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 serrulata of the world. Numerous cultivars have been selected, many of them with double flowers with the stamens replaced by additional petals. In cultivation in Europe and North America, it is usually grafted on to "Prunus avium" roots; the cultivated forms rarely bear fruit. It is viewed as part of the Japanese custom of Hanami. There are several varieties: Some important cultivars include: Prunus serrulata Prunus serrulata or Japanese cherry, also called hill cherry, oriental cherry or East Asian cherry, is a species of cherry native to China, Japan, Korea and India, and is used for its spring cherry blossom displays