Soybean Sudden Death Syndrome
Sudden Death Syndrome (SDS) in soybeans has been appearing this year in the Corn Belt and reports indicate that it appears it is widespread. Heavy rains and late-summer flooding is thought to be at least somewhat to blame for the widespread SDS pressures.
SDS is caused by the fungus Fusarium virguliforme, which causes a unique set of symptoms of soybean. It is closely related to Fusarium solani, regarded as a chronic pathogen of many legumes such as alfalfa and soybean. The SDS pathogen likely arose as a mutant from the general population and is a much more virulent form of the species.
According to XB Yang, Department of Plant Pathology, Iowa State University, this year has had one of the worst epidemics since the disease was found in Iowa in 1994.
For more on management of this disease, see: http://www.extension.iastate.edu/CropNews/2010/0813yang.htm
Also, this online seminar for CCAs on Sudden Death Syndrome: https://www.certifiedcropadviser.org/videos/play/certified/education/soybean-sudden-death-syndrome.flv