It is powerdy mildew on those leaves in the last pic. Question is, did the mildew form on the leaves after death or was the mildew the cause for the trouble. Usually powdery mildew forms on the new tip growth or in areas of poor air circulation. In your case it appears as though it is plenty open and the new tip growth doesn't "appear" to be infected. You likely had a ton of rain right? Have you recently applied a fungicide. If so, what did you use? What type apple is this chiilipete? Check that new tip growth to the right in the photo. It looks kinda white...is there any sign of white powdery/fuzzy stuff? The more I look at the pics, I think powdery mildew was the culprit. Looks like there is still some there on the good foliage...can't tell. Sulfur is the best remedy for powdery mildew in my experience.

Anna's will go dormant but still have some leaves left on. If it is an Anna. Phoenix has had some very low night temps in the last couple of weeks and I agree with avid that it is going dormant. I am much colder (snow) and some of my apple trees still have some leaves. The rest of the orchard is leafless. I would not worry. If you receive no rain in the next couple of weeks then you may need to water a LITTLE. Even though it is dormant it needs a little water. Just FYI never have a landscaper pick out your fruit trees, plant them or trim them. Bad idea. If you need help you can come on this site or go to the fruit/orchard site and people will be glad to help you and you will be glad you did. Camp Verde

I have an irrigation system and it is watered every other day. With the rain, it's getting rain pretty much daily. I spread out the roots all around with a little buried a little to try to emulate established roots that went out as far as the canopy. I put down a time release fertilizer that was supposed to good for fruiting trees (can't remember what kind) shortly after planting. I just don't get it. I know its been very hot temperature-wise, but it hasn't been too dry. I haven't let it go more than 3-4 days if we haven't gotten regular rain to bring the hose over and throw a few gallons more water as I read the young trees need a lot to get established. I appreciate the reply. I'll keep up the watering as of now. It just looks like the trees stressed. The only thing I had an issue with until now was some aphids that I cured with a spray bottle w/soap occasionally. I noticed the leaf tips we're turning in. This most recent issue has come on *quick*. The other 3 trees look fine, one of which is a bit smaller Fuji as well and is probably w/in 20 yards, though it gets a bit if shade.

Looks like its getting burnt to a crisp. When did you plant it? If it doesn't have any roots set up, it's getting blazed with hot sun, and you fertilized it, I think that would cause the burning. There could be something wacky with your soil too.