Jim from Northern, Wi writes
How do I get rid of/prevent cluster flies (hundreds) They do die......but "after" they are in the house.
Demand CS is not a contact kill so once a fly contacts a treated area it could still get inside before it succombs to the insecticide, but that does mean that it is working. If the cluster flies have already made their way indoors they will be harder to control because they usually hide in a wall void or other inaccessible area and are only visible when the house warms up. If the cluster flies are in an attic or drop ceiling or other dark area, a fly light would do a great job controlling the population. Using small fly lights such as the FlyWeb Fly Light in the house would also help to catch the flies. Spray Talstar directly on baseboards, window frames, door frames, and places where utilities (pipes, wires, cables) enter in to the building and any other crack, crevice or gap where insects can enter. We also have a great guide here on "How to Get Rid of Cluster Flies" that might help.
Answer last updated on: 06/02/2016