Common Diseases that Affect Deciduous Trees and Shrubs

Just as plants and lawns acquire diseases, so do our trees and shrubs. From physical deformities to poor leaf color, here are common diseases that affect deciduous trees such as maple, oak and hickory trees.

Deciduous Tree Diseases

Anthracnose fungus disease occurs in the late spring and early summer, especially if spring is cool and wet. Anthracnose is most prominent on the lower half of the tree and shows spots or lesions that range from tan to reddish brown or black. Root feeding is strongly recommended to help the tree combat the disease. 

Cedar Apple Rusts or Cedar Rusts are leaf fungi that will commonly appear on crab and hawthorn trees. Cool and wet springs play a factor in the development of this deciduous tree disease. Cedar Apple Rusts can leave hawthorns sparse and weak, and will result in continual leaf drop all summer. Cedar Apple Rust also causes “gelatinous” galls on certain varieties of juniper and cedar trees. 

Dutch Elm disease is the most destructive shade tree disease. Dutch elm disease causes serious economic and aesthetic losses in cities and towns where the elms are the principal shade tree. The activity of Dutch elm disease is like Oak Wilt, in that the fungus spores are transferred from tree to tree via root grafts and insect activity (the elm bark beetle). Combating this disease has been a long concern of municipalities, since the transmission of the disease is so widespread. 

Fire Blight is a bacterial disease common to the Mountain Ash tree. Fire Blight disease causes branch cankers, and damage to twigs and leaves. Leaves will appear scorched, turning reddish-brown, thus the name, fire blight. However, don’t get confused with Leaf Scorch, that is a result a deficiency of water supply to the leaves. Hot dry winds and lack of moisture contribute to Leaf Scorch. 

Poplar Cankers is a fungus disease whose activity results in cankers or physical deformities. Poplar tree disease begins when the tree has physical damage or breaks in the tree and can quickly kill the tree and spread to other nearby trees. If your deciduous trees have these diseases or want to learn more about prevention and control, contact your neighborhood lawn care professional at Spring Green. Your Field Service Professional will be able to provide the best recommendation against deciduous tree diseases, and a 2-Step Tree Program to nourish and protect your trees this season.