Pezicula malicorticis (H. Jacks.) Nannf
Distribution: Uncommon in the east, but has been reported in Canada, MI, and some New England states.
A distinct margin develops between healthy and diseased tissue, which causes the bark to crack around the infected area.
Gary Grove, Washington St. Univ.
Branch lesions first appear as small, circular spots that are purple or red when wet. As lesions enlarge, they become elliptical, sunken and turn orange to brown. A distinct margin develops between healthy and diseased tissue, which eventually causes the bark to crack around the infected area (A). The infected bark tissue over the canker separates into small pieces and curls upwards from the lesion. On older cankers, the bark sloughs off leaving only the last fibers behind. These fibers run lengthwise across the lesion and their appearance as such has often been referred to as "fiddle strings". Anthracnose cankers typically do not enlarge during their first year of growth.