"MOTIVATING" TECHNIQUES

What are flying insects attracted to? The answer includes a variety of factors, including temperature, food, light and sex.

What are flying insects attracted to? The answer includes a variety of factors, including temperature, food, light and sex.

Hmmmmm...the aroma of good food in the air. From where does it resonate? Which restaurant? It seems to be coming from that direction. Almost there. Ahhh, there it is...the dumpster of my dreams.

Of course, were I a fly, I might have such dreams. Food is the largest motivating factor governing a fly’s life. Not only do I need to find a meal for myself, but, if I am a female fly, I must find proper food for the little ones I hope to produce. Provided, of course, I find a suitable mate (and as a fly, I know that won’t be a problem).

Despite the "ignorance" of people in general when it comes to flies, these insects are an integral part of our existence. More than 110,000 species of flies have been identified and named and these insects occupy most every ecological niche on the planet. As is the case with most groups of insects, only a relative few species are pests of man and fewer still are pests within structures.

Mosquitoes occupy most of man’s attention to flies because they are responsible for so much human misery throughout the world. Americans should consider themselves extremely lucky in this regard — the West Nile encephalitis problem in the Northeast notwithstanding.

House flies, blow flies and fruit and phorid flies are largely the species involved in most structural issues involving flies. Other important pest flies include moth flies, fungus gnats and cluster flies. What motivates flies and how can we use that to our advantage?

Jerry O’Hara of Anderson Environmental Systems in Chicago sums it up nicely when he lists the three motivators for flies as food, light and sex. I will add one additional motivator: temperature. Which flies respond to which motivator most depends largely on the type of fly involved.

TEMPERATURE. Flies are highly motivated by temperature. House flies and blow flies prefer conditions in the low 80s and will be attracted by cool currents emitting from buildings on hot days. In fact, the dumpster may attract the flies to the building but the air currents exiting through doors or cracks around doors and windows are what actually draws the flies inside. Cluster flies are motivated by the warm walls of buildings during the fall — the warmth is an indicator of an ideal site to spend the winter.

Unfortunately, little can be done to minimize temperature as a motivator for flies. The interior of buildings are heated or cooled, depending on the season, and one can’t stop the sun from heating the walls of a home. We can, however, understand temperature’s importance and take better steps to seal the building and to prevent air currents from exiting and attracting flies. Exclusion is a critical step, after sanitation (see related story on page 28), in minimizing fly infestations.

FOOD. As mentioned previously, food is an overriding concern for all flies. It is the strongest motivating force in a fly’s life, instilling a persistence that transcends annoying when it comes to human/fly interactions. Witness your attempts to keep a fly off your mashed potatoes at an outdoor picnic. You better eat quickly if you really want the fly to leave you alone.

Nothing — NOTHING — is more effective at limiting fly infestations than sanitation. No earth-shattering fly control technique exists beyond sound, regular sanitation practices in both commercial facilities and homes. Unfortunately for the pest professional, sanitary efficiency is beyond his control — we must depend on the customer to make the necessary changes in sanitary practices to demotivate flies to be attracted to buildings.

It doesn’t take a genius to understand that food odors attract flies to buildings and from there it’s a short flight to the inside where better food or a more ideal temperature might be found. With food and food odors, the goal is to remove or limit the motivator. Less odor means fewer house flies, blow flies and flesh flies. Less exposed garbage results in less potential for flies breeding on site — next to (or even inside) the building.

What about the small flies: fruit flies, phorid flies and moth flies? These flies readily establish indoor breeding sites in areas where decaying organic matter is permitted to accumulate.

Literally any crack at floor level can trap enough food and moisture to breed flies. Drains are also critical for phorid flies and moth flies (see "Cleaning Up Profits," page 40). Can you find and remove these motivators? A challenging task, indeed. Surely, the most frustrating days spent by pest professionals are those spent looking for the source(s) of a fruit fly or phorid fly infestation.

What steps are prudent for these flies?

  • Regular emptying and cleaning of inside trash receptacles.
  • Regular and careful cleaning underneath kitchen equipment, dining room booths, etc.
  • Regular cleaning of drains.
  • Cleaning, drying and sealing of cracks at floor level where organic matter accumulates and flies are found to be breeding.
  • Regular removal of cans and glass designated for recycling.
  • Rotation of fresh fruits and vegetables not stored in coolers.

Likely the single greatest obstacle to successfully addressing of all these sanitary practices, inside and out, is the customer. They are running a business and usually don’t appreciate the importance of these efforts. Sure, they appoint various tasks to their employees, but follow-up is often lacking to ensure satisfactory completion of cleaning efforts. Food and breeding sources are huge motivators for flies and customers must be sold on the idea that their own practices dictate the majority of a successful fly control program. This, by far, is the toughest sales job in this business — gaining the customer’s cooperation (in the absence of a health inspector’s recent and direct oversight).

