Do Yellow Bug Light Bulbs Work?

Jun 08, 12 Do Yellow Bug Light Bulbs Work?

Ah…summertime. Warm weather, pool parties, barbecues, and bugs. Lots and lots of bugs. Few things can turn a summer day into utter misery faster than a swarm of flying insects. You’ve tried greasy bug spray, citronella candles, Tiki torches, maybe even blowtorches. So we can imagine your surprise when you saw a yellow-colored “bug light bulb” at your local hardware store. Could it be true? Could screwing in a light bulb solve your bug problems for good?

To answer that question, let’s start by clearing up some myths about yellow incandescent bug lights and their energy-saving cousin, compact fluorescent bug lights. Bug lights do not kill bugs (you’ll need a bug zapper or Paraclipse fly trap for that), nor do bug lights repel bugs. Bug lights simply attract fewer bugs than other light bulbs. In short, a bug light will not magically solve your bug problem, but it will make you and your home less visible to most flying insects.

As discussed in a past article, light is divided into multiple wavelengths, measured in nanometers (nm), as you can see in the graph below. The human eye can only perceive a small band of wavelengths in the light spectrum, from about 390 to 750 nm. Insects perceive a similarly small band of the light spectrum, though their band of vision is shifted further to the “right” of the spectrum than ours. In fact, any wavelength higher than about 650 nm is virtually invisible to most flying insects.

Visible Light Spectrum

Image courtesy of Chemistryland.com

So why are bug lights yellow? Wavelength and color temperature have an inverse relationship, which you can also see in the graph. As the wavelength of a light source decreases, its color temperature increases (as according to Wien’s displacement law). Low color temperatures are red-yellow and exhibit a long wavelength, while high color temperatures are blue-violet and exhibit a short wavelength. By coloring a bulb yellow, then, the manufacturer has decreased the color temperature and in doing so increased the wavelength into a spectrum unseen by insects.

That’s the science of how bug light lights work, but the larger question is whether they are effective. From personal experience, I can say yes, they are. However, bug lights are not a panacea for all your bug problems. This is for a couple reasons. One is that not all insects are the same; different bugs see slightly different wavelengths. Second, no light source is made up of one, pure wavelength. Even an apparently yellow light may exhibit some shorter (and bluer) wavelengths that insects may still see.

To get the most out of your bug light, remember this: The bugs aren’t there because they like the light; they’re there because they like the smaller (and tastier) bugs that buzz around the light. If these smaller bugs sense any light whatsoever, it won’t be long before they buzz their way to bask in it. And once the small bugs are there, it won’t be long before the bigger bugs follow. Once that happens, you have a bug party on your hands, light or no light. The best thing to do to avoid a swarm of bugs is to turn the light off when you don’t need it.

1000Bulbs.com

Benjamin is a writer for 1000Bulbs.com.

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24 Comments

  1. fun to read – thanks!

  2. bob johnston /

    I heard somewhere that bugs cannot see the light from the new LED bulbs—-true or b.s.?

    • Benjamin Rorie /

      Yes, that is true, though I am still researching the topic to learn why. My working theory is that LEDs emit little, if any, UV light, which is the part of the light spectrum that bugs find most appealing.

      Thanks for bringing up the topic. I’ll post an update as soon as I figure it out!

  3. GAry Kelley /

    Our yellow LED light seems to attract a swarm of bugs. More than the white LED one did. We’re going to try the incandescent yellow to see if there is a difference. Why do you think that is?

    • Benjamin Rorie /

      Thanks for the question, Gary. Without knowing the brand and part number of your LED bulbs, it’s hard to know for sure. However, it could be that the yellow bulb produces more heat than the white bulb, so that the heat and not the UV emission is attracting the bugs.

    • Luke /

      Just because a light is “yellow” doesn’t mean it is absent the other visible light in a spectrum. It appears yellow because it has a peak wavelength that falls in the yellow range. It could have a secondary peak that has a shorter wavelength that is attracting the bugs.

      • Benjamin Rorie /

        Excellent point, Luke. Couldn’t have said it better myself.

    • BrandyA /

      Whatever is powering the light source means nothing. It could be that the yellow in the incandescent is a different color temperature than the yellow in the LED. And like the article said, bugs are attracted to light they can see, The yellow in your LED is just not the right one. I just bought CFLs because my fixture has started eating bulbs, for some reason. The yellow is much more brilliant, so we’ll see if it’s a hit or a miss.

