Plant Health Initiative

Sudden Death Syndrome - Management

• Plant high-yielding SDS-resistant varieties
  Variety selection is the number one management tool. If SDS is causing defoliation in your field, do not plant highly susceptible varieties. Ask your seed dealer for information on varieties with partial resistance or tolerance to SDS. Growers in the southern areas of the region currently have better options when selecting resistant varieties. It's harder to find SDS resistant varieties in the early maturity groups. This is currently a high research priority for soybean breeders.
  
  Several universities conduct extensive testing of varietal reaction to SDS.  For example, the Southern Illinois University SDS program tests from 800 to over 1000 commercial soybean varieties (MG1 to V) each year for their reaction to SDS. Go to “SDS Variety Trials” for direct links to these test results and others.    

Select varieties with solid agronomics. In many areas resistance to both SDS and SCN is needed.

• Manage Soybean Csyt Nematode (SCN)
  NCSRP researchers are finding that most soybean fields infested with SCN also have SDS. Assume if you have one or the other, you probably have both, and make management decisions based on both.
  
  The SDS fungus can overwinter in cysts of the soybean cyst nematode (SCN), thus increasing its survival ability from season to season. The presence of SCN can alter the reaction of a soybean variety to the SDS pathogen. Management practices to reduce soybean cyst nematode populations are thought to also delay onset of SDS.

• Planting high quality seed in warm dry soil results in better emergence and seedling vigor and less SDS. Seed treatment with fungicides have not been shown to impact late season SDS. Photo credit: United Soybean Board

  Plant early, but in warm, dry soil
  The pathogen prefers cool, wet soil for infection. Move planting dates a week or two after regular early planting dates or till to promote earlier warming of soils. This is easier to do in southern areas of the region than the northern ones, where yield potential may be lost the later a field is planted. NCSRP researchers recommend to plant early as long as a SDS- tolerant variety is planted, but don’t plant a susceptible variety in a field with a history of SDS. If you have a field with a history of SDS, try to plant it later than other fields.
• Use high quality seed
  Quality seed has more vigor and germinates and emerges more quickly. Maintain crop fertility based on soil tests.
• Current seed treatments are not effective against SDS
  Commercially available soybean seed treatment products have not been demonstrated in the field to be effective for reducing severity or incidence of sudden death syndrome. This disease has proven to be a challenging target for fungicides. Newer seed treatment fungicides are under development that may have more potential for management of SDS, but these are not yet registered and available for use.
• Manage soil compaction
  Compaction leads to higher levels of SDS. In some areas, depending on soil type, depth and other factors, ripping or chisel plowing can have a big impact on the amount of SDS that develops.
• Harvest corn fields cleanly
  Research shows that corn is a good crop for harboring the SDS pathogen, especially corn kernels. This is consistent with producers’ observations that severe outbreaks of SDS can occur after a few years of continuous corn. A clean corn harvest may help reduce the risk of SDS, while a high amount of harvest loss increases your risk of SDS the next time you plant soybeans.

These recommendations are the cooperative effort of soybean researchers and Extension specialists throughout the North Central states, funded with soybean checkoff dollars through the North Central Soybean Research Program.