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

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.