Canker Diseases - Hardwoods
Canker on aspen stem caused by Entoleuca mammata.
Saperda insect galls and cankers starting to form at the location of the gall (two stems on right).
Perithecia are produced in clusters within black/grey stroma on the older cankers.
Perithecia of Entoleuca mammata in stroma produced on the surface of an old canker. A part of the stroma has been cut away to show the base of the perithcia within the stroma. Asci produce ascospores that cause infection in wounds made on aspen.
Conidial pillars (hyphal pegs) and areas producing asexual spores of Entoleuca mammata on surface of a canker. Conidia do not appear to have a role in infection.