Cluster flies are not associated with carrying infectious disease but can present a nuisance due solely to their large numbers.
Control is very difficult. Aerosol fly killers can be effective on small numbers but with larger clusters it is difficult to achieve adequate contact. Another treatment is to use a vacuum cleaner and then dispose of the bag in another sealed bag.
We do not offer a service for the control of cluster flies but can provide advice. There are local and national companies that can provide a service, try searching a local telephone book or the Internet for pest control.