Plant Diseases/Plum Shothole, bugs or disease?
Hello Dr. Vann, My 3-4 yr.old Catalina Plum has Shothole on the leaves for 2nd season now. The tree continues to grow, but i notice other things along with it. It looks like a layer or 2 of bark peels/rolled-back on the truck and the heavier branches. And, there are 1/16th-1/8" bumps this year growing from same limbs. Right under the bump "skin" it's bright green and if i cut off the bump it looks like there is a center going into the tree.
Timewise i think this started after i spread leaf mulch under this tree and the 2 citrus next to it. There is also a rotating barrel type of composter close by, and a full size Apricot in the yard with no problems except age. I have tried Daconil, Malathion, Neem Oil. We are 4 miles from the coast in S. Calif. if that helps!? Thanks for your help!
I do not recognize an infectious disease issue from your images. Looks like maybe an insect activity on the leaves with tattered look. Shothole usually has distinct round holes in the leaves. I do not see much of that here. Consider carrying a few leaves to your local garden center/nursery to check this out. The bumps that you mentioned look like lenicels, which are normal "pores" for gas exchange in the bark.
For many foliar insect/disease issues, raking up and destroying fallen leaves is useful, especially during early spring BEFORE the new leaves start to form on the tree. This practice can reduce these pest problems.