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Here is the situation: Soybean cyst nematode (SCN) is the worst pest of soybeans in the United States. Missouri soybean producers can help protect their crop against this pest by planting soybean varieties that have some resistance to SCN and by rotating soybean with corn, grain sorghum, cotton and certain other crops.

The first step toward protecting soybean against SCN is to test the field soil for it.

Soybean growers should take this test to beat this pest.

Although soil samples for SCN may be collected at any time, the ideal time to sample is as close to soybean harvest as possible. SCN numbers tend to be highest when the plants are almost mature to shortly after harvest. Sampling near harvest allows sufficient time for the nematode laboratory to process the sample and provide you with information, and enough time for variety selection or choosing alternative crops for next year.

Large fields may be subdivided into sections of about 10 acres each, and a single sample from each of the different sections should be submitted for analysis. Collect 10 to 20 soil cores six to eight inches deep in a zigzag pattern across the area to be sampled. Bulk the cores in a bucket and mix thoroughly. Place about one pint of the mixed soil in a plastic bag and label the outside of the bag with a marker to identify the field number and owner. Store the sample away from sunlight in a cool area until it is shipped for testing in the lab. More information about collecting and shipping soil samples for nematode tests is at http://soilplantlab.missouri.edu/nematode/samples.htm or call your County Extension Office.

More information about SCN is available in the recently revised MU Extension guide number 4450 titled, Soybean Cyst Nematode: Diagnosis and Management. Color copies of this revised guide are now being printed, and they will be available at County Extension Offices in the near future. The guide is available on the web at http://muextension.missouri.edu/explore/agguides/crops/g04450.htm.

Remember, take the test to beat this pest. Following these suggested procedures will give soybean producers a better chance of producing a profitable soybean crop in 2007.

Allen Wrather
University of Missouri-Delta Center