Tree Diseases: Crown Gall

Introduction Crown gall is a tree disease of many woody shrubs, and some herbaceous plants. The disease is caused by the bacterium Agrobacterium tumefaciens, a…

Tree Diseases: Dutch Elm Disease

Introduction Dutch elm disease is a fungal infection that affects many species of elm. It is one of the most destructive tree diseases in North…

Tree Diseases: Gall Producers

Gall diseases are common on many trees and shrubs. Galls are abnormal swelling growths that form on the leaves, twigs, branches, roots, and flowers of…

Tree Diseases: Galls on Plants

Introduction Galls are abnormal swelling growths that occur on the leaves, twigs, branches, roots, and flowers of plants. A gall’s characteristics are determined by its…

Tree Diseases: Cedar-Apple Rust

Introduction Cedar-apple rust is a fungal infection that commonly affects junipers, apples, and crabapples. It is caused by a pathogen called Gymonosporangium juniperi-virginianae. Cedar-apple rust…

Tree Diseases: Canker Diseases

Introduction Canker diseases are symptomatic of an injury associated with a plant that has become infected by a fungal or bacterial pathogen. Canker diseases frequently…