[Fly Control]

Filth flies. The name alone conjures negative images of garbage dumps and decay. Yet these insects may be among some of the most misunderstood creatures in the animal kingdom, according to Bob Davis, Ph.D., board certified entomologist and a frequent speaker at pest control industry meetings and other educational events.

Davis, a market development specialist for BASF Specialty Products, explains that these two-winged flies, which belong to the biological order Diptera, "have been very successful, which shows that through evolution they’ve done something right." For this alone, they should earn some degree of respect.

While some Dipterous insects, which include mosquitoes and various types of flies, have the potential to damage crops and plants, inflict painful bites and even spread serious diseases such as West Nile virus, most of the 120,000 species are beneficial. They cycle carbon and nitrogen through the ecosystem, encouraging plant and animal growth. And while we may be repulsed by their dining preferences, many serve as scavengers, helping to break down carcasses or decaying organic matter and returning important nutrients to the soil. Some species are parasites that control populations of other types of insects, and many pollinate plants.

Yet filth flies, despite their honorable family tree, are considered nuisances by most people and a market opportunity for most pest control professionals. "They’re not so beneficial in Mrs. Jones’ living room," Davis says. Controlling filth fly populations, which include house flies, stable flies, blow flies and flesh flies, requires an understanding of the flies’ life cycle and biology. "Certain types of control only work for certain stages," Davis says.

In explaining the complete metamorphosis of filth flies, Davis recalled his days as a student at the University of Nebraska where he and his cohorts challenged state fair attendees to guess the correct number of larva "on a huge tray of seething maggots." (In case you ever wonder, bunches of maggots can be counted simply by waiting a day or so until they pupate, freezing them and running them through a seed counter.)

TAKING CONTROL. Pest control professionals who are faced with the challenge of ridding an area of filth flies must first identify the type of fly and conduct a complete inspection to locate the flies’ breeding area. Gaining control of the fly population is much easier once the source of eggs and larvae are isolated and cleaned. In general, these insects lay their eggs in clusters of 75 to 150 where the larvae can feed as soon as they hatch. And true to their nickname, filth flies often choose rather unappetizing locations for their young’s first meal. Decaying meat, animal feces, carcasses, grass clippings and other sources of moist, nutrient-rich organic matter are popular choices.

Knowing what types of areas these creatures prefer is key because the eggs are tiny, and many species are difficult to pinpoint because they match the color of the substrate in which they reside. For this reason, Davis urges pest management professionals to educate their clients about the importance of reducing potential breeding sites. "Something as simple as cleaning up after the dog goes outside in very important," he says.

Once a filth fly grows up, it becomes a "general feeder," searching for food wherever it lands. "They can go straight from a pile of dog feces to your mashed potatoes," Davis says, which is why flies have such a bad reputation for spreading disease. Indeed, these insects are knows to carry millions of bacteria on the microscopic hairs that cover their legs and other body parts. As they search for food sources, they can transmit bacteria to human foods and directly into open wounds. Davis notes that house flies have been documented as carriers of more than 100 different diseases including typhoid, dysentery, cholera, tapeworms and giardia. "So when we provide control, we’re doing a wonderful medical preventive service for our customers," he adds.

Davis recommends that all pest management professionals carry magnifiers, vials, small plastic bags and rubbing alcohol in order to capture and clearly identify the specific Diptera in an area. Identification guides are readily available online and through many state university extension offices. In fact, Davis suggests that pest management professionals share Diptera fact sheets from these sources with their clients as part of the educational process to help decrease the fly population.

MANAGEMENT. Besides cleaning, removing or drying out potential breeding sites, pest management professionals must address control of the adult fly population. Again, clients must be educated about how they can help in the battle against these bugs. In many cases, pest management professionals can find torn or missing screens, uncovered vents or holes in a structure that may allow flies to enter. Simply making basic repairs with caulk and properly fitted screening is the best exclusionary tactic a client can employ.

Light traps are one popular method for ridding an area of flies, and various chemical controls are available as sprays, strips and traps. In determining which type of control to use, consider the area. "You don’t want bug strips hanging right inside the door of a grocery store," Davis says. And hanging bug strips by warehouse rafters isn’t extremely helpful, because such control mechanisms should be placed within five feet of the ground in order to attract the most insects.

Another consideration with using insecticides for fly control is that the high number or generations these insects create during a single season makes them good at developing resistance to various pesticides. Therefore, pest management professionals must remember to rotate various classes of insecticides in order to prevent this problem from developing.

Once a fly population has decreased in a particular area, it is important for pest management professionals to evaluate their efforts and recheck the area on a regular basis. Davis adds, "This is very critical with flies because they can build massive numbers quickly, and if you’re not on top of it, the sit-uation’s going to get out of control."

The author also wrote a book called The Edge Up and offers marketing and customer service to help her customers attract more clients. She can be reached at 800/779-0067 or at jvanklaveren@giemedia.com.