NC State explores promising pest-control strategy with high-impact potential for sub-Saharan Africa

An NC State University agricultural research project that started with a high-technology nanoparticle solution to food security problems has gone low-tech. And in doing so, the project has won a $1 million grant from the Bill & Melinda Gates Foundation’s Grand Challenges Explorations initiative.

The grant will allow university researchers to further study and develop a simple technique they call “wrap and plant.” Not only could the method help smallholder farmers reduce pest problems, it also could increase food security and spawn new industries in sub-Saharan Africa.

The method involves wrapping seed pieces in chemically treated, biodegradable paper as a way to reduce crop damage from parasitic worms known as nematodes.

Right now, farmers have virtually no effective treatments for protecting seed pieces – plant parts used to propagate crops that aren’t grown from seeds – against nematodes. And several of sub-Saharan Africa’s most important food sources, including potatoes, yams, sweet potatoes and cassava, are sown with seed pieces.

Wrap and plant got its start in 2012, when Drs. Julie Willoughby and Steve Lommel received initial funding via the Grand Challenges Explorations’ call for proposals to help protect crops from stresses such as pest infestations. Such infestations cause close to $160 billion in worldwide crop damage each year.

Willoughby, a former NC State assistant professor in the Department of Textile Engineering, Chemistry and Science, and Lommel, director of NC State’s North Carolina Agricultural Research Service and a professor in the Department of Plant Pathology, pulled together a multidisciplinary team of university scientists from plant pathology, fiber and polymer science, chemical and biomolecular engineering, and toxicology to quickly vet their ideas for helping smallholder farmers manage nematodes.

The scientists tested four types of paper containing low rates of the commercially available nematicide abamectin; they found that the paper cut nematode populations but didn’t inhibit plant growth or root development in greenhouse-grown plants.

They also found that an inexpensive paper made from banana fibers worked best. The paper was produced by a senior design team of Textile Engineering and Technology students using NC State’s Forest Biomaterials Laboratory.

Meanwhile, the scientists also explored whether plant virus nanoparticles could be used to deliver the nematicide. And they were surprised by what they discovered.

“What we found was that just adding the compound to the paper was more effective than adding the compound to the virus and then adding the virus to the paper,” said Dr. Jing Cao, who worked on the project as a fiber and polymer graduate student.

And that meant a simpler, more practical and cost-effective solution, explained Dr. Tim Sit, a plant virologist and principal research scientist in the Department of Plant Pathology.

Sit is among three leaders of a team that won a follow-up grant to further develop the wrap-and-plant method. The others are the lead principal investigator Dr. Charles Opperman, a nematode expert and professor of plant pathology, and Dr. Saad Khan, a professor in the Department of Chemical and Biomolecular Engineering.

The team will test the technique in field trials at a central North Carolina research station while they work with collaborators and interested growers in sub-Saharan Africa to conduct similar trials there. Meanwhile, at NC State, Khan will explore the best methods for impregnating banana paper with a nematicide while also tweaking the release of the compound from the paper. Right now, the researchers envision a prototype paper roll with perforated sections, much like toilet paper.

The team is focusing on nematodes because they not only reduce crop yields but also leave crops vulnerable to other damaging pathogens and to drought. Thus, they reduce the amount of food available to smallholder farmers’ families and cut the farmers’ chances of having surplus food to sell to local markets.

But while the focus is on nematodes, the team believes the wrap-and-plant technique could help farmers with other food-security problems by delivering other types of pesticides, biological control agents and fertilizers to farm fields.

As Opperman notes, “The simplicity of wrap and plant is the beauty of it. Theoretically … anything that can absorb into the paper, we can apply. So you could customize solutions to whatever your local problem is. And that’s a big deal.”

Lower pest populations and higher yields aren’t the only outcomes that the researchers predict. They also believe that their research could lead to the creation of local paper-making industries. Once they get more evidence that the wrap-and-plant method is effective under real-world conditions, the scientists will work with African companies and individuals interested in producing the paper.

“With this Bill & Melinda Gates Foundation grant, we have two years to develop the product,” Opperman adds. “But it’s not just about developing a product that will raise yields, it’s about developing an industry around it that provides new opportunities for the people of sub-Saharan Africa.”

-Dee Shore