11 October 2023

Nanoparticles are a sustainable weapon against soil pests


According to the University of California, the use of plant-derived nanoparticles can reduce the amount of pesticides used and the chances of soil contamination

by Matteo Cavallito


The use of nanoparticles could enable effective control of agricultural pests by reducing pesticide use. This is claimed by engineers at the University of California San Diego who have developed a new solution for combating nematodes, microorganisms that are harmful – but sometimes not – to plants. Their work is detailed in a paper published in the journal Nano Letters.

The collateral damage of pesticides

Pesticides used against nematodes, a University of California statement says, tend to adhere to the upper layers of the soil. Only a small part of the substance, in other words, manages to reach the roots where the pests create the greatest problems.

This characteristic therefore requires the use of large quantities of the product, resulting in an increased risk of soil and groundwater contamination.

To solve this problem, researchers led by Nicole Steinmetz, a professor of nanoengineering at the Jacobs School of Engineering at the University of California San Diego and director of the Center for Nano-ImmunoEngineering, which she founded, has chosen a novel path. That is, to develop plant virus nanoparticles capable of transporting pesticide molecules deep into the soil to where they are most needed.

The experiment

The researchers used tobacco green mosaic virus, which has the ability to move easily through soil, whose nanoparticles they modified, making them noninfectious to crops by removing their RNA. “We set out to develop a platform for pesticide delivery targeting nematodes in the rhizosphere (the part of the soil near the roots, ed.),” they explain in the study.

In detail, “Spherical nanoparticles (SNPs) were obtained by thermal shape-switching of the tobacco mild green mosaic virus (TMGMV).” The products “were encapsulated into SNPs to achieve 10% mass loading. SNPs.”

According to the authors, there are two main advantages of this solution. On the one hand, the low cost of the process, which would make it possible to develop a product easily accessible to farmers. On the other, the system’s ability to preserve the structure of the pesticide, which, when placed in the nanoparticles, does not chemically bind to the soil.

Mobility of nanoparticles is decisive

The study once again highlights the potential of nanomaterials, those structures that by definition are no more than 100 nanometers (one ten-thousandth of a millimeter) in length and are increasingly being used to optimize soil properties. “Our technology enables pesticides meant to combat nematodes to be used in the soil,” explained Adam Caparco, one of the researchers involved in the study.

“These pesticides alone cannot penetrate the soil,” he added. “But with our nanoparticles, they now have soil mobility, can reach the root level, and potentially kill the nematodes.” The technique, the researchers explain, will be field tested in the future to further verify its effectiveness in collaboration with the U.S. Horticultural Research Laboratory, an agency of the U.S. Department of Agriculture.