When evaluating flying insect management strategies, each building is different and as such will have different needs and problems which must be addressed through an integrated program to achieve satisfactory flying insect control. To accomplish adequate fly control it is helpful to divide the environment into three basic zones, keeping in mind during each aspect of the evaluation, what can be done in each zone to reduce the overall fly activity in each of the critical areas. The first area of concern is the exterior environment. The second zone is the structural barrier between the exterior and the interior; that is the walls, entry doors, overhead doors, and conveyor entries that separate the exterior from the interior working area. The third zone is the basic interior working areas.
OVERALL CONTROL PLAN
The overall philosophy of fly control is to reduce the attraction of flies to the general exterior environment (zone #1) by all practical means and control those that get near the building(s) before they are able to gain entry. The second priority is to set up and maintain the structure in such a way as to prevent as much fly entry as possible. Finally the third step is to pick up flies on the interior with insect light traps and other control methods before they reach more sensitive storage or manufacturing areas where food or other product contamination may occur.
THE EXTERIOR ZONE IS THE "STARTING POINT”
The place to start when making such an evaluation is on the exterior because no matter what steps are taken, there will always be flies on the outside of the building(s). The exterior zone is inspected first because the more that is done to reduce the number of flies on the outside, the fewer the number of flies that will be able to gain entry.
SOME ASPECTS ARE NOT CONTROLLABLE
Not all aspects of the plant environment that might affect the level of fly activity can be controlled by our efforts. Examples include exterior temperature, humidity, or odors issuing from the plant. It is important therefore to identify these attributes of the plant environment and take steps to control fly activity on the exterior applying control approaches that effectively compete with these factors.
One of the most important environmental factors that we can control is the attraction due to the type of exterior lighting. Wherever possible or feasible, sodium vapor lamps should be used rather than either mercury vapor lamps or incandescent bulbs. The reason for this is simply that mercury vapor and incandescent bulbs emit a much higher concentration of the wavelength of light that attracts insects than the sodium vapor lamps. Therefore, using sodium vapor lamps will significantly reduce the number of flies that are attracted to the area during the evening hours.
GARBAGE AREAS & OTHER AREA(S) OF ATTRACTIVE PRODUCT SPILLAGE
Another aspect of the plant environment that is critical in keeping fly activity under control is proper maintenance of garbage areas. This includes the covering of dumpsters, the hosing down of those areas in which excessive spillage may occur or wet garbage may be present, and careful inspection to assure that any drainage associated with the garbage is free-flowing and cleaned at least on a daily basis. In addition, to keeping the area around garbage dumpsters clean, steps should be taken to prevent harborage and breeding of flies inside the garbage containers themselves. Complete emptying and cleaning of the dumpsters at regular intervals can best achieve this; as well as keeping dumpsters covered when not actually being used.
ACCUMULATION OF DEBRIS & EXTERIOR STORAGE
Excessive accumulation of debris and other material near the building will only serve to harbor insects and rodents and contribute to pest problems on the interior of the structure. These materials should be sorted and any unnecessary items discarded. Those items that cannot be discarded should be moved away from the building as far as possible and stacked in an organized manner elevated off the ground. These measures will help reduce the tendency of insects and rodents to harbor and breed among the debris.
VEGETATION NEAR BUILDING
Excessive vegetation and weeds growing near the structure are not only unsightly, but serve as a prime harborage and breeding area for a wide variety of flying insects, and invite the presence of many other insects as well as rodents. Any vegetation (grass, shrubs, etc.) should be carefully landscaped - upkeep is the key word! When mowing near the building, grass clippings should not be blown up against the building forming a pest supporting mulch. In all non-landscaped areas, a soil sterilized or bare stone border should be maintained around the perimeter of the structure. This is best achieved by enlisting a properly trained weed control specialist to treat these areas on a yearly basis.
