Scorching begins on leaves at the base of the tree and moves upward through the canopy. Leaves on branches that were affected during the previous season appear normal in the Spring but later show symptoms. Some premature defoliation may occur. Affected trees are very attractive to elm bark beetles and are much more susceptible to Dutch elm disease than trees free of leaf scorch. This disease affects primarily pin and red oak but has also been found in white oak.
Leaf margins die and have a distinct yellow border separating the dead tissue from the green tissue.
The symptoms progress toward the base of the leaf in an undulating front. Defoliation is not usually a symptom on red oak. However, water sprouts or epicormic shoots do develop on red oak as this disease progresses. In Georgia, the bacteria were successfully isolated from twigs November to January but not from February through July. In late June or July, olive green discoloration of leaf margin develops and the margin dies.