[Annual Fly Control Issue] Air Currents and Fly Management

In today’s pest management environment, it is extremely important to consider all aspects of fly management when putting together an environmentally sound IPM program for managing fly populations in various types of accounts. This article brings to light some strategies to consider when you tackle a fly problem, whether for immediate population reduction or ongoing fly management.

Air currents and fly management are often overlooked, and with limited research published on this topic in scientific journals, the pest management professional may wonder where this concept might work in his or her day-to-day fly management strategy. Let’s look at how air currents can reduce fly populations, as well as enhance the efficacy and effectiveness of standard fly management products. Selecting, using and convincing your customer that air movement equipment will help reduce flies can be a challenge, but your efforts will be worth the time invested in this endeavor.

Background. You may have experienced this situation without really noticing it. Have you ever spent a day at the beach, camping or on a fishing trip dodging and avoiding green head flies (Tabanidae) and mosquitoes? One only has to be bitten by a green head fly to find ways to avoid these voracious blood feeders. You may have noticed that warm, still days at the beach mean an onslaught of mosquitoes or green heads. They even venture out in the heat of the noon sun when the wind is still. Most saltwater fishermen know that when the wind is blowing a certain direction and at a certain velocity they can fish comfortably without being tortured by green head flies and mosquitoes.

Have you ever wondered why insects tend to disappear proportionately as the wind velocity picks up? Simply put, flying insects need a lot of nutrients for their flight muscles, and flying into wind and air currents takes a lot of energy consumption for the insect. Many flying insects will seek harborage and avoid wind and air currents. If we take this example of outside insects and bring it inside, we may have a winning combination.

Air Currents, Fans & Flies. Through-out my career, I have been conducting field evaluations on air currents on fruit flies (Drosophila) and other small organic breeding flies (SOBF), as well as some preliminary work on using fans to keep mosquitoes at bay. A search of the literature and research, as well as surveying colleagues, shows that this subject has been looked at but there is not much published on fruit flies and mosquitoes. Dr. Richard Kramer reported in PCT in 1999 about a study done by Appel and Smith on perception and repellency of moving air by American and smokybrown cockroaches (Blattidae) in the Journal of Economic Entomology.

A Dayton fan (one of three total) sits on a bar in a hotel in Connecticut. The fan is useful for keeping fruit flies away, and works as an IPM solution. Management reported no problems with fruit flies since the fans were placed, and started placing fans on the bar overnight as well.

The authors reported that moving air is repellent to all stages of smokybrown and American cockroaches at velocities greater than or equal to one meter per second. This strategy can be used to repel these two cockroach species from sensitive environments and force them to move to habitats less suitable for survival and reproduction.

Harry Katz reported in PCT in 1977 that Dr. Eric Smith, author of the NPCA Field Guide to Structural Pests, had for years used an aerosol can of plain air to flush cockroaches from harborages in sensitive situations such as in pet shops, schools, electronic equipment and more. But more sophisticated tools creating directed, sustained pulses or intermittent breezes into familiar foci of cockroaches and other pests is likely to be added to the 21st century arsenal for our industry. The development of systems that blow air steadily into kitchen and bathroom cabinets, wall voids and equipment has been suggested.

Here is a success story that shows air movements work extremely well. A large five-star hotel chain was having a heavy fruit fly (Drosophila spp.) problem around its morning breakfast buffet. Fruit flies were causing customer complaints, and resulted in “comped” hotel room bills. Management wanted something done immediately.

After increased sanitation and some aerosol treatments at night, the hotel’s problem continued. A team effort resulted when the PMP service team and the head chef placed small oscillating fans strategically (to the rear of the tables) to blow air back and forth over the fruit areas of the breakfast bar (see photo, above right). All exposed fruit was either wrapped in plastic wrap (which actually increased the shelf life of the fruit) and/or placed in food containers with lids. The fans were placed on the lowest setting during customer hours and the customers actually thought the fans were there to cool them off. When the food was removed and the areas cleaned, the fans were turned on “high” and left to run overnight. There were zero fruit fly complaints the first day of installation.

At this Florida hotel, the PMP service team and the head chef placed small oscillating fans strategically (to the rear of the tables) to blow air back and forth over the fruit areas of the breakfast bar.

The credit went to the head chef and the PMP service team. The chef actually became a champion of this effort and proudly shared the technique with other head chefs. The validation that this technique works was that two years later the fans were still being used and most every other hotel in the area had adopted this technique.

Integrating Air Currents. Air currents certainly can be used to reduce the activity and sightings of flying insects. During the summer months customers would probably not associate fans with insect problems, they would just think the fans were put out to cool the occupants off. Certainly fans can keep flies out of certain areas and if placed correctly could channel flying insects toward your insect light traps (ILTs), fruit fly traps, baits or other fly control devices. The next time you go into the fruit storage area of a restaurant or food vendor and find fruit flies hovering around the fruit, simply grab a fan (or ask them to position it), point it toward the flies and watch how quickly they disperse. Fruit flies and small organic breeding flies “hone” in on these areas at night to lay eggs. Having fans running 24/7 may dry up and eliminate breeding sites and not allow the female flies to lay eggs, thus breaking up the life cycle of flies.

Other Situations. Keep in mind the air compressor and vacuum. There may be situations where no pesticides or odors can be tolerated and you may be asked to get rid of cockroaches, ants, bed bugs or stored product pests. It may be labor intensive, but could anything be more “green” than coming in and flushing out insects with compressed air and as they run, vacuumming them up with a HEPA-filtered, heavy-duty vacuum? Certainly (if anything) it will set you apart from your competition and will definitely increase the effectiveness of your overall pest management program.

Conclusion. Air currents certainly have a role and fit nicely in green and advanced IPM concepts, and best of all, in many circumstances, your clients can do much of this work at their cost (and not yours).

I would be remiss if I didn’t mention air doors and air curtains as they have been around our industry for many years. Air doors and air curtains have provided the food industry and pest management industry with much success over the years. All along air movement went right over our heads, many times while visiting food-processing areas. Just like me, you probably always took them for granted, but now have a better appreciation for their use and the use of air currents and insect control. I hope PCT readers will take this to the next level and share their success stories. I know we will have more successes to share.

Author’s note: Special thanks to those colleagues who helped me with their wisdom, thoughts, experiences and encouragement on writing this article.

The author is a Board Certified Entomologist and the director of technical and training for Viking Termite and Pest Control, Bound Brook, N.J. His career in pest management started soon after he graduated from the University of Delaware in 1974. Email him at bkolbe@giemedia.com.

References
Reduction of Mosquito (Diptera: Culicidae) Attacks on a Human Subject by Combination of Wind and Vapor-Phase DEET Repellent. Eric J. Hoffmann, James R. Miller. Journal of Medical Entomology, Vol. 39, Issue 6, p. 935-38. November 2002.

Perception and Repellency of Moving Air by American and Smokybrown Cockroaches (Dictyoptera: Blattidae). A. G. Appel, L. M. Smith Ii. Journal of Economic Entomology, Vol. 92, Issue 1, p. 170-75. February 1999.

Effect of Airflow on House Fly (Diptera: Muscidae) Distribution in Poultry Houses. Christopher J. Geden, Jerome A. Hogsette, Roger D. Jacobs. Journal of Economic Entomology, Vol. 92, Issue 2, p. 416-20. April 1999.