EXTERIOR RESIDUAL TREATMENT
In addition to sanitation and engineering controls, it is important to consider what chemical steps or treatment methods can be used to further reduce the fly population during the warm months of the year. The first step in an exterior chemical control program is the application of materials to exterior structural surfaces that the flies land on before they enter the building. Engineering controls and satisfactory sanitation are the first tools to use to reduce fly activity to acceptable levels in exterior areas. If fly activity prevails in spite of these measures, residual insecticide applications should be made to exterior building surfaces as well as the ground and vegetation immediately adjacent to the structure. Flies frequently harbor in vegetation next to buildings and usually land on the structural surfaces adjacent to entry points before flying in. For these reasons residual applications to these surfaces will yield the best results. The need for this service, as well as the frequency and scope of the actual treatments will depend on structural design and operation. New spray-on bait is useful for those situations where flies can be expected to land and feed on surfaces on or near the building. The spray-on bait is typically most effective for flying insects that feed on sugars such as house flies, wasps, and yellow-jackets.
FLY TRAPPING, PHEROMONE ATTRACTANTS, & BAITING
In areas where flying insect activity is especially heavy, fly trapping using non-poisonous traps baited with materials attractive to the flying insect most prevalent can significantly further reduce the exterior fly population. These traps are especially effective for instance in the control of yellow-jackets. Loose granules of fly-bait may be applied using an applicator that the flies feed from. This method works by placing fly bait materials in devices designed to optimize fly visitation to the bait stations and is another effective complement to the fly control program in heavily fly-infested exterior areas.
Another effective fly control material that does not attract flies from long distances, which could complicate control, but does a very effective job of attracting the flies in the immediate area is the application of a pheromone-based quick-killing fly feeding material. These dual-purpose fly control devices, using the naturally occurring pheromone flies are most attracted to plus a very quick killing fly bait material, are extremely effective where houseflies are breeding out of control. These key areas include garbage areas, intake and other areas where the spillage of food may attract flies, and any other areas where flies congregate around the building(s). It is important to use pheromone-impregnated material because it contains a naturally occurring sex-attractant chemical that flies are drawn to resulting in excellent control.
KEEPING DOORS CLOSED
Once all practical preventive measures have been applied to the exterior zone to reduce the total number of flies around the facility environment, the next step is to make sure that all potential entry points to the structure are designed so that they can effectively exclude flies which may get there. The most common and yet most effective means of excluding flies from a normal entry door includes the maintenance of proper closures on the exit door and the screen door, and the efforts should be taken through supervision of personnel to be sure that doors are not propped open and employees realize their responsibility to close doors after themselves. Doors that are not used for regular traffic of personnel should be posted for emergency exit only. Whenever practical, emergency exit alarms should be installed on doors to curtail their unnecessary use.
POST COMMON ENTRY DOORS TO PLANT WITH SIGNS
Doors which open to air conditioned office areas frequently will not result in excessive fly entry because of the reluctance of flies to enter these cooler areas. Obviously some doors to plant operating areas will need to be used regularly. It is helpful to post such entry ways with signs at eye level which remind employees to close them after entry or departure.
SANITATION: SCREENING OF FAN VENTS
The fan vents observed in your facility are screened at this time in an attempt to exclude insect pests. However, the screening is too large and insects will simply pass through it and get inside the plant. It is recommended that a finer mesh screen be installed that will be more insect exclusive and effectively reduce the number of pests getting in. If restricted air flow is a concern, a larger faced opening could be attached to the exterior end of the vent allowing a finer mesh screen to be installed without decreasing the amount of air that is allowed to pass through the screen.
GENERAL ILT RECOMMENDATION
Dock doors and entry doors should only be opened for entry/exit or while unloading cargo from trucks. Dock bumpers at all such docks should be employed and maintained to prevent excessive fly entry during normal operations. However, even when these measures are followed closely, fly entry may occur and steps must be taken to control flies as soon as possible after entry to prevent their migration to more sensitive plant processing areas. For doors which can be used only for entry and unloading and do not need to be open for periods in excess of 10-15 seconds on a regular basis excellent control can be achieved through the use of properly designed insect light traps. Repeated tests have shown insect light traps that include adequately reflective interior surface areas, BL type bulbs significantly reduce a fly population and, if properly installed and positioned, provide an excellent means of controlling flying insects in buildings.
FACTORS INFLUENCING LIGHT TRAP EFFECTIVENESS
Before installing insect light traps several factors should be considered to aid in the selection of units which are effective and positioned for optimum control. Insect light traps (ILT s ) do not attract flies well enough to actually reduce a given population unless several criteria are met.
