University of Illinois

No. 20/August 8, 1997

Soybean Cyst Nematode Clinics

Extension educators in crop systems and IPM will conduct clinics during the next few weeks in the central and northern parts of Illinois to help farmers manage this most serious pest of soybeans. The soybean cyst nematode (SCN) is ranked yearly as the most damaging crop pest of soybeans throughout the Midwest, costing Illinois growers alone 18 to 20 million dollars yearly. Losses of 5 to 15 bushels per acre are possible and may even occur without visible aboveground symptoms. This finding is especially true for soybeans grown in the central and northern parts of the state. Clinics conducted last year indicated that over 80 percent of the samples examined had SCN levels above the economic threshold. Many farmers reported no obvious symptoms (stunting, yellowing, circular patches in fields, etc.) and only detected a problem because yields were lower than expected.

The state of Illinois is unique among midwestern states because our Extension educators take a proactive position in SCN management by offering regional clinics where farmers can bring soil samples to be tested for SCN while they wait. I believe we are the only state in this region to offer clinics regularly and to provide information on SCN management at local sites. This is an excellent opportunity to determine if SCN is a problem this year in central and northern Illinois and prepare for the next season. The $15-per-sample fee is waived at these clinics, and samples are processed exactly the same as if sent to campus.

Clinics provide educational materials on SCN management as well and provide farmers with management options, depending on what is found in the soil sample. Upcoming clinics are

August 11, LaSalle County Farm Supply at Streator
August 12, Boone County, FS Plant, Belvidere
August 14, Will County, Joliet Junior College

Extension educators ask that you limit the total number of samples per farmer to three to ensure that we can process them all during the day. We typically begin processing samples about 9:30 a.m. and continue as needed.

SCN infestations in the central and northern parts of the state may or may not produce aboveground symptoms, due to the richness of the soils as well as soil-moisture levels. However, by the time you do detect substantial yield losses, numbers will be far above the threshold, and management can be more complicated. Smaller yield losses can go undetected for years and may be attributed to herbicides, compaction, fertility, and other agronomic factors rather than to SCN. The clinics offer an opportunity to begin management or to confirm that you do not have a problem if you are farming near one of these sites.
H. Walker Kirby, Extension Plant Pathology, (217)333-8414