Three Diseases To Watch Out For On Your Oak Tree

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Oak trees are beautiful, magnificent plants. If you're lucky enough to have one of these trees in your backyard, it's important to keep a close eye on it. Oaks are susceptible to a number of diseases, which often require proper care. Here's a look at three common oak diseases, and what to do about each one.


This common fungal condition can actually affect most any tree species, but it's pretty common on oaks. The most obvious symptom is the appearance of brown or black splotches along the veins of the leaves. Twigs might also develop little cankers or brown spots, and some might die and fall from the tree. Luckily, anthracnose is not a serious or deadly tree disease. However, having to fight it off can leave your oak tree in a weakened state, allowing other diseases to creep in and cause more serious damage. Thus, it's important to treat anthracnose if you notice it.

Having the more damaged branches pruned away while the tree is dormant (in late fall or early winter) is advised. All fallen leaves should also be burned, since they contain fungal spores that could re-infect the tree the next spring.

Leaf Spot

The spots caused by fungal leaf spot diseases are usually dark brown in color and about the size of a the eraser on the back of a pencil. They are perfectly round, whereas the spots caused by anthracnose are irregularly shaped. Sometimes, the leaves of oak trees with anthracnose may develop a yellowish color overall. Leaf spot is not an overly serious disease, but it can weaken the tree. The best way to treat it is to have the tree sprayed with fungicides when it is first budding in the spring. This is best left to a professional, since the large size of oak trees makes them hard to spray evenly and completely.

Oak Wilt

Of all the diseases that affect oak trees, this is the most serious. It is always deadly, and the fungus that causes it is easily spread from tree to tree by insects. The first sign of oak wilt is usually leaves that begin to wither and fall off prematurely. Soon, entire branches of the tree will begin to die.

It's important to call a tree care expert (like those at Arborcare Tree Service) if you think your tree may have oak wilt. He or she can confirm the diagnosis to ensure you take the right measures when it comes to dealing with the diseased tree. If the tree does, in fact, have oak wilt, it's important to have it removed from your property sooner rather than later. This will minimize the spread of infection to other oaks.