Q: This grub and small ants are in the crotch of my large maple tree. What type of grub is it? How should I treat it?
A: This is one of the many bark borers that afflict trees. It may be a longhorned borer larva.
The adult beetle bores in to a maple trunk, lays eggs and the larvae tunnel beneath the bark.
There’s not much you can do to the borer while it’s under the bark.
Your best bet is to spray the nearby bark with a garden insecticide three times per year, March, April and May.