Hi there. Could you post some photos of the leaves?

Spring is not an ideal time to plant a tree, the best time is autumn. If you did not give the tree sufficient water ( a few gallons at least weekly, twice weekly in hot or dry spells) then I'd expect leaves to brown and fall off as evidence of insufficient water at the root. It takes a couple of years for a tree to form wider spread roots than the rootball it had when you planted it, and until it does, you need to water it well.

You say its dwarf - if its on Pixy rootstock, it should also have been planted in such a way that nothing else is growing for 18 inches all round at the base of the trunk, including grass. And hopefully, planted into a well dug area which had been emended with composted animal manure or good garden compost beforehand.

Hard to say what the holes in the leaves might have been caused by without seeing the problem, but if you have not been watering as described, then leave the hose trickling at the base of the tree for a couple of hours now, and ongoing, keep watering until winter arrives. It may leaf out again this year, or next spring. If you didn't prepare the soil properly beforehand, once the soil at the base of the tree is good and damp. mulch with composted animal manure or garden compost, but don't allow the mulch to sit against the trunk of the tree, leave that clear.