Coryneum blight -- also called shot hole disease, California blight, peach blight or pustular spot -- is caused by the fungus Coryneum carpophilum. In Colorado it affects mainly peaches and apricots, and to a lesser degree sweet cherries.
Severe foliar shot holing may weaken a tree, while the most apparent damage is infection of the fruit.
Once established in an orchard, Coryneum blight is difficult to eradicate. Bud and twig lesions may continue to produce spores for two to three years, but the fungus does not overwinter in old infected leaves.
A conscientious program of chemical control and removal of dead wood is necessary to eradicate the disease.
Please see the fact sheet "Coryneum Blight."
