Sudden Death Syndrome in Soybean... What to know...

Sudden Death Syndrome (SDS) is a fungal disease that often becomes apparent in fields around the late July to mid August timeframe. Although the visual symptoms are showing up now, the infection occurred quite a while ago.SDS typically infects soybean roots shortly after emergence while soybeans are very young. Infection is favored by cool and wet soils when soybeans are in the seedling stage. The fungus (Fusarium vulguriforme) then grows on the roots as the plants develop. About the time flowering occurs in plants, the increased stress on the soybeans allows for SDS to begin to flourish. Toxins are released and pushed up the stems into the leaves showing the characteristic browning as seen in the photo above. Rain or irrigation during the reproductive phases can intensify the foliar symptoms caused by the root infection. The foliar necrosis and preceding root infection cause eventual death of the plant.In many cases with SDS, the blue growth found on the outside of the roots can be seen as in the photo above. In other cases, it is important to split the stems at the base on diseased plants to ensure that SDS is the true cause of the symptoms. Brown stem rot or charcoal rot can also cause similar symptoms to SDS but will have very visible brown pith inside the stem or black growth on the outside of the stems. When SDS is the cause, a split stem will still have a white pith and green/white vascular system.Timing of the onset of foliar symptoms will determine how much yield impact is seen. SDS symptoms showing up later in the season often have reduced impacts on yield. Nematodes, compaction, and soybean varieties can have impacts on the severity or frequency of this disease. Foliar fungicide applications will not control SDS. Any management for this disease needs to begin this fall and next spring. Choosing soybean varieties that have genetic resistance to SDS is a key first step to managing this disease. Secondly, choosing a good seed treatment like ILEVO can help protect against SDS. ILEVO provides protection against SDS and nematodes providing two methods of protection against development of this disease. Utilize ILEVO with your integrated SDS plan to manage this disease.