Maple trees are striking landscape additions that can add value, shade and fall color to a property. Some varieties also produce syrup for consumption. Unfortunately, several diseases affect these trees, particularly those that grow in urban areas and are already stressed from soil compaction, poor nutrition and air pollution. Recognizing and understanding the different types of maple tree diseases will help with prevention when it comes to selecting and planting future trees.
Verticillium wilt is a common disease in maple trees and other plants, such as tomatoes, that can be fatal. Also called maple wilt, it is a fungal infection that begins in the root system and works its way up the tree’s vascular areas, from the trunk all the way through the tips of the leaves. This disease causes cankers and spots on leaves, mimicking scorch. The branches can also show signs of infection with unhealthy leaves. Olive-colored streaks can sometimes be present within the sapwood; they are visible when the bark is pealed away from infected limbs. A mild form may only cause poor vigor and little growth.
Anthracnose is an aggressive, obvious disease that causes extensive defoliation, twig death and dieback of shoots. The symptoms can be so severe that it can be misdiagnosed as frost damage or scorch. However, unlike the latter two, which exhibit symptoms along leaf margins, this disease will cause the affected leaves to turn brown in irregular areas. Canker will occur on the trunk and main branches and the veins of the leaves will exhibit a purple hue.
Tar spot is just as its name suggest. Rather than appearing as visible areas on the trunk, branches or stems, it occurs as large black spots on the leaves. This disease attacks several maple tree species.
Root rot is a soil-borne ailment that attacks the roots of a maple tree and moves its way up through the vascular system. The fungus cuts off the tree’s ability to suck up water and nutrients from the soil, thereby choking it to death.
Sapstreak disease affects sugar maples by entering via damaged roots and basal trunk scars, often during the warm summer months. It is often found in trees that were wounded from nearby logging activities. The fungus causes stunted foliage around the crown, gradual branch dieback and a streaked gray stain occurring on the lower boll and roots. Trees usually die about three to four years after they become infected.