To fight off the tomato pinworm, silicon might just be the answer. The tomato pinworm (Phthorimaea absoluta) is an invasive pest species that originates in South America and is now found in Europe, Asia, and Africa. The pest can cause 100% tomato crop failure, causing $1–10 billion annual losses in Africa.
"When the pest invaded Kenya, it did not have a coevolved natural enemy," says Fathiya Khamis, head of the Integrated Biosciences Platform at the International Centre of Insect Physiology and Ecology (ICIPE) in Nairobi. "We wanted to see how we can come up with a soil amendment approach that can increase the plant's resilience against the pest."
The team's solution involves mixing just 4 g of silica nanoparticles in a kilogram of growing substrate (Proc. Natl. Acad. Sc. USA 2025, DOI: 10.1073/pnas.2427314122). Once taken up by the tomato plants, the silicon brings about a biochemical modification of the protective shields, called glandular trichomes, on the stems of the tomato plants that defend the plants from extreme temperatures, UV radiation, and insect attacks. The modification results in the trichomes growing pigmented masses, akin to a cyst or wart, full of sugars and waxes.
The tomato pinworm usually lays its eggs on the leaves of the tomato plant, attracted by volatile chemicals released by the leaves. But this pest-plant interaction is disrupted when tomato plants take up silica, and the pest instead lays its eggs around the base of the trichomes on the stem.
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