- Bulbs must be replaced at least annually. The phosphor chemical that emits the wavelength of light most attractive to flying insects breaks down over time even though the bulbs may appear the same to the human eye which is incapable of detecting the near ultraviolet light to which flies are most readily drawn.
- Units should be maintained with BL type bulbs for maximum effectiveness. These are white fluorescent bulbs with a very slight bluish cast. The BLB (dark blue bulb) has proven ineffective both alone and when used in combination with a BL type bulb.
- ILT s must be designed with escape resistant enclosures that house the entire unit and catch tray. Alternative open grid designed units allow insects to be blown or fall into sensitive areas and pose a significant potential fire hazard.
WIDE CATCH-TRAYS ON INSECTOCUTOR TYPE UNITS
Manufacturers which have designed a wide catch-tray base on their units instead of the recommended housing also reduce the effectiveness of the units because of the obstruction of the fly’s visibility to the trap caused by the wide bottom tray.
WALL-MOUNTED INSECT LIGHT TRAP AS FIRST CHOICE
Whenever possible a wall mounted insect light trap should be installed in the near vicinity to each entry point. Since optimum control of flies results from units located two to three feet from the floor, wall mounted insect light traps are generally most effective. The RG-1002 Supreme is recommended for this purpose and can be attached flat to the wall or corner mounted.
GLUE BOARD ILT s IN SENSITIVE FOOD AREAS
When all steps have been taken to control flies at entry points around the building perimeter, flies may still escape into interior areas and steps must be taken at this point to control them. While smaller wall mounted ILT can be relocated to more interior areas they will serve, in most cases, to monitor fly activity but may not result in completely satisfactory control. The most effective monitoring and control in interior areas where food is processed, packaged, or otherwise exposed is is obtained by installing a mobile glue board ILT such as the GT-200 Elite. This ILT design provides monitoring by attracting flies using the same "BL" type bulbs proven effective in other units, but uses a glue pad to capture the insects rather than the electrocution grid found in other units. This is the only method acceptable to the FDA in sensitive food handling areas because flies cannot explode scattering insect fragments into the air which may contaminate food.
PROPER POSITIONING OF ILT s
When wall mounted units are selected they should be mounted on the same wall the entry is on or on a close by perpendicular wall. They should not be placed on walls directly across from entry doors because this will result in flies being attracted into the facility by the unit when the door is open.
AVOID LIGHT TRAP RECOGNITION
In entry lobbies, employee break areas, food serving, and other areas it may be desirable to provide monitoring and control of flying insects with a light trap that is not easily identified as a pest control device. In these situations the attractive WS-85 Wall Sconce insect light trap is ideal. This unit is intended to provide optimum silent control and has been designed so it appears as a decorative lighting device and is not easily recognizable as an insect light trap.
CONDITIONS NECESSITATING AIR SCREENING
Exterior doors which must be open for longer than 10-15 seconds at a time for loading/unloading or normal work procedures must be adequately air-screened to prevent fly entry during periods of extended operation. Because ILT s normally are insufficient to adequately control flies which enter entry, conveyor, and loading areas (which are open for extended periods), air curtains must be carefully evaluated based on internal negative air pressure in the plant and the size and dimensions of the opening. Units must be mounted on the exterior of the door to prevent a vacuum effect from sucking flies and debris into the facility.
INTERIOR NON-RESIDUAL CONTACT & SPACE TREATMENT
While sanitation, engineering controls, and insect light traps are the best methods of controlling flying insects, occasionally the interior fly population can get out of control. In these instances it may be advisable to apply a low-toxicity pyrethrum-based insect control space treatment material. In areas that the covering of equipment or food may be difficult or impossible, a contact non-residual material for the control of flies and other insects can be applied to the floor and wall surfaces that insects alight on and provide control without complete space treatment of the whole volume. It is best to use an industrial aerosol for this purpose that is labeled for application based on the cubic or square footage of the treated area(s). These materials should be of an adequate concentration to result in effective and quick knockdown of the flying insects in the treated area(s).