Soybean cyst nematode is the most significant disease threat to soybean ptoduction 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 and monitoring critical for two different reasons. First, soil sampling is the best way to initially detect SCN, this is increasingly important in the western, central, and nonheastern pans of the state. Second, monitoring egg levels allows growers to evaluate how well their management tools are working and is increasingly important in the southeast and east central parts of the state. In 2013, the NDSC and NDSU developed a free-sampling-bag program for growers, in order to encourage growers to sample for SCN. Since 2013, over 4,000 samples have been sublhitted by North Dakota producers using this program. Maps generated from the project have served as a highly-leveraged tool to increase awareness of the expanding SCN problem in North Dakota. We propose to continue this sampling program in 2021.

l . 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).
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.
3. Create and distribute grower-friendly Extension publication of results (2013-2020) and impacts of the sampling program SCN sampling program.

l . Sample bags distributed to soybean growers.
2. Maps of SCN distribution in the state. These will be distributed throughout winter and summer events, websites, the NDSU Crop and Pest Report, ag media and others.
3. Extension publication that details results and impact of the SCN Sampling program
(2013-2020). We anticipate this as a grower-friendly infographic with maps and graphs.

Updated December 1, 2021:
2021 Mid-Term Progress Report
Prepared by: Sam Markell
Date: 12/01/21

SCN sampling bags were delivered to every NDSU County Extension office in the first two weeks of August, 2021. Instructions and sampling forms were sent along with sampling bags, and also through NDSU listservs. Print, radio and TV interviews were conducted in attempt to emphasize the importance of sampling and the opportunity provided by the North Dakota Soybean Council and program. Upon request, sampling bags (and materials) were provided to multiple crop consultants, elevators and other grower-advisors directly by Dr. Markell.

Sampling is likely done for the year, although growers and their advisors can sample anytime until freeze-up. Beginning December 1st, draft maps will be created. Final maps for 2021 will be created for use in winter programming, beginning early January. Maps will be distributed at winter meetings (real and/or virtual), through NDSU Extension, the SCN Coalition (www.thescncoalition.com), willing media partners and likely by partnerships (magazine, media, etc..) with the North Dakota Soybean Council and North Dakota Growers Association. We thank the North Dakota Soybean Council for their support.

Updated August 19, 2022:
Technical Report
Soybean Cyst Nematode Sampling Program: 2021
PI: Sam Markell, Ph.D.
Co-PI’s Guiping Yan, Ph.D.
Collaborators: NDSU County Extension Agents

Research Conducted:
This project is designed specifically to 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), and 2) Creation of a SCN distribution maps (limited resolution – no farms or growers can be identified) that can be used to determine how widespread SCN is. Maps are widely distributed in an effort to inform and encourage growers to sample and/or manage SCN.

Soybean Cyst Nematode sample bags were obtained from Agvise in June 2021. Bags were labeled with distinct yellow tags containing funding and identification numbers. Bags and accompanying instruction/submission forms were distributed to every Extension County office in early August. The number of bags distributed was roughly proportional to acreage (i.e., Richland and Cass County received more bags than Divide and Williams County). Bags were also distributed though the NDSU Plant Pathology Department, the NDSC Research Directors office, field days, NDSU Research Extension Centers and any other means appropriate. To advertise the availability of the program, multiple radio interviews were delivered, NDSU Crop and Pest Reports were written and other advertising was done.

Soybean growers were encouraged to sample around the time of harvest (before or after) which is when SCN numbers are known to be highest. Growers submitted samples to Agvise directly, or though the NDSU County Extension offices. Upon receipt, Agvise processed the samples and sends results thought the U.S. mail back to the submitter. Dr. Markell received geographic data points and egg levels and construct a map of SCN egg levels and distribution in the state. No additional personal information about submitters was obtained or used.

