Rotating Soybean Cyst Nematode Resistant Varieties, Non-Host Crops and More

The mega-threat of soybean cyst nematode (SCN) looms large over your growers’ soybean fields. SCN is the No. 1 yield-reducing soybean pest, causing more than $1.5 billion in annual losses.¹ In 2025, it claimed more than 70 million bushels in the U.S.²

Here’s a layered approach you can use with your growers that includes SCN-resistant varieties, crop rotation and seed treatments.

Soybean cyst nematode management strategies

Because no single management solution effectively combats SCN, encourage your growers to attack the pest from several angles.

1. Rotate soybean genetics and crops to combat SCN in soybeans

As many as six generations of SCN can cycle through your growers’ soybean fields in a single season.³ That means SCN evolves constantly, and diligent rotation of soybean genetics and crops is crucial to breaking its lifecycle.

Rotate resistance sources, not just varieties

Advise growers to rotate among soybean varieties based on different resistance sources, since soybean cyst nematode populations increasingly overcome varieties bred from PI 88788 and Peking SCN-resistant sources. This approach also gives researchers a longer runway to introduce innovations such as BASF’s Nemasphere™ nematode resistant trait, anticipated in 2028 pending regulatory approval.

Rotate to non-host crops to combat SCN

Encourage growers to rotate the crops they grow in soybean fields. Appropriate rotations can include alfalfa, corn, oats, sorghum and wheat. None of these harbors soybean cyst nematode. This is especially important if a grower has SCN counts higher than 10,000 eggs per 100 cc of soil.⁴ Planting a non-host crop can reduce egg count up to 50%.⁵ The non-host crop approach often works best when implemented over several consecutive seasons.

2. Understand soybean cyst nematode resistance ratings

Next, help growers monitor resistance in their soybean fields using HG type testing, which pinpoints resistance sources likely to limit SCN reproduction, and the female index, which helps estimate SCN volume and potential yield damage.

HG type testing for soybean cyst nematode

This stands for Heterodera glycines, the scientific term for soybean cyst nematode. The goal of this test is to figure out how different varieties of soybeans grown for their ability to resist SCN are performing compared to one another.⁶ HG type testing can be performed by dropping off or mailing about half a gallon of soil to a local university laboratory.

Using the female index to calculate soybean cyst nematode

The SCN female index is calculated using information from the HG type test. If a grower’s female index is less than 10, resistance is working in their soybeans. If it’s between 10 and 30, resistance is moderate. If it’s 30-60, their crop is moderately susceptible to SCN. And if it’s greater than 60, their crop is rated susceptible. Keep in mind that varieties with a female index under 50 will still generally yield more than those with higher scores, even when SCN levels are high enough to curb yield.⁷

3. Pair resistant soybean varieties with seed treatments

Another tactic that can combat SCN resistance is using seed treatments such as BASF’s Ilevo® alongside SCN-resistant soybean varieties. Ilevo seed treatment also provides protection from sudden death syndrome (SDS).

Experts are available to assist you in selecting soybean cyst nematode-resistant varieties for your growers and in helping them manage SCN. Reach out to your seed retailer, a nearby extension office agent or a seed company professional like your regional BASF representative.

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Endnotes

1. Tylka, Greg. “New Data-Based Calculator Estimates Economic Yield Loss from SCN in Individual Fields.” Integrated Crop Management, Iowa State University Extension and Outreach, 10 Nov. 2023,https://crops.extension.iastate.edu/cropnews/2023/11/new-data-based-calculator-estimates-economic-yield-loss-scn-individual-fields. Accessed 15 June 2026.
2. Allen, T., et al. “Soybean Disease Loss Estimates from the United States and Ontario, Canada—2025.” Crop Protection Network, 2026. CPN-1018-25. DOI: 10.31274/cpn-20260306-0.https://doi.org/10.31274/cpn-20260306-0. Accessed 15 June 2026.
3. “Strengthen SCN Control Through Effective Weed Management.” The SCN Coalition, 8 Apr. 2026,https://www.thescncoalition.com/news/2026/04/08/scn-weed-hosts-integrated-weed-management/. Accessed 15 June 2026.
4. Porter, Nancy. “Know Your SCN Numbers: Free Fall Sampling Program for Soybean Cyst Nematode.” University of Minnesota Extension Crop News, Sept. 2023,https://blog-crop-news.extension.umn.edu/2023/09/know-your-scn-numbers-free-fall.html. Accessed 15 June 2026.
5. Tylka, Greg, and Meaghan Anderson. “SCN and Winter Annual Weeds—A Dangerous Combination?” Integrated Crop Management, Iowa State University Extension and Outreach, 4 May 2026,https://crops.extension.iastate.edu/post/scn-and-winter-annual-weeds-dangerous-combination. Accessed 15 June 2026.
6. Strunk, Connie, and Byamukama, Emmanuel. “HG Type Testing: A Management Strategy for Soybean Cyst Nematode Control.” SDSU Extension, South Dakota State University Extension, 10 Feb. 2022,https://extension.sdstate.edu/hg-type-testing-management-strategy-soybean-cyst-nematode-control. Accessed 15 June 2026.
7. Lindsey, Laura, and Terry Niblack. “Verification of SCN Resistance in Soybean Varieties.” Step Up Soybean Production, College of Food, Agricultural, and Environmental Sciences, The Ohio State University,https://stepupsoy.osu.edu/soybean-production/variety-selection/verification-scn-resistance-soybean-varieties. Accessed 15 June 2026.