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Schmidt: Soybean cyst nematode sampling continues

By Staff | Sep 29, 2017

The NDSU Extension Service and the North Dakota Soybean Council are working together again to coordinate a Soybean Cyst Nematode (SCN) soil testing program. A total of 2,000 SCN soil test bags will be available on a first come first serve basis.

As in the past, pre-labeled SCN soil test bags will be sent to each County office in the state. The bags (and instruction sheets) began arriving in County Extension offices in early September and the Pierce County office has 25 bags available to growers on a first come first serve basis. Growers are able to obtain up to three SCN soil test bags each. Each bag is pre-marked with billing information that will be covered by the North Dakota Soybean Council.

To submit a sample, fill the bag with soil, provide site information and send the bag to the partner lab (Agvise). Results will be mailed directly to the growers and the laboratory fees are covered by checkoff dollars from the North Dakota Soybean Council.

As in 2013, 2014, 2015 and 2016, NDSU will use egg levels and geospatial positions of samples to create a map of SCN in North Dakota. This map helps growers know where SCN is occurring and moving. Importantly, NDSU does not have access to any personal information just the egg level and geospatial data to generate a map.


We encourage soybean and dry bean growers to sample for soybean cyst nematode. Below are some commonly asked questions and answers.

Q: Why should I sample?

A: Soybean cyst nematode can cause very high levels of yield loss before you see symptoms. Soil sampling is the best way to detect SCN. We have solid management tools for SCN on soybeans, so it is worth your time to look for it.

Q: Are my soybeans at risk for SCN?

A: While it is possible that any soybean grower in North Dakota could have SCN, the greatest risk is in the Eastern part of the state. The highest egg levels have been reported in Richland, Cass, Traill and Southern Grand Forks Counties. To date, SCN has been found in 19 North Dakota counties.

Q: Are my dry beans at risk?

A: Soybean cyst nematode can infect dry beans and SCN has been spreading into areas where dry beans are very common. While all market classes can be infected, recent data suggests that kidneys are the most susceptible market class and blacks might be the least susceptible. Pinto and Navy beans appear to be moderately susceptible.

Q: What’s the most common symptom of SCN?

A: Healthy looking soybeans. Typically, the first thing you will notice is a spot in the field that doesn’t yield well. After you have relatively high egg levels in a spot, you may start to see stunting or yellowing that appears in August.

Q: When is the best time to sample?

A: Just before or after harvest. The nematode population builds through the season, so sampling at the season ends maximizes your chances of detecting it.

Q: Where do I sample?

A: Anything that moves soil can move SCN. Consequently, we tend to find SCN in places where soil is deposited from other sources, such as the field entrance (soil moves on equipment), low spots (from overland flooding) or shelter belts / fences (from wind-blown soil). Additionally, consistently low yielding patches or yellow spots that appear in August may be a result of SCN. Lastly, SCN likes high pH; if you have a low yielding and yellowing high pH spot, it could be SCN.

Q: How do I sample?

A: Use a small soil probe or a shovel and aim for the roots. Take 10-20 small samples, mix up, and fill soil bag with the composite sample. Keep the bag relatively cool and get to the lab in the next few days.

Q: What do the results tell me?

A: Your results will be reported in eggs / per 100cc of soil. Essentially, this is how many eggs you have in about half a cup of soil. Positive egg counts mean you should begin managing SCN, negative egg counts mean you should be happy, and sample again when you put soybeans back in the ground. One point of note, very low numbers could be false positives (50 to 200). Resampling may be a good idea.

For more information or to pick up sample bags stop by or call the Pierce County Extension office at 701-776-6234 ext. 5.

Parts of this column were adapted from the recent issue of the NDSU Crop and Pest Report and Dr. Sam Markell, Extension Plant Pathologist.

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