I have a plum tree with loads of fruit on it, but I think that I have an infection on the tree as the leaves are curling up and going black. Please advise on how to treat it.
Miniature Victoria Plum
Certified GKH Gardening Expert
This is sooty mold. It happens when the plant gets a pest infestation, likely aphids. I would recommend using neem oil, as this will get rid of the sooty mold fungus and kill the pests. Here is some articles that will help you: