How plant viruses can be used to ward off pests and keep plants healthy

Imagine a technology that could target pesticides to treat specific spots deep within the soil, making them more effective at controlling infestations while limiting their toxicity to the environment.

Researchers at the University of California San Diego and Case Western Reserve University have taken a step toward that goal. They discovered that a biological nanoparticle a plant virus is capable of delivering pesticide molecules deeper below the ground, to places that are normally beyond their reach.

The work could help farmers better manage difficult pests, like parasitic nematodes that wreak havoc on plant roots deep in the soil, with less pesticide.

"It sounds counterintuitive that we can use a plant virus to treat plant health," said Nicole Steinmetz, a professor of nanoengineering at the UC San Diego Jacobs School of Engineering and senior author of the study. "This is an emerging field of research in nanotechnology showing that we can use plant viruses as pesticide delivery systems. It's similar to how we're using nanoparticles in medicine to target drugs towards sites of disease and reduce their side effects in patients."

Tobacco mild green mosaic virus outperformed most of the other nanoparticles tested in the study. It carried its cargo down to 30 centimeters below the surface. As a next step, Steinmetz and her team are testing Tobacco mild green mosaic virus nanoparticles with pesticide loads. The goal is to test them in the field in the near future.