Leaves Curl, Yellow on Honeycrisp Apple
I have an approximately 6-7 year old dwarf Honeycrisp apple tree. Every year toward late summer leaves start to curl and yellow. People at the local greenhouse said it could be low iron so I treated the soil with iron. Several years ago they said red mites, so I sprayed tree for same, even though I didn't see any mites. This is the first year it has some apples albeit they are few and small. Three other 20+ year old apple trees of various kinds are close by and have had no such problems. Any ideas would be appreciated.
Olmsted County Minnesota honeycrisp apple
I can't be sure without seeing the tree or sharp photos of the leaves, but it may be affected by a physiological condition specific to Honeycrisp called leaf zonal chlorosis or Honeycrisp leaf complex. Mottling and curling are typical symptoms. The complex isn't caused by disease, insects or nutrient deficiency and usually doesn't affect the tree's growth or productivity.
Compare your tree's leaves to photos and information at the following websites: