Device for killing grain pests
Lethal effects of short-wavelength visible light on insects
We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light.
To examined the immediate and 24 hours post- irradiation germicidal effects of UV-C lamp on eggs and adults of house dust mites Dermatophagoides pteronyssinus (D. pteronyssinus) and Dermatophagoides farinae (D. farinae).
This study investigated the immediate and 24 hours post irradiation mortalities of adult mites exposed to UV-C at different exposure times (5 mins, 10 mins, 15 mins, 20 mins, 30 mins and 60 mins) and distances (10 cm, 25 cm, 35 cm, 45 cm and 55 cm). Fresh eggs of the 2 dust mites were also irradiated at 10, 35 and 55 cm for 0.5, 1, 2, 3, and 5 minutes, and observed daily post- irradiation for up to 7 days.
Highest immediate mortality of 100% occurred with direct irradiation at 10 cm distance from UV-C lamp and for 60 mins, for both species of mites. The post 24 hours mean mortality rates were (58.4±17.4)% for D. pteronyssinus and (27.7±9.7)% for D. farinae when irradiated for 1 hour at 55 cm distance under UV-C lamp. When mites were irradiated in the presence of culture media, the highest mortality rates were lower compared to the direct irradiation; at 10 cm distance and 60 mins exposure, the mean mortality was (74.0±6.8)% for D. pteronyssinus and (70.3±6.7)% for D. farinae. Egg hatchability for both species of mites was also notably reduced by greater than 50% following irradiation.
Ultraviolet C irradiation is lethal to an array of organisms by damaging their nucleic acids (DNA and RNA). This study demonstrates the increasing mite mortalities with increasing exposure times and decreasing distances.
Keywords: Physical control, UV-irradiation, Dermatophagoides farina, Dermatophagoides pteronyssinus, Mortality
January 11, 2015
Zzzzzzap! Ahhh, the gratifying sound of another insect biting the dust on a humid summer night. The hauntingly seductive blue glow of the bug zapper attracts thousands of unsuspecting insects to their untimely demise. Phototactic creepy-crawlies simply cannot resist moving toward the light, and when they arrive, a 2,000-volt wire mesh awaits them.
As handy as these tiny execution chambers are, they are not at all useful for farmers who are trying to protect precious stored grains and other crops from being eaten by insects. Instead, it is typical for farmers to control pests, such as beetles and moths, with insecticides. Because insecticides are toxic to humans, however, finding a substitute would be ideal. Now, such an alternative might exist.
Japanese researchers from Tohoku University describe in the journal Scientific Reports that certain wavelengths of visible light are lethal to certain species of insects. For instance, blue light (wavelength = 467 nm) was nearly 100% lethal to fruit fly pupae, while ultraviolet A light (wavelength = 378 nm) was only about 40% lethal. (See figure; ignore lower case letters.)
The authors went on to show that blue light (467 nm) also had a lethal effect on fruit fly eggs. Any adults that survived the light treatment had greatly reduced lifespans and produced fewer eggs.
Similarly, other insects were killed by visible light, but at different wavelengths. The authors showed that pupae of the London Underground mosquito (Culex pipiens molestus) were killed by violet/indigo light (417 nm), while pupae of the confused flour beetle (Tribolium confusum) were killed by several different wavelengths of light, ranging from violet to blue.
The authors conclude that lethality due to visible light is wavelength-dependent and species-specific. In other words, some kinds of light kill some types of bugs, while other types of light kill other types of bugs. Additionally, previous research suggests that the insects are dying because blue light likely triggers the production of reactive oxygen species, which damage important cellular structures and molecules.
An obvious benefit from their research is that farmers could use this knowledge to kill certain species of pests, while leaving friendlier insects unharmed. It would also have the benefit of reducing pesticide use. The downside is that multiple wavelengths of light (and hence, multiple LEDs) would be required to kill all of the pests that threaten farmers. Thus, UVC light, the most lethal type of UV light, would be far more efficient at killing insects. However, UVC light itself has drawbacks, such as its indiscriminate killing of insects and toxicity to humans and other mammals.
Source: Masatoshi Hori, Kazuki Shibuya, Mitsunari Sato & Yoshino Saito. "Lethal effects of short-wavelength visible light on insects." Scientific Reports 4, Article number: 7383. Published: 09-December-2014. doi:10.1038/srep07383
In the farmer's bag of cereal must not be alive. The worst damage is caused by pests that are not seen. The butterflies make a small hole in the berries and lay eggs there. Later the larva will feed on the core of the grain. One butterfly deposits up to 500 eggs. Several cycles of breeding and much of the harvest are compromised.
These studies show the lethal effect of UV light and blue light depending on duration and intensity.
In line with the requirements of this challenge, I designed a device that is intuitive, inexpensive and helping farmers save their harvest.
Imagine a bright baton inserted into the grain bag and, in a short time, kill everything that is alive, butterfly, larva or egg. After exposure to a zone, the bright baton will be removed and moved to the surrounding area. By successive exposures the whole grain bag will be decontaminated. Even if butterflies or larvae do not quickly die, it is important that eggs are sterilized and that the mutation will be made to prevent their multiplication.
The device will show the bright baton in Fig. 1
The particularity of the stick is the type of light. There will be UV light and blue light. It may be together because LEDs that generate UV and LEDs that generate blue light will be used.
In developing the device, I was inspired by the UV flashlights in Figure 2.
We need to penetrate the light inside the grain bag. The length of the light stick will be similar to the length of the storage bag.
The rod of the baton will be made from a quartz tube, Fig. 3, because only the quartz allows the total passage of the UV.
Typical glass blocks the passage of UV light, and plastics are degraded and mature shortly.
These light sticks will be used in areas less familiar with the technique and need to have good mechanical strength. For mechanical stiffening in the tube will be distilled water which also has the role of optical fiber to transmit light in all directions.
The batteries will be put in the baton handle. The device will also be provided with a power outlet from the power grid, because in rural communities there is a strong solidarity and these devices will go hand in hand until all of them save their grain.
UV light is toxic to everything that's alive. Nothing live must be in the grain bag.
There is no need for special instructions to safely use this dispenser, it should be known that the rod will be submerged in the grain bag, then the button that lights the LEDs will be pressed in order to attach people's eyes to the harmful effect of UV. Short-term exposure is not harmful, people go to the sun to tan with UV.
The regular UV-LEDs can be replaced with stronger LEDs, as shown in the picture, to be a powerful luminous spot that kills pests in a short time.
If you have any questions