House Flies: suck liquids containing sweet or decaying substances. Larva feed on moist food rich in organic matter. In the summer months they are found outside in garbage, manure, anywhere there is decaying matter. The key to controlling house flies is to remove organic matter, ensure general sanitation is good, and to ensure screen doors are in place to keep all pests out.
Cluster Flies: Cluster Flies typically, as the cool fall days approach, cluster flies gather together on the south and west sides of a building — they often gather close to windows and door frames, preparing to hibernate in gaps on the interior of the structure. On warm winter days, or as spring approaches, the cluster flies emerge and crawl across walls and windows, becoming more active as they warm up. They are attracted to light, so you may find collections of dead cluster flies lying beneath a left-on light bulb in an attic or near a window frame.
Small Flies: prefer a warm, moist environment with plenty of food. Food builds up in cracks and crevices. Many times, food is pushed down floor drains in the process of washing floors. The organic matter builds up over time, creating a perfect breeding ground for small flies. A regular cleaning program is required to take away the food source of small flies. This includes the hard-to-reach areas under counters and equipment. By removing the food source, you break the cycle of the small fly.