I have heard window screen mentioned as a protection from peach tree borers several times over the years and have recommended it for people growing peaches organically. So far I have no reason to question its effectiveness but it is certainly more time consuming than a single squirt of Lorsban once a year. I recommend attaching it with something that stretches, like rubber (not vinyl) electric tape to avoid possible girdling although vinyl will work if you re-wrap annually.
[NAFEX] window screen as borer barrier,
Alan Haigh, 11/06/2008