<unk>  is a plant disease of<unk>  trees that is spread by leafhoppers or by root grafts.<unk> , also known as<unk>  phloem necrosis, is very aggressive, with no known cure.<unk>  occurs in the eastern United States, and southern Ontario in Canada. It is caused by phytoplasmas which infect the phloem (inner bark) of the tree. Similar phytoplasmas, also known confusingly as<unk> ', also occur in Europe. Infection and death of the phloem effectively girdles the tree and stops the flow of water and nutrients. The disease affects both wild-growing and cultivated trees.
Elm yellows
Saber shin
Jaipur foot
Reflex hammer
Squawk 
Clubfoot
Greenpilot
Lockets