Have you noticed large numbers of flies appearing all at once on sunny autumn and winter days? You may have a cluster/Autumn fly infestation.
About Cluster flies: Genus Pollenia in the blowfly family Calliphoridae. Unlike more familiar flies cluster flies do not present a health hazard because they do not lay eggs in human food. That is not to say they're not extreamly distressing and unpleasant. Cluster flies are strictly parasitic on earthworms, the females lay their eggs near earthworm burrows, and the larvae then infest the worms. When the adult flies emerge in the late summer or autumn, they enter houses to hibernate, often in large numbers. Cluster flies can be difficult to eradicate because they prefer hard to reach, quiet spaces such as roof and wall cavities. They are often seen on windows of little-used rooms. They're also sometimes known as attic flies.
The typical cluster fly Pollenia rudis is about 5/7 mm long and irregular light and dark gray areas on the abdomen. Autumn flies often having a yellow or orange abdomen. Cluster flies are often slow-moving and are easy to swat.
Treatment options when controlling cluster flies in Dorking. In an ideal world it would always be possible to seal entry points from the loft space or wall cavity,and physicaly stop the flies from entering your home. However this is often not possible. The next line of attack is to treat some of the loft beams (where possible) with a residual insecticide. The residual action of the insecticide kills flies that come into contact with it. I often use either Ficam W or Demand CS insecticides for this purpose. I have also found that using a total release aerosol spray to fog the void spaces is highly effective in killing cluster flies.
Please note: the treatment may have to be repeated each autumn over several years to stop the problem completely!
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