Watch For SCN From Combine

Soil test would confirm when the pest is responsible for low yielding spots.

Published on: Sep 26, 2013

While combining soybeans this year, you might see spots in the field where plants are thinner and smaller and yields are lower. You might want to mark the spot and test the soil, suggests Adam Spelhaug, agronomist, Peterson Farms Seed, Harwood, N.D.

"SCN was first discovered in our region in 2003, and can now be found in at least 12 counties in North Dakota and almost all soybean growing counties in Minnesota and South Dakota," he says.

Yield losses can become significant as the SCN population multiples in the soil.

Variety selection is currently the number one tool to fight SCN. Resistant varieties are available. Crop rotation helps to reduce SCN numbers, Spelhaug says, but will never rid the soil of the pest. Rotation to non-host crops and some seed treatments can reduce numbers but will not fully protect yield.

Spot Soybean Cyst Nematode signs from the combine.
Spot Soybean Cyst Nematode signs from the combine.

SCN affects soybean yields by reducing yhe root mass, thus robbing nutrients and water from the plant. Yield is affected before visual symptoms are noticeable.

"If reduced yield spots appear during harvest, and you cannot attribute the spots to other factors, test your soil! Fall is still a good time to soil test for SCN by sampling the top 6-8 inches of soil," he says.

You can sample the problem spots, or sample areas in the field that are more prone to SCN introduction. Common areas for SCN introduction include field entrances, flooded areas and fence lines.

Read more about SCN management in the September issue of the Dakota Farmer. See page 54.