Taphrina pruni Taphrina pruni Taphrina pruni is a fungal plant pathogen of blackthorn (Prunus spinosa) that causes the Pocket or bladder Plum gall, a chemically induced distortion of the fruit (sloes), producing swollen on one side, otherwise deformed and flattened fruit gall without a stone. The twigs on infected plants may also be deformed with small strap-shaped leaves. "T. pruni" produces a distinctive tongue-like growth, similar to other closely related species such as "Taphrina alni" on Alder ("Alnus glutinosa") and "Taphrina padi" on Bird Cherry "Prunus padus". The growth is the distorted fruit and not a fungus in its entirety. "T. pruni"
Prunus serrula typical of "Prunus", are produced in clusters of one to three. The fruit is a small oval bright red drupe. "Prunus serrula" is grown as a ornamental tree, especially for winter interest. It tolerates a variety of soil types and has a wide pH range. It prefers full sun and does well in USDA hardiness zones 5 to 8. Its potential as an invasive species is low, as it is susceptible to many common garden diseases and pests such as fire blight, powdery mildew and Japanese beetles. It is sometimes grafted to "Prunus serrulata" (Japanese cherry) crowns, forming a tree