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…

Tree Diseases: American Chestnut Blight

Introduction Chestnut blight, also called chestnut bark disease, is a fungal infection that has significantly reduced the chestnut population in North America. The fungus is…

Tree Diseases: Sooty Mold

Introduction: Sooty mold is a collective term applied to several species of dark fungi. The fungi grow on honeydew excreted by insects, or exudates from…

Tree Diseases: Beech Bark Disease

Introduction Beech bark disease is an insect-disease complex responsible for causing significant mortality and defect in American beech (Fagus grandifolia) and European beech (Fagus sylvatica).…

Gypsy Moth Outbreak in Massachusetts

Earlier this year, Massachusetts, Rhode Island, and Connecticut were beset by the most severe outbreak of gypsy moth since 1981. The rapacious insects were especially…

Common Tree Diseases: Anthracnose

Anthracnose is a group of fungal diseases that affect many deciduous and evergreen tree species. It causes dark sunken lesions to appear on leaves, stems,…