My Baldwin and Orleans Reinette seem to do that too. Doesn’t seem to bother them.
How’s the moisture level in the soil, are they wilting?
I looked at the pictures earlier (my wife thinks the photos are beautiful, by the way) but didn’t say anything because I’m not sure I’m on the right track, but I thought that maybe the leaves are curling to conserve moisture because some mite or aphid is trying to suck the life out of them. But that’s definitely just speculating.
Leafhoppers can cause leaf curl like the picture
It’s been dry, but I’ve been watering.
Mine are doing the same. I don’t remember where, but I just watched a youtube video a couple of weeks ago that said leaf curl can come from a large disparity between daytime highs and overnight lows.
Both my goldrush on g.222 are showing severe leaf curl (like your picture above). I’ve started watering weekly (2 5 gallon buckets, trees are heavily mulched) several weeks ago, and the foliage is still curling. It is putting on fresh growth though. I think it doesn’t like the heat. It’s been above 95 F for the past few weeks and hasn’t rained.
The odd thing is my Akane on g.890 barely has any leaf curling, and the varieties on M.111 are not curling either. William’s pride on g.210 was curling, but seems to have calmed down some (some curling, but no as bad as your picture). Only a little curling on the Arkansas Black on g.41.
From my broken off fruit trees, curled leaves, lack of water. Definitive.
I’m watering tonight since, once again, the humongous storms everywhere on radar managed to stay just far enough away for me that we didn’t get a drop of rain.
All 4 of my apple trees are doing the same thing (and a lot of my other plants too). Not sure if it’s a lack of water, the soil is fairly moist an inch down. It’s been hot here though all summer, and they have full sun all day. I wonder if it’s more due to high heat and a bit of sun scald? I’ve heard that plants do that as a reaction to conserve moisture, and that once a leaf curls, it does not uncurl later on even after moisture levels have been restored.