FMC Professional Solutions: Flies

By Richard Spigler, BCE, Northeast Pest Market Specialist

When dealing with flies in homes, businesses or restaurants, it important to look at the big picture. Proper management includes these five steps:

1. Sanitation is still the best method of controlling house flies in and around the home, commercial facility or on the farm. Locate and thoroughly clean breeding sites. Eliminate feces, manure or other animal excrement, as well as any other organic waste (dry and wrap organic waste before placing in the garbage). Do not let refuge accumulate, and ensure garbage cans have sound bottoms and tight-fitting lids. Encourage customers to clean or replace Dumpsters.

2. Like other pest problems, fly control begins with a thorough inspection of the premises, and by knowing where and what to look for. Once the breeding sites are found, identify the specific species involved and proceed accordingly. House flies are usually 0/25-in. long; they are dark grey and have four longitudinal stripes on the thorax. In contrast, fruit flies are smaller, tan and usually have reddish-colored eyes. Cluster flies are bigger, have a golden sheen and typically don’t appear until fall.

3. Exclusion methods often start with ensuring windows have well-fitting screens in good repair. Air-curtains and fans placed above doors also have been successful in excluding flies in commercial accounts. PVC/plastic strip doors (also called freezer or cooler strips) can reduce entry of flies when maintained and kept clean. In areas with high humidity, aluminum screens last longer than plastic or fiberglass types. Treat and/or seal cracks and crevices around windows and doors to eliminate entry. Ensure tops and doors on Dumpsters are kept closed.

4. Insect light traps (ILTs), sticky and pheromone traps are the most commonly used forms of mechanical control. ILTs are highly effective at reducing populations in enclosed areas. However, minimize outdoor use so that you don’t attract and eliminate beneficial or non-target insects. Proper placement inside will also prevent attracting insects from outside the structure.

5. Chemical control includes applying exterior barrier sprays to areas where flies rest. Pesticide bait formulations are also available for outdoor fly control. Pay close attention to Dumpsters and refuge areas. Indoors, flushing and contact aerosols can be used to knock down breeding sites around drains or in trash cans, though these sites often are hard to find.