You can prevent this type of injury by using a regular pest control program this growing season. With the wet weather last spring and summer, apple scab was everywhere. This year could be another bad year for scab, unless you plan now to prevent this disease from getting started.
Apple scab is one of the most severe diseases of apple trees and some flowering crabapple varieties.
Apple scab development depends on the length of wet spells and the temperature during these spells. The fungus that causes apple scab favors the humid, temperate climate of New Hampshire. Our favorite apple varieties of McIntosh and Cortland are highly susceptible to the fungus. Soon after, these spots become more circular and turn olive green with a velvety grayish-dark surface. When the velvety surface disappears, the spots appear slightly raised and metallic black in color.