Wednesday, March 24, 2010

Cluster Flies Hit the Headlines

News of the early cluster fly invasion has reached the media. The Dominion Post has reported ‘Wet summer brings a plague of flies’ The reports suggests that Wairarapa, Manawatu and Horowhenua are the worst hit areas, but I know from the evidence of enquiries from many other parts of the country that the problem is much more widespread.

The report says that professional pest management companies are being kept busy. You can deal with an infestation yourself by following the instructions in my last blog.

Using residual (long lasting) surface spray to kill flies in existing clusters and treating the surfaces where clusters formed you can remove them and keep them away for the winter. Don’t forget to treat the grass areas around your home with Lawngard Prills in spring so that you reduce the risk of clusters invading your home next autumn.


  1. Hello David,
    I live in the UK. Yesterday was a very sunny day.I left my house around 9am. To find my car(sliver) on the drive cover in flies. They were also on the bay window which was recently painted white. They had gone, well a large number by evening. Today is and still is a very wet day. However l can still see some on the waist high picket fence which i have been spraying with a fly killer. l do have a medium size plant which has been there for years. l have never experience this and we have live here for a very long time. Nothing in house thank God, long may that continue. Do you think that they are cluster flies? Please help.
    Thank you

    1. Hello Tina,
      Thank you for your question.
      It is unlikely that the flies are cluster flies. It is a bit early for clustering of cluster flies to begin in the UK. And they usually congregate in dark spaces such as attics.
      More likely they are flies that have all emerged from a breeding site at the same time and have perhaps congregated for mating.
      Aerosol fly killers do not usually have any long lasting effect and will only kill those you apply it directly to. If they continue to be a problem you should ask your local hardware store for a long lasting surface insecticide for application to the fence etc.
      Kind Regards



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