Locust tree leaf curl
I live in Albuquerque NM about 5000 feet elevation. in general I have good soil. I have several Locust the purple and white flower variety. The Purple does seem to have a problem with a fungus each year where its leave get splotchy and white. I do have a single problem with another variety of locust which I cannot tell you the exact tree name. the leaves are curling up like when you might stretch out your hand flat and then curl up your fingers into a fist.
the leaves are still green but the tree will also loose half the leaves. the tree is about 3 years old about ten feet tall and espicall slow to grow compared to the other varieties of Locust like the purple. I give it a deep watering once a week I have given it a tree fertilizer spike at the beginning of the growing season and later on some fish fertilizer toward summer. When I plante it I made sure the roots were in a good sized hole with fresh garden soil.