Taphrina pruni being larger than the healthy one. As a fungus, cool and wet weather conditions promote the germination of spores, whilst warm and dry weather results in infection rarely taking place. Colonisation can become extensive and eradication very difficult. The disease can to some degree be controlled by carefully removing infected branches, witch's brooms and fruit before the infective air borne spores are produced. Applications of copper-containing fungicides have a degree of control over the fungus. 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
Prunus avium parent species of "Prunus cerasus" (sour cherry), by way of ancient crosses between it and "Prunus fruticosa" (dwarf cherry) in the areas where the two species overlap. All three species can breed with one another. "Prunus cerasus" is now a species in its own right, having developed beyond a hybrid and stabilised. Pliny distinguishes between "Prunus", the plum fruit, and "Cerasus", the cherry fruit. Already in Pliny quite a number of cultivars are cited, some possibly species or varieties, Aproniana, Lutatia, Caeciliana, and so on. Pliny grades them by flavour, including dulcis ("sweet") and acer ("sharp"). and goes so far