Monochromatic Light As a Species-selective Insecticide 44
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.
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Of course, these guys [youtube.com] won't be happy, but hey, you can't please everyone all the time.
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"Of course, then the people who work with the fruit will start to have trouble sleeping...."
That's the LEAST of their problems. Let's add macular degeneration and blindness to that list, shall we? I had to have eye warnings on my LED grow lights because the blue was so intense. It was physically painful to look at the light.
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For growers that could be a problem, but for distributors you wouldn't need as strong a light as it would be for the sole purpose of killing bugs.
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For the sole purpose of killing bugs, you'd have to get outside of the range of light plants can utilize for photosynthesis. We know that can go from IR to UVA (and possibly UVB) and really it's intensity that matters. You want as much as you can rationally throw at the plant without causing photon bleaching of plant tissues.
Re:BONG! (Score:2)
I bet evolution wins within two years (Score:4, 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?
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It isn't.
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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.
Wow (Score:5, 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....
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Humans are. That little amount of blue a the right time is enough to seriously compromise your melatonin production and greatly degrade your quality of sleep.
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Humans are. That little amount of blue a the right time is enough to seriously compromise your melatonin production and greatly degrade your quality of sleep.
And you mean to say that at the wrong time (say somewhere in the morning) it could greatly improve our quality of life during daytime?
Re:Wow (Score:5, 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.
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Remarkable. Does your business have a web site?
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Not any longer. I sold off the actual business a couple of years back and went on still making my own stuff. I usually get my customers directly from Google Helpouts. [google.com] I fix their horticulture problems, they're usually more than happy to buy stuff from me, or contract me out for development work, from LED lighting to designing and building the entire facility [google.com] for the client. Yes, I pretty much do it all.
Current development - driverless AC-direct flickerless LED. Just need a better remote phosphor with some p
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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
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It's nothing to do with laws, it's simply that Japanese shops base their model on high turnover while UK shops base theirs on high margins. It's more common in Japan for prices to be low but people replace stuff regularly. In the UK because the prices are high people hang on to things forever, so the margins have to be higher.
It takes two weeks because to cut costs they make the glasses up at a central location. In Japan many shops have the equipment in the back, or somewhere nearby and will get the complet
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protein? (Score:4, Insightful)
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Complex molecules have characteristic absorption spectra. More energy per photon will not work if you move it outside the specific energy gap (a classical analog would be resonance, if the frequency fits little energy will suffice).
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You dont have to guess, they came up with their own explaination:
Blue-light irradiation injures organisms by stimulating the production of ROS. Many microbial cells are highly sensitive to blue light as a result of the accumulation of photosensitizers such as porphyrins and flavins29. Mammalian retinas can also be severely damaged by ROS produced by blue-light irradiation4, 5. It is probable that the lethal effect of blue light on insects is caused by the production of ROS, because the effective wavelength
Some work may still be needed (Score:3)
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.
most photosynthesis LOVES 440 NM (Score:4, Interesting)
Way cool.
Applicable (Score:1)
Finally some worthwhile research being carried out on the planet. Great job, Japan! Forget about those stupid humanoid robots!
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I think there's enough Japan for blue lights AND humanoid robots...
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You forget the third leg in the Japanese project triangle: sexy. So you can have blue humanoid robots but they won't be sexy, or you can have sexy humanoid robots but they won't be blue.
The sexy blue faction was really happy with the attention Avatar brought to their often overlooked cause.
Blue light also slows tumor growth (Score:1)
This isn't surprising, in light of 2008 research [sciencedaily.com] that showed that the same blue light dentists use to cure filling material slows the growth of tumors in mice.