Sudden Death Syndrome ( SDS ) can only be differentiated from Brown Stem Rot ( BSR ) by cutting open the lower stem and root crown to see if there is any grey brown oily appearance visible in the lower stem and root like that shown in the left plant stem in the above photo.The right plant stem is of a normal healthy plant.BSR ( Brown Stem Rot will not express this symptomology but instead display a brown discolouration in the pith tissue - see photo below ) PHOTO COURTESY OF SUZIE DEVOLDER - Chatham Diagnostic Lab
Brown Stem Rot ( BSR ) differs from SDS in that when plants are sliced open the pith tissue appears brown as shown above.( double click on the photo for a better view )PHOTO COURTESY OF SUZIE DEVOLDER - Chatham Diagnostic Lab
This is another shot showing how BSR infects the plants pith tissue turning it brown.The top plant stem shows the BSR infection while the bottom plant stem is healthy.If you take note of the leaf symptomology for both BSR and SDS in the above photos you'll see that these two diseases cannot be differentiated by leaf tissue death alone as they both appear relatively the same.The only true way to truly differentiate them is to cut stems open and take note of how the infection is expressing itself.Both diseases usually start to show evidence of upper leaf tissue death sometime in early August as pod fill progresses.Through the use of molecular markers Pioneer has been able to breed several highly resistant lines to both SDS and BSR.If either of these diseases is a concern of yours talk to your Pioneer sales about varieties that could help resolve your problem.( double click on the above photo for a better view )PHOTO COURTESY OF PIONEER IMAGE LIBRARY - DESMOINE IOWA