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Management of SCN

Although SCN is a serious soybean pest, it can be managed profitably. Crop rotation coupled with SCN-resistant varieties are the cornerstones for the management of SCN. Non-host crops, such as corn, sorghum, sunflower, and alfalfa can reduce SCN population densities each year they are grown.

Providing a plant the best possible growing conditions will reduce stress and yield losses due to SCN. Maintain optimum soil fertility to optimize plant growth and development. Weed control not only reduces plant stress, but some weeds act alternative hosts for SCN. Disease and insect control maintains plant health and minimizes damage due to SCN.

The number of SCN in a field can be greatly reduced through proper management, but it is impossible to eliminate SCN from your field once it has become established. Therefore you must choose appropriate management practices so that you can continue profitable soybean production.

Management recommendations based on soil test results

NOTE: Egg counts are reported as eggs per 100 cubic centimeter (about ½ cup) of soil and are only estimations of actual SCN population densities.

Infestation category

Soybean not next crop to be grown

Soybean next crop to be grown

Management Recommendation

No SCN eggs detected



No management strategies are necessary. However, not finding SCN in a soil sample does not prove that it is not present in the field. Follow-up sampling is recommended to check for SCN infestations in future years.


1 - 4,000

1 - 2,000

If this is first discovery of SCN, follow the rotation described below starting with Year 1 the next time soybeans are to be grown. If Years 1 – 4 of the rotation described below already have been completed, continue with Year 5 of the rotation.


4,001 - 16,000

2,001 - 12,000

Begin Year 1 of the rotation described below the next time soybeans are to be grown.




Grow several years of a nonhost crop and sample field again every fall to monitor decrease in SCN population densities.


Suggested crop rotation to decrease population densities of SCNYear 1 - SCN-resistant soybean with PI88788 source of resistance

Year 2 - Nonhost crop (such as corn, oats, alfalfa)

Year 3 - SCN-resistant variety different than the one planted in Year 1.
Note: If an SCN-resistant soybean variety with resistance from a source other than PI 88788 is not available for use in Year 3, grow a soybean variety with SCN resistance derived from PI 88788 that is different from the one that was grown in Year 1. Grow the exact same PI 88788 SCN-resistant soybean variety in Years 1 and 3 only if no other SCN-resistant soybean varieties with PI 88788 or other sources of resistance are available.

Year 4 - Nonhost crop (such as corn, oats, alfalfa)

Year 5 - SCN-resistant variety different than the ones planted in Year 1 and Year 3, or susceptible soybean.
Note: What determines whether a resistant or a susceptible soybean variety should be grown in this year? Almost all SCN-resistant soybean varieties available to Iowa and other growers in the North Central United States and in Canada have the PI 88788 SCN resistance (“PI” stands for plant introduction). Because SCN-resistant varieties allow low level of reproduction, SCN populations can become “resistant to the resistance” as resistant varieties are repeatedly grown, especially if only one source of resistance is used.

Growers concerned about this possibility can prolong the effectiveness of a single source of SCN resistance by growing a susceptible (non-resistant) variety when SCN numbers are low. But SCN causes much greater damage and seems to reproduce at a greater rate in hot, dry growing seasons than in years with adequate to excess rainfall. So if a severe drought is anticipated, growers might opt not to grow a SCN-susceptible variety in an SCN-infested field, even if SCN population densities are low.

Year 6 - Non-host crop (such as corn, oats, alfalfa)


Cover of the soybean cyst nematode management guideAn excellent reference is the Soybean Cyst Nematode Management Guide originally published by the SCN Coalition and recently updated and reissued by the North Central Soybean Research Program (NCSRP).

The fifth edition is available to read or print in pdf format»