Question
Hi Jim

I have a neighbor who is concerned about a maple on his parkway with missing bark on the south side of the bole (please see attached photo, the "facing" notations refer to the direction the trunk is facing, not the camera).

The pictures were taken several months ago.  Now the south side of the crown is turning autumn red while the other leaves remain green.

Are these Insects?  Disease?  Did the bark fall off by a natural action?  Is there a treatment?

Thanks.

Pete

Answer
It looks like old borer damage. The insect infest wounds and as a result the bark will become loose and fall off. Does not look like any active signs of borers now. About all that can be done is to gently remove the loose bark back to solid bark and then fertilize the tree with 10-10-10 fertilizer at the rate of 1 lb. per inch of trunk diameter scattered around the tree and watered in good. Apply just before a rain event and you will not need to water. This will increase the overall health of the tree and prevent more borer damage and encourage the bark to grow over the wound area. Do not put anything on the wound itself unless then is fresh saw dust from a new borer. Then apply an insecticide to the are--Merit is the preferred insecticide for borers.