Question
i have a giant very old (50+ yrs) maple tree being infested by something.  A large part, about 4 X 6 feet, of the heavy bark is being girdled off and underneath on the smooth wood of the trunk are many tiny insect holes.  In addition, there are some gobs, on the trunk and by the base of the tree of orangy, rustlike colored sap substance.  The rest of the tree looks great, foliage is green all to the top.  Any ideas?  How do I find a reputable person to help us try to save the tree?  It is a great source of shade.  silver maple, Columbus Ohio area

Answer
Sounds like an insect called a borer. they will bore into the trunk and the wound will form and the bark will peel off the wound leaving the wood exposed. The small insects are just feeding on the fungi growing there and are not a problem. I would spray the wound area with an insecticide called Merit. This will kill the borer in the wound and prevent other insects from infesting the wound. You can cut the loose bark off the wound and this will help the tree heal--do not apply any wound dressing to the area this will slow down the healing process. Check with your local nursery fro Merit.

Borers infest trees that are under stress so I would also 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. This will increase the health of the tree.