Answer: I don't know whether your trees have developed a disease or the spots are caused by an environmental condition. If the orange spots are integrated into the tissues of the the leaves it can be that they were burned - either by chemical overspray or water droplets on the leaves in the hot afternoon sun. If the orange spots are raised, it might be the beginning of a fungal disease called rust. I'd collect a few of the affected leaves and take them to your local cooperative extension office, Master Gardener plant clinic, or well staffed nursery for help with diagnosis. Once you have a confirmed diagnosis you can take the appropriate control measures (if any). Best wishes with your apple trees.
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