Butternut Canker and Others

Canker Diseases - Hardwoods

Butternut Canker


Cankers on butternut caused by Ophiognomonia (old name: Sirococcus) clavigignenti-juglandacerarum. The bark has been removed to show the cankered areas.

butternut cross section

This cross section of a butternut tree shows cankers were produced for many years. At first only a few cankers were on the tree and the tree recovered. However, in later years the number of cankers and size of the cankers increased. Coalescing cankers kill butternut trees.

Butternut canker

Pycnidia form on cankered stems producing conidia. No sexual state is known.


Black Knot of Cherry


Main stem of cherry with black knot, Apiosporina morbosa.


Branches of cherry with black knot.

Black knot

Perithecia are formed in the black stroma producing ascospores that cause new infections.


Diamond Willow


Cankers on willow stems


Cross section through a canker on willow showing 4 perennial cankers. The white regions are the only areas where the sapwood is still alive.


Golden Canker

Golden Canker

Canker caused by Aurantioporthe (old name: Cryptodiaporthe) corni on the main stem of alternate leaf dogwood. The canker has a bright golden coloration. The dark reddish bark is the natural color ofthe bark and the area not yet affected by the canker causing fungus.

Golden canker

Pycnidia and perithecia form on the cankered stems.