My coworker's family runs an orchard. He claims that there is basically no difference between organic and non-organic fruit. (He said vegetables are another matter.) It's just marketing so they can charge more, he says. They apply pesticides to both, only different types. He said that the FDA/USDA require fruit producers to use pesticides, and if they didn't the fruit would be so infested with insects as to be uneatable. A small home fruit tree might be able to get by without pesticides, but not a commercial operation. He also said that one difference is that on "organic" fruit they may use manure instead of nitrogen fertilizer, with the result that there may be dangerous bacteria on your organic fruit. Make sure to wash them well!
Another person online said the same thing.
But I don't know if it's true.
This article from Scientific American says organic farms use pesticides:
An online search yields mixed results. Some sources are suspect (might be industry sites). These sources seem reasonable and inconclusive about the health benefits of eating organic: