Holes in apple Tree Bark from ???
See pics. There are a couple dozen apple trees and a few cherry and plum trees in the same area as the apple tree in the pic. Most of the trees are much younger (2-4 years old vs. 11 for the one in the pic.)
1. what's making the holes?
2. how big a problem and how to treat? (OK, that's 2 questions)
3. are other trees significantly at risk from trhe same pest?
as always, thx for help.