Bacterial leaf scorch
| Bacterial leaf scorch | |
|---|---|
| Large pin oak (Quercus palustris) stricken with bacterial leaf scorch during leaf-out | |
| Common names | BLS | 
| Causal agents | Xylella fastidiosa | 
| Hosts | trees and crops | 
| Vectors | leafhoppers | 
Bacterial leaf scorch (commonly abbreviated BLS, also called bacterial leaf spot) is a disease state affecting many crops, caused mainly by the xylem-plugging bacterium Xylella fastidiosa. It can be mistaken for ordinary leaf scorch caused by cultural practices such as over-fertilization.