How do I know if I have a Problem?
If you have a Cluster Fly problem you will notice dead, dyeing or live flies around windows or in loft spaces. You may even see them sunning themselves on outside walls.
The time of year is important. If you are seeing flies in the Summer then they are probably another type of fly, maybe a Bluebottle or related species or perhaps House Flies.
Preparation Prior to Treatment
There isn’t much you can do prior to treatment but the insecticides used last much longer on clean dust free surfaces.
We will treat the infested and surrounding areas with one (or all) of the following insecticide sprays: Demand CS'* which contains Lambda-cyhalothrin, HSE Number 6287, made by Sorex or Permost Uni, HSE Number 6399 which contains Permethrin & Tetramethrin & made by Hockley International or K-Othrine WG250, HSE Number 5390 which contains deltamethrin 25%. These insecticides are the most modern insecticide available. Also a powder might be used called Ficam D*. This contains an insecticide in a dust formulation @ 1% w/w Bendiocarb. A smoke generator may have been used, this is called a Coopex Smoke contains Permethrin. The type of insecticide used will depend on individual circumstances and be decided by the technician.
All these insecticides are biodegradable, almost odourless, non-tainting & do not corrode or stain. They are not highly toxic towards mammals but are extremely so to all forms of crawling and flying public health pests. All the resting places will have been sprayed and possibly dusted.
What do I do afterwards?
After treatment do not let domestic animals walk on treated surfaces until dry and if bare skin comes into contact while wet then wash. As long as the surfaces that have been treated are not washed down the insecticide will remain active for up to 3 months. This really only applies to clean areas inside.
Dying flies may be seen in some numbers up to 4 weeks after treatment. There is a strong possibility that any survivors will build up their numbers to nuisance level again in the following years. In fact once a hibernation site is selected it will be used year after year. The treatment will not eliminate the fly infestation but kill the vast majority of flies present at the time of treatment, flies will take time to die, how quickly depends on temperature and how much insecticide they have absorbed.
Flies - General Information
Cluster & Swarming Flies
These flies may be found in large numbers in houses, usually lofts, causing annoyance to the occupants. They enter during the autumn to hibernate and leave in early spring, sometimes appearing on warm winter days. It is at these times when they become a nuisance and treatment is necessary.
There are 3 types of cluster fly: cluster fly, parasitic on earthworms, autumn fly, and green cluster flies, both breed in cow dung. All 3 species lead solitary lives except when they gather in the autumn to hibernate.
Before moving into their hibernation place they will collect on the outside of buildings, especially on sunny walls before finding their way inside to form clusters of many thousands in such sites as roof spaces, under tiles, window frames and in window sash boxes. They are not a health hazard in the same way that House Flies are and are only coming into the building to hibernate, not to breed or feed.
Once a hibernation site has been chosen the flies descendants will use the site, the memory of the site seems to be passed on to subsequent generations. It is not understood how this happens.