No Silver Bullet for Pale Cyst Nematode: PAPAS Research Featured in AGDAILY
A new article in AGDAILY written by PAPAS researchers Paige Hickman, Ph.D., and Louise-Marie Dandurand, Ph.D., brings national attention to the pale cyst nematode challenge in Idaho.
“No Silver Bullet: Controlling Idaho’s Potato Cyst Nematode Takes a Full Toolbox” explains how the discovery of the pale cyst nematode (Globodera pallida) in Idaho shaped the last twenty years of regulations, why eradicating PCN has been such a challenge, and the research efforts that are driving new solutions for the path forward.
The toolbox: Control strategies for PCN in Idaho
Because G. pallida is under a federal regulatory program aimed at containment and eradication rather than simple management, the goal of all control efforts is to reduce nematode populations to below detectable levels. That requires patience and multiple approaches used in combination. No single tool is sufficient on its own.
Some of the control strategies that PAPAS and University of Idaho researchers have developed and validated include:
Crop rotation
Cysts can harbor viable eggs for up to 30 years even in the absence of a potato host. Strategic multi-year rotation using a resistant potato variety combined with a trap crop is highly effective at reducing PCN populations before planting a susceptible potato variety.
Trap crops
Certain plants trick PCN into hatching but prevent reproduction, interrupting the life cycle and reducing population densities. Litchi tomato (Solanum sisymbriifolium) can reduce PCN egg densities by more than 80% in a single growing season, and by 99% when used in rotation with a susceptible potato. Quinoa reduces PCN by up to 40% and offers growers the added benefit of a marketable crop.
Biofumigation
Incorporating plant material into soil, typically from the mustard family, releases compounds toxic to nematodes. Seed meal extracts from Brassica juncea and Sinapis alba reduce PCN populations substantially and show additive benefits when combined with trap crops.
Resistant varieties
A highly resistant potato variety causes PCN to hatch but limits its ability to reproduce, putting additional downward pressure on populations. Developing a PCN-resistant russet potato for Idaho production is a primary PAPAS objective. Over 40 varieties now carry resistance to the golden nematode (G. rostochiensis) found in New York, keeping that pest below detectable levels across regulated fields.
Chemical fumigation and novel nematicides
Soil fumigation with Telone II remains part of the eradication toolkit. Litchi tomato-derived compounds are showing direct toxic effects on PCN eggs and juveniles beyond the plant’s value as a trap crop, pointing toward new bionematicide chemistry.
What growers need to know
The pale cyst nematode remains contained, but the lesson of 2006 — that a single introduction can disrupt markets and restrict land use for decades — applies everywhere. Equipment sanitation and awareness of where soil moves are the most practical steps any grower can take.
The first deregulated field in Idaho proves that eradication is achievable. Getting there took 19 years, strict protocols, and every tool in the toolbox. PAPAS is working to make that process faster, more effective, and more accessible for growers.
For more on PAPAS research into PCN management, trap crops, resistant varieties, and bionematicide development, explore PotatoNematodes.org.
