plum tree trunk and branch disease
My plum tree is 15 yrs. old. I have tan to brown hard lumps on the bark of the branches. They appear to be honeycombed, or possibly dried sap. The leaves are small and sparse, and the fruit is small also. What have I got? And how do I get rid of it?
If the areas are more bump-like and tan in color, then your tree may have scale. And yes, it is likely sap on the tree or honeydew residue left behind from these pests. Neem oil is an effective treatment for the scale issue and is often found in stores as fruit tree spray.