This symptom is often mistaken for frost injury. The lateral buds behind the dead twig will eventually produce new growth and a new flush of leaves, giving the tree a bushy appearance. Twig infection is not common but may occur in ash, elm, hickory, hophornbeam, linden, maple, oak, poplar, and walnut. The buds may be killed before the end of dormancy because of a girdling canker that has formed below the buds. Shoot blight begins after the leaves emerge and resembles frost injury.
Leaves suddenly die and later drop from infected twigs.
The severity of the blight depends on the temperature during the two-week period following the emergence of the first leaves. Back to Top Disease Cycle Anthracnose fungi that primarily attack the leaves commonly overwinter on the ground. Intensification of the disease from summer spores is especially noticeable on walnut and ash, leading to pronounced early defoliation. With fungi that attack both stems and leaves, overwintering commonly occurs within infected buds, the bark of twigs, and branch cankers. Rain splash disperses the spores to emerging leaves, causing infection.