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 hortulana drupes with white dots, reportedly sweet and pleasant-tasting. The species grows in upland forests and near streams. There are several domesticated cultivars and hybrids with other "Prunus". Prunus hortulana Prunus hortulana, called the hortulan plum and wild goose plum, is a fruit shrub in the rose family found in the central United States in: Arkansas, Iowa, Illinois, Indiana, Kansas, Kentucky, Massachusetts, Maryland, Missouri, Nebraska, Ohio, Oklahoma, Tennessee, Texas, Virginia, West Virginia. Populations east of the Appalachians probably represent naturalizations. "Prunus hortulana" is a deciduous tree with a trunk diameter of up to and an overall height of or more. Leaves