Apple Scab

Apple scab is a fungus and occurs on apple and crabapple trees.  In late fall to early spring round black dots appear primarily on infected leaves from the previous year.  Spores are released from these spots in the spring and blown by wind or splashing rain to new growth on nearby trees.  The fungus infects leaves, fruit, petioles, and blossoms of the tree.  Symptoms on infected leaves initially appear as velvety brown to olive colored spots then turning black.  Heavy defoliation may occur, causing trees to be less attractive, reduce growth and yield, and increases susceptibility to winter injury.  Fungicide applications or injections may be necessary to control apple scab.