A cool, wet spring often brings increased fungi growth on trees, shrubs and other plants in the landscape. Sometimes the fungus doesn’t become evident until late summer or during the fall season. Brown, black and yellow spots, leaf blotches and distortion, and early leaf drop are all symptoms of fungal diseases. Keep in mind, these symptoms can also indicate other problems and it’s important to have the plant properly diagnosed before treating.
Once it’s determined that it is a fungus disease infecting your tree or shrub, it’s time to come up with a course of action. The plan is determined in part by the particular fungi and its’ host. For example, fall season leaf spots on maple trees are often tar spot. Because tar spot occurs much later in the growing season, it causes mainly cosmetic damage and doesn’t severely harm the tree. Remove infected leaves from the landscape as they drop from the tree. This will help prevent re-infection the following year.
There are fungal diseases that harm tree growth and vitality. Apple scab is a fungus commonly associated with crabapple and hawthorn trees. Symptoms typically appear in the summer and often cause massive leaf drop in severe infections. Repeated infections may cause tree decline. Anthracnose is also a common fungal disease and actually refers to many fungi, each different depending on the host tree. Anthracnose affects many commonly used trees, such as sycamore, ash, maple, oak and linden. Control methods will vary by tree host and level of infection.
Once fungal symptoms become evident, control methods will not cure what is already present on the tree. Most chemical applications should be done before symptoms appear, usually in early spring. What can be done now is ensuring the fallen leaves from an infected tree are removed from the landscape. Tree pruning may also be an option to help with air circulation and light saturation, which will benefit the tree in the future.
Suspect a fungus? Call us today to have a certified arborist properly diagnose your tree and provide beneficial recommendations with the health of your tree in mind.