leaf drop on lemons

A friend planted a lemon tree a couple of months ago. It now has large lemons on it but about a month ago the leaves started turning yellow and dropping. Any ideas why? I've read that over-watering (which his wife does) and over-fertilizing (ditto) can be causes. They haven't mentioned seeing any insects.

Thanks!

I think you just answered your own question.

Once a tree is established, you can and should, cut back on the watering. Tell her to cut the watering down by 1/3rd and see if the new leaves show improvement. Hard for me to say how much to water because it really depends on type of soil and current weather conditions.

Hope that helps....

Can you get a picture of the overall tree and a picture of the leaf? I might do better at identifying the problem with a photo...