Q. I have a flowering plum which I first noticed this morning has a problem with loss of bark on the west side of the trunk. My yard faces south. What should I do?
|Borer damage to ornamental plum on the west side of the trunk|
A. This is borer damage to the trunk. You can read more about this insect and the type of damage it does to ornamental and fruit trees and how to correct it from the links below.
Your picture was extremely helpful but the other thing that keyed be in was that you said it was on the west side of the trunk. This is the side of the trunk getting very hot in the late afternoon. Heating up on this side from the sun leads to sun damage. Sun damage to the trunk attracts boring insects. They like to lay their eggs on these kinds of damaged sites.
|Concentrated form for commercial applicators and professionals|
Since you are not eating the fruit of this tree you can apply a liquid soil drench insecticide. This product comes in several trade names so I cannot list them all but the key chemical ingredient is Imidacloprid. This will be listed in the active ingredients.
|Homeowner version found in many nurseries and garden centers|
Follow the label directions and apply it after it finishes blooming. Otherwise take a clean knife and clean up the damaged area and let it heal as explained in the posts on my blog below.