It has been interesting to see the publicity surrounding cluster flies over the past couple of days. In my Pest Advice Blog last week I mentioned that Kiwicare had been receiving enquiries to the kiwicare.co.nz website and via phone and email at about twice the rate of the peak of last year. The increase in enquiries is also 3-4 weeks earlier than last year (I wonder what the flies know that we don't).I have dealt with cluster flies both here in NZ and in the UK and Ireland and they can be eliminated with a program of control, and they can be largely prevented with a bit of pro-active treatment of grass and pasture in spring and summer.The trick with eliminating them from an infested building is to understand that the dead flies AND the surfaces where the flies clustered will continue to 'smell' with pheromone that attracts more flies. So collect and dispose of dead flies once killed AND treat the areas where clusters formed with a long lasting surface insecticide.Persistence pays.ps Katrina, the flies circling each other in the middle of your room are house flies or lesser house flies. They often do this annoying dance inthe middle of rooms or under tree canopies.
I sometimes get a small group of three flies or so that just fly around the middle of the room in like a triangle formation, like they are hypnotised. Are they cluster flies or just weirdo house flies.