Submitted to: World Wide Web New Crops Center Purdue University Bulletin
Publication Type: Experiment Station
Publication Acceptance Date: 9/8/1998
Publication Date: N/A
Citation: N/A Interpretive Summary: Soybean yield losses due to sudden death syndrome (SDS) occur regularly. This relatively new disease caused by a toxin producing form of the Fusarium solani fungus has become a serious disease of soybeans in the southern and midwestern states. This bulletin summarizes the cardinal characteristics and disease cycle associated with SDS of soybeans. Diagnostic characteristics associated with the fungal pathogen, soybean disease symptoms, and disease control strategies are included in this bulletin. The information will be useful to extension and crop specialists in diagnosing and recommending control measures for soybean production where the disease is a major problem.
Technical Abstract: Soybean yield losses due to sudden death syndrome (SDS) occur regularly. This relatively new disease caused by a toxin producing form of the Fusarium solani fungus has become a serious disease of soybeans in the southern and midwestern states. Abundant moisture during the early reproductive stages of the host enhance SDS damage. Root infections are common and occur early, but seldom advance into the taproot prior to the flowering stage. Delayed planting and management practices that improve plant health during the flowering period help reduce disease losses. Results of yield loss and foliar symptom studies with diverse soybean germplasm sources indicate the disease can be very destructive. Most soybeans tested to date are somewhat susceptible to the disease. Only a few soybean varieties derived from a narrow genetic base have been identified as having some degree of resistance. Equally important, variety reaction to SDS appears to be conditioned to some degree by the soybean cyst nematode (SCN). Some SCN race 3 resistance genes are linked to SDS resistance genes, but SCN race 14 resistance is linked to increased SDS susceptibility. In addition, SDS evaluations of selected germplasm identified P.I.437654 (resistant to all known SCN races) as highly susceptible to SDS. This information will permit pathologists and breeders to employ and recommend control strategies that can minimize important yield losses caused by SDS.