Soybean Cyst Nematode Populations Across the Cornbelt 2021-2022
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Agronomy Research Update
Written by Mary Gumz, Pioneer Agronomy Manager
Key Findings
- Potentially damaging levels of soybean cyst nematode were found in soybean fields in several Midwestern states.
- 35% of fields sampled had SCN population levels capable of causing high levels of crop damage.
- Farmers can reduce the risk of soybean cyst nematode damage by planting resistant varieties, rotating between PI 88788 and Peking resistance sources, and using a nematode protectant seed treatment such as ILEVO® HL.
Study Description
- 2144 soybean fields in Iowa, Minnesota, Missouri, Indiana, Illinois, Michigan, Wisconsin, Kansas, North Dakota, South Dakota, Nebraska, Delaware, Maryland and Ohio were sampled to determine soybean cyst nematode (SCN) pressure in 2021 and 2022.
- Soybean fields were sampled during the growing season at a depth of approximately 6 inches. Subsamples from across the field were blended into a composite soil sample and submitted to a nematode testing laboratory.
- Samples were analyzed using a sugar-floatation method and sieved through a 120-mesh sieve for adult cysts and a 500-mesh sieve for cyst larva not yet in the root system.
| SCN Population (Eggs/100cc Soil) |
Yield Loss with No Management |
Loss/A 70 bu/A $14/bu |
|---|---|---|
| Zero | - | |
| Low (<500 eggs) | Unlikely | |
| Moderate (500-2000) | ~10% | $98 |
| Mod High (2000-5000) | ~20% | $196 |
| High (5000 – 8000) | ~50% | $490 |
| Very High (>8000) | Very High | $882 |
Figure 1. Potential lost revenue per acre if no SCN management was done in a soybean field.
Strips of SCN-resistant and non-resistant soybean varieties in a SCN-infested field showing damage to the non-resistant varieties.
- Potential for SCN damage describes the likely damage to a SCN-susceptible soybean variety with no SCN management performed (i.e., no varietal resistance or seed treatment). and is based primarily on the number of eggs per 100 cc of soil. Some samples with very high adult or larva counts may be rated as a higher potential damage class than they would have been if based on egg counts alone (Figure 1).
Results
- SCN infestations were found throughout the study area, with over 80% of fields sampled having some level of SCN infestation (Figure 2).
Figure 2. Soybean cyst nematode pressure levels across all 2144 soybean fields sampled in 2021 and 2022. Click here or on the image above for a larger view.
Figure 3. Distribution of SCN populations across the Cornbelt in 2021 and 2022. Click here or on the image above for a larger view.
- 35% of fields sampled had SCN population levels capable of causing moderately high to severe crop damage (Figure 2).
- All areas sampled in this study were within the known geographic range of SCN in the U.S. (Tylka and Marett, 2021).
SCN Management Recommendations
- Test soybean fields for SCN.
- If no infestation is found, use good management practices and rotate a combination of resistant or susceptible varieties in the field.
- If SCN is found:
- Plant SCN resistant soybeans. Rotate between varieties with PI 88788 resistance and Peking source resistance.
- Consider using a nematode protectant seed treatment such as ILEVO® HL. The LumiGEN™ system offering includes ILEVO® HL fungicide/nematicide seed treatment, which has activity against SCN. A Pioneer study including 193 on-farm trial locations found an average yield response of 4.9 bu/acre in high SCN fields when ILEVO® HL fungicide/ nematicide seed treatment was added to the standard fungicide and insecticide seed treatment package (Fluopyram use rate of 0.15mg ai/seed).
- Rotate to non-host crops such as corn.
- Control alternate weed hosts such as henbit, purple deadnettle, field pennycress, shepherd’s purse, small-flowered bittercress and common chickweed.
SCN on soybean roots
Reference
- Tylka, G.L., and C.C. Marett. 2021. Known distribution of the soybean cyst nematode, Heterodera glycines, in the United States and Canada in 2020. Plant Health Progress. 22:72-74.
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