Question
My silver maple tree is 15 years old. We live in Indiana. The bark started splitting during the winter. Now around 2 feet of bark is missing showing smooth wood.We saw some worms under the bark that fell off. The leaves are all brown, wilted and hanging by a thread with around 50% of them missing. Some of them however, have small green leaf shoots like it wants bloom. Not on the trunk, but on the ends of the branches. This makes me think that might still be hope for survival.  We want to save this tree if possible. Thanks

Answer
Sounds like an insect called a borer.

Maple callus borer, Synanthedon acerni.
The larva of this clearwing moth is a borer in maple trees, especially around wounds. There is one generation each year. The moth has a wing spread of about an inch; both fore and rear wings are transparent with narrow purplish margins, tips of forewings are pale yellow, and there is a conspicuous black mark 2/3 of the way toward the tip of the front wing. Prevention of injury will be helpful in keeping the larvae out of the trees. Keeping trees vigorous and irrigated during prolonged drought helps to reduce borer injury. Merit is an insecticide that will control this insect applied as a trunk spray can control the moths before they lay eggs and the larvae in the trunk. A more thorough control would be expected if treatments are timed to coincide with adult activity.

Sugar maple borer, Glycobius speciosus.
This is the most destructive pest of the sugar maple. It is a beautiful, black, longhorned beetle with brilliant yellow decorations, including a W-shaped mark across the base of the wing covers. It is about an inch long and emerges in July. The female lays eggs in slits in the bark, and the young larvae tunnel in the inner bark and sapwood, overwinter in a chamber excavated in the sapwood, and the following spring cut large galleries in various directions, though usually in a spiral course upward and partly around the trunk. Sometimes two or more borers in a tree may completely girdle the trunk and the tree breaks. They pass the second winter in chambers 4" from the bark. Two years are required to complete the life cycle. Tree growth over the wound generally results in a series of scars and ridges that show prominently on the trunk.

Choice shade trees may be examined carefully at least twice a year, in September and May, for sawdust on the bark. When a burrow has been discovered, the grubs may be cut out, or killed by running a wire into the burrow. The opening to the burrow may then be closed. Maintaining adequate watering may be helpful in preventing infestation. Or spray the trunk with Merit.

Borers attack trees under stress so I would fertilize the trees with 10-10-10 fertilizer at the rate of 1 lb of fertilizer per inch of trunk diameter scattered around the tree and watered in good.