About Tree Diseases

Tree diseases are not only a drain on the income of homeowners who need to replace dying or dead yard trees, they also take a significant toll on commercial expenses related to the future losses of forest products. In the United States, there are greater than 30 different common tree diseases that home owners should be on the lookout for. Here are four of the most common tree diseases and how you can combat them.

4 Common Tree Diseases and How To Fight Them


Anthracnose is most commonly found on flowering dogwood and sycamore trees, however it can surface on quite a few different trees and shrubs. This disease is caused by fungi attacking the twigs, leaves, fruits, and flowers of a tree. The symptoms of anthracnose vary but may include, twig blight causing witches blooming, branch dieback, premature leaf defoliation, and tree death to some or all above-ground parts of the tree.

To combat anthracnose, the tree owner should start foliar applications of fungicides approximately two weeks prior to bud break or inject the trunk with a systemic fungicide. In the case of dogwood anthracnose, foliar applications have to start at bud break and keep going throughout the growing season. Propiconazole is a suggested fungicide in this case.

Cedar Rusts

These common foliar diseases can be found on rosaceous plants, like crabapple or hawthorn. The symptoms of these diseases are rust-colored or orange sports on the tree’s leaves in the spring, spore-producing structures on juniper branches, and twig cankers which can grow and cause dieback. To combat cedar rust, use fungicide on deciduous hosts starting at bud break or when spore masses start to develop on junipers. Also, prune out rust galls on junipers as they appear.

Lethal Yellow

Lethal Yellowing is a disease that most affects palm trees in Texas and Florida. It is commonly found on coconut palm, Canary Island date palm, date palm, and other non-native palm trees. This disease is caused by a phytoplasma from a planthopper insect. Most common symptoms are flower death, yellow foliage, and premature fruit drop. Palms that have been infected will typically die in three to five months. To combat lethal yellowing, you can use therapeutic and preventative antibiotic treatments injected into the palm’s trunk.

Oak Wilt

This systemic fungal disease can cause tree death. It is caused by infected beetles and affects more than twenty different oak species. The most common symptoms on red and white oak are rapid discoloration, leaf wilt, and early defoliation. For live oaks, look for veins that turn yellow prior to defoliation. To combat oak wilt, treat white oaks therapeutically. For red oaks, prevention must occur during growing season with a systemic fungicide.

If you have trouble identifying or fighting tree diseases then you should contact a specialist in tree care. These professionals can help home owners with seeding, planting, fertilizing, care, and removal of yard trees. When in doubt, it is always better to seek the help of professionals to ensure your trees are as healthy as possible and avoid any unnecessary damage.

Emma is a freelance writing currently living in Boston, MA. She writes most often on education and business. To see more from Emma, say hi on Twitter @EmmaSturgis2. The information used in this article was gathered from Schulhoff Tree & Lawn Care, Inc.