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Barrick: The search for soybean cyst nematode

National 4-H Week and National Science Experiment

Tina Dangel, 4-H Youth Development Educator will be in the Courthouse Community Room in Armour on October 6 to mark National 4-H Week and the National Science Experiment: Biofuel Blast. The event runs from 3:30 to 4:30 p.m. All youth are encouraged to attend.

The Search for Soybean Cyst Nematode

I have been collecting samples of soil from soybean fields in search of the soybean cyst nematode. So far no luck in Douglas County. That's a good thing, but probably not realistic. I've even sampled some where the producer suspected he had a problem. Every county east of us and Charles Mix County have found it.

South Dakota Cooperative Extension Service Plant Pathologist Larry Osborne said soil samples from four more counties, Charles Mix, Kingsbury, Codington, and McPherson counties tested positive for the pest for the first time in 2008. That brings the total to 25 counties in the state that have tested positive for the pest.

Soybean cyst nematode, or SCN, is the most damaging pest of soybeans in the United States. Thought to be native to Asia, soybean cyst nematode was first found within the United States in North Carolina in 1954.

In South Dakota, SCN was first detected in Union County in 1995. In addition to the four counties added in 2008, it has also been found in Clay, Yankton, Bon Homme, Lincoln, Turner, Hutchinson, Minnehaha, McCook, Hanson, Davison, Moody, Lake, Miner, Brookings, Deuel, Hamlin, Grant, Roberts, Day and Brown counties.

"The nematode is spread with soil movement, and can be transported on tires, shoes, tillage equipment, and planters," Osborne said. "The nematode has likely spread to even more areas, but because not all soybean growers test their soil, the pest can go undetected, silently robbing as much as 10 to 30 percent of soybean yields."

SCN testing at the SDSU Plant Diagnostic Clinic is free of charge for South Dakota growers thanks to a grant from the South Dakota Soybean Research and Promotion Council, which has funded SCN testing at SDSU for more than 10 years.

"The testing is simple and growers usually receive their results in just a few days," diagnostician Connie Tande said. The SDSU Plant Diagnostic Clinic will also test and process out-of-state samples for a fee of $20.

Osborne said fields can be sampled several ways - by taking soil cores throughout creating a representative sample, or by focusing on certain "hot spots." SCN tends to be discovered near field entrances and fence lines and in low-lying areas where water tends to accumulate, or in high pH soils. Often, growers first begin to check for SCN when yields are consistently low in areas, however many producers don't even know they have a problem until the pest has been present for several years.

To properly sample your soil for SCN, collect 15 to 20 soil cores in a zigzag pattern across the sampled area (ideally 20 acres or less). Mix the cores together and fill a soil bag or other suitable container for transport to the lab. To properly complete the testing, the clinic needs about a pint of soil. Sampling information and a submission form can be found at Additional information and a link to the "Soybean Cyst Nematode Management Guide" can be found at the North Central Soybean Research Program Web site: SDSU scientists contributed to the soybean checkoff-funded publication.

You can send in your own samples or give me a call and I'll take as many samples as I can.