I think starting with disease resistant varieties helps.....I know mainly this variety of peach, blood cling, and have been able to harvest successful crops many years.
https://permies.com/t/23607/trees/Propagating-Blood-cling-Peaches
I start 'knocking' the tree soon after the bloom and continue for awhile to avoid a lot of curculio (the worm found at the pit of the peach when mature). Apparently they lay an egg in the early early fruit set. I think you are supposed to do this with a sheet on the ground to then catch and squish them but I find it works OK to just gently knock once or twice a day.
I look over the trees thoroughly over the winter and prune out dead stuff and scrape all of the bark gently.
I also pile
wood ashes against the trunk to prevent borers....when the ashes are wet I smear them up the trunk also.
I pick off mummies and shake to thin the fruit on the tree and then try to pick up as much as I can and throw it off in the woods.
I think peaches are a bit harder to grow organically than other fruit, but well worth it.
We just appreciate them the years they do well and figure they are getting a much needed rest in the years there is no crop.
We've moved away from these trees just last fall...writing this makes me want to go visit them
EDIT...this variety rarely has brown rot although when we have a humid wet summer it's unavoidable. The years they do the best is when there is no killing freeze of
course and when it is a wet spring and a dry, low humidity summer...then I
water the last month or so before they are expected to ripen.