Q.peach tree fungus
Rotten peaches, mold and mildew – is it ok to treat peach tree while there is fruit on it?

The application of Green Cure fungicide is earth friendly and about as safe a treatment as you can get. Here is a link to their website, check it out: http://www.greencure.net/
I have used this product on my rosebushes and on my cucumber and pumpkin crops successfully for several years. If you have another product of choice you wish to use, read the label on the product well to see what it says about spraying while still bearing fruit, or call their 800 line if the label information is not clear.