention is to seal any gaps or cracks in your home’s exterior. Inspect windows, doors, roof eaves, and vents for any potential entry points and use caulk or weatherstripping to seal them. It’s important to ensure that the gaps around windows and doors are tightly closed, as cluster flies can squeeze through surprisingly small openings.
2. Install Fly Screens
Install fly screens on windows and doors to prevent cluster flies from entering your home in the first place. Make sure the screens are properly fitted and free from holes. This will help reduce the likelihood of an infestation during the autumn months.
3. Call Devon Pest Control
If you already have an infestation, insecticides may be an effective solution. A professional pest control company can apply insecticides in the attic, roof spaces, or any other areas where flies have gathered.
Cluster flies are a common autumn pest in the UK, and while they are mostly harmless, their large numbers can make them a real nuisance. The key to preventing a cluster fly infestation is taking proactive steps to seal entry points, install fly screens, and monitor your home for signs of infestation. If you already have a problem, taking swift action with traps or insecticides can help minimise the disruption. By staying vigilant and addressing the issue early, you can ensure that your home stays free of these unwelcome autumn invaders.
