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SCN is important in Missouri because:

  • SCN is present in approximately 85% of Missouri fields.
  • There can be as many as 6 generations per growing season.
  • SCN is adapting to resistance.
  • SCN can reproduce on PI 88788, the most widely used source of resistance in the state.
  • SCN is becoming more aggressive on resistant varieties and this is reducing yield.
  • Yield loss occurs in the absence of symptoms (up to 30%).
  • SCN can survive under adverse conditions in cysts. 

SCN Distribution

SCN Management Recommendations

There are multiple tactics for managing SCN:

  • Rotate to non-host crops
  • Rotate resistance sources
  • Rotate varieties with the same resistance
  • Consider a nematode-protectant seed treatment (test it for yourself)
  • Manage weedy hosts
  • Maintain plant health

Soil testing tips:

  • Where in the field? To determine if SCN is present in a field, take samples from the top 8-inches of soil in the root zone, a sample from 10-acre sections with 10-20 subsamples and collect samples in a zig-zag pattern along the rows. To sample a problem area within a field, take samples from the top 8-inches of soil in the root zone and collect several subsamples from margins of symptomatic areas
  • When? After the harvest of a soybean crop or in the spring before planting soybeans
  • What? SCN egg count test
  • How often? Every three years
  • Where should soil test samples be sent?
    SCN Diagnostics
    1721 East Campus Loop
    University of Missouri
    Columbia, MO 65211-5315

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What to know about rotating different resistant varieties:

  • Not all resistant varieties perform equally
  • Growing the same resistant variety repeatedly can lead to an increase in SCN reproduction on that variety

What to know about rotating different sources of resistance:

  • Ask your seed dealer the source of SCN resistance in the soybeans you are planting
  • Repeated use of the same resistance source can lead to SCN population shifts
  • To preserve their effectiveness, rotate the source of SCN resistance
  • An SCN (HG) type test can help you determine how effective a source of resistance is against SCN in your field

What to know about rotating to non-host crops:

  • SCN cannot reproduce in the absence of a suitable host
  • Rotate to non-host crops such as alfalfa, barley, canola, corn, cotton, forage grasses, oats, rye, sorghum, tobacco, or wheat

Nematode-protectant seed treatments:

  • Nematode-protectant seed treatments do not eliminate SCN from your field and can be variable in their reduction of SCN
  • If considering a nematode-protectant seed treatment, test it in your own field
  • Nematode-protectant seed treatments should always be used in conjunction with SCN resistant varieties

Other need-to-knows about SCN:

  • Soil sampling is the best way to determine SCN population densities in your field
  • Reduce plant stresses that can increase SCN damage such as nutrient deficiencies, insect damage, or other diseases
  • Weed management is critical because many weeds can be SCN hosts
  • Once present in a field, eradication of SCN is not possible

University of Missouri Experts

Melissa Mitchum | Nematologist

University of Missouri


Kaitlyn Bissonnette | Extension Plant Pathologist

University of Missouri