what have you tried so far? what are you fertilizing with now?

what have you tried so far? what are you fertilizing with now?

It only happens to the older leaves. I use foliage-pro on it.

Looks like nitrogen deficiency to me. Not sure why your foliage-pro isn't fixing that though. Do you divide the total annual amount up and apply it in several small amounts at watering between Jan and Sept? Since it is related I would assume a white sapote would be fertilized like a citrus.

the plant wasn't doing to well when I first got it. It almost lost all of its leaves, until I started fertilizing it with foliage-pro at every watering. It responded well to it and shot out new growth, which is what you see are the healthy leaves up top, but then a few days later the older leaves started to turn yellow and get the black blotches on it and fall off easily.

I'll try to give it more nitrogen next time I water.

It might just be dropping the older leaves?? The new ones sure look good! I've discovered the same thing as you with my little sapote: they are pigs and like a lot of food. Mine really languished until I started giving it regular fertilization (I do about every other week when it's actively growing). Mine is NOT a show piece, hah, but at least it's somewhat presentable. Keep us posted. Happy gardening!