According to a new study, red nets are better at keeping out common agricultural pests than plain black or white nets. Researchers tested the effect of red, white, black, and mixed-color netting on deterring onion thrips from eating kojo leeks, also known as Welsh onions. In both lab and field tests, red nets were significantly better at stopping insects than other colors. Also, in field tests, onion crops that were partially or completely covered with red netting required 25-50% less pesticide than a completely uncovered field. Changing agricultural nets from black or white to red can help reduce pesticide use and associated negative impacts on the environment, while supporting more sustainable and efficient agricultural practices. can

Insects can be a nightmare for any gardener. As the fresh buds emerge they are then covered in aphids, beetles and other insects looking for a tasty snack. While synthetic pesticides are widely used to control pests in gardens and agricultural crops, many pollute the natural environment by leaching into soil and water supplies and poisoning plants, wildlife, and harmless insects. Known for Some pests are also becoming resistant to chemicals, so farmers are running out of options on what to use and need to apply more often.

Agricultural netting is another way to protect crops and reduce pesticide use. When you walk through an orchard or vegetable garden, you usually see greenhouses with white, black or blue netting. Like mosquito netting on a bed, they physically prevent insects from reaching crops. It makes sense to think that the most important characteristic of these nets would be the size of the holes in the net. The smaller the hole, the smaller the worm has to be. However, a research team from the Kyoto Prefectural Agriculture, Forestry and Fisheries Center and the University of Tokyo found that net color may act as an even more important deterrent.

“We tested red nets with a mesh size that was larger than the insect’s body, but was still more effective than other conventional black or white nets with a smaller mesh size. This ‘optical paste’ ‘Control’ depends on the nature of the insect’s color vision. Keep the insects away,” explained Masami Shimoda, a professor at Tokyo University’s Graduate School of Agricultural and Life Sciences. “Most insects don’t have red photoreceptors in their eyes and have a hard time seeing red, so we found it interesting that an invisible dye could be used to control them.”

The team focused on one pest, the onion thrips (Thrips tabasi). These insects are highly resistant to pesticides and cause extensive damage to many important crops worldwide by feeding on them and spreading harmful viruses. The researchers tested three color combinations of red mesh (red white, red black and red red) in three mesh sizes (2 mm, 1 mm and 0.8 mm). They also tested common black, white, and black-white combination nets of the same size in the laboratory and in the field.

Overall, all nets that included red fibers performed significantly better at keeping out onion thrips than black or white nets. In a second outdoor trial, researchers tested the effectiveness of red netting at different levels of cover: no cover, full cover, top only and side only. Due to an outbreak of onion thrips in the area, insecticides were used. A fully covered plot required minimal amounts of pesticides and yielded onions of high commercial value. Plots that were only roof or side covered required an additional application of insecticide compared to fully covered plots. Compared to fully exposed plots, red-mesh plots reduced the overall number of pesticide applications by 25-50%.

“These new red 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 involved in spraying pesticides,” Shimoda said. are effective,” Shimoda said. “My dream is that in the future we can make red nets that don’t look red — at least not to the human eye, but they’ll have an effect on insects. Hopefully that will reduce production costs, and We can find ways to increase stability.”

In addition to reducing onion thrips infestation, another advantage of red nets is that because they depend on color and not mesh size, they can have larger holes. It improves breathability, reduces the chances of fungal infections and improves access to sunlight. Also, due to better air flow, the temperature inside the greenhouse is not as high, making it easier for farmers to work inside.

“If consumers are interested in this type of sustainable agriculture and using less chemical pesticides, I have no doubt that this simple yet effective solution will become widespread,” Shimoda said. “My family has been a full-time farmer since the Edo period (17).Th century), and I enjoy growing vegetables and fruit myself on a small scale, although insects can make it difficult. Growing your own fruits and vegetables and eating them fresh is incredibly rewarding.”