How can I tell if my tree has a pest or disease?

Trees show stress in a few common ways: leaves that are smaller, thinner, spotted, wilted or turning color early; branches that die from the tips; bark that cracks, peels or has small round holes; and fungus growing on the trunk or roots.

Many of these signs have more than one cause. Drought, salt, soil changes and root damage can look like a disease. That is why a correct identification matters before anyone sprays or treats.

Take photos of the leaves, bark and base of the trunk. Note when you first saw the change. Your county extension office or a certified arborist can often help identify the problem.

Be careful with anyone who diagnoses a serious disease over the phone and pushes an expensive treatment right away. Ask what they found and how they know.

Our tree problems library describes many common pests and diseases.