Ultralawn, Inc. 1055 East 260th Street Euclid, Ohio  44132 (216) 731-7756 (440) 951-3738 Lawn Problems   We welcome the opportunity to answer your questions   Scab   Scab is the most destructive fungal disease affecting flowering crab apple trees. It is most severe in areas that are cool, humid and rainy. It results in leaf blotches, leaf yellowing and premature leaf drop. Fruit may develop dark, leathery spots that affect its ornamental value. Symptoms and Life Cycle: Early in the spring, infected leaves from the previous season which have been lying on the ground all winter produce spores. Primary infections on new leaves develop when rain causes the spores to be forcibly ejected. In mid-May to early June, infections begin to develop on the underside of leaves, as these are the sides first exposed when the fruit buds open. The young spot or lesion has rather indefinite margins, but within two to three weeks the boundaries become very distinct and the entire lesion becomes velvet-green in color, indicating spore production. These spores are spread by rain and wind and will infect the newly developing fruit and other leaves throughout the rest of the summer and into the fall. If infection occurs in late summer or early fall, rough black, circular lesions may develop on the fruit in storage. These lesions are usually very small, varying in size from tiny specks to 1/4-inch in diameter.   Management: Control of scab is possible through fungicide treatments. Copyright 2010-2011 Updated December 9, 2011 About • Lawn Care • Trees/Shrubs • Pest Barrier • Questions • Contact