Catch The Flying Dollars

Many of your competitors will balk when it comes to fly control. Many of the accounts I have been able to acquire have been on the basis of their fly control problems. When queried, most PCOs say fly control is too difficult or time-consuming, or that you never get the customer to cooperate, or that the flies are coming from down the block. For some companies, these may be justifiable excuses for not attempting fly control for their customers. Even a light trap may provide some relief, depending upon the species pestering the client. If sold, started and maintained properly, a fly control program can be a significant additional revenue source for any pest controller.

Fly control, as seasoned veterans are particularly aware, is not an easy task. The identity of the species involved is crucial. Killing the adults is fine, for today. Tomorrow, next week or even next month, more adults will emerge and cause the dreaded callback.

THE FUNDAMENTALS. Some basic biology of the dipterans (members of the order Diptera, which in addition to flies includes mosquitoes and gnats) is necessary at this point.

All dipterans have complete metamorphosis and include a pupal stage. The immature or maggot stage usually feeds on decaying material away from the habitat of the adults. Maggots are much easier to control with environmental extremes, habitat modification and cultural controls than with sprays.

Pupae are the resting stage during which the maggots undergo a developmental change in features from the eating-machine immature stage to the flying, reproductive, pestiferous adult stage. Pupae are best controlled with a hammer. Pesticides will not work because they will not penetrate the pupal cuticle. Adults will emerge anywhere from a few days to a few weeks after the onset of pupation. This lag time is where we get into trouble. The problem goes away, but comes back.

Another biological point about flies is that they have a high reproductive capability. Each fly may produce from 200 to 2,000 eggs in its lifetime, which lasts only a few days. There is tremendous genetic variability built into the population, and any pesticide used will produce resistant strains quickly.

THE CLEANER THE BETTER. One of the keys to successful fly control is sanitation. Locate the feeding sources for the maggots and eliminate them. This eliminates the egg-laying areas, the maggots, and ultimately the problem. Make sure the client understands the lag time in complete control, but don't let the client get sloppy later and provide the same initial sanitation problems.

What are some frequent sanitation problems? Obvious ones would be trash left in a garbage can for weeks, or a dumpster that is never washed or emptied. Less obvious food sources might be the rotting roots of over-watered plants (both indoors and out), standing water in a glass with a plant in it on an office desk (mosquitoes), or filthy drains or food disposals in a home, clinic or dishwashing area. The food disposal must have been invented by a frustrated PCO who wanted a lot of filth fly business!

These are but a few of the problem areas. Always look for sources of moisture. This is usually the key. This may include water soaking cardboard reinforcements in walls and floors, rotted drains that leak into the surrounding sub areas, refrigerator drain pans, or condensation on cooler motors that pools underneath the machines. As you can see, the list is a long one.

One of the areas that most PCOs neglect is the area of fly baiting. When you have tried source reduction and sprays and have met with limited success, perhaps it would be a good idea to "trap out" the remainder of the population. In reality, trapping and baiting will not get every fly, but it is a proven effective tool as part of an overall program.

Prior to baiting, trapping or any other method, the fly species must be identified. Collect a sample and identify it. This will provide you with a basis for where to search based on the food preferences of the species.

If it is a blue bottle fly, are you going to look in the fruit bin for spoiled fruit? Is it a Fannia species or a Drosophila species? These are important differences to consider. You may assume it is one species, spend a lot of time, effort and money, then find out you have missed it due to an incorrect identification.

One of the keys to fly baiting and trapping is the use of exclusion to herd the flies to the area of yo ur traps. Screens over windows, blowers over doors, plastic strips in doorways, and correct lighting and placement of light traps all will effectively reduce the population and herd the remaining flies toward your traps. Another simple, inexpensive and extremely effective method of exclusion is to keep doors shut when they're not in use.

SEEING THE LIGHT. Insect light traps are a dependable resource to remove a large number of flies before they obtain entry into your account. Originated in the 1930s and 1940s, these devices utilize the ultraviolet spectrum of light to induce flies to land on them. The older models have an electronic grid that zaps the fly into pieces, which fall into the collecting tray below. Unfortunately, some pieces do not fall into this tray, but instead fall outside the trap.

Some manufacturers have responded to this problem with the use of low-voltage, intermittent electronic pulses through the grid to stun insects instead of killing them. The stunned insect then exhibits a downward corkscrew flight pattern into a glueboard below. Some light trap manufacturers have even eliminated the electronic grid altogether, relying on the old style glue tray at the bottom or back of the trap to capture and hold the flies.

These traps must be placed up to six feet up and just inside the doorway so that the light emitted from the trap does not compete with the natural light from outside. Select hallways or receiving areas for placement of these traps. Trays or glue trays should be checked and changed monthly or weekly depending on the population pressure and how quickly the traps fill up. Use the types and numbers of flies on and in the traps to identify the species involved and to determine the severity of the problem. Even during the sales inspection, pull out the light trap trays. Most pest control technicians forget to check these traps, and the flies start to build up.

What if there are light traps already in place, but they are not really catching anything? Ask the customer when the bulbs were last changed. Bulbs should be replaced every 12 months, usually in early spring before the fly season starts.

LOWER-COMPLEXITY TOOLS. Some of the simpler models of fly capture devices include glue strips or rolls with imprinted fly designs. Most of these add a sex attractant to them. Flies are supposed to be brought into the trap with the visual and odor stimuli. These items work with marginal success.

