The cluster flies are the genus Pollenia in the blowfly family Calliphoridae. They are strictly parasitic on earthworms; the females lay their eggs near earthworm burrows, and the larvae then infest the worms. However, the flies are a nuisance because when the adults emerge in the late summer or autumn they enter houses to hibernate, often in large numbers; they are difficult to eradicate because they favour inaccessible spaces such as roof and wall cavities. They are often seen on windows of little-used rooms. They are also sometimes known as attic flies.
The typical cluster fly Pollenia rudis is about 7 mm long and can be recognised by distinct lines or stripes behind the head, short golden-coloured hairs on the thorax, and irregular light and dark gray areas on the abdomen. Cluster flies are typically slow moving.
Cluster flies have a widespread distribution. Eight species are found in Britain and thirty one in Europe. Pollenia species are also and numerous in Australia and New Zealand (over 30 spp); they are a common pest in North America.
Damage/Illness caused by Cluster Flies:
The cluster fly is a nuisance pest for homeowners. It does not bite people, carry diseases, or cause any real damage to a home.
Method of removal:
- The treatment for cluster flies consists of an exterior treatment to the clients home or building
- This treatment is done in the 6 week window between the 3rd week of August and the end of September.
- The treatment is a spray that is applied to exterior siding, eves, roof lines and around the windows.
- This application will form a barrier that will prevent the cluster flies from entering the structure as the weather cools and the cluster flies are looking for more favorable conditions to wait out the winter season.
- This treatment also works for Lady Bugs and any other insect trying to find a warm home.
- This treatment for cluster flies is done a once per year in the fall.