I am trying to grow an apple tree in Texas. Its suppose to be resistant enough to survive here. I see the leafs have been curling for 3 months now but look healthy, no browning. I dont know if its just the heat or something else i do water every 3 days after checking the soil with a moisture meter and tree-prep fertilize once month. 4 months ago i noticed 2 leaves inverting and saw a few aphids and spayed them once and have not seen any more or ants either that were feeding on them. But the leafs have now curled mostly inward. May be nothing, may just be babying it to much. I have seen a cacoon like spider webbing on one leaf but wipped it off and never seen it again so no pics on that. Any advice?

how much water are you giving it each time?

based on the pictures, it looks like it is just the leaves on the ends of the branches, is that accurate? Aphid damage stays with the leaves, even after aphids are gone. That curl looks a lot like aphid damage. I'm not certain, but my guess would be that it is left over damage from the aphids. If that's the case, it isn't a big deal. The tree doesn't care much and the leaves won't be getting any worse over time. My little apple tree has a patch from when the aphids were there too.. it is kinda like a timeline. heh. And THESE leaves are the ones that were new when the aphids hit...