  4. Emison /

    Baffling contradictions! I just bought one 60watt yellow Philips bulb with sub names: adios mosquitos and buglezzz. Paradoxically (Vis-à-vis the above explanations) here they instruct that the yellow bulb should be placed +/-4 metres from its white counterpart. I am confused! Meaning one attracts them and the other repels the same?

    • Benjamin Rorie /

      Yellow bulbs repel bulbs, white bulbs attract bulbs. Put yellow bulbs in outdoor areas where you need light but don’t want bugs. I hope that clears things up.

  5. Phil /

    In Arizona, we used regular light bulbs in our entry way lights. The drew thousands of flying insects and along with them came hundreds of black widow spiders. Changed to the yellow fluorescent bulbs. Problem solved?

    • Jordan Loa /

      Thanks for reaching out to us, Phil!

      Black widow spiders? That doesn’t sound good at all! However, as the article states, your yellow bug light will decrease the amount of bugs that flock to your bulb, but it will not completely solve your bug problem. The best way to lower your bug problem is to shut off the light when you don’t need it. However, if shutting off that bulb won’t work for you, I’d recommend you check out our insect control devices. Hope this helps!

  6. Joseph Shepard /

    How about a bulb with even longer wavelength, ie orange or orange-yellow?

    • Jordan Loa /

      Thanks for the question, Joseph.

      Good news. Bulbs with a higher wavelength, like the orange and the orange-yellow lamps you mentioned, should have the same desirable effects as the yellow bulbs. Hope this helps!

  7. Rose M. /

    DO OTHER COLOR LIGHT BULBS(LIKE REGULAR BULBS-NOT THE NEWER KIND OF BULBS IN GREEN)WORK TO HELP DETER BUGS OR IS IT ONLY THE YELLOW BULB? THANKS…RLM FROM GEORGIA, WHERE THE OLD CLICHE’REALLY DOES APPLY: MOSQUITO IS OUR STATE BIRD!

    • Jordan Loa /

      Thanks for the question, Rose!

      If you were to put just a regular bulb in the fixture, you’re probably going to have a huge bug party on your hands, so I suggest sticking with the yellow bulbs to decrease the number of winged pests. Hope this helps!

  8. B. Barlow /

    How many watts should a yellow outside bulb be?

    • Jordan Loa /

      Great question here, B. Barlow!

      There’s no right or wrong answer here, as the number of watts you need is determined by how much light you need. We have 25, 40, 60, and 100-watt yellow bug lights, found here: http://www.1000bulbs.com/category/yellow-bug-light-bulbs/. Now, these are 130-volt bulbs, which last longer than 120-volt bulbs, but produce 24 percent less light than their 120-volt counterparts, so this is something to keep in mind when choosing your bulb. Hope this helps!

  9. Doug Mellen /

    I have a large number of Philips Hue bulbs which are app/network controllable and are capable of producing 64 million colors. Selecting the color you want is quite simple, you nearly move a marker over a picture (which you can choose) and it picks up and translates that color to the bulb. Since there are so MANY shades of yellow, I’m wondering if anyone knows of a photographic representation of a color that will work best. In reading above, “any wavelength higher than about 650 nm is virtually invisible to most flying insects” leads me to believe that colors made up of high nm numbers would be decreasingly visible to insects, i.e., orangish, reddish colors should work best. Thoughts?

    • Jordan Loa /

      Excellent question here, Doug!

      To reaffirm what the article stated, an LED source with a warmer color temperature (650 nm and above) should not attract most flying insects, since these are likely not to provide UV radiation or short visible wavelengths.

      In regards to colors, yellows and reds have high energy at long wavelengths, while blue has low energy in the UV and short wavelengths. These colors have low insect attractiveness.

      Hope this helps!

  10. Scott John /

    What makes the bulb yellow? Is the glass treated?

    • Hi Scott. Usually, yellow bulbs have been dipped in a high-temperature paint and that’s what gives them their color. Thanks for the question!

  11. Elisabeth /

    We would like to watch moths nectaring on flowers at night. Do you have any suggestions for a bulb that they won’t “see”?

    • Thanks for the question, Elisabeth! Because insects cannot see the color yellow, a yellow light bulb would be great for what you’re looking to do. However, if you’re looking for a light that attracts them that they still can’t see, then we’re not exactly sure. If you can, it would be a good idea to check with your local agricultural office or entomology department at the nearest university. We hope this helps!

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