Red nets are better at keeping away a common farming insect pest than the usual black or white nets. Scientists have tested the consequence of red, white, black, and combination-colored nets on discouraging onion thrips from consuming Kujo leeks, also known as Welsh onions. In both laboratory and field tests, red nets were significantly better at preventing the insect than other colors.
Also, in field tests, onion crops partly or fully enclosed by red netting required 25-50% less insecticide than was required for an uncovered field. Altering agricultural nets from black or white to red could help decrease pesticide use and its undesirable impact on the environment, while supporting more maintainable and effective agricultural practices.
Insect pests can be terrifying for any gardener. As soon as fresh buds appear they are enclosed in aphids, beetles, and other bugs looking for an easy snack. Artificial insecticides are broadly used to regulate pests in gardens and many are identified to cause damage to the natural environment by leaking into the soil and water supplies and intoxicating plants, wildlife, and harmless insects. Some pests are also becoming unaffected by the chemicals, so farmers are running out of choices for what to use and need to apply more often.
Farming nets are an alternative way to defend crops and reduce insecticide use. You may see the characteristically white-, black- or blue-netted greenhouses when you see an orchard or vegetable field. Like a mosquito net covering a bed, they physically avert insects from reaching the crops.
It makes sense to think that the most significant feature of these nets would be the dimensions of the holes in the mesh. The smaller the hole, the smaller the insect has to be to pass. However, a research team from the Kyoto Prefectural Agriculture, Forestry and Fisheries Center and the University of Tokyo have indicated that the net’s color may act as an even more significant restraining tool.
We confirmed red nets which had a mesh size that was greater than the insect body, but still more effective than other orthodox black or white nets with a smaller mesh size. This ‘visual pest regulator’ depends on the nature of insect color vision to keep pests at bay, described Professor Masami Shimoda from the Graduate School of Agricultural and Life Sciences at the University of Tokyo. Most pests don’t have red photoreceptors in their eyes and it is hard for them to realize the color red, so we found it interesting that an invisible color can be used to regulate them.
The team specified one pest, the onion thrips (Thrips tabaci). This insect is extremely resilient to insecticides and causes widespread damage to a variety of vital crops worldwide, by consuming them and by distributing harmful viruses. The scientists confirmed three color groupings of red nets (red-white, red-black, and red-red) at three mesh sizes (2 millimeters, 1 mm, and 0.8 mm). They also tried typical black, white, and black-white blended nets of the same sizes, in the lab and the field.
In General, all nets that included red fibers performed much better at keeping out onion thrips than black or white nets. In the second outdoor experiment, the scientists tested the efficiency of red-red netting at diverse levels of cover: no cover, complete cover, top only, and side only.
Due to an eruption of onion thrips in the area, pesticide was used. The fully enclosed plot needed the smallest amount of insecticide and produced onions of high marketable value. The plots that were only ceiling- or side-covered needed one extra application of insecticide, compared to the fully enclosed plot. Compared to the uncovered plot, the red-netted plots in general reduced the number of insecticide applications required by 25–50%.
These new red nets are more costly than pesticides, however they are economical since they can be utilized for years. They are also very efficient in regulating pests without all the work involved in crop-dusting pesticides, said Shimoda. In the future, we can make red nets that don’t look red—at least not to humans, but they would have the same result on pests. Confidently, this would decrease manufacturing expenses, and we can find ways to increase resilience.
As well as reducing invasion by onion thrips, another benefit of red nets is that since they depend on color and not mesh size, they can have larger holes. This expands breathability, decreases the chance of fungal infections, and improves contact with sunlight. Also, due to improved airflow, temperature is maintained within the greenhouse, making it easier for farmers to work within the nets.
If customers are interested in this form of justifiable agriculture and using less chemical insecticide, I do not doubt that this humble yet effective resolution will spread widely, said Shimoda. My family has been full-time farmers since the Edo period (17th century), and I enjoy growing vegetables and fruits on a minor scale, even though pests can make it challenging. Growing your fruits and vegetables and consuming them fresh is exceptionally worthwhile.
The findings of this research appear in Scientific Reports
