Perennial canker (also called Valsa canker, Cytospora canker, Leucostoma canker, and peach canker) is one of the most common and debilitating diseases of peach trees in the Northeast. It also occurs regularly on sweet cherry, apricot, and plum trees, but is not generally as damaging on these crops. Successful long-term production of peaches is seldom possible if the disease is not controlled.