Cherry-plum, infected with pocket plum disease

I had been hoping for a good cherry-plum harvest this summer - the fruits make excellent jam - but the hedgerow trees that I had my eye on are infected with pocket plum disease, caused by the fungus Taphrina pruni. In the first picture you can see one uninfected developing fruit, green, and then the rest are red, swollen and deformed so that they are flattened, resembling pockets. Soon spores will erupt from their surface.

In previous years I've seen infections on sloes and on bird cherry. This is the first year I've seen a severe infection on cherry-plum.

 

Bullfinches eating cherry plum blossom

 Cherry plum Prunus cerasifera is in full bloom here in County Durham and its blossom is attracting bullfinches, that feed on the flower buds. You could almost say that their territory is defined by the availability of fruit tree blossom buds. This cock bird is one of a family party that can always be seen from a footpath along a disused railway line that's bordered by wild cherry, blackthorn, cherry plum, crab apple, and pear trees that must have grown from discarded cores, providing flower buds from now through until May. Later in the year I often see them feeding on seeds of dandelions, docks and brambles.