By Eric H. Smith

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Why bother doing a light profile? Simply put, by reducing the attractiveness of a facility to night-flying insects, PMPs can drastically reduce product contamination problems created by insect presence and can help protect the customer’s brand. A more extensive protection strategy, which becomes important closer to the building(s), involves employing good exclusion methods and harvesting those insects that do manage to get inside before they cause a problem — but these are full article topics in themselves.

The three most common long-distance attractants to insects are odor (production odor, sanitation odors), exterior lights and the structure’s physical properties (size, shape, color). Once insects get closer to the facility, the availability of moisture, food and harborage become important.

As the warmer weather of spring arrives, it also brings with it night-flying insects that are attracted to a facility’s lights. Conducting a light-profile inspection is done after sunset. Go outside and slowly walk around the building, looking for where lights are positioned, the color of light produced and any light escaping from inside the building to the outside.

To ensure your customer’s facility isn’t a magnet to swarms of night-flying insects, here are nine light management tips you can implement around your facility to make your facility less of a nighttime attraction.

1. What kind of night lights are present?

• Any kind of white light (including fluorescent, incandescent, mercury vapor, halogen and LED) should not be used within 50 feet of the building. Printing a night-time Google map of the facility can be informative for an overall perspective.
• The best kind of lights to use on the facility’s exterior are high-pressure sodium lights, which are the least attractive to insects. This includes lighting the grounds around a facility, which can be done by mounting these less attractive high-pressure sodium vapor lights on stand-alone poles.
• If flood lights are needed to illuminate a sign, relocate the sign away from the building (at least 50 feet away from the building if possible).
• Many people choose to use mercury vapor lights because they are less expensive to buy than sodium vapor lights. However, while sodium vapor lights do cost more per light, they are actually cheaper to run. So, you will reach a break-even point on the cost.

2. Think safety first. For safety and security reasons, lights must be mounted in high-travel entrance areas, especially ones that have steps. In such situations, the best solution is to mount a sodium vapor light on the building on the hinged side of the door so that it will shine on the area where people walk.

3. Eliminate escaping white light. Keep white light from escaping from inside the building, since all white light attracts insects.

• Inspect each outside door and add or repair weather seals to stop the light from coming out.
• Inspect the boots on dock doors. Repair or replace damaged boots, and seal any holes in adjacent walls.
• Repair or replace damaged dock doors.
• Dock door levelers. The floor-level side brushes should be in good repair.

4. Screens. Screens with mesh that is small enough to keep out most insects are so tightly woven that they impede air flow, which is unacceptable. However, regular window screens will keep out larger flying insects.

• All windows should be properly screened if they can be opened.
• Vents and air intakes need to be screened and/or filtered, and if dock doors are kept open for ventilation purposes, they need proper roll-up screens.

5. Install vestibules. In high-traffic areas, such as main entrances, it is best to have a vestibule so the insects that enter along with the people are slowed down and don’t enter directly into the building. This makes them more vulnerable to capture by insect light traps.

6. Tint entrance door and dock door windows. By tinting the windows on doors, much less light shines through the door so it isn’t as attractive to insects, but you can still see the people inside or activity outside.

7. Replace interior white light.

• Given that white light is like a searchlight to insects, any area where there is an opening to the outside, whether screened or not, should have sodium vapor lights for the first two rows of interior lights. Changing the escaping light to sodium vapor will drastically reduce the number of night-flying insects seeking and attempting to come inside. This is critical in dock door areas.
• To additionally reduce the light escaping to the outside and the number of flying insects entering, implement a policy that dock doors will not be opened until the trailers are in the boot, and doors will be closed before any trailer leaves the boot.

8. Use air curtains.

• Air curtains used on people doors and dock doors can help keep insects out by blowing the air to the outside whenever the door is opened. They should be wired to come on automatically whenever the door is opened. However, they will only work for buildings or areas of buildings with positive air pressure.
• Even in buildings with negative air pressure, air curtains can be used internally to help protect or isolate sensitive areas.

9. Use interior insect light traps. A properly designed interior insect light trap program should be used to help monitor where, which, and possibly how flying insects are managing to find access to the inside of the facility. It also will help to harvest flying insects that manage to get into the facility. Strategic placement is critical for maximum capture.

Final Thoughts. Performing a light profile of a facility can tell a pest management professional many things about the facility.

For instance, a light profile can provide you with major reasons why a facility is attractive to night-flying insects, strategies to decrease its attractiveness, ways to reduce the number of these insects that manage to find a way to enter the facility, and thereby, how to reduce the possibility of product contamination.

Smith is director of technical services/staff entomologist with Dodson Bros., Lynchburg, Va. He holds an undergraduate degree from Miami (Ohio) University in botany and master’s (Purdue) and doctorate (Ohio State) degrees in entomology. He has 30+ years experience in pest management, is past president of Pi Chi Omega, past chair of the Copesan Technical Committee, a B.C.E. and senior author of the NPMA Field Guide to Structural Pests. Reach him at esmith@giemedia.com.