Variation in Field Susceptibility of Native and Exotic Ash Species to Anthracnose    (View PDF)

Karel Jacobs and Donna Danielson

Abstract: Eight Fraxinus species and several cultivars of F. americana (white ash), F. pennsylvanica (green ash), F. angustifolia (Syrian ash), and F. excelsior (European ash) were evaluated for susceptibility to anthracnose disease during 1997, 1998, and 1999. Budbreak and leaf emergence rates were also recorded. The following results were found: F. chinensis (Chinese ash) was most susceptible followed by F. angustifolia, F. pennsylvanica and, to a lesser degree, F. mandshurica (Manchurian ash). The European F. excelsior was similar to F. mandshurica and appeared moderately susceptible, while the North American native F. tomentosa (pumpkin ash) and F. americana were comparatively tolerant of the disease. Fraxinus quadrangulata (blue ash) was resistant and showed virtually no symptoms in any year. Significant variation existed among cultivars and varieties of certain species including the widely planted green ash in which 'Patmore' and the newly available 'Cimmaron' appeared least susceptible. Despite weak statistical support, we observed a general trend in which trees that leafed out earlier developed more disease than those that leafed out later.

Keywords: Differential resistance; Gnomoniella fraxini; Discula fraxinea; phenology; Mycosphaerella; Fraxinus spp.; anthracnose.

https://doi.org/10.48044/jauf.2002.005