Hm, the leaves are really going reddish, rather than brown. You didn't have a sudden cold snap recently, did you?
I'd try a douse with some dissolved Epsom Salts - about a tablespoon dissolved in a gallon of water. It is basically magnesium sulphate, and magnesium deficiency can look like that, a reddish color to the leaves. If it doesn't respond, by greening up again, then another solution might be the ticket, but the Epsom salts surely won't hurt. If it does work, you'll see a difference in color in a few days, and you should put another gallon on after a week or so.
Have you given the tree any fertilizer since planting it? A balanced, timed release pelleted fertilizer for fruit trees would be a good idea about now if not.
I hate to say so but that little tree is really much too young to support producing fruit. The first year after you plant a fruit tree, you really should remove all the fruit to let the tree grow a good root system and lots more leaves. Nobody likes to hear this advice, I know.
