According to http://www.ent.uga.edu/peach/peachhbk/fungal/brownrot.pdf
Wild plum thickets are an important source of spores for both primary and secondary infections. Wild plums bloom before and during peach bloom, and the fruit mature continuously from early to late in the season, providing a continuing source of inoculum. Removal of wild plums adjacent to a peach orchard is an important sanitation procedure.
Unfortunately, I have lots of wild plums which are providing privacy for a place which I sometimes have fires. I waited 5 years for these plums to get tall and thick enough to provide this cover, now I learn I have to remove them if I'm ever to expect a decent peach harvest.
Is there anything economical enough to spray on lots of trees for the sake of a few peach trees? And that isn't going to kill my fish and frogs in the pond I have 500ft downhill from the trees?
I don't expect to ever be rid of the fungus, I just want to make it as uncomfortable for the fungus as I can and without spending much or going to much effort. Ideas?