Can you tell me what disease, if any, my plum tree has? It is about 3 years old and the leaves are starting to curl and they are going brown and a lot of them have brown spots on them.
Certified GKH Gardening Expert
It could be plum tree aphids (look for pale greenish insects inside curled leaves) or peach tree borer, which also affects plum trees and other fruit (look for sawdust-like residue). Additionally, it could be canker (which would be my guess due to the amber colored sap). Here is more information: https://www.gardeningknowhow.com/edible/fruits/plum/control-leaf-curl-plum-aphids.htm