A Japanese study found benefits against onion thrips. Here is what it showed—and what a local trial would still need to establish.
The evidence concerns particular nets, onion thrips and tested crops. It does not show that any red shade cloth controls every pest.
What the study found
Research published in 2024 compared net colours in laboratory and field experiments involving onion thrips, Thrips tabaci. The field work included Kujo leeks, a type of Welsh onion, in Japan. Nets containing red fibres performed better than the tested conventional alternatives in deterring the pest. [1]
The University of Tokyo reports that red-netted plots required 25–50% fewer insecticide applications than uncovered plots in the trial. That comparison is not a promise of the same reduction for a Namibian farm. [2]
Colour is only one specification
The researchers tested several colour combinations and mesh openings of 0.8 mm, 1 mm and 2 mm. The work supports investigating an optical effect alongside physical exclusion. It does not justify treating a product’s colour alone as a complete purchasing specification. [2]
Ask a supplier for the actual mesh opening, material, intended pest and supporting trial. Keep a sample and product description with your records.
A useful local comparison
Before covering a whole production area, consider a small, matched comparison. This is a proposed learning exercise, not an experiment already conducted by Living Earth.
- Identify the crop and pest before selecting the net.
- Compare similar plants under the candidate net and your usual protection.
- Record pest counts using the same method each time.
- Track crop damage, harvest, temperature and any treatments.
- Record net cost, installation labour and damage over time.
Where the crop needs pollinator access, include that requirement in the design. Seek local crop advice before changing a working protection system.
What remains uncertain
The supplied social-media screenshot is a lead to research, not local field evidence. Durability, availability and performance against other pests need checking. Report a trial’s failures as well as successes so the next grower can judge where the method might fit.
Sources & further reading
- Tokumaru et al. (2024) — Advanced methods for insect nets
- University of Tokyo — Red nets and onion thrips
Developed from Red crop nets deter pests.pdf by tracing its claim to the original study and university report.
Research summary for review. No Namibia-specific effectiveness claim is made.