We are seeing sudden death syndrome (SDS) in soybean fields across Iowa. Caused by the soilborne fungus Fusarium virguliforme, SDS is among the most destructive soybean diseases in the state. There are no in-season management options, but documenting where the disease occurs and noting how different cultivars perform will be valuable for making future management decisions.
It’s important to confirm that symptoms are SDS and not a look-alike disease such as brown stem rot(BSR) or red crown rot (RCR).
- BSR can look similar to SDS from above, but splitting stems will reveal a brown discoloration in the pith, which does not occur with SDS.
- RCR causes reddish discoloration at the crown and small red structures (perithecia) on the lower stem.
Important: Red crown rot has not been identified in Iowa. If you suspect RCR, please contact Daren Mueller at dsmuelle@iastate.edu and/or send a plant sample to the ISU Plant and Insect Diagnostic Clinic for confirmation.
Correct diagnosis is essential for tracking disease distribution and making future management decisions.
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- Extension Plant Pathologist