Cluster Flies

Control Cluster Flies At Your Home Or Business With A Local & Reliable Pest Control Company

Treat Cluster Flies- Bentley Environmental Pest Control

Cluster Fly Treatments

Treatments are available for control and prevention of Cluster Flies, Yellow Swarming Flies, Lady Birds & Lacewing. Both domestic & commercial properties covered.

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Common Signs Of An Infestation

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Most frequent questions and answers

Insecticides are applied to window casings and external walls (if extreme numbers) A ULV fogging machine is used within loft areas where a rapid knockdown is applied. 

Yes. When being used by a trained professional. We only use the necessary product amounts that are required for each treatment we carry out.

Usually in early spring when the weather is turning warmer, or in the autumn when the weather is cooling back down. 

Treatments can vary depending on several factors, but on average a treatment will usually take between 1-2 hours.

Unfortunately it is very rare that one treatment will stop flies from returning. Fly infestations are usually an ongoing battle and its essential to keep the fly numbers as low as possible with multiple treatments to prevent re-infestation.

If you have bats roosting in your loft, we can’t treat this area. In Britain all bat species and their roosts are legally protected, by both domestic and international legislation. More information is available by clicking here.

Where Do We Cover?

Our service area is mostly Hampshire based, however we aren’t restricted so can also offer  cover to parts of Wiltshire & Berkshire.

Calls are usually responded to within 24 hours, but if we are particularly busy then it may take us a little longer.

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Further Information On Cluster Flies

Cluster flies are found throughout Europe and the UK. They are harmless, and do not carry any diseases that affect humans so they pose no health issues.

Cluster flies get their name due to their habit of clustering together in large numbers to over winter. There are several species found in the UK, and they can be found in mixed swarms. These sizes vary between species to species ranging from 3 to 8mm in length. Only the adult flies over winter, these start to cluster from September and onwards.

Once the flies have found a suitable site to hibernate for the colder months they emit a pheromone which attracts other flies. Often its possible you can smell their pheromone when large numbers of the flies are together, this is a sickly sweet smell. They will return year after year to the same site in ever increasing numbers, which is why it’s important to carry out treatment for the cluster flies.

They emerge in early spring congregating on walls, roofs, fences, and trees etc. to warm up in the sunshine. They then fly off to lay their eggs, these are usually laid in turf, leaf litter, compost heaps, or even muck heaps.
Once hatched the larva which are parasitic seek out earthworms, they then bore through the worms skin and proceed to eat it alive.
When the worm dies the larvae emerge and pupate in the surrounding soil, the adult flies feed on the nectar of garden and wild flowers.

During the summer, cluster flies don’t tend to be a nuisance, only as the autumn approaches do they become a pest as they start to invade peoples house’s and offices.

Cluster flies look for a warm place to hibernate throughout the winter months, homes in rural areas are usually more susceptible to infestation. They usually cluster within roof spaces and window frames or any other spaces they find suitable.



To treat a cluster fly infestation we carry out loft/roof space treatments with either an insecticidal aerosol total release spray or with fogging/ULV (Ultra Low Volume) equipment. This kills the flies within the loft and will help to reduce the numbers of flies in and around the property dramatically.

We also carry out treatments to internal and external window frames, where we apply a residual insecticide. The flies land on the window casings and absorb the insecticide through their body when they come into contact with the insecticide.

In extreme cases, we can also apply external treatments to window frames, walls and soffits and fascias. Although the treatments have to be timed well as bad weather can wash the treatment away instantly!

The amount of treatments for Cluster fly infestations can vary. We have customers that need a single treatment, or a single treatment each year until numbers are drastically reduced. A heavy infestation of flies can take several treatments over the course of a few years to eradicate the cluster fly population completely. 

It is rarely possible to totally proof a building to prevent the flies from gaining entry. Sealing window frames, sky lights etc. will help along with any other potential entry exit points.

Electronic Fly Killer Unit

Electronic Fly Killer Units

We also supply and install Electronic Fly Killers (EFK's) for our customers.
A popular location for installation is in kitchens and in conservatories.

This deals with Cluster Flies in the season, but also deals with any other flies and insects, such as moths and wasps that enter into the house through open doors and windows. It just offers some reassurance for fly control all year round.

We can supply and install the more common commercial looking EFK, or we have a range of domestic units designed to be discreet and blend in to the home.

Please note that we can only install the EFK's to a nearby plug socket (within 1 meter). In some cases an electrician sourced by the customer would be required to install new electrical points.

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