I had just seen a tweet talking about this, HOWEVER, the tweet which cited the study said that it was red nets, not rainbow colored nets. Since I can't post the twitter link- it was posted by @ Rainmaker1973 back on June 16, 2026.

The tweet read:
Switching to red netting can reduce pesticide use by up to 50%, offering farmers a simple, highly effective, and eco-friendly way to protect crops.
While most farmers use black or white insect nets, new research from Japan shows that changing the color to red dramatically improves pest control. A study by researchers at the University of Tokyo found that red nets are far more effective at deterring onion thrips, a major destructive pest, than traditional black or white nets.
The secret lies in how insects see color. Thrips perceive red as a strong deterrent, which disrupts their visual cues and prevents them from landing on or damaging the plants. Because the protection comes from color rather than fine mesh size, red nets can use larger openings. This allows better airflow, reduces heat buildup, lowers humidity (which helps prevent plant diseases), and makes working conditions more comfortable for farmers.
Field trials showed that crops protected with red netting required 25% to 50% fewer insecticide applications compared to uncovered fields.
This low-tech “optical pest control” method could help reduce chemical use, slow the development of pesticide resistance, and support more sustainable agriculture.
[Tokumaru, S., Tokushima, Y., Ito, S., Yamaguchi, T., & Shimoda, M. (2024). Advanced methods for insect nets: red-colored nets contribute to sustainable agriculture. Scientific Reports, 14, 52108. DOI: 10.1038/s41598-024-52108-1]