While soybean cyst nematode (SCN) populations in an infested soybean field can never be brought to zero, rotating crops can be an effective tactic for managing SCN.
Learn which crops are non-hosts for SCN — and how interrupting life cycle and reproduction with a non-host crop reduces SCN for soybeans.
Non-host crop suppression of soybean cyst nematodes: Which crop is best?
A handful of soil containing 100 SCN eggs will contain approximately 50 females, each of which can produce 250 additional eggs. Even with a high mortality rate, three generations of SCN later, that adds up to 24,414 eggs in that same handful of soil.¹
This is why it is critical to interrupt the life cycle of SCN to slow the nematode’s rate of reproduction.
Rotating non-host crops into your soybean operation should be considered. Corn is the most popular non-host crop used in rotation with soybean crops to deal with SCN infestations. However, small grains, sorghum and alfalfa are also good options for non-host crops for SCN suppression.
Avoid dry beans, clover and hairy vetch as these crops can all host SCN, defeating the purpose of the rotation entirely.
Benefits of corn crop rotation for SCN population reduction
During the first 1 to 2 years of a corn rotation, SCN population densities can be expected to decline 50% to 75% each year.²
Growing continuous corn for subsequent years still helps reduce SCN, but the initial rate of reduction declines after the first year, and population densities never reach zero SCN eggs.
Additionally, research has shown a connection between soil composition and levels of SCN. Soil pH and SCN population levels before corn rotation are two major determinants of the expected SCN mortality after annual corn rotation.³ Lower soil pH is connected to lower SCN levels, with SCN typically establishing first in areas of your field with a soil pH greater than 7.
Concerns with continuous corn
Continuous corn poses its own challenges, including increased nitrogen requirements, heavy residue and increased risk of seedling diseases. Adding a third rotation of a non-host corn alternative may be ideal for managing SCN.
Pair soybean cyst nematode crop rotation with other management methods
Managing SCN isn’t a one-and-done task; it requires a multifaceted strategy that uses methods such as crop rotation, soil fertility management and rotating different SCN-resistant traits.
Management starts with awareness. The first step is testing soil samples to determine the level of SCN infestation present in your fields. Next, implement non-host crop rotation and manage weeds that could harbor SCN through the winter, and rotate between SCN-resistant soybean products.
Still have questions? Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent, or a company professional like your regional BASF representative.
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Endnotes
- Frequently Asked Questions About SCN and The SCN Coalition.” The SCN Coalition, 3 May 2023, www.thescncoalition.com/resources/faq/. Accessed 8 Sept. 2024.
- Bartels, Melissa, and Kyle Broderick. “Managing Soybean Cyst Nematode Starts Now.” CropWatch, 18 July 2022, cropwatch.unl.edu/2021/managing-soybean-cyst-nematode-starts-now. Accessed 9 Sept. 2024.
- Giesler, Loren. “Influence of Irrigation and Crop Rotation Sequence on Soybean Cyst Nematode (SCN) Populations.” CropWatch | University of Nebraska–Lincoln, cropwatch.unl.edu/soycal/app/exploratory-research/Summary%20-%20Disease%20-%20Effect%20of%20Irrigation%20and%20Crop%20Rotation%20on%20Soybean%20Cyst%20Nematode.htm. Accessed 9 Sept. 2024.
