Submitted to: Illinois Agricultural Pesticides Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 10, 1999
Publication Date: N/A
Technical Abstract: Illinois often ranks number one among states in soybean production with over 10 million acres planted in 1998. Diseases often limit maximum yield potential. One disease, sudden death syndrome (SDS), has received more attention recently and has become a concern to Illinois soybean growers and commercial seed companies. Disease symptoms include mottling, interveinal chlorosis and necrosis on the upper leaves at flowering and also root and crown rot, vascular discoloration of stems, defoliation and pod abortion. The disease is caused by a soilborne fungus that infects plant roots. Field patterns of SDS vary from strips, distinct patches, to large extensive patches that coalesce. The disease is normally seen on plants during the mid to late reproductive growth stages often from mid to late August. In 1998, a state-wide survey showed that SDS occurred in all agricultural statistics districts in Illinois with some districts having as shigh as 43% of the fields with at least some SDS. It is not known if the pathogen is spreading or if changes in weather conditions, tillage patterns, varieties, a combination of these and/or other factors have contributed to increases in SDS occurrence over the state. The best recommendation at this time is to plant less susceptible varieties.