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 simonii is particularly aromatic, much more so than "Prunus salicina", with a comparatively high level of hexyl acetate, which gives apples their aroma. Plant breeder Luther Burbank devoted a lot of work to hybridizing this species with the Japanese plum ("Prunus salicina") and developed a number of cultivars from the hybrid. Of these, the cultivar 'Climax' was particularly notable for its importance to the fruit shipping industry of California. Other influential plum cultivars that Burbank developed with "P. simonii" ancestry include 'Maynard', 'Chalco', 'Santa Rosa', and 'Formosa'. Those two species and the European species "Prunus cerasifera" have contributed the majority of