NEW- seasonal pest
Cluster flies

Cluster flies can be an enormously frustrating pest for both domestic and commercial properties. 


Often entering buildings in very large numbers, contrary to popular belief, the flies don't lay their eggs in lofts and windows but rather in the soil. The larval stages (maggots) are parasites of earthworms, emerging once they have pupated during the summer. The flies then overwinter in houses, usually causing problems to the south facing side as they 'arrive' in autumn and then again as they emerge in early spring.


Unlike most flies where effective control is linked to removing the source of the problem (eg covering or removing rubbish), with cluster flies, the source is not something that can be practically dealt with and therefore, control is left to a combination of proofing and physically and chemically removing the flies that enter a property. technicians, after a detailed survey inspecting the site and confirming the species, may recommend a combination of a range of treatments- these include 'painting' a special clear insecticide on to selected areas of windows, misting or ultra low volume (ulv) applications to the loft, smoke generators, localised residual sprays and or physical traps.


Proofing can be hard as they will often squeeze into tiny gaps but again, we will advise if we can see anything that may help provide a solution. In extreme cases, electronic fly killers can trap large numbers although care should be taken to ensure that the catch isn't so high that it clogs the grid of the machine Care should be taken if trying to carry out any treatment without professional advice, especially in lofts ( where bats etc may be present). Given the biology of this species, a simple aerosol can be effective in knocking down low numbers of problem flies. In very severe infestations, a vacuum cleaner can be used to remove very large numbers.


Whilst the main cluster fly is a species called polenia rudis, there are 2 other flies which exhibit very similar behaviour- the green cluster fly and the much smaller yellow swarming fly. For more information, including discussing treatment options, please contact the local technician or email This email address is being protected from spambots. You need JavaScript enabled to view it.