@pclark42 it could well be scab. Not much you can do other than clear and destroy/dispose of all fallen leaves but a winter wash may be of benefit (easy to spray while they are relatively small) and these days those are based on plant oils, so not poisoning anything. I would be careful to keep them deeply watered during any dry spells and mulch the ground beneath with home-made compost in the autumn, if you can.
Scab is very common and usually not too damaging, but trying to keep trees as healthy as you can is the best defence.
A trowel in the hand is worth a thousand lost under a bush.
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I gave up on the apple trees I had here. It was becoming a chore to keep on top of the scab rather than a pleasure having the trees.
I live in west central Scotland - not where that photo is...