Free Soybean Cyst Nematode Testing Offered in Missouri

By Blake Jackson

The University of Missouri Extension, in partnership with SCN Diagnostics and the Missouri Soybean Merchandising Council, is once again providing free testing for soybean cyst nematode (SCN), the most damaging soybean pathogen in the United States.

Mandy Bish, MU Extension plant pathologist and director of the SCN Diagnostics clinic, explained that Missouri soybean producers can submit up to four soil samples at no cost for SCN egg counts through the Columbia-based clinic.

Additional tests may be requested for a small fee. Bish noted that soybeans infected with SCN often look healthy above ground, making the pest difficult to detect without testing.

SCN is a microscopic roundworm that attacks soybean roots, restricting water and nutrient uptake. This can result in stunted plants, poor pod formation, and significant yield losses.

Recent research from MU doctoral student and research specialist Jeff Barizon shows that more Missouri fields now have detectable SCN populations compared to 10 years ago, and those infestations are denser. Barizon is currently leading a statewide survey to better understand parasitic nematodes in Missouri soybean production.

According to Bish, the best time to collect samples is in the fall, near or just after harvest. Fields that have never been tested or have not been tested in over five years should be prioritized.

Sampling for SCN requires specific techniques. Bish recommends taking 1-inch diameter soil cores at an 8-inch depth in a zigzag pattern. Fields should be divided into 10-20-acre sections using natural boundaries, such as topography changes, previously observed SCN symptoms, sudden death syndrome, or historically low-yield areas. Because SCN populations are unevenly distributed, proper sampling is essential for accurate results.

Farmers can download submission forms and find details on sampling procedures. For more information, contact the SCN Diagnostics lab at 573-884-9118 or scndiagnostics@missouri.edu, or reach out to Bish directly at bishm@missouri.edu or 573-882-9878.

Photo Credit: istock-urpspoteko