Fungal Tree Diseases: Symptoms To Recognize

Posted on: 4 November 2015

Tree diseases can be a serious threat to your landscape plants. Trees are generally caused by viral, bacterial, or fungal vectors. In this article, learn some common signs of fungal infections and what you can do to prevent the disease from spreading to you healthy trees.

Symptom #1: Galls

These look like growths, typically on the trunks or branches when caused by fungus. Galls on leaves are usually harmless and caused by an insect laying eggs. They are sometimes roughly circular in shape, although sometimes galls develop irregular three-dimensional shapes. The galls are actually the growth structure of the fungus inside the bark or trunk of the tree. Galls are generally harmless but unattractive.

Symptom #2: Cankers

Cankers are actual wounds on the tree. They can appear on leaves, branches or trunks. Leaf cankers typically resemble brown or black irregular spots on the otherwise green surface. Your tree can usually fight off leaf problems if it is otherwise healthy. Those that form on wood parts of the tree develop a sunken area that may or may not appear wet or weepy. Cankers can be dangerous to the health of the tree, especially those that form on trunks, because they give an opening for worse pathogens or insects to infect the tree. The best treatment for a canker is to prune off the infected branch. If this isn't possible or if the canker is on the trunk, trim the infected bark around the wound and then paint an antifungal treatment for trees onto the wound.

Symptom #3: Mushrooms

When actual mushrooms, such as the shelf fungi sometimes seen on falling logs, begins sprouting from your tree it is time for prompt treatment. These usually grow near the base of a tree and indicate that rot has occurred somewhere in the trunk, since most tree mushrooms are a symptom of wood decay. If the mushrooms are growing from a branch, you may be able to save the tree by removing the infected branch. Those growing on the main trunk usually indicate that it is time to remove the tree.

Symptom #4: Powdery Leaves

A final major symptom of fungal infection is a white, gray, or black powdery residue on the tree leaves. These are a type of mildew, which can cover the leaf surface during hot, humid weather. There are antifungal sprays available which treat mildews. Raking up and properly disposing fallen leaves each year can also help prevent the overwintering and spread of these fungal spores.

If you suspect that a tree has a fungal disease, prompt treatment is your best option. With proper pruning, watering, and fertilizing, your tree may survive. Contact a local tree specialist like Destiny's Tree Service LLC to see if removal is necessary, or if treatment is possible.



Keeping Your Trees Healthy

About a year ago, I realized that our front trees were starting to look a little funny. Some of the leaves were wilted, but we weren't anywhere near autumn. The bark on the trunk also seemed to be rotting away, which was frustrating and disappointing. Fortunately, a friend of mine told me to call a professional arborist for help. He came out, inspected the trees, and injected some special pesticides into the trunk. Within a few months, they started to look a lot better. Our arborist also trimmed our trees to reduce the weight load on the branches and to improve their shape. Check out this blog for information about tree trimming.