I have got a Acer Palmatum deshojo one year ago and the leaves started to become dry.
I keep him on balcony on direct sun, water him once a day, sea is very near and sometimes there is wind but I try to keep him as much as can protected.
I also noticed something brown with some like cotton under it and I removed all (see on picture). I'm planning also to put it in a bigger pot .
I uploaded the tree photo can someone help me?
At this time of year it is normal for leaves to start to die off. As long as it is outside it will be fine, it is hardy. Do not repot do not add any fertiliser, slow down on watering as the leaves drop. Once the leaves are gone only water when the surface starts to dry, Outside this may only be once a month, just keep an eye on it. Next spring you can repot.
Ok I will follow what you told me thank you, only I'm surprised that the leaves didn't turned red. During summer I was not able to keep it on sun and just one week ago i started keeping him on sun as temperature drop bellow 30 deg C (presently 24 deg C).
dry leaves on a maple with outside temps still in the 20+C means something else than fall is going on. In your climate, you should have had nice fall colors.
Do share pictures. I am concerned you may have a tree with damaged roots.