Late maturity cultivars were believed to be more diseased because of lush vegetative growth and later flowering. Wisconsin evaluated soybean cultivars for reaction to Sclerotinia stem rot in 1992. Cultivar performance in the presence of Sclerotinia stem rot is influenced by inoculum density, cultural practices, and climate. In most cases, yield was inversely related to the percent incidence of Sclerotinia stem rot, but there were exceptions. Specific cultivars may express a high incidence of Sclerotinia stem rot, but produced an above average yield.
Cultivars differ in the ability of infected plants to set seed.
Two cultivars with similar yield potential and disease incidence can differ in yield. There is evidence that some cultivars may compensate for diseased plants better than others. The crop canopy can greatly affect environmental conditions needed for infection and for subsequent disease development. Thus, cultural practices that modify the canopy environment have a potential impact on the incidence and severity of Sclerotinia stem rot. Wisconsin studies conducted in the mid 1980s showed the incidence of Sclerotinia stem rot to be greater in narrow row than wide row systems.