Judith writes,
As a possible preventative, I have, just this fall, cleared an area a foot or so from the trunk down to bare dirt and will try to keep it that way...the idea I read was if you could keep the larvae in the soil stirred up they wouldn't make it to the trunk? doubtful but not a lot of effort to do.
I have had good luck clearing away the debris about half way to the tree's trip line to keep borers away from peaches, plums, apricots, cherries and almonds. My understanding is that the peach tree moths lay eggs in and around the lower part of the trunk throughout spring, summer and early fall. Removing the ground litter near the trunk gets rid of some of the eggs, though the base of the tree remains vulnerable to borers under the bark. Carefully examining the base of the tree while the ground is cleared allows me to see if any sap is running. When I do see a bubble of sap, I assume a borer is at work. I pull the sap away and use a heavy duty stainless steel basting syringe (cooking gadget available at Walmart) to inject neem oil into the hole.
To further protect the ground, I plant garlic around the base of the tree in autumn since I'm clearing the ground anyway and garlic is generally a good bug deterrent. Pulling the garlic in spring is another opportunity to clean up and poke around for signs of larve.
Since using this approach for about 20 years, I have never lost another stone fruit tree. I hope this works for you Judith!