When the main stem is affected near the soil line, the entire plant may be killed. Sclerotia survive in the soil for several years. Ascospores commonly colonize senescent petals that are attached or detached. The fungus may remain viable in blossoms for a month. Plant surfaces in contact with blossoms must remain continuously wet for 48 to 72 hours for infection to occur.
White mold is generally more severe in fields with heavy canopies.
Other plant surfaces, especially the lower stem near the soil surface, appear to be susceptible, even before flowering. It is possible that some sclerotia germinate directly and infect the crown of a plant through mycelial invasion. Sclerotinia sclerotiorum infects many cultivated plants and weeds. Ascospores may blow in from other fields and start epidemics in beans. Rotation with nonhosts, such as small grains and corn, may reduce soil inoculum.