Welcome to permies Terry!
It sounds like you got the borer in that hole, their
should just be one per hole.
Borers are usually a sign of a stressed tree. Mine were stressed once due to being in a wetter spot and had a few borers, since peach
trees like well draining soil. I eliminated the borers and helped the water drain away and they recovered, and I haven't had any borers since.
Best of luck Terry, hope you get some good peaches soon!