Trusted, Local, Cluster Fly Control and Infestation Removal Services across Herefordshire & Worcestershire

Cluster flies (Pollenia rudis) are larger and slower than houseflies, with dark grey bodies and golden hairs on the thorax. They don’t feed on waste or breed indoors but instead enter buildings to hibernate during autumn.

Cluster flies are typically larger and slower moving than common house flies. They have a characteristic golden or yellowish-brown colour, a distinct pattern of golden hairs on their thorax.

In autumn, cluster flies squeeze through tiny gaps in roofs, eaves, vents, or cladding to hibernate in warm, undisturbed areas such as lofts. In spring, warm temperatures make them cluster around windows and light as they try to leave.

The most obvious sign of a cluster fly infestation is the presence of the flies themselves. They may be found in large numbers, especially in the upper levels of the home. In addition, you may notice a musty smell in the affected areas.

Cluster flies release pheromones that attract new generations back to the same site every year, meaning untreated homes are repeatedly re-infested.

No — they are not a health risk, do not spread diseases, and don’t breed indoors. The main issue is the nuisance of large numbers of flies.

However, they can be a nuisance in large numbers, creating unsightly situations and potentially spreading germs if they come into contact with food in the same way other flies would.

Their life cycle lasts several weeks to a year. In Europe (including the UK), Pollenia rudis typically takes 10–12 months to complete a generation.

They enter through tiny cracks and gaps around windows, doors, eaves, vents, cladding, or roof tiles. Even well-sealed homes can be invaded.

Small numbers → use a vacuum cleaner or aerosol fly spray.

Large infestations → professional pest controllers use fogging, ULV treatments, insecticidal smokes, or sprays in lofts and voids.

• Seal gaps in eaves, cladding, and window frames.

• Use fine mesh insect screens.

• Apply insecticidal dust behind cladding or in roof spaces.

• Install UV electric fly killers in lofts.

• They don’t damage the building itself.

• Droppings and dead flies can stain walls and windowsills.

• Accumulations may attract secondary pests like carpet beetles and larder beetles

• Cluster flies → 6–10 mm, dark grey, with golden hairs and striping behind the head, move sluggishly.

• Houseflies → smaller, fast-moving, grey with clear stripes.

• Bluebottles → metallic blue bodies, buzz loudly.

Cluster flies typically enter homes and buildings through small cracks or openings, such as around windows and doors. They are attracted to warm, protected areas, such as lofts, walls, and chimneys.

Preventing cluster fly infestations in the first place is the best way to control them. This can be achieved by sealing any cracks or openings around windows, doors, and other potential entry points, and ensuring that screens are in good condition.

Cluster flies are not harmful to humans or pets — they don’t bite, sting, or transmit diseases. However, they can still be a nuisance pest, especially when they gather indoors in large numbers.

Yes, there are natural ways to get rid of cluster flies, such as using traps, vacuuming, and exclusion devices, such as screens, that can prevent flies from entering the home.