I don't think this is leaf curl. The tree is growing under a glass roof, doesn't get direct rain. It's irrigated, so moisture supply seems adequate. The leaves don't unfurl but have no sign of discoloration or deformity. If unrolled they look completely normal. The tree is a four-year-old Frost on a dwarfing rootstock. Growth has been poor, less than 6 inches on the main leaders last year, and about a third of them have dead tips this spring. Last year most of the leaves were affected, this year maybe a third of them. The tree has set some fruit, about a dozen of them are growing normally. Nutrient deficiency? Nematodes? What do you think?
I think it isn't leaf curl because the leaves don't develop any of the characteristic discoloration or blistering distortion that I've seen in all the other cases of that disease. Also the tree is under cover and does not get rained on, which is how I believe leaf curl is spread. Am I wrong about this?
