Soybean growers in the Midwest face ongoing challenges from sudden death syndrome (SDS), a soil-borne disease caused by the pathogen Fusarium virguliforme. The disease infects soybean roots and can significantly reduce yield, making early management critical. A research team at Kansas State University, supported by Soy Checkoff funding from the Kansas Soybean Commission and the North Central Soybean Research Program (NCSRP), is exploring practical strategies to reduce SDS through field management practices.
The project, led by plant pathologist Rodrigo Onofre, is testing the impact of row spacing, plant population, and variety selection on SDS severity. Initial findings from the first year of field trials indicated that SDS was more severe in higher plant populations, particularly 160,000 and 200,000 seeds per acre, and in narrower 15-inch row configurations. The second year of trials, conducted during the 2025 growing season, expands these comparisons to include 15- and 30-inch rows, a broader range of seeding rates, and both SDS-susceptible and resistant soybean varieties. Results from this round of trials are expected later this year.
A key component of the project is a predictive model being developed by graduate student Madison Kessler, which estimates the likelihood of severe SDS in specific fields. The model draws on ten years of field trial data from Rossville and Topeka, Kansas, and a site in Iowa, integrating rainfall, soil temperature, and soil moisture data to identify conditions favorable for disease development. The goal is to provide farmers with actionable insights approximately six months before planting, allowing them to implement preventive measures such as seed treatments, resistant varieties, wider row spacing, or lower seeding rates.
“The model is designed to help farmers plan before the seed hits the ground,” Kessler explains. “Once SDS appears in the field, there’s little that can be done. Accurate predictions allow proactive management to protect yields and profitability.”
In addition to management trials, the team is analyzing the genetic diversity of the Fusarium species complex in Kansas. Samples collected from 18 counties have confirmed the presence of Fusarium virguliforme, ensuring that control strategies target the correct pathogen and that seed treatments and chemical applications are effective.
The ultimate aim of the project is to provide soybean farmers with practical tools and guidance to minimize the impact of SDS. Onofre and Kessler plan to promote the predictive model at grower meetings across Kansas once it is fully validated, helping producers make informed decisions to safeguard their crops and improve overall management of this persistent disease.
