{"id":18671,"date":"2019-06-20T12:57:23","date_gmt":"2019-06-20T16:57:23","guid":{"rendered":"https:\/\/extension.umaine.edu\/ipm\/?page_id=18671"},"modified":"2025-02-11T10:16:18","modified_gmt":"2025-02-11T15:16:18","slug":"5061e","status":"publish","type":"page","link":"https:\/\/extension.umaine.edu\/ipm\/ipddl\/publications\/5061e\/","title":{"rendered":"Phomopsis Gall"},"content":{"rendered":"

\n \n \"Print\n <\/a>\n <\/div><\/h3>\n

Pest Management Fact Sheet #5061<\/h3>\n

Developed by Alicyn Smart, Assistant Extension Professor & Extension Plant Pathologist, University of Maine Cooperative Extension, and Nathan Andrews
\n<\/em><\/p>\n

For information about UMaine Extension programs and resources, visit extension.umaine.edu<\/a>.
\nFind more of our publications and books at extension.umaine.edu\/publications\/<\/a>.<\/strong><\/p>\n

Pathogen:<\/strong> Phomopsis<\/em> sp.<\/h4>\n

Introduction<\/h3>\n

In Maine, the species of most vulnerability are oaks (Quercus <\/em>sp.), maples (Acer <\/em>sp.), and highbush blueberry (Vaccinium <\/em>corymbosum). The species of most vulnerability is a reflection of the fungus\u2019 adaptation to infect plants with thinner barks. This disease can be commonly mistaken and confused with other galls, including the wasp-induced Gouty Gall and the bacterial disease Crown gall.<\/p>\n

Host Plants<\/h3>\n

Oaks (Quercus<\/em> sp.), Maples (Acer<\/em> sp.), Highbush blueberry (Vaccinium corymbosum<\/em>), Forsythia (Forsythia <\/em>sp.), Hickories (Carya<\/em> sp.), and American elm (Ulmus Americana<\/em>).<\/p>\n

Symptoms and Signs<\/h3>\n

This disease cycle has not been studied in depth. However, galls appear to start forming on twigs and small branches before infection of larger branches or the main stem. Galls begin to form as patches or roughened bark with disorganized hard wood underneath compared to the wood grain of the rest of the plant (Figure 1). When galls are fully formed, they may range from pea size up to the size of a basketball in extreme cases (Figure 2). On most plants, Phomopsis galls appear as clusters of wooden nodules pressed tightly together. On Acer <\/em>species, the galls will begin as smooth swellings where the bark will eventually roughen and crack as they grow. Phomopsis gall may cause girdling and dieback on infected branches and stems, however, it is not typically fatal for the host. Hosts can live for years and years with galls on the main stem or branches.<\/p>\n\n\t\t