[Best Practices] Small Flies

Fruit flies, drain flies and Phorid flies all may look the same to the naked eye, but a closer look will prove the flies to be as different as are their feeding and breeding habits. QA asked industry experts for their best advice on how to monitor and manage these small flies.

1. Identification and Inspection. There are important differences between the three most common small fly pests and these are key to locating your pest source (see “Phorid, Fruit or Drain”). Once identified, the areas need to be recorded on a detailed report and physically pointed out to all those responsible for cleaning and maintenance. If a structural issue, such as broken pipes under a slab, is found, the situation should be corrected a quickly as possible. Insect light traps (ILTs) can be valuable tools for monitoring or control of small fly activity.

• Place traps in areas where flies have been seen and where the trap will not be disturbed.
• Additional traps should be placed beside or above, and within 12-15 feet, of doors or other exterior openings.
• If the cause of a sudden small fly occurrence is unknown, ILTs can provide temporary control while the source is identified.
• To monitor fly activity, remove the lid, count the number of adult flies, record trap counts, and monitor changes in activity. 

2. Communication and accountability. After you have identified the pest and its food, water and harborage sources, communicate with plant staff. Your pest management provider can present information on the pest and its control at team meetings to ensure that all who are responsible for cleaning or fixing the deficiencies are fully aware of the problem and your determination to rectify it. If your team does not buy in and details are skipped, the problem will continue.

3. Prevention. Once a small fly infestation occurs within the facility, it can be difficult to find the breeding source and control the population. Unlike larger flies that generally breed outdoors, small flies will reproduce indoors, so potential breeding sites must be kept clean. As with most pests, sanitation is key to prevention.

• Keep food surfaces and areas clean to minimize fly attraction.
• Clean drains of food debris, and treat with a microbial foam treatment or enzyme-eating liquid.
• Empty trash cans in all areas on a daily basis.
• Never store trash inside near doors, windows or vents, and keep exterior Dumpsters as far from the building as practical.
• Ensure all doors, windows and makeup air vents throughout the building have well-sealed screen units that can be easily cleaned.
• Cracked floor tiles, missing grout and peeling baseboards can allow water and food particles to seep behind tiles, and provide sufficient space for small flies to lay eggs. While pressure washing has some cleaning advantages, it can make small fly problems worse by driving food and water into cracks and crevices. Use microbial cleaners and keep tile and baseboards in good repair.

4. Temporary relief. Plants can attain immediate but temporary options for high populations by:

• installing insect light traps for capture and monitoring.
• fogging by your provider with an approved insecticide.
• using timed aerosol dispensers or fan spray spot treatments on surfaces in non-food areas where flies land.

5. Partnering. Teaming up with your pest management provider to implement inspection, prevention and management programs will give you the best small fly control. Otherwise, without strict sanitation measures throughout the plant, actions taken by your provider will generally provide only temporary control. And if a problem persists despite thorough sanitation and control measures, the situation can be discussed with your provider, as the source could be very obscure, and you’ll need to work together to identify and eliminate it. 

Tips provided by: Rick Brown, vice president of sales and marketing, Rasco Industries; Jack E. Harris, marketing director, Insect-O-Cutor; Patrick Kelley, ACE, general manager, Fumigation Service & Supply; William Robinson, technical director, B&G Equipment Company; Dr. Cisse W. Spragins, CEO, Rockwell Labs Ltd; Richard Stevenson, chief technical officer, Modern Pest Services; and Nick Tresslar, marketing manager, Whitmire Micro-Gen.