I’ve been told my oak trees have bacterial leaf scorch, what is that?

Bacterial Leaf Scorch is a devastating disease of shade trees caused by a bacteria. The bacteria themselves live inside the tree’s water conducting tissue. They “cluster” inside the water transport tissue and essentially block water transport, which leads to the scorch symptoms.

The disease will slowly progress throughout the tree for up to a decade causing dieback and eventually killing the tree.

What trees are affected by it?

Symptoms and damage are usually most visible on pin and red oaks, but shingle, bur and white oak can be affected as well. It can infect elm, sycamore, mulberry, sweetgum, sugar maple, and red maple.

How does it spread?

Insects like sharpshooters, treehoppers, leafhoppers, and spittlebugs spread the bacterium from one tree to another. These insects feed on the xylem tissue and will inoculate the tree if they carry the bacteria with them.

Can you treat for this?

It is best to treat before the tree has Bacterial Leaf Scorch or in the early stages of it. Your Arborwell Arborist can develop treatment plans after determining the scope of the problem on your site. They can determine if preventative treatments or early curative treatments are required. If certain pests are prevalent, treatment to prevent their establishment may be recommended.

Also remember that a stressed tree will develop symptoms faster, so keeping trees properly watered and mulched are another way to help reduce the spread of this disease.

If you are concerned about bacterial leaf scorch, or other problems on your trees, contact your Arborwell arborist to help you create the most effective management plan for them.