[Sarajevo]

It looks like a nitrogen deficiency. This link may be helpful:

Citrus: Identifying Disease and Disorders of Leaves and Twigs

[rightly_dividing]

Thanks for that link. I was afraid that it was too much nitrogen. When my wife came home after I posted the question, she said she fertilized it with some nitrogen that we had on hand, about a month ago. It was repotted during the spring, but don't remember just when.

It's all we can do to grow stuff, diagnosing sick plants is beyond us altogether. This same plant dropped all it's leaves once before and died. What we currently have is a sucker that came up much later from the root.