Cluster flies are so named due to their habit of forming ‘clusters’ when hibernating. They are also known as ‘attic flies’ as they are usually found in roof spaces and lofts. They are frequently confused with ‘autumn flies’, which also have a tendency to gather in large numbers in the autumn/winter months.
They live outdoors during summer and lay their eggs in soil, compost and leaf litter, but when the temperature drops during the autumn months (from late August to November), they migrate indoors seeking a protected place to overwinter. They favour lofts and roof spaces and can often be found in vast numbers in roof voids. They enter by crawling through small openings in walls or roof tiles, which makes them very difficult to guard against.
The most common species, Pollenia rudis, is slightly larger than a house fly at around 6-10mm in length. Unlike a house fly, they are rather sluggish in flight. Cluster flies can be recognised by their distinctive stripes behind the head, short golden hairs on their thorax and a mottled light/dark grey abdomen. Other species include Dasyphora cyanella, which is similar to a greenbottle, although less shiny. Autumn flies (Musca autumnalis) are also commonly found in large numbers, sometimes with cluster fly colonies – the males of the species have an orange abdomen with a dark central stripe; females are similar to a common house fly. Although annoying, cluster flies pose no risk to humans as they do not lay eggs in human food. They are classed as a pest because of the numbers that 'cluster' together, which can be very large.
When and where do cluster fly infestations occur?
Cluster fly infestations mostly occur in rural or semi-rural areas and are often found in lofts, roof spaces and sash window boxes. Once a cluster of flies has found a suitable place to settle they emit a pheromone which attracts others of its species. If has been known that if the 'clusters' are large enough to detect the pheromone, they will return year on year in even greater numbers. The presence of cluster flies is usually first detected on a warm, sunny day when the flies become active and are often then seen in large numbers at windows or in little-used rooms.
How do I get rid of cluster flies?
Trying to prevent cluster flies from entering your home by sealing window frames, doors and any other potential entry points will help but can be costly and is rarely effective.
Cluster fly control is best achieved by finding and treating resting sites and harbourages by applying a residual cypermethrin-based insecticide to alighting surfaces and by activating foggers or smoke bombs to fumigate the area and flush them out. If initial cluster fly treatment is carried out in the autumn months, a follow-up treatment in the spring is often advisable.
Our Cluster Fly Treatment Kits contain a range of cluster fly killer products to enable you to get rid of cluster flies in your home or loft and prevent future cluster fly infestations. This kit is supplied with Pest Expert Formula 'P' Foggers rather than smoke bombs.
Our Cluster Fly Treatment Kits contain a range of cluster fly treatment products to enable you to get rid of cluster flies in your home or loft and prevent future cluster fly infestations. This kit is supplied with Pest Expert Formula 'P' Fumer smoke bombs.
Pest Expert Formula 'C' is a highly effective cluster fly killer spray with a fast knockdown and a long-lasting residual effect helping maintain cluster fly control. Ideal for the elimination of cluster fly infestations in lofts and other areas. Can also be applied to alighting surfaces including windows and window frames. Supplied with free safety mask and gloves. (ONLY £7.49 WHEN ORDERING MULTIPLES!).
Pest Expert Formula 'C' is a highly effective insecticidal cluster fly killer spray with a fast knockdown and a long-lasting residual effect that helps maintain cluster fly control. Ideal for the treatment of cluster fly infestations in lofts and other areas. Can also be applied to alighting surfaces including windows and window frames. Recommended for use with a Pressure Sprayer. (ONLY £24.95 WHEN ORDERING MULTIPLES).
Pest Expert Formula 'P' Cluster Fly Smoke Bombs are a highly effective cluster fly killing fumigation device. Perfect for flushing out cluster fly infestations in lofts and roofspaces. For a more comprehensive cluster fly treatment, use together with Formula 'C' Cluster Fly Killer Spray and Formula 'P' Powder or see our cluster fly control kits. (ONLY £2.66 PER SMOKE BOMB WHEN ORDERING MULTIPLE PACKS).
The Pest Expert Formula 'P' Super Fumer Cluster Fly Smoke Bomb is more powerful than a standard Smoke Bomb, treating an area 3 times the size and so making it ideal for flushing out cluster fly infestations in larger areas such as lofts and roof spaces. For longer-lasting cluster fly control, the Super Fumer should be used together with Formula 'C' Cluster Fly Killer Spray and Formula 'P' Powder.
The Pest Expert Formula 'P' Cluster Fly Fogger is a fumigation device which kills cluster flies fast. The Fogger works in the same way as a traditional smoke bomb but treats a larger area and offers a safer alternative as it requires no naked flame. (ONLY £5.65 EACH WHEN ORDERING MULTIPLES).
The new super-size Pest Expert Formula 'P+' Cluster Fly Fogger is ideal for eradicating cluster fly infestations in larger areas such as lofts and open-plan living spaces. With a coverage of more than 300 cubic meters and containing 100% natural pyrethrins, the Power Fogger offers a safe yet highly effective cluster fly treatment. From £8.29 when buying multiples!
Formula ‘P’ Cluster Fly Killer is a powerful permethrin powder specifically developed to have a rapid knockdown effect on cluster fly infestations. Designed for direct application to window frames, roof timbers and any other alighting surfaces, killing cluster flies on contact and for several weeks after application.