SDS Recently Spotted in Central Iowa
By Nora Schultz, Sales Agronomist, CCA
Soybean sudden death syndrome or SDS is a fungal disease that has increasingly become a focus point for soybean producers. Found originally in Arkansas over 40 years ago, the disease can be found in most of the North Central region of the U.S. including the states of Iowa, Minnesota, Nebraska, Missouri and Illinois. The impact of infection can vary widely, from almost unnoticeable to nearly complete yield loss in heavily infected areas. Yield loss is determined greatly by when symptoms begin to express themselves. The earlier in reproductive stages the higher the potential losses as flowers and pods are aborted, causing a total loss of grain. Yield impact is lower when symptom development occurs later during pod fill, causing a reduction in grain size.
What is it?
- SDS is caused by the fungus Fusarium virguliforme.
- Infection occurs between planting and seedling emergence.
- Infection is more prevalent when the seed is planted in cool, wet and/or compacted conditions, which slows emergence and prolongs exposure to the fungus.
- When scouting your soybean fields, look for areas that are developing a yellow, golden or tan discoloration to them. Common areas to start include headlands (compaction zones) and wet areas of the farm (low points or side hill seeps).
- Foliar symptoms begin to show in late summer with small bright green patches on the leaves first; which progressively get larger and yellow, eventually killing them. Splitting the stem will reveal a white pith, if pith is brown, it could be BSR (brown stem rot).
- There is no foliar cure, but management of SDS starts with good documentation of where past infections have occurred. This will help your seed dealer to correctly place a more tolerant variety, partnered with specific seed treatments.