[Nobbie]

https://i.imgur.com/T8lVxWE.jpg

From a quick google it appears I have Plum Pocket on my 'Opal' plum in the garden and on a Damson at the allotment. Damson is particularly badly affected with almost all branches suffering dieback in adddition to the miss shaped fruits. Anybody had any experience of this before? This is the second season of this and I'm not sure the Damson is going to survive. Spraying seems a bit impractical given the size of the trees.

[hasbeans]

I spent yesterday removing 99% of the fruit from a gage and a miracot.  I was hoping to make wine from the summer glut too.  From what I gather there's not much to do but dispose of the fruit and hope it doesn't return next year.  Might try winter wash, which I've previously not done.  Interestingly, the victoria plum I have that was planted too deep had pocket on the gage branches from the rootstock but not one bad fruit on the plum branches.

[Nobbie]

Interesting regarding the rootstock, I noticed on the plum that it is mostly the lower branches that are badly affected which are sheltered by the shed and fence. Above this not so bad and on the allotment there is a big cherry that overshadows the Damson completely, so I think the more sheltered the worse the problems seems to be.

[hasbeans]

I had slightly less infection on the highest fruits.  I'd assumed these were the last to flower and missed the spores but it may be that the spores just landed on the lower branches then fell/blown onto the rest of the tree.
Good luck next year!