We planted this dwarf apple tree in January 2010 in Northern California. Initially as the leaves started growing everything looked perfect. Now, starting from the tips of the leaves going back, they are turning a dark brown/black color, curling up and look to almost have a white mildew on them. This is happening on all of the leaves. We believe we are watering the tree enough. One thing I did notice is that the sprinkler system is misting the entire tree every morning as it waters the nearby grass. I have attached pictures of the tree with leaves. Does anyone have any idea what is causing this problem with the leaves? Thank you in advance.