Research on the soybean disease SDS or "Sudden Death Syndrome" has identified Indiana isolates of Fusarium solani capable of causing both root rot and leaf symptoms. Highly virulent isolates obtained from soybeans with SDS symptoms produced the rarely observed Nectria sexual stage in culture. This Nectria/Fusarium association has not been identified previously with soybean isolates of the fungus. Although ascospores were not required for hypocotyl infection, virulence of the F. solani isolates that produced Nectria in culture was higher than that of other isolates. Identification and production of Nectria ascoma stage in culture provides an excellent opportunity to initiate screening of soybean germplasm for SDS resistance.

The majority of fungal pathogens causing yield losses occur regularly in most soybean fields each year. It is also evident that several fungi infect plants long before disease symptoms are recognized. The early plant infections not only serve as an important inoculum source for late season disease development, but have an impact on the performance and yield potential of the soybean host. Latent development of these fungi can be triggered by factors such as host resistance and environmental conditions. The USDA-Purdue Integrated Pest management System has demonstrated that late season disease development and seed health are influenced by crop rotation, tillage operation, and weed control. This work demonstrated that latent infections by Diaporthe, Phomopsis, Colletotrichum, Septoria, Cercospora and Macrophomina represent a complex of interactions that reduces seed yield and quality