Is My Apple Tree Diseased?

Q. My apple tree has several different things going on with it and I’m wondering if it is suffering from some sort of disease. Other than that, the tree appears to be growing normally.

A. Let's cover these pictures one at a time.

First picture. The tree was damaged on the trunk but it is mending. You can see how the bark is beginning to roll back from that damage. It looks like the trunk was damaged either by sunburn or possibly borers. The damage stopped, the bark peeled away from the trunk leaving the dead interior exposed. Now the living part of the tree is growing over the top of the dead interior wood. The center of the trunk in all apple trees is dead. The only living part of the trunk is the outside cylinder that continues to expand year after year. This is nothing to worry about. Just keep the tree in good health and it will heal completely.

Second picture.  This is either some borer (insect) damage or a disease called crown gall. The only way to find out is to take a sharp, sanitized knife and dig down and see what's going on. If this is insect/borer damage then the bark will peel away easily and you will see evidence of this kind of damage under loose bark. You can go to my blog and search using the word “borer” and several postings will come up with pictures showing you what borer damage looks like when the bark is

removed. If this is borer damage, then remove all of the loose bark and allow the tree to mend itself in the same way it did in the previous picture. If this is crown gall it is not a serious problem. Don't cut it out or worry about it. It will not be a big problem for the tree in the future. It just looks ugly and it will get larger over time.

Third picture. This does look more like crown gall. It does not look like borer damage because it is on the underside of the limb. Borer damage usually occurs on the upper surface of a limb or on the side of limbs facing West. Very seldom do we see borer damage on the underside. Take a sharp, sanitized knife and see if any of that bark is loose and can be removed for closer inspection. If not, leave it alone and it will not be a big problem in the future.

Fourth picture. This looks like sun damage in the crotch of a limb. It is also possible there are borers in that spot causing some damage. Take a sharp, clean knife and remove any dead bark down to the wood. Allow the tree to heal over that area.