insect, the leaf hopper. Unlike Dutch elm disease, elm yellows typically affects the entire crown of an elm tree all at once, turning the leaves yellow in late summer and causing them to drop prematurely.1 Trees may develop witch's broom—dense sprouts in tiny patches in the crown.
Elm yellows is caused by a bacteria that is spread by a sap-suckingBy the time symptoms have appeared, the tree is infected systemically, and may die right away, or within a year or two. When infected, the inner bark of several species of elms develops the odor of wintergreen; that of slippery elm acquires the smell of maple syrup.2
- 1. . 1998. How to identify and manage Dutch elm disease.
- 2. . 2008. Plant Answers.