Category Archives: Tree Pests

Did someone shoot your ornamental flowering fruit trees with a shotgun?

Identifying and Treating Flowering Plum, Cherry and Apple Trees Leaf Blights

In the spring and early summer in the Portland and Wilsonville region, do the leaves on your fruiting or ornamental plum, cherry (Prunus spp.) or flowering crab apple (Malus spp.) trees look as if someone was using them for target practice with a shotgun? Are the leaves all peppered with a gazillion small holes? 

Not to worry, your miscreant neighbor doesn’t have a vendetta against either you or your trees. However, an airborne fungal pathogen called coryneum blight or “shothole fungus” is most likely the culprit for the cherry and plum trees. For crabapple trees, a different fungus called apple scab with similar symptoms as coryneum blight is likely the guilty party. 

On the flowering cherry and plum trees, “shothole fungus” (Thyrostroma carpophilum formerly called Wilsonomyces carpophilus) overwinters in dormant infected leaf buds, blossom buds and Continue reading