North Dakota State University Partner
SCN is important because:
- SCN causes yield loss in North Dakota soybeans every year.
- SCN continues to spread in the state.
- Soybeans infected with SCN may not show above ground symptoms until they experience a 15-30% yield reduction.
- SCN also impacts dry edible beans.
SCN Management Recommendations
There are multiple tactics for managing SCN:
- Early detection of SCN is very important for effective management.
- Soil sampling at the end of the season is the best way to detect SCN.
- The North Dakota Soybean Council supports an SCN sampling program that covers SCN laboratory fees for soil samples. Contact NDSU Extension for more information.
- Plant a resistant soybean variety if you have SCN.
- Crop rotation with non-host crops, such as corn, cereals, sunflowers, canola, flax, and others is very important for keeping egg levels low. Dry edible beans are hosts for SCN.
- In some cases, a seed treatment may be considered but is not a substitute for crop rotation and resistance.
- If you find SCN, even at a very low level, you need to manage it right away. SCN can explode in our soils and climate, keeping egg levels low is the most effective way to prevent yield loss.
Soil testing tips:
- Where in the field: Concentrate in areas of the field where soil containing SCN is likely to have entered the field; field entrances (on equipment), low areas (flooding) and shelterbelts (wind). Additionally, pay attention to low-yield spots or high-pH areas of the field.
- When: SCN is most likely to be detected at the end of the growing season.
- How often: Soil sampling should be done every year. In fields not known to have SCN, annual sampling will alert you if the nematode is introduced. In fields where SCN is known, monitoring egg levels by soil sampling will help determine if management tools are working.
- Where should soil test samples be sent? Soil tests for SCN are different than soil tests for fertility. Agvise, the NDSU diagnostic lab, and others may have SCN tests.
What to know about rotating different resistant varieties:
- Rotating varieties, even if they both have the same source of resistance, is important.
- Rotating varieties with different sources of resistance is ideal, but may not be practical in our region.
What to know about rotating different sources of resistance:
- Most soybean varieties have the PI88788 source of resistance, which is usually effective in North Dakota.
- A small number of resistant varieties have the Peking source of resistance, which is effective in North Dakota.
What to know about rotating to non-host crops:
- Dry edible beans are susceptible to SCN, and not a preferred rotation crop for SCN management.
- Planting soybeans on soybeans is the most likely way to increase SCN levels quickly, especially if susceptible varieties are used.
- Many crops can be rotated with soybeans to help manage SCN, including: barley, canola, chickpeas, corn, durum, flax, lentils, peas, sugar beets, sunflowers and wheat.
- Rotating away from soybeans for one year is helpful, but two years is better for SCN management.
Nematode-protectant seed treatments:
- Nematode protectant seed treatments may add another tool of protection against SCN, but are not a replacement for planting a resistant variety and crop rotation.
- Seed treatment nematicides may be useful in some situations.
- Additional data is being collected on the efficacy of SCN seed treatment nematicides in North Dakota.