Phyllocoptes eupadi Phyllocoptes eupadi Phyllocoptes eupadi is a mite that chemically induces a pouch gall to develop as a sub-spherical distortion rising up from the upper surface of the lamina of leaves of blackthorn shrubs "Prunus spinosa" and other "Prunus" spp. Synonyms are "Eriophyes padi" (Nalepa) and "Phytoptus padi prunianus" (Nalepa 1890). The gall's appearance on the upper surface is sub-spherical pustules, hairy and opening below, often clustering along the midrib, but also found over the whole leaf lamina surface and may vary in colour from pale yellow-green to deep red. The adult mite lives on sap, sucked from the cell tissues.
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