Q.Can Anyone Help Me To Identify What Disease Of My Golden Plum Tree?
This Golden plum tree is already 15 years old, since 2 years ago it looks weaken year after the other year, I live in california(Southeast side from SF), we experienced drought for many (7)years, texture of soil more like clay/loamy soil, did soil drainage test, 2 inch drop every hour,this year not many fruits produced, and those plums look so small and the leaves look like some kind of deficiency? many branches are die back, gummy stuff leaking on the trunk, can anyone tell me what is going of my golden plum tree? what kind of disease on the branches and the gummy stuff on the trunk? Can I still save my tree (use any methods) or I should cut it down? Please help, urgent!

Certified GKH Gardening Expert
This tree could have black knot disease. Here's a link to an article that explains the possible diseases that may be present: https://www.gardeningknowhow.com/edible/fruits/plum/plum-tree-diseases.htm
I recommend you take a sample of a small branch like this to your local garden nursery or extension agency to find out the best way to treat the tree.