An Invasion of Cluster Flies is a Huge Nuisance - PEST UK

Providing pest control services in Berkshire, Buckinghamshire, Essex, Hampshire, Hertfordshire, Kent, London, Middlesex, Northamptonshire, Oxfordshire, Surrey, West Midlands, West Sussex, Wiltshire. Est. 1985.

An Invasion of Cluster Flies is a Huge Nuisance

In Featured, Pests

It’s necessary to get rid of cluster flies as they infest homes in such large numbers.

Are cluster flies a health hazard?

Cluster flies aren’t a health hazard in the same way that house flies are. For instance, they aren’t attracted to your food or waste as somewhere to lay their eggs. They only invade homes when they’re looking for somewhere dry and sheltered to hibernate.

What are cluster flies?

Cluster flies are always sluggish. They look similar to house flies but they don’t buzz around. Living and breeding in fields during summer, they feed on nectar, plant sap, fruits and other organic matter. They lay their eggs in the soil and their maggots become parasites of earthworms until they mature.

How are they a nuisance?

Cluster flies often hibernate in houses close to open spaces and fields. From late summer they start to gather in large numbers on sunny, light-coloured outside walls. Eventually they find their way inside and form clusters of hundreds of flies in upstairs rooms, roof spaces, lofts, around window sash boxes or in wall cavities. Also cluster flies and their descendants tend to return to the same building to hibernate year-after-year.

What are the signs of problems with cluster flies?

Finding dead, dying or lazy flies around windows or in the loft in autumn or on warm days during late winter are signs that cluster flies have become a problem in your home.

How to get rid of cluster flies

Preventing cluster flies from accessing your home is impossible, so getting rid of them often becomes necessary. Fogging the infested and surrounding areas with a biodegradable insecticide is the best solution. The insecticide penetrates into the narrow cracks where flies may be hibernating. If the flies are inside the wall cavity, a small hole can be made in the wall and the insecticide sprayed into the cavity.

Dying flies may be seen for up to four weeks after treatment as it depends on temperature and how much insecticide they have absorbed. The treatment will not eliminate the fly infestation but it will kill the vast majority of flies present at the time of treatment.

The insecticide doesn’t harm mammals or humans, it’s almost odourless, non tainting and does not corrode or stain.

If you would like advice on how to get rid of cluster flies or a quote, call us on 0800 026 0308 or email us at


PEST UK provide fast, reliable and effective pest control services for homes and business premises.

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PEST UK have offices throughout the southeast including BalhamCamberwellEalingSurbiton and Walthamstow

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