[Annual Fly Control Issue] No Hot Air

My fascination with insects started at a young age while growing up at the Delaware shore. During my early years I spent a lot of time dodging and avoiding green head flies (Tabanidae) and mosquitoes. While diseases such as West Nile virus and various strains of Encephalitis were not health issues for us, one only has to be bitten by a green head fly to find ways to avoid these voracious blood feeders. I quickly learned that the warm, still days at the beach meant an onslaught of mosquitoes and green heads. They even venture out in the heat of the noon sun when the wind is still.

A future article may include information about temperatures and humidity and the emergence of flying insects, but for now I’m going to concentrate on air currents and how we can integrate this practice into Integrated Pest Management procedures. 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.

AIR CURRENTS, FANS AND FLIES. Recently 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 in the literature 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 (Dictyoptera: Blattidae), Journal of Economic Entomology, 92(1): 170-175. 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, has 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, etc. 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. Oswald et al. suggested the development of systems that blow air steadily into kitchen and bathroom cabinets, wall voids and equipment.

I personally can attest to using air movements for German cockroach control. In the 1980s a large pharmaceutical company was finishing a long-term study and was in the final stages of the drug trial. German cockroaches were so numerous the test primates were eating the cockroaches. Fearing contamination the researchers charged us with getting rid of the cockroaches without any chemicals whatsoever. They didn’t even want two-sided tape in the room for fear of the odors and solvents.

Noise was not an issue so we finally set up a new compressor in the hall, ran in air hose and used a parts blower to inject air into the cracks and crevices and used a new vacuum to suck up the cockroaches. We were able to get 90 percent plus control; cockroach sight-ings by the staff were zero and we were heroes.

So, we know air movements can cause cockroaches to move so why not use this for flies? Well we have. Taking this novel approach to the structural pest control industry takes some thinking outside the box and acceptance from our clients. (See photo and description at left.)

SUCCESS STORY NO. 1. Here is a success story that shows air movements work extremely well. A large five-star hotel chain was having a heavy fruit fly problem around its morning breakfast bar. Fruit flies were causing customer complaints and "comped" hotel room bills. Management wanted something done immediately.

After increased sanitation and some aerosol treatments at night, the hotel’s problem continued. Together our service team and the head chef placed small oscillating fans strategically to blow back and forth over the fruit areas of the breakfast bar. (See photo at left.) All exposed fruit was 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 "low" 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.

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

SUCCESS STORY NO. 2. At the recent PCT Fly Management Summit in Atlanta, pictures of ceiling paddle fans installed over the fruit and vegetable section of a supermarket were shown. Jerome Goddard, a medical entomologist for the Mississippi Department of Health and clinical assistant professor of preventive medicine at the University of Mississippi Medical Center, Jackson, Miss., told attendees that since the fans were installed fruit flies have not been a problem in that area. Pedestal fans can be placed at salad bars and left running just prior to lunch being served. This will keep fruit flies and other nuisance flies from landing on the food. The fans can be taken away as the customers come in.

However, the issue of blowing dust onto the food must be considered so the area must be cleaned continuously. Air filtration units would overcome this obstacle (if it is an issue at all). Fans certainly can be used more extensively in the "back of the house" and bar areas at night. After our service team solved the fruit fly problem with fans, they went after fruit flies in bar areas.

At night the clean-up crew mixed a solution of bleach and water. The mixture was applied thoroughly to the floor and areas that were routinely overlooked from deep cleaning. Four 20-inch box fans were set up around the bar to create wind currents, dry out the area and aerate the bleach solution. We found out that the wind stopped the fruit flies from landing, loafing, feeding and best of all, laying eggs. The best thing about this procedure is that the account can do it themselves and we are not called upon to space treat at night or have them rely on a pesticide solution.

SUCCESS STORY NO. 3. My last experiment and field research is one of a personal note. My wife Pattie is a human mosquito magnet. (Note: Mosquito Magnet is a mosquito control unit that is gaining reputation as a tool in mosquito control and has been tested by the USDA. More details can be found at www.mosquitomagnet.com.)

Last year we were sitting out on the deck on a still night at dusk. The mosquitoes came out and were quickly at our ankles. West Nile virus (WNV) was all over the news and there had been about 12 deaths attributed to it. At the first bite Pattie said, "I’m going inside, I can’t stand these mosquitoes." I quickly decided that I wasn’t going to let mosquitoes chase us inside and I went to the garage for a can of pyrethrin aerosol. By the time I got back to start spraying she was in the house. She didn’t want to smell the pyrethrin.

Thinking about the success with the fans on the fruit flies, I went inside and got a 20-inch box fan, plugged it in, put it on medium and aimed it at my chair. Within seconds the mosquitoes were gone. A few were buzzing around my head, so I moved the fan back and put it on high. The results were amazing. Pattie came back out and we finished a nice evening on the deck.

A few days later I saw an ad for a Misting Fan (see photo at left). This is an oscillating pedestal fan that attaches to a garden hose. Once the water is turned on and the fan is running misting nozzles create a nice cooling mist that is blown to cool you off. I ordered one and use it during hot weather. The combination of the air movement and water vapor prevents mosquitoes from flying. Flying insects have to work harder against air currents and water on the scales of their wings weigh them down and chase them away. How many times do you see insects flying during rainy weather? Not much.

Through personal experimenting, we now enjoy mosquito-free evenings on our deck at night and around our pool. Cool mist fans can be found at outdoor patio and deck companies or you can search the Internet for a long list of suppliers. Our friends in hot weather climates are familiar with misting devices to keep them cool in the summer. Theme park companies, such as Disney, use misting nozzles to keep clients cool while waiting in line. You won’t see many house flies or mosquitoes loafing around the mist.

CONCLUSION. My hope in writing this article was to share what I consider a unique yet simple way of dealing with some of the nuisance flies we encounter. Air currents certainly have a role and fit nicely in 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 as they have been around our industry for many years. Mars Air Doors have provided us with much success over the years and all along air movements went right over my head, many times while visiting food-processing areas. I 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 technical and training manager for Western Pest Services, Parsippany, N.J. He can be reached at wkolbe@pctonline.com.

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.