Question
I found a piece of bark loose and when i pulled it fell off and inside looked rotten.i dug a little and found a large (around 3" long) white worm curled up,it was about as big around as a small finger.I dug more and found a seond one. The damage was at base of tree .I have no idea what they where,can you help.The tree is a purple maple about 45 years old.

Answer
These are insects called borers. If a thin barked tree like maple has a wound the insect will lay its eggs under the bark and the larvae will borer under the bark and into the woody cell. You can cut the grubs out or use a wire to poke into the wound area to kill the grub and then I would spray the trunk area with an insecticide called Merit or Onyx. Check with your local garden type store for these products.

Keeping trees vigorous and irrigated during prolonged drought helps to reduce borer injury. 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.