As a personal rule for tropical plants, IÂm not sure what others have experience but leaves that turn yellow and drop arenÂt such a bad thing, for me it usually means something stressed the plant and its going on coping well. Leaves that turn yellow and DONÂT drop has usually been a very bad sign for me.
I seen large potted plants moved from one location to the other, either getting more shade or more sunlight, or whatever reason, starts to defoliate.

As for the cherimoya, it could be several reasons but maybe the rain triggered it to defoliate. I usually start defoliating the leaves myself in the beginning of the year. But this past year was the first time I seen my large cherimoya defoliate itself, I think it had something to do with the heavy rains we had. I had also read somewhere that in South America the rainy season is what triggers it also. Either way once it defoliates you should start seeing new growth and flower buds. Keep an eye on it, hopefully its just this!!!

Oh thank you Eggo, I feel much better now! I was hoping it was just some sort of stress. Hopefully I can put it in the ground soon, once we get more truckloads of good soil in to make more planting "hills."

Lisa