There are many species of flies and they are all more prevalent during the warmer weather. The common species most likely to cause problems to us all are Houseflies, Blue Bottles and Cluster flies.
Houseflies in low numbers are easily dealt with by proofing, household fly spray or old fashion sticky paper traps.
Blue bottle infestations are usually due to a dead bird or rodent decomposing somewhere nearby. Remove the source and treat the same as for houseflies.
Cluster flies Cluster flies can be a nuisance, particularly in the autumn months when they enter properties often in large numbers seeking refuge from colder temperatures and again in the spring when the warmer temperatures cause them to become more active.
Infestations are usually found in lofts and roof spaces, although they can also be found in sash or casement windows and in rooms that are seldom occupied. Unlike house flies, they are not carriers of disease however cluster flies are still regarded as a nuisance pest due to their presence in large numbers.
It is extremely difficult, if not impossible to prevent cluster flies entering a property. Fly proofing a building is not 100% effective. However, caulking around windows, and sealing obvious entry points can help. Cluster flies often select the same premises year after year to cluster and more than one treatment may be necessary. Ultra Low Volume (ULV) or smoke generator insecticides are proven methods of treatments.