Flies are not usually a significant pest problem, but there are two that can be quite prolific and difficult to control.
The Phorid Fly
The Phorid fly is a small, black, hump backed fly often mistakenly identified as a fruit fly. Sometimes called scuttle flies, Phorid flies can often be identified by their habit of scurrying across a surface rather than flying when trying to escape capture—thus the nickname. They feed on decaying organic matter and they frequent unsanitary places, including drain pipes—so another common name is the drain fly. Because the live and thrive in filthy conditions, they may transport various disease-causing organisms to food material.
The fruit fly is similar in size to the Phorid fly, but is brown to yellow in color with red eyes. Their name stems from the face that their favorite food is decaying fruit. These are the flies that you often see in the produce section of the grocery store or at the farmer’s market—and may be bringing them home with you.
Spraying the adults of these flies with pesticide is not a very effective control measure. You should thoroughly inspect the interior of the structure to make sure there is not simply an overlooked unsanitary condition that can be cleaned up—an over-watered potted plant or aquarium where scum has built up, kitchen appliances with moldy seals or dirty drawers or bottoms, dirty garbage cans, dirty showers, bathtubs, sinks and toilets, un-mopped kitchen and bathroom floors, leaky plumbing areas.
Eliminate all possible sources mentioned above and perform a thorough cleaning. Drains should be cleaned—not just rinsed with beach, but the stoppers removed and scum cleaned from them and the sides of the drains. All fruit and food items should be stored in the refrigerator or in tightly sealed containers in the pantry. If you believe you have done all you can to eliminate food sources and breeding grounds and the infestation persists, it is time to call The Pest Force.