Diseases of the Silver Maple Tree
Native to North America, the silver maple (Acer saccharinum) grows in USDA hardiness zones 3 to 9. The tree can grow to 80 feet in height by 60 feet in width, with a thick trunk measuring 5 to 6 feet across. Silver maples experience some diseases, but are generally hardy trees. Homeowners can plant them with little serious concern over disease management.
Most types of maple, including the silver maple, can contract Anthracnose, a disease caused by many different fungi. Maple leaves develop purple lines along the veins and brown spots in between the veins. The leaves fall prematurely from the tree. Twigs and branches less than 1 inch thick die back. Since the fungus can overwinter in the ground, TreeHelp.com recommends raking fallen leaves each year. Gardeners can treat this disease with fungicide containing mancozeb and prune to increase air circulation, which moves fungus through the tree.
Verticilium wilt can kill maple trees if not treated, and displays its symptoms most often in the summer. Affected maple leaves turn yellow or brown; leaves on entire branches may wilt at once. Branches and twigs die back. The disease can target one area or side of the tree, with other areas seeming fine. Sometimes, verticilium wilt occurs once while other times the tree gets re-infected. Growers cannot treat this disease with fungicide. To help your maple tree, prune annually to increase air circulation and provide the tree with regular water when the soil dries out. Trees with minor infections can recover. If the tree worsens each year or dies, cut it down.
Tar spot targets silver maple, among other maples. Rhytisma acerinum and Rhytisma punctatum fungi cause this disease. Affected leaves develop dark black, raised spots in the midsummer. While the disease looks ugly, it isn't serious and won't harm the tree's health. Homeowners do not need to treat this disease with a fungicide; however, if they wish, one containing mancozeb or triadimefon will cure tar spot. Rake and dispose of leaves when they fall since fungi overwinters in the leaves.