Becoming more popular, especially with homeowners, are dome and bag fly traps. While flypaper traps will always be used by a certain segment of the population, some companies such as Farnam have developed and successfully marketed disposable fly traps that are very useful in an overall fly control program. The concept of these traps is to use an attractant lure to pull the flies into a holding area where they die of starvation or drown in a liquid solution. The downside is that in high populations, the bags and jars must be replaced almost twice to three times a week. Remember to calculate that into the cost of the job.

Depending upon the species of flying insect and whether you are able to locate the breeding area(s), traps may be placed around breeding sites to capture as many adults as possible.

The next area of baiting is the use of a sex attractant and a feeding stimulus chemical to get the flies to land on, feed on and ingest a pesticide. This material has been around for a long time. It will attract flies from up to 50 feet away with a good breeze.

Unfortunately, with the highly variable and pliable genetic makeup of the typical fly population, resistance is likely to occur quickly. In dairy, swine and poultry operations, these baits are heavily used. If you are dealing with a population of flies coming from one of these areas into a suburban neighborhood, be aware that these baits may not work.

CASE STUDIES. Let's take a look at some real-world fly control problems.

Small gnats are reported in a dentist's office, and the accounting department seems to have them the worst. If flies have been spotted in the waiting room near the fish tank, look for water leaks, algae growth, and other moisture sources. In the dentist's office, check the sanitation levels around the examination chairs.

Have the trash cans been emptied and washed out this week (or month)? Are they using plastic trash can liners and throwing the liners out each day? Some custodians will empty the trash, but keep using the same liners until they are fuzzy, green, growing and crawling. Many times gnats may be breeding in biohazard trash bags.

The presence of body fluids and blood will attract flies and supply the larvae with a wonderful growth media. The places where patients rinse their mouths during examinations or minor dental work is also important. If patients rinse their mouths directly into sinks, suggest that the staff use a strong bleach solution in hot water in each drain every evening for sanitation purposes. With this recommendation, you are increasing the sanitation and also killing fly larvae and eggs through decreased food and the chlorine fumes.

Make sure to obtain a positive identification of the species of fly involved. Do you think we're done here yet? Problem solved? Not yet! The gnats in the accounting office seem not to be associated with the drains or trash cans. You find a specimen on the window ledge. It is a typical fungus gnat. These insects may infest plant soil as larvae, feeding on the rotting roots of over-watered plants. Check the plants on the desks for over-watering. The best recommendation at this point is to replace the soil with fresh soil, wash off the plant roots, wash the pot with soap and water, and then re-pot the plants. Afterwards, make sure the customer doesn't continue over-watering.

FRUIT FLIES. An office has an infestation of what you identify as fruit flies. Now what? Inspect for rotting fruit. You inspect the entire area, inside trash cans and under liners, in recycling bins, in desks, behind cabinets, and there still is no rotting fruit. All of the plants are plastic. Now you are stumped. Before admitting defeat, check the window sills. Is there one that has more flies on it than the others?

The flies are seen throughout the office areas. Look in the bathrooms, sink traps, below sinks, and any other areas where there may be a water leak. Check the air conditioning system. Many times water may condense into pools in the ventilation system, allowing algae and insects to infest. The ventilation system enables easy dissemination of flies throughout the area.

Lastly, check around the exterior of the building. Are the planters over-watered? Are there trash cans or recycling bins overflowing or not attended to near doorways or alcoves? Re-check your ID to verify that the pest is not a fungus gnat or phorid fly. The best control method is elimination of food sources and/or breeding areas.

A small day care center has a major fruit fly problem in the patio area. They do not allow any type of spray, even pyrethrin, in or around the facility. Now what? The trash cans should be emptied daily and washed out. The dumpster lid should be kept closed and locked when not in use.

Also, as you may have noted in the May 1995 issue of PCT, a pest control distributor now has a type of fruit fly trap that is reputed to be very effective. This bag trap should be placed every six feet (in radius) from the walls and other traps. Hang them from the ceiling and check them every other day. During the hot summer months, it may be necessary to change the traps every other day.

SETTING A PRICE. One of the most frequent questions asked is how much to charge for this type of fly control service. Make sure to charge the customer three times the cost of the materials, travel time and on-site time at your calculated man-hour rate. Factor in the weekly reinspections and trap services. If sanitation is going to be the turning point for control of the infestation, check on prices with a local cleaning service to do the work for the customer. What's the worst the customer can do, say no?

Lastly, factor in the hidden cost of maintenance of the account with a fly-free area. Will the sanitation go back down? Make sure to place a cancellation clause in the contract so that you may use it as leverage if the customer refuses to clean up the messes that are causing the newest fly problems.

Fly control is not the easiest of services to perform. It requires a thorough inspection and understanding of fly identification and biology. The use of traditional pesticides is rapidly being removed from the equation; thus we must focus on alternative techniques. The proper program that takes into consideration sanitation and cultural, environmental and human factors will provide excellent long-term control.

One last note: It's a good idea to keep on hand a couple of good references for fly control. I recommend Stoy Hedges' PCT Field Guide For The Management Of Structure Infesting Flies and Truman's Scientific Guide To Pest Control Operations.

Jim Harmon, a Board Certified Entomologist, manages the industrial pest management division of A Perfect Pest Control Co., San Gabriel, Calif. He has a master's degree in urban entomology.