Hi! I have three each trees. One, in particular, about half of it's fruit is turning brown. It starts on one side then spreads. As well as a bit of the fruit is falling off. I fertilize it with an organic mix specific for stone fruit trees. Three times per year. Thanks for the help!!
Sounds like your peaches have brown rot, an extremely common problem in peaches in Maryland. Many people elect not to grow peaches for that reason. To control brown rot spray with a registered fungicide starting at bloom stage and then roughly every two weeks until two weeks before harvest. Even if you spray, you may still get brown rot. http://extension.psu.edu/plants/gardening/fphg/stone vw