August 7, 2006
Sudden Death Syndrome (and Look-alikes)
Soybean Sudden Death Syndrome (SDS) became very evident in some soybean fields within the last week. While generally is has been found in parts of fields (generally the lower, wetter areas), in some instances it is nearly field wide.
Be sure to examine the plants closely to differentiate between SDS and brown stem rot (BSR) as both diseases can exhibit the same leaf symptoms. I have also been in a field where white mold was occasionally showing the same leaf symptoms.
Nothing can be done for plants with SDS, BSR, or white mold. However, accurate identification of the disease can be of assistance in variety selection the next time soybeans are grown in the field. An excellent description of SDS can be found on pages 152 – 153 of the August 19, 1996 (ten years ago!) Integrated Crop Management (ICM) Newsletter or at http://www.ipm.iastate.edu/ipm/icm/1996/8-19-1996/scoutsds.html. An excellent picture of the leaf and stem symptoms of brown stem rot can be found on page 113 of the September 13, 2004 ICM Newsletter or at http://www.ipm.iastate.edu/ipm/icm/2004/9-13-2004/falldis.html. White mold is addressed on page 193 of the July 3, 2006 ICM Newsletter and at http://www.ipm.iastate.edu/ipm/icm/2006/7-3/whitemold.html.
If you have any questions, please feel free to contact the Iowa State University Extension Office.
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