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How To Get Rid of Cluster Flies

Rowan Burgess |

No insect infestation is desirable, but cluster flies can be particularly annoying. They often travel in swarms and gather in windows or the cavities of your walls. They're deeply unsightly and can be truly bothersome if left untreated, which is why it's essential to act fast. If you suspect you may have an infestation, it's time to take action with the right fly control products.

If you aren't sure where to start, you're in the right place. We'll walk you through everything you need to know about cluster flies, including what they look like, the tell-tale signs of an infestation, and the best products to use for their removal. Let's get into it. 

What Do Cluster Flies Look Like?

Cluster flies can sometimes be tricky to identify because, for the most part, they look just like common houseflies or bottle flies. They are dark grey in colour and measure around 8-10mm in length, so mistaking them for any other fly isn't difficult to do.

The main giveaway is their size. They tend to be larger than the average housefly, so if you see groups of flies that look bigger than you'd typically expect, they could be cluster flies. They also aren't particularly fast. Whereas house flies might zip around with near-frantic speed, cluster flies move much more slowly and generally only in one direction. 

Signs of a Cluster Fly Infestation

The most obvious symptom of a cluster fly infestation is its visual presence. If you've started to notice more flies around your home or feel like you're constantly reaching for the insecticide, it could be because cluster flies have moved in and claimed your home as their own.

Some other key signs that are a little more subtle include:

  • A new, unusually rich scent
  • Large numbers of flies gathering at and around windows
  • Swarming flies when disturbed (for instance, when you enter the space that they occupy)

The most common places to find cluster flies are around windows or in your loft. They are also commonly found within internal frame cavities of double-glazed units or wall voids, or any similarly small space you'd never think to find them. Cracks and crevices are the ideal home for cluster flies, and they seek them out very successfully. 

How Long Does a Cluster Fly Infestation Last?

If left untreated or without intervention, a cluster fly infestation could last up to three months due to the average life cycle of a cluster fly. However, if the cluster flies are able to successfully lay eggs in the cracks in walls or in soil, then the process will simply start again.

Likewise, cluster fly eggs take around three to four days to hatch. 

How Do You Get Rid of Cluster Flies?

Fly Sprays

This is arguably one of the easiest ways to solve a cluster fly problem. Automated fly spray dispenses mean your involvement in the process can be minimal. All you need to do is fill the dispenser with an approved indoor pesticide, and the rest will be taken care of. There are numerous sprays out there designed for this purpose.

At Dalton Engineering, one of our more popular products for this purpose is the Digrain Wasps and Hornets Destroyer. Despite its name, this insecticide works perfectly well against cluster flies. Intended for manual use, all you need to do is spray the flies wherever they gather, and they won't last long. 

Fly Traps

Another popular option is the use of fly traps; these can look different depending on the use case. One of the more popular choices is glue paper, which the flies stick to over time, but other options include specially designed sticks and bags to lure the swarms. There are also a variety of powder-based traps. All are effective solutions.

Luckily, we offer a wide variety of these at Dalton Engineering, including electric fly zappers and many others. Traps are a popular solution as they work entirely independently, so all you need to do is replace them when needed. Though it's possible flies could avoid them easier than a spray, they remain highly effective. 

Fly Smoke Bombs

Last on our list of solutions, and perhaps one of the more unconventional, is the use of fly smoke bombs. These work by pumping smoke into smaller areas such as sheds, animal pens, and kennels, among other areas. They are only appropriate for smaller spaces but can provide a fast-acting, powerful solution to your problem. 

To use them, all you need to do is light the non-sparking wick and leave it in the affected location. The bomb will gradually pump out smoke fumes and ultimately kill the cluster flies. Smoke is ideal for this purpose as it can get into more hard-to-reach corners, many of which you wouldn't be able to reach otherwise. 

How to Prevent Cluster Flies

Although we're all well aware of the phrase ‘prevention is cheaper than the cure’, in the case of cluster flies, this might not be that helpful of a saying here. Preventing cluster flies can be a tall order, especially when you need ventilation to ensure proper air circulation.

Thankfully, there are certain steps you can take. Applying residual insecticide sprays during autumn months can help prevent cluster flies from hiding beneath your walls, and sealing cracks or tiny gaps with caulk can prevent them from entering completely. 

Frequently Asked Questions

Are Cluster Flies Bad?

In terms of being a household annoyance and an unsightly presence, yes, cluster flies are bad. The good news is that they don't carry diseases as house flies do, nor do they bite humans. Still, you shouldn't keep them around, as they will only fester further. 

Does Killing Cluster Flies Attract More?

No. If you're thorough with the removal process, killing cluster flies should permanently end the problem. Make sure you dispose of the bodies accordingly; otherwise, you might attract other pests. 

Do Cluster Flies Cause Damage?

In their own way, yes. Though they aren't likely to cause structural damage to your home or directly harm your health, they can contaminate food preparation areas and even the food you eat. It's best to be rid of them entirely. 

Looking for Insect Control? Shop Dalton Engineering!

Wanting to remove the cluster flies from your property permanently is an understandable desire. If you aren't sure how to proceed, browse our full collection of fly control products at Dalton Engineering. We're certain that you'll find the solution you're looking for, and you can once again exist within a cluster fly-free space.