According to this article, the best home method is to get a free range dog. ;) There are some other ideas here that might help you. Wishing you the best.
I don't have problems with deer, but I have been told they don't like mint, lavender or vanilla. Could put some in spray bottle and spray the tree, and it won't hurt the apples.
My co-worker says they do not like sage either.
You can also consider a motion-sensored sprinkler. It would shoot water when motion is sensed, and scare them away from the apples. Good luck!
We had issues with them eating our tomatoes (during a bad CA drought) so we sprayed the plants with a pepper oil we made from boiling habenaro peppers. Be aware that if your boil them too long or too many you could experience some stinging in your eyes lungs. We didn't notice any issue when we ate the tomatoes because we'd watered them and the oils washed off by then.