Agricultural nets are one way to protect crops from insect pests and reduce the use of insecticides.
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Typically, greenhouses are covered with such nets in white, black or blue.
However, a research group of Japanese scientists found that it is more effective to use red grids. This was reported by the press service of the University of Tokyo (Japan).
Like a mosquito net over a garden bed, it physically prevents insects from reaching the crop. It is logical to assume that the most important feature of these meshes will be the size of the holes in the mesh – the smaller the hole, the smaller the insect must be to get inside. However, the research team found that the color of the mesh may be an even more important deterrent factor, the article notes.
The study found that red meshes, whose mesh size was larger than the insect’s body, were more effective than other regular black or white meshes with even smaller mesh sizes.
According to scientists, the reason for this is the color vision of insects.
Most insects do not have red photoreceptors in their eyes and have difficulty seeing red, so we thought it was interesting that invisible color could be used to combat them, the researchers note.
In their study, the scientists focused on one pest: onion thrips (Thrips tabaci). This insect is highly resistant to insecticides and causes significant damage to a number of important crops around the world by eating them and spreading harmful viruses. The researchers protested:
- three color combinations of red mesh (red-white, red-black and red-red) with three mesh sizes (2 mm, 1 mm and 0.8 mm);
- typical combined black, white and black-and-white grids of the same sizes in the laboratory and field.
In general, all meshes containing red fibers provided significantly better protection against onion thrips than black or white meshes, the paper noted.
In a second outdoor test, the researchers tested the effectiveness of red-red mesh at different coverage levels:
- without cover;
- full coverage;
- coating only on top;
- cover only on the side.
Due to an outbreak of onion thrips in the area, insecticide was used. As a result:
- a completely covered area needed the least amount of insecticide and produced onions with high commercial value;
- areas covered only on the top or sides required one additional application of insecticide;
- Compared to a completely open area, in areas covered with red mesh, the number of required insecticide treatments was reduced by 25-50%.
Nets are more expensive than pesticides, but they are economical because they can be used for years. They are also very effective at controlling pests without all the work associated with spraying pesticides, the researchers note.
Scientists hope that in the future they will be able to create red nets that do not look red – at least not to the human eye, but will have the same effect on pests.
Scientists have rediscovered a formula forgotten after World War II.
Source: Racurs
I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.