Key Features
- Scorched leaf edges
- Yellowing between veins
- Some branches fail to leaf out
Symptoms
Symptoms begin with a few branch tips showing scorched or curled leaves. By the end of the season after infection, most leaves are scorched and will drop in late summer or early fall. Trees die within a few years of infection.
Biology
Bacterial leaf scorch is caused by the bacteria, Xylella fastidiosa. Leafhoppers carry the bacteria between shade trees and inject the pathogen into leaf veins. Bacteria move throughout the tree in the vascular system. As bacteria multiply, they clog the channels that carry water and nutrients. Leaf tissue becomes scorched when it dries out from a lack of water. Trees become less vigorous as more leaves are affected. Most trees die within a few years of infection.
Management Recommendations
There are no effective prevention or management strategies for bacterial leaf scorch. Injections of oxytetracycline by a professional arborist into the root flare of the tree may provide temporary relief of the symptoms, but would require regular injection, possibly on an annual basis. There are no long-term studies that show this approach is successful. Protecting a tree with symptoms of bacterial leaf scorch from drought stress and injury may prolong its life. Dead branches should be removed to protect both people and property from falling debris.
Effective Pesticides
Pesticides are neither available nor recommended for managing this disease.
Resources