Drains — One area where the pest professional can be of direct service in regards to sanitation is through the application of bacterial products to drains, dumpsters and wet areas where organic matter may accumulate. Vector Bio-5 (Whitmire Micro-Gen, www.wmmg.com), KB4-F (BioStim), DF 5000 (Anderson Environmental Systems), DrainGel (American Bio-Systems, www.bio-systems.com) Bio-Action (Athea Laboratories) and DFM 32X (Genesis W.E. Company, www.genesiswe.com) are popular bacterial drain products. Such products added regularly to drains eat away at organic matter and eliminate potential food for fly larvae. Additionally, the bacteria may even directly attack and injure/kill fly larvae.

Bacterial products may also be sprayed directly into and beneath dumpsters and to wet areas in commercial kitchens where wet organic matter is or may accumulate. Check the label for instructions for such applications.

Traps A number of fly traps are available, especially for attracting the filth flies (e.g., house and blow flies). Such traps use various food "baits" to motivate flies to enter the traps. The traps may consist of disposable plastic bags or refillable plastic jars and all will usually trap large numbers of flies. They can be placed in dumpster areas or at the perimeter of a property to draw flies away from buildings.

Zoecon’s QuikStrike Fly Abatement Strip uses a mixture of three attractants to lure flies to the strip where they feed on a bait and die. This product has a wide range of outdoor uses including dumpster areas and livestock facilities. It is best used by placing it in a 5-gallon bucket set at ground level. You may want to punch holes at the bottom of the bucket to drain rainwater. Use one side of the strip for about one month, then turn the trap over and activate the second side. Follow label instructions for the most effective use of the product.

Fruit fly traps, such as the BioLogic Natural Catch Plus and the Victor Flying Insect Bottle Trap, are useful in capturing adult fruit flies and pinpointing where breeding sites might be located. The BioLogic trap contains vinegar, but the Victor trap requires adding fruit juice, vinegar, or banana and water to attract flies. Such traps should be spaced evenly through and infested area. The traps capturing the most flies will normally be closer to the breeding source.

Finding and removing the breeding sources is the ultimate key to eliminating the infestation. These traps may also be located in areas where you want to capture adults so fewer will be seen until the breeding source(s) is found. Examples include produce shelves in a supermarket and a salad bar in a restaurant. The BioLogic trap is smaller and doesn’t look like a trap so it is more suitable for visible areas.

LIGHT. All flies respond to food stimuli, but which flies will be attracted to insect light traps (ILTs)? Not all fly species are motivated by light and understanding which species are motivated by such stimuli may be important to the success or failure in controlling a fly infestation.

For example, flies that generally invade from outdoors — house flies and blow flies — respond strongly to light, but those that breed inside — moth flies and phorid flies — will not be very attracted to ILTs. Placement of an ILT will not have great benefit for infestations involving these latter flies.

Once entering a building, flies take a while to become adjusted to interior lighting and thus responsive to the light wavelengths given off by an ILT. A period of 15 minutes to even hours may elapse before a particular fly becomes attracted to an ILT. In addition, a fly may need to be within 25 feet of a trap to see it. For these reasons, the following mistakes involving ILTs should be avoided:

  • Placing the trap too high above the floor (higher than 5 feet).
  • Locating the trap too close to doorways. Flies fly past the traps before they actually see it.
  • Mounting traps beneath bright interior lighting can wash out the UV wavelengths and require the fly to be close to the ILT before it responds.
  • Placing too few traps. ILTs need to be spaced throughout a facility following the natural flight path flies might take as they move through the building. Establish traps to intercept flies. Redundancy (within economic reason) improves performance of the ILT system.

Additionally, it is important to change the UV bulbs at least once per year — possibly twice per year in southern states. ILT bulbs lose about 15 percent of their remaining effectiveness each month. Installing fresh bulbs during the spring ensures the highest performance during the peak fly season.

SEX. Of course, all flies, especially males, will respond to sex pheromones issued by females of their respective species. A commercially available pheromone exists only for the house fly. Other flies must be lured to traps and baits using food — and as mentioned previously, light. Fly baits containing the house fly sex attractant may still be available, however, baits need to be applied inside specially designed stations or reapplied after rainfall.

SUMMARY. Understanding the factors that motivate insects and other pests to be attracted to, invade and thrive in structures is key to devising prudent and responsible methods for controlling and minimizing infestations. With flies, much of the responsibility for success lies with the customer and the professional serves as an investigator and consultant in pointing out areas requiring attention. Valuable fly control services, such as drain applications and ILTs, can be offered to customers but if sanitation and exclusion are largely ignored, any such services are bound to be ineffective.

The author is manager of technical services, Terminix International, Memphis, Tenn. He can be reached at shedges@pctonline.com.

COMMUNICATING CLEAN-UP TO CUSTOMERS

Accepted standard practices — in anybody’s sanitation book — include the following:

  • Put the dumpster and trash cans as far from the facility as possible.
  • Sit dumpsters only on concrete pads — not soil or gravel.
  • Keep tight-fitting lids on trash cans and equip dumpsters — where possible — with lids.
  • Dispose of garbage and trash inside plastic bags to reduce escaping odors.
  • Train facility employees to place trash bags in dumpsters to limit bursting of bags.
  • Have dumpsters emptied regularly.
  • Clean the dumpster and the ground beneath at least once per week.
  • Around homes, dog waste should be picked up daily (or at least every other day).
June 2001
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