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.