Hortiscope: Take steps to keep insects away from tree

Q: I have what I believe is an amur maple that is about 5 years old. I just noticed that the tree has a hole in the trunk. The hole is about 3 inches long and an inch or so wide. I saw something inside the hole and dug it out, but it fell in the snow and I couldn’t find it again. It looked like a grayish-white oval bug. This hole goes about halfway through the trunk. Last summer, the tree did fine. However, I cannot imagine a hole this deep is good for it. Is this tree a goner?

By: Don Kinzler, INFORUM