Why the Research is Important to ND Soybean Farmers:
Early detection of SCN is critical to avoiding yield loss. Distribution of cost-free SCN sampling has had buy-in among North Dakota growers. This has facilitated a likely detection of new positives and increased active management of SCN. Additionally, secondary benefits of this program have occurred, including the increased talk among growers about SCN, many press interviews and a significant amount of positive press for the North Dakota Soybean Council and its mission to serve the North Dakota growers.

Final Findings of the Research:
In 2021, 490 total SCN samples were received. This is slightly below the running average of sampling submission since the program was established in 2013 (520 per year) (Figure 1). Approximately 46% of the samples received were positive, the highest percentage since the start of the program. Additionally, the highest percentage of samples with medium to very high levels (categories exceeding 2,000 eggs/100cc) occurred in 2021. The relatively high levels recorded were likely a result of environmental conditions favoring SCN reproduction (hot and dry). Distribution of SCN in North Dakota remains most heavily concentrated in the East and Southeastern Counties, although positives are recorded in nearly half the counties in the state (Figures 2 and 3). To better visualize egg level distribution, ‘Heat maps’ were created for the southeast and southcentral counties (2013-2021) (Figure 4). While heat maps are intuitive and provide a useful visualization of risk, they should be viewed with a high level of caution, as SCN is very patchy; many fields in areas indicating the presence of high egg counts will actually not have SCN, and some fields in areas without SCN eggs will appear positive.

Results of the findings were distributed to growers and their advisors by numerous means, included but not limited to; NDSU Extension agents, winter meetings in 2022, and traditional and social media. Additionally, A new NDSU Extension publication ‘Soybean Cyst Nematode’ was published in April 2022 (Chowdhury et al. 2022). The publication included fundamental information about the importance, biology and management of SCN, along with results from the sampling program in this project. The publication was a joint effort between Dr. Guiping Yan’s nematology program and Dr. Markell’s Extension Plant Pathology program.

Benefits/Recommendations to the North Dakota Soybean Farmers and Industry:
We continue to recommend that growers actively sample for SCN. 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 and frequently flooded areas in fields. In fields where SCN is known to occur, we recommend that growers soil sample to determine if current management strategies are working (i.e. keeping egg levels low).

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

Citations:
Chowdhury, I., A., Yan, G., Halvorson, J., Thapa, A., Halvorson, M. and Markell, S. 2022. Soybean Cyst Nematode (SCN). NDSU Extension Publication PP1732.

View uploaded report

View uploaded report 2

Executive Summary
Soybean Cyst Nematode Sampling Program: 2021
PI: Sam Markell, Ph.D.
Co-PI’s Guiping Yan, Ph.D.
Collaborators: 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:
SCN causes damage before above-ground symptoms appear, making detection by soil sampling the most effective way to identify an SCN infestation. Additionally, monitoring egg levels is the best way to determine if management tools are working (resistance, rotation, seed treatments, etc). This program directly supports North Dakota soybean growers’ efforts to monitor, identify and manage SCN.

Final Findings of the Research:
In 2021, 490 total SCN samples were received. Nematode eggs were detected in approximately 1/3 of the samples. Distribution maps from 2013 to 2021 (Figures 1) 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.

Direct benefits are anticipated for both growers who, 1) do not know if they have SCN, and 2) have been dealing with SCN for years. For growers who do not know if they SCN, or are in areas where distribution of SCN is expanding (the western, central and northern parts of the state), this program benefits them by providing them a mechanism and incentive (lab fees paid by NDSC) to sample for SCN. Early detection ofSCN is critical to avoiding yield loss and proactively management the nematode. For growers who know they have SCN, this program benefits provides them by providing a mechanism and incentive to determine their SCN egg count, which can help them evaluate how well their management tools are working.
Secondary benefits, such as incleased awareness of SCN, are anticipated. This includes the increased talk among growers about SCN, many press interviews and importantly and positive press for both NDSU Extension and the NDSC and their missions to serve the ND growers.