Soybean cyst nematode is the most significant disease threat to soybean production in the United States, and it continues to spread in North Dakota. Management tools for SCN are available, but a 15-30% yield loss is common before above ground symptoms appear, making proactive identification critical to avoiding yield loss. In 2013, the NDSC and NDSU developed a free sampling-bag program for growers, in order to encourage growers to sample for SCN. Between 2013 and 2018, approximately 3,600 bags have been submitted by North Dakota producers, and an additional 500 submissions are anticipated in this growing season (2019). Maps generated from the project have served as a tool to increase awareness of the expanding SCN problem in North Dakota. The economic impact for every grower that proactively detects SCN before incurring yield loss is very high. We propose to continue this sampling program in 2020.

1. Provide incentive for growers to sample for SCN by covering the cost of up to three SCN samples (pre-labeled bags) per grower on a first-come first-serve basis (up to 2,000 bags total). Bags will be distributed through Extension County offices, my office, Research Director Nichol’s office, at field days and by any other means appropriate.
2. Creation of a SCN distribution map (limited resolution – no farms or growers can be identified) that can be used to determine how widespread SCN is. This map will be widely distributed in an effort to encourage growers to sample and/or manage SCN.

1. Sample bags distributed to producers through County Extension offices, my office, field days and other areas convenient for producers to access them.
2. Maps of SCN distribution in the state. These will be distributed throughout winter and summer events, websites and media.

Updated December 1, 2020:
2020 Mid-Term Progress Report
Prepared: Sam Markell
Date: 12/01/20

To date, 615 SCN soil samples have been processed by the partner laboratory (Agvise Laboratories). More samples are still in process and final numbers from fall sampling in 2020 should be known by January 1, 2021. Samples were up approximately two-fold from 2019, likely due to a much more favorable harvest season.

We anticipate SCN map creation will be completed by January 1, 2021. Maps will be distributed at winter meetings (real and/or virtual), through NDSU Extension, the SCN Coalition (www.thescncoalition.com), willing media partners and by partnership with the North Dakota Soybean Council. We thank the North Dakota Soybean Council for their support.

Updated June 30, 2021:

View uploaded report

Soybean Cyst Nematode Sampling Program: 2020
PI: Sam Markell, Ph.D.
Co-PI’s Guiping Yan, Ph.D.
Collaborators: Berlin Nelson, Ph.D., and NDSU County Extension Agents

Research Conducted:
This project is designed to encourage growers to soil sample for Soybean Cyst Nematode (SCN), the most damaging soybean pest in the United States. Growers submit soil samples to the partner laboratory in pre-labeled bags, the North Dakota Soybean Council covers the laboratory fees, and growers receive data directly through the mail. NDSU Extension receives egg level and geographic data to construct distribution maps (no additional information about submitters is obtained).

Why the Research is Important to ND Soybean Farmers:
This program provides an incentive and mechanism to sample for SCN by covering the laboratory fees. SCN causes damage before above-ground symptoms appear, making detection by soil sampling critical. Growers can use this sampling program to help determine if their management tools are working (resistance, rotation, seed treatments, etc).

Final Findings of the Research:
In 2020, 603 total SCN samples were received. Nematode eggs were detected in approximately 1/3 of the samples. Distribution maps from 2013 to 2020 (Figures 1) and 2020-only demonstrate that SCN is most common and in highest levels in the southeastern North Dakota (Figure 2).

Benefits/Recommendations to the North Dakota Soybean Farmers and Industry:
For growers who have not detected SCN before, we recommend that they concentrate on areas in the field where SCN is most likely to first be introduced, such as field entrances. For growers who know they have SCN, we recommend they soil sample to determine if current management strategies are working.

Acknowledgements:
We express our thanks to the many growers, Extension agents, crop consultants and others who participated in this program, to Michaela Halvorson for map construction, to Agvise for sample processing, and finally to the North Dakota Soybean Council for support.

[Captions for associated figures]
Figure 1. Distribution of soybean cyst nematode (eggs/100cc soil) in North Dakota received though the NDSC / NDSU Extension sampling program 2013-2020.

Figure 2. 2020-only distribution and egg level of soybean cyst nematode (eggs/100cc soil) in southeast and east central North Dakota received though the NDSC / NDSU Extension sampling program. Note of caution: SCN is very spotty in regions and fields, and heat maps (while visually appealing) do not have the resolution to reflect the presence or level of SCN in any specific fields.

Early detection of SCN is critical to avoiding yield loss, and SCN can be managed with available tool. Importantly, two of the most effective (crop rotation and selection of resistant soybeans) do not need additional cash inputs by growers to be utilized effectively. Additionally, secondary benefits of this program have occurred, including the increased talk among growers about SCN, many press interviews and importantly, a positive press for both NDSU Extension and the NDSC and their missions to serve the ND growers.