Search IPCM Newsletter Archives

Here is the situation: Soybean cyst nematode (SCN) is the worst pest of soybeans in the USA, and the situation isn't getting any better. This nematode suppressed soybean production in the USA about 123 million bushels during 2006, and the valued at $804.6 million.

Fortunately, University of Missouri scientists have developed several highyielding soybean varieties resistant to SCN that are adapted for planting in Missouri and learned that crop rotation is a great SCN management tool. But soybean farmers must take steps to protect their crop against SCN.

The first step toward protecting soybean against SCN is to test the soil for it. University of Missouri Extension Regional Agronomists have information about taking and submitting soil samples for SCN analysis, and more information is available at the University of Missouri Website http://soilplantlab.missouri.edu/nematode. March is a great time of the year to collect samples for SCN analysis because the results will be available in early April so farmers can make SCN management plans if necessary.

If SCN is present, soybean farmers should take steps to protect their crop. Crop rotation is a great SCN control because nematode numbers drop during years when crops such as corn, grain sorghum, or cotton are planted. The number of years these crops should be planted before planting soybean again will depend on the number of SCN in the soil.

Soybean farmers should be cautious when selecting SCN resistant. University of Missouri scientists recently surveyed Missouri for SCN and learned that races one, two, three, four and five were present, but races one and three were most common in the central and north part of the state, and races two and four were found in the south part. Information about soybean variety resistance to SCN is available at the University of Missouri Variety Testing Website, http://agebb.missouri.edu/cropperf/vartest. At this Site, visitors should click on "2006 Soybean Test Results," then in the next window click on "Characteristics of Varieties," then select the soybean seed company name and click on submit. This source provides information about varieties tested during 2006 and the source of SCN resistance used to develop each variety.

The Missouri soybean farmer checkoff managed by the Missouri Soybean Merchandising Council funded much of the research by University of Missouri scientists to develop SCN resistant varieties and determine that crop rotation is a great SCN tool.

More information about SCN management is available at the University of Missouri Extension offi ces. Additional information is available at, Soybean Cyst Nematode: Diagnosis and Management, http://muextension.missouri.edu/explore/agguides/crops/g04450.htm, and in, Soybean Cyst Nematode Management Guide, http://planthealth.info/scnguide/.

Following these suggested procedures will give soybean farmers a better chance of producing a profitable soybean crop in 2007.

Allen Wrather, Professor University of
Missouri-Delta Center
WratherJ@missouri.edu