Butternut canker (Ophiognomonia clavigignenti-juglandacearum) is a fungal pathogen. It is a native of Asia and was first detected in Wisconsin in 1967.
Sirococcus clavigignenti-juglandacearum is a mitosporic fungus that causes a lethal canker disease of Butternut trees but can aparasitize other members of the Juglans genus.
For more information about this plant pest, see the CABI data sheet.