University of Arkansas Partner
SCN is important in Arkansas because:
- SCN is a yield-limiting pest in soybean.
- It has been reported in every soybean-producing county of the state.
- SCN is one of three important plant-parasitic nematodes of soybean in Arkansas. The others are southern root-knot nematode and reniform nematode.
SCN Management Recommendations
There are multiple tactics for managing SCN:
- Crop Rotation
- Host Plant Resistance
- Nematicides: Fumigants and Seed-Applied Non-Fumigants
- Tillage Practices
- Agronomic Practices
What to know about rotating different resistant varieties:
- Soybean varieties with resistance to SCN or root-knot nematode are not resistant to all biotypes of SCN or species of root-knot nematode.
- Soybean varieties are often only resistant to one or two SCN biotypes or species of root-knot nematode, thus resistant varieties should be selected based on biotype or species or root-knot nematode on a field by field basis.
- Tolerance is not a “type” of resistance and growing tolerant varieties sustains or, with some varieties, increases nematode population densities.
What to know about rotating different sources of resistance:
- There are limited sources of resistance to many of the SCN biotypes and to southern root-knot nematode in commercial soybean varieties.
- Some soybean varieties with the same genetics are marketed with a different variety of names by different seed companies, but all contain the same source of resistance to SCN.
What to know about rotating to non-host crops:
- Crop rotation with any crop other than soybean is an excellent way to manage populations of SCN.
- Corn, cotton, soybean, and some grain sorghum hybrids are poor rotation crops for southern root-knot nematode as they can maintain or in some cases increase nematode population density.
- Rice is an excellent rotation crop for both root-knot and SCN in fields where a flood is maintained for the majority of the cropping season.
- Peanut is an excellent rotation crop for both southern root-knot and SCN.
- A rotation sequence of 2 to 3 years out of soybean may be required to reduce SCN population densities below damage threshold.
Nematode-protectant seed treatments:
- There are several seed-applied nematicides, made up of both chemical and biological active ingredients, marketed for use against soybean nematodes.
- Seed-applied nematicides may provide some protection of the developing seedling, but do not provide season-long nematode control.
- Seed treatments are most beneficial when used in areas with a low population density of SCN and when paired with moderately resistant cultivars.