Sunburning resembles anthracnose infection and can be differentiated only by laboratory examination. Sunburning usually occurs on the south or southwest side of a tree, especially on those in exposed locations. Early infection of maple wilt in a large tree, or a girdling root, may resemble this trouble. Norway maples are notorious for producing roots that grow around the tree instead of away from the trunk in the normal manner. As girth increases, the girdling root strangles the tree, causing leaves on one side to scorch, or small leaves sparsely arranged on twigs, and a dying back of branches.
Growth is slow, and the whole tree dies.
A flat side on the trunk usually indicates a girdling root is below ground. When the root can be found early enough and cut off at the point where it begins to curve, the tree can recover. Insect Problems Cottony maple scale, Pulvinaria innumerabilis . This is a brown, oval, soft scale on the bark of the branches of silver and red maple in winter, but in June the large egg masses are formed, and their wax covering resembles a tuft of cotton. The young crawl in July and some of them live for a time on the leaves, but return to the twigs to pass the winter.