USDA has awarded a University of Idaho-led research team $6.8 million to help potato farmers better control nematodes.

Most nematodes benefit soil, but parasitic nematodes attack roots and may kill entire plants.

The work focuses on the pale cyst nematode — found in a small area of eastern Idaho in 2006 and the focus of ongoing eradication efforts — and the golden nematode, which is found in New York.

These nematodes, which produce cysts that can remain viable for decades in the absence of a host, are especially concerning to the industry, the university said in a release. Keeping them from spreading is vital for trade.

Potato packers, processors, farmers, regulators and large agriculture businesses submitted more than 70 letters of support for the project, the university said.

“Potato cyst nematodes are an internationally regulated pest, said Louise-Marie Dandurand, who heads the project and is with UI’s Department of Entomology, Plant Pathology and Nematology. “If an infestation gets out of hand, there’s an 80% yield reduction potential.”

The four-year project is funded through the USDA National Institute of Food and Agriculture’s Specialty Crop Research Initiative. Workshops are slated in the third and fourth years.

Goals include developing support models to guide growers’ management decisions, identifying molecular assays to differentiate nematode pathotypes, developing resistant potato varieties and creating a chemical for nematode-specific control.

An assay finds and measures a specific substance. Pathotypes are organisms that are the same in species and in how they originate or produce disease.

Little research has been conducted on nematode population thresholds that warrant fumigation. Having the ability to identify nematodes by pathotype or race would allow potato farmers to select appropriate resistant varieties, the university said.

Researchers aim to identify a gene responsible for nematode resistance within litchi tomato, a plant in the nightshade family known to stimulate nematode cysts to hatch in the absence of a host. Breeders would then introduce the trait into popular potato varieties using biotechnology.

Researchers suspect litchi tomato contains a chemical that is highly toxic to nematodes. The project calls for identifying it and using it as a nematicide that likely would not harm beneficial nematodes and insects.

Conventional breeding efforts to develop nematode-resistant potato varieties also are underway.

The researchers have made substantial progress toward introducing resistance through traditional breeding methods, developing potato varieties with up to 50% resistance, Dandurand said. The project aims to significantly boost the resistance level by producing varieties that incorporate multiple resistance genes.

Researchers also will evaluate how crop rotations involving resistant potato varieties affect nematode populations. Trials will be in infested fields and include various safety measures. Work on golden nematodes will be in New York trial fields already set up for nematode research.

The team will also evaluate other nematodes important to the industry, such as Columbia and Northern Root-Knot nematodes. Researchers are from UI and from Washington State, Oregon State, Michigan State and Cornell universities, the University of Wisconsin and USDA’s Agricultural Research Service.