If you are referring to peach tree borers (most common stone fruit borer) they can be found anywhere in the U.S. where peach trees are grown, but are more common in areas where peaches are more common.
The biggest problem with peach borer is with young trees. Once the trees get some age, you can easily see the sap and treat the base with an insecticide. Young trees are a little harder to see the sap until a lot of damage is done.