Of my 6 apple trees, this is the only one showing any spots. There are 5 different varieties (braeburn, golden delicious, macintosh, winesap, fuji) grafted onto this tree. I want to do a closer inspection as it seems that the yellowing leaves may only be on one variety (the Macintosh?)
I have issues with Cedar Rust in my area, so I have been spraying all of my trees with Immunox on a regular schedule. Over winter I used neem oil and copper mixture.
Anyone have any guesses? Could it just be stress from heat and drought?
Probably this. Younger trees are more drought sensitive than older trees.
Older leaves turning yellow / spotted is pretty normal. As long as the tree is putting out new growth and the new growth looks normal everything is probably fine.
I don’t think it’s aphids. A lot of times aphids cause leaf curling and distortion especially rosy apple aphid. Aphids are easy to see if you check the back sides of the trees leaves. You could check the back of leaves and see if you see any but I don’t think you have them. Here are some aphid links.
Often the small leaves that are formed when the trees first leaf out in the Spring will yellow and drop while the larger leaves are green and healthy. This happens on some of my trees.
The leaves look like they may have scab. Purdue University rates McIntosh as very susceptible to scab and resistant to cedar apple rust and powdery mildew. So it could be scab.
It’s possible it’s some kind of leaf spot but I think that is less likely. Here is some links to leaf spot.
