Managing Light, the Key to Reducing Night-flying Insects

Managing Light, the Key to Reducing Night-flying Insects

You say, why bother checking out your outside lights?  Simply put, by reducing the amount and/or changing the color of outside light, you can drastically reduce the attraction of night-flying insects to your home.  The second and third aspects of this insect reduction strategy, which become important closer to your home, are employing good exclusion methods, which is the topic for another blog.

The three most common long-distance attractants to insects are odor (cooking odors, sanitation odors), exterior lights, and the structure’s physical properties (size, shape, color).  Once insects get closer to the house, 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 by a home’s lights. So after sunset, go outside and slowly walk around your house looking for where lights are positioned, the color of light they produce, and for any light escaping from inside your house to the outside. 

To ensure that your home isn’t a magnet to swarms of night-flying insects, here are six light management tips you can implement around your home to make your home less of a night-time attraction.

  1. What kind of night lights are present and what kind should be present?
    • Any kind of white light (including florescent or incandescent, mercury vapor, halogen, and LED) should not be used within 50 feet of the building. Printing off a night-time Google map of the home can be very informative for an overall perspective.
    • The best kind of lights to use on the home’s exterior near entryways is yellow florescent or yellow LED lights. The best place to mount such lights is on the hinged side of the door so that its light will shine minimally to the inside of your home when the door is opened.
    • If you need to light large exterior areas for security reasons, then use high-pressure sodium lights, which are the least attractive to insects. This includes lighting the yard/grounds around your home, which is best done by mounting these less attractive high-pressure sodium vapor lights on stand-alone poles. Many people with basement garage entrances mount this light high up on the gable.
    • If flood lights are needed to temporarily illuminate part or all of your home’s exterior grounds for security or recreational reasons, locate the lights off the building but shining on the area of concern. Locate the lights as close to 50 feet away from the building as possible.

    Note: 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. Eliminate escaping white light. Keep white light from escaping from the inside of your home, since all white light attracts insects.
    • Inspect each outside door including any garage doors, and add or repair weather seals or install door brushes to stop the light from coming out.
    • Inspect all windows and add or repair weather seals to stop light from escaping out.
  3. Screens. It should be noted that screens whose mesh is small enough to keep out most insects are so tightly woven as to interfere with seeing out and will impede air flow (= unacceptable). However, since regular window screens will keep out the larger flying insects, they are valuable tools. So, all windows should be properly screened if they can be opened.
  4. Tint entrance door and garage 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.
  5. Replace interior white light at entryways. Escaping white light is like a search light to insects. Any area where there is an opening to the outside, whether it is screened or not, should have the escaping light changed to less attractive LED (LED lights do not emit attractive UV light), so this will reduce the number of night-flying insects seeking/attempting to come inside.
  6. Use interior insect light traps (ILTs). A properly designed interior insect light trap program can be used to help monitor where, which, and possibly how flying insects are managing to find access. They will also help to harvest flying insects that manage to get into your home.

Placement is critical so as to not attract flying insects inside and for maximum capture. Properly placed insect light traps will reduce the number of both day-flying and night-flying insects that may gain entrance into your home. There are some very attractive looking wall sconces ILTs available. It is recommended to use the services of a pest management professional for effective design.

In summary, performing an exterior night-time light inspection of your home can reveal many things about your home. For instance, it can tell you major reasons why your home is attractive to night-flying insects, how to decrease its attractiveness, how to reduce the number of these insects that manage to find a way to enter your home, and that you may possibly want to consider the installation of insect light traps.

Eric H. Smith, PhD, BCE
Dodson Bros.