The direct value of the wheat harvest in Oregon in 2022 was approximately $431 million, ranking sixth in value among the state's agricultural commodities. That economic weight means growers stay vigilant against threats to yield and quality — including soilborne wheat mosaic virus (SBWMV), a persistent but often misunderstood pathogen.
The virus spreads slowly but persists in the soil. The more researchers understand its triggers and control points, the better they can help growers avoid yield loss and protect the long-term viability of wheat production.
As the research and outreach efforts continue, Oregon’s wheat industry is gaining new tools and deeper insight into one of its most elusive disease threats.
The virus, first reported in the Midwest in 1919 and later found in Western Oregon in 1994, was identified in three adjacent fields in Eastern Oregon in 2008. Since then, research by Oregon State University scientists has shown the virus is more widespread than previously believed.
The virus spreads slowly but persists in soil. The more researchers understand its triggers and control points, the better they can help growers avoid yield loss and preserve the long-term sustainability of dryland wheat systems.
To help address this threat, Christina Hagerty, associate professor of plant pathology based at Oregon State University’s Columbia Basin Agricultural Research Center, and her colleagues have continued to advance research on SBWMV in recent years.
Recent studies reveal that the Walla Walla Valley, along the Oregon and Washington border, has a higher concentration of infections and greater yield losses than earlier estimates suggested.
In trials conducted across 15 commercial winter wheat fields in the valley, Hagerty and her colleagues documented significant reductions in grain yield, biomass and head density in severely infected areas. The studies, focused on the susceptible wheat variety UI Magic, were conducted during the 2017 and 2018 growing seasons. Findings from the trials were published in the journal Crop Protection and were supported by funding from the Oregon Wheat Commission.
The researchers are working with public and private breeding programs to test wheat varieties for genetic resistance to SBWMV. A very limited number of lines now include resistance genes, though some still involve tradeoffs such as lower initial yield potential. However, current trials are showing promise in identifying resistant lines that maintain competitive yields.
They are also advancing early detection methods. In 2023, they published a study that showed hyperspectral imaging identified infected plants in the lab with nearly 70% accuracy. Simulated data from simpler multispectral cameras slightly improved detection, and real-world field tests confirmed the potential of this non-destructive technique. These tools could allow growers to act earlier and reduce crop damage.
Beyond lab and breeding work, Hagerty continues to focus on practical solutions. Her Extension program provides growers with clear tools for diagnosis and management. She co-authored a widely used field guide that helps identify wheat soilborne mosaic virus and other common wheat diseases of the Pacific Northwest.
Thanks in part to these outreach efforts, more growers in the Walla Walla Valley are now recognizing the disease’s symptoms, leading to improved awareness and more accurate field diagnoses.
As the research and outreach efforts continue, Oregon’s wheat industry is gaining new tools and deeper insight into one of its most elusive disease threats.