University of Missouri University Partner
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 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?
1721 East Campus Loop
University of Missouri
Columbia, MO 65211-5315
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