Slashdot Mirror

← Back to Stories (view on slashdot.org)

Monochromatic Light As a Species-selective Insecticide

Posted by Soulskill on from the not-to-be-taken-lightly dept.

An anonymous reader writes: The harmful effects of ultraviolet light have been long known. But now researchers at Tohoku University in Japan claim that visible blue light is also lethal to many insects, possibly even more so than UV, even at reasonable daylight intensities. Moreover, they report that certain species are more sensitive to specific wavelengths: Given the same intensity (3x10^18 photons/sec/m^2), light in the 440-467nm range was far more lethal to fruit flies than light of longer or shorter wavelengths. The wavelength 417nm was three times as effective at killing mosquito larvae than the shorter 404nm light, contradicting the notion that higher-energy photons always cause more damage. The research has wide implications for modeling the effect of natural and manmade environmental changes on insect populations and for selectively controlling populations of certain species.

9 of 44 comments (clear)

  1. I bet evolution wins within two years by holophrastic · · Score: 3, Interesting

    This sounds like something that evolution would beat-out in two years flat. Visible light harming members of a population differently. . . how many generations do you think it would take?

    1. Re:I bet evolution wins within two years by LynnwoodRooster · · Score: 2

      Well that depends... If it's 100% effective, then NONE will survive and propagate genes that provide appropriate resistance.

      --
      Browsing at +1 - no ACs, I ignore their posts. So refreshing!
    2. Re:I bet evolution wins within two years by Chikungunya · · Score: 2

      In the results it is shown dose dependant mortality up to 100%, the differences in harm appear between species not members of a population. Most likely this would lead to replacement of the sensitive bugs by resistant species instead of adaptation.

  2. Wow by Rei · · Score: 4, Informative

    That's surprisingly little energy. Blue light is that band about 2,7 eV per electron, so 2,7 * 3e18 = 8,1e18 eV/s/m^2 = 1.3 W/m^2. If you wanted to generate that much via a LED bulb with an external quantum efficiency of 20% then it'd take only 6,5 watts.

    Is it really possible that a little 6,5W blue LED bulb could kill all the fruit flies in a square meter box - are insects really that sensitive to light? That would be amazing. Greenhouses that use supplimental lighting could fine-tune their frequencies to kill off particular pests pretty darn easily. A grower with heavy LED light supplimenting uses a couple hundred watts of LED per square meter. I mean, at those levels the right frequencies should be killing bugs on the *undersides* of leaves....

    --
    "We consider that six courts and an asylum claim are a rather odd way of returning to Sweden within a month."
    1. Re:Wow by Khyber · · Score: 4, Interesting

      "If you wanted to generate that much via a LED bulb with an external quantum efficiency of 20% then it'd take only 6,5 watts."

      At what distance from the plants?

      "Is it really possible that a little 6,5W blue LED bulb could kill all the fruit flies in a square meter box - are insects really that sensitive to light?"

      Yes, they are, which is why I'm selling a combo UVB-420nm broad-spectrum light to greenhouses for pest control and also additional plant lighting. I learned about the effects of blue light long ago when I decided that then-current leds using a shit 8:1 red:blue ratio were not providing enough in the blue range, and pumped to 4:6.

      Spidermite problem, GONE. One of the WORST infestations to battle, wiped the fuck out, nuked from orbit.

      --
      Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
    2. Re:Wow by AmiMoJo · · Score: 2

      I get my prescription glasses made in Japan and they always offer a blue light filter coating as an option. It's supposed to reduce fatigue when working with computer monitors, because apparently they produce a lot of blue light. I can't really say if it has helped, but blue light is a definitely a thing over there.

      I thought it might just be marketing bunk, but it looks like there could be some truth to it.

      Off topic, but it takes two weeks to get prescription glasses made in the UK. In Japan it takes about 40 minutes. You get light weight frames and lenses with a blue light/anti-reflection coating for about £60, where as similar stuff in the UK is around £250.

      --
      const int one = 65536; (Silvermoon, Texture.cs)
      SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
  3. protein? by Lehk228 · · Score: 3, Insightful

    if I had to guess the light is probably damaging a particular protein in these species, with fruit flies and mosquitoes being on the more delicate side i suspect this will not work for more solidly built species such as roaches or bedbugs.

    --
    Snowden and Manning are heroes.
  4. Some work may still be needed by hyades1 · · Score: 2

    Apparently several Winnipeg mosquitoes were observed slathering themselves with DEET and lying under the 417 nm to get a little colour on their underbellies.

    A researcher who attempted to turn the light off was beaten badly, and is now reporting that several Goliath beetles used in another experiment now appear to be pregnant. Also the cat.

    --
    I've calculated my velocity with such exquisite precision that I have no idea where I am.
  5. most photosynthesis LOVES 440 NM by WindBourne · · Score: 3, Interesting

    It would appear that this is about the same wavelength that many plants want. As such, by sweeping over plants with high levels of it for short periods, it might help the plants while at the same time, killing pests.
    Way cool.

    --
    I prefer the "u" in honour as it seems to be missing these days.