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 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 northeastern parts 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. Between 2013 and 2021, approximately 4,700 samples have been submitted by North Dakota producers using this program, with many more expected in 2022. 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 2023, update extension materials on SCN and disseminate results during winter meetings in 2024.

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 1,000).
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.

1. Sample bags distributed to soybean growers and/or those that advise them (they submit samples).
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.

Updated January 5, 2024:
2023 Mid-Term Progress Report

Prepared by: Sam Markell

Date: 11/30/23

SCN sampling bags, instructions and sample submission forms were delivered to every NDSU County Extension office in August, 2023. Electronic versions of instructions and sample submission forms were also distributed through NDSU listservs. Interviews were conducted to advertise and 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.

To date, 539 samples have been received. 207 were reported as ‘negative’ (no eggs present). 100 samples were reported to have a very low level of eggs (reporting 50-200 eggs/100cc soil), which should be considered ‘inconclusive’. For clarity, many of these will be positive, but as other nematode eggs can be found in the soil, low level positives should be views with a level of uncertainty. The remainder were clear positives are varying levels, with the most frequent range being 2001-10,000 (92 samples). This highest recorded sample was 55,200 eggs/100cc.

Maps will be created shortly, and 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.

View uploaded report

Updated June 24, 2024:
We are please to report completion of the project. Please find attached; technical report, executive summary, figures 1 and 2. Thank you for your continued partnership and support.

View uploaded report

View uploaded report 2

View uploaded report 3

View uploaded report 4

Executive Summary
Soybean Cyst Nematode Sampling Program: 2023
PI: Sam Markell, Ph.D.
Co-PI’s: Guiping Yan, Ph.D, Febina Mathew, Ph.D, and Wade Webster, Ph.D.
Collaborators: NDSU County Extension Agents

Why the Research is important to North Dakota Soybean Farmers:
The plant parasitic nematode Soybean Cyst Nematode (SCN) was first confirmed in North Dakota in 2003 (Richland county) and has been spreading since its introduction. Soil sampling is the most reliable way to detect the presence of SCN and the most effective way to determine how well management tools are working in soybean fields. This project provides soybean growers a mechanism to submit samples for analysis at no-cost, and increases our understanding of SCN prevalence in North Dakota.

Research Conducted:
Pre-labeled soil-sampling bags are distributed to soybean growers and their advisors through NDSU Extension in late summer and early fall. The NDSC covers the laboratory fees of samples submitted to Agvise (partner laboratory), growers receive their data directly through the mail, and NDSU Extension receives egg level and geographic data to construct maps (no additional information about submitters or field is obtained).

Findings of the Research:
In 2023, 588 total SCN samples were received, of which 343 were found to have at least 50 eggs+J2/100cc soil, a positive rate of 58.3%, the highest recorded since the onset of the program. Sufficient data were received to map 539 samples. Since 2013, 5,666 samples have been received and 5,561 have been mapped. SCN is now thought to be present in two dozen counties.

Benefits and Recommendations to the North Dakota Soybean Farmers and Industry:
SCN is spreading and causing economic loss to our soybean farmers, and soil testing is the first step to active management and protecting yield. For growers who have not detected SCN before, we recommend that they sample field areas in 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 how well current management strategies are working.

Acknowledgements:
We thank growers, Extension agents and others who participated in this program, Honggang Bu for map construction, Agvise for sample processing, and the North Dakota Soybean Council for support.

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. 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.