Trends and Management of Plant-Parasitic Nematodes in Missouri Soybeans: Webinar Recording
Plant-parasitic nematodes are root-associated parasites that can reduce soybean plants’ ability to take up water and nutrients, leading to yield losses. The severity of damage depends on the nematode species, host susceptibility and environmental conditions.
Because above-ground symptoms may not be obvious, nematode damage can go undetected until significant yield loss has occurred.
In this webinar, Dr. Mandy Bish, assistant professor, and Jeff Barizon, Ph.D. candidate and research specialist from the University of Missouri, share findings from a 2024–2025 survey of 200 soybean fields across 81 Missouri counties.
The survey aimed to identify plant-parasitic nematode taxa and their prevalence, assess population densities, and evaluate soybean cyst nematode (Heterodera glycines; SCN) virulence phenotypes and intensity.
Researchers identified 10 plant-parasitic nematode taxa in the surveyed fields. Spiral nematodes (Helicotylenchus spp.) were the most prevalent, found in 84.5% of fields, followed by root-lesion nematodes (Pratylenchus spp.) at 83.5% and SCN at 80%.
Nematode population densities varied across the region. Most fields had low population densities, but some contained localized high-density populations. Multiple nematode taxa were also found in individual fields, although the impacts of many of these species on soybean production are not yet well understood.
SCN remains the primary nematode threat to Missouri soybean production. First identified in Missouri in 1956, SCN prompted the establishment of a quarantine, but the nematode was confirmed in northern Missouri in 1971 despite those efforts.
Today, managing SCN remains a major challenge, in part because many populations can reproduce on the soybean varieties that are planted as sources of SCN resistance. Rotating soybean varieties with resistance to SCN is important to extend their effectiveness.
The survey findings highlight the importance of regular nematode testing, even in fields without obvious symptoms. If SCN is found in a field, it is time to start managing it.
Presenters
Dr. Mandy Bish is an assistant professor and extension plant pathologist. She also serves as the MU Integrated Pest Management (IPM) Coordinator and director of SCN Diagnostics. Her research focus is to identify economical and sustainable solutions for disease management in crop production with specific focus on corn and soybean.
Jefferson Barizon is a PhD candidate at the University of Missouri and the Nematode Testing Coordinator for SCN Diagnostics. He earned a BS in Agronomy from the Universidade Federal da Grande Dourados (Brazil) and an MS in Plant Pathology from Iowa State University.
For his PhD research, Jefferson focuses on two key areas: plant-parasitic nematode density patterns and soil characteristics in soybean and reniform nematode virulence in cotton.
