UW Soybean Plant Health
SCN |
Disease Cycle |
Detecting SCN |
What is the HG type test? |
SCN-resistant soybean varieties |
Managing SCN |
SCN links |
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Checking the root system for signs of SCN. |
Crop rotation with nonhosts and with SCN-resistant varieties are the foundation of a SCN management plan. SCN populations are suppressed significantly in fields where two or more years of a nonhost crop is planted. Good nonhost crops are corn, small grains, alfalfa and red clover. Edible beans are a host for SCN.
Soybean variety selection and rotation
The number of SCN-resistant varieties increases every year. Some SCN resistant varieties are also resistant to brown stem rot, white mold, and Phytophthora root rot. SCN does not appear to break down brown stem rot resistance. The Wisconsin Soybean Variety Test Results (UW-Extension publication A3654) has information on performance of specific soybean varieties in SCN-infested fields.
Several sources of resistance are used by soybean industry:
- PI 88788 (95% of varieties)
- Peking
- Cyst-X
These varieties effectively suppress the reproduction of the soybean cyst nematode. However, there is now known to be races of SCN—genetic forms of SCN found that can reproduce on soybean varieties with the PI88788 source of resistance. These SCN populations will affect the performance of specific SCN-resistant varieties. Therefore, it's important to rotate SCN-resistant varieties with different sources of resistance. If other sources of resistance are not available, rotate within varieties with PI88788 resistance.
Crop rotation recommendations for Wisconsin
Recommended 6-Year Crop Rotation Plan to Manage SCN |
| Year 1 - a nonhost crop such as corn |
| Year 2 - SCN-resistant soybean with PI 88788 source of resistance |
| Year 3 - a nonhost crop (recheck the population level at the end of season) |
| Year 4 - SCN-resistant variety different than the one planted in Year 2, such as "Peking" source of resistance. |
| Year 5 - a non-host crop (recheck the population level at the end of season) |
| Year 6 - a susceptible variety if soil analysis shows that SCN density is below threshold level, otherwise plant a non-host crop or a SCN-resistant soybean different from the one planted in Year 2 or 4. |
For a good discussion on how to use SCN-resistant varieties see:
So Many Choices, So Much Potential: Soybean Cyst Nematode-Resistant Soybean Varieties by Greg Tylka, Iowa State University (pdf)
Tillage
We have some evidence that SCN is not as damaging in no-till systems.
Weed control
Broadleaf weeds common to Wisconsin soybean fields are not hosts to SCN. SCN-resistant soybean varieties withstand more weed pressure than susceptible varieties.
Information from this site can be copied and distributed for educational use. Please credit the source with our name and URL: University of Wisconsin-Madison, Departments of Agronomy, Entomology, and Plant Pathology at www.plantpath.wisc.edu/soyhealth.