Common Disease Pests of Oak in North Carolina

Many diseases can impact oak (Quercus spp.). Damage ranges from aesthetic damage to tree mortality. Symptoms vary greatly and can be include leaf deformation and necrosis, premature leaf drop, dieback, fungal growth of many forms, and more. This guide is intended to assist North Carolinians diagnose common disease issues of oaks utilizing images and short descriptions and includes links to more details synopses of the disease pest. Oak leaf blister (caused by Taphrina caerulescens) is a fungal disease that most commonly affects red oak species. The disease causes blister-like yellow (chlorotic) raised spots on leaves. As the blisters accumulate, the leaf will curl. In severe cases, leaves may drop prematurely. The pathogen spends the winter on leaf scales and buds, and spores infect the leaves in early spring. More information about oak leaf blister can be found from Penn State Extension. Bacterial leaf scorch (caused by Xylella fastidiosa) is a serious disease which often results in tree feath over time. It most frequently affects red oak, white oak, pin oak, and shingle oak. The symptoms are often described as similar to drought stress, and include leaf burn (browning on leaf tips), leaf drop, and a discolored, yellow margin separating the dead tissue from living tissue, often occurring in mid to late summer. It is typically concentrated to one portion of the canopy rather than spread evenly through the crown. The disease progresses every year, causing more symptoms through time. Additionally, it can be spread by leafhoppers, including the grass sharpshooter and the redheaded sharpshooter (Draeculacephala minerva and Xyphon fulgida, respectively). More information about scorch diseases can be found from NC State Extension.Original Article: https://content.ces.ncsu.edu/common-disease-pests-of-oak-in-north-carolina