A white fan of fungus is found under the bark at the base of the tree. Dark brown, shoestring-like threads may be found under or on the surface of the bark. Armillaria Remove infected trees. Bacterial Leaf Scorch Browning of oldest leaves along their margins begins mid to late summer on one branch or a few branches on the lower portion of the tree. A wavy reddish brown band sometimes develops between the brown and green tissue of the leaf.
Symptoms progress upward to include more leaves and toward the ends of branches .
Xylella fastidiosa Infected trees may survive for years. Severely affected trees should be removed. Dark streaks of sap, usually foul smelling, ooze from holes or cracks in the bark. The heartwood is discolored dark brown. Pin oaks are especially prone to wetwood.