Apple trees look like they have been caught by weedkiller
see photo what is the cause is it insects,virus or chemical no aphids to be seen
I does look like typical aphid damage.
If there are no aphids to be seen, maybe ladybird larvae have already visited and eaten them all.
That's exactly what I found on my blackcurrant bushes. Masses of aphids causing similar leaf damage, then the ladybirds finally arrived and have cleaned them up nicely and new leaves look good - but not many blackcurrants
Chemical damage from over spray I guess is a possibility, but most of the older leaves look good.
Knowledge is knowing that a tomato is a fruit.
Wisdom is not putting it in a fruit salad.
Thanks Pete.8 could be the reason no aphids around cheers