How do i treat plum trees with black fungus?
If your “black fungus” is black swellings along the branches – then what you have there is Black Knot. Unfortunately, it’s not a fungus. It’s caused by bacteria. There is no cure except to prune it out in winter – going back 6 to 12 inches into “good” wood to make sure you get all the affected parts. It’s easier for you to see what parts of the tree are affected when its dormant, and it’s also a better time for the tree to receive the pruning. If you do nothing, the tree will die eventually, one branch at a time. If it’s mostly affected, with less than half the tree leafed out, it might be time to cut your losses and take it out, replacing with something resistant. There is no treatment to prevent it. Pruning is the only way to deal with it. (Okay, technically, you could spray the whole thing with antibiotics every spring – but it would be crazy-expensive even if it were available and legal) If you want to save your tree, then you’ll probably need to prune it every year. I have a lovel
