|Grau, C - U OF WISCONSIN, MADISON|
Submitted to: Soybean Disease Compendium
Publication Type: Book / Chapter
Publication Acceptance Date: August 10, 1999
Publication Date: N/A
Technical Abstract: Sclerotinia stem rot of soybean was first reported in Hungary in 1924 and since has been reported in Argentina, Brazil, Canada, India, Nepal, South Africa, and the United States. At canopy level, wilting and eventual death of upper leaves, the first canopy-level symptoms of Sclerotinia stem rot, generally develop at growth stages R2 and R3. Leaves become grayish-green as necrosis begins, and eventually turn brown and frequently remain attached to the stems. The causal fungus, Sclerotinia sclerotiorum, produces hard, black, irregularly shaped sclerotia (2 to 22 mm in diameter). A sclerotium may produce one to many cup-shaped apothecia, borne on slender stipes. Sclerotia of S. sclerotiorum survive in the soil for long periods. Soybean cultivars differ in reaction to S. sclerotiorum.