Inspect very closely. Is there any webbing at the tips? Did the problem start near new growth, and then spread to the trunk and older growth? It sounds very similar to the spider mite-like plague that has been sweeping the Keys the last few years. If so, be careful, it is extremely aggressive, and can sweep through a yard, vanishing otherwise healthy plants in a matter of days.
If this were the case, it requires frequent spraying of Neem oil to keep it at bay, and occasional blasting of water, as well as making sure your plants are well watered generally - two days in our scorching summer sun with no water can be enough to make it more susceptible. But of course don't overwater - just make sure they get some. And plants that get it the worst (usually with tender new leaves), need to be scrubbed with a soft bristle brush and mild soapy water along the entire trunk and up under the leaves on occasion to get rid of it. If you are unfortunate enough that you have what we have down here, good luck - it is very aggressive and comes back over and over again. Sugar apples grow naturally in our soil and shouldn't take almost any work at all to keep alive and happy - hence why they used to be a commercial crop in the area. So assuming you weren't doing anything to alter it, and it had been happy all this time before now, it sounds like the kind of scenario that happens a lot down here. You'll have to throw away all debris from the dead plant (DON'T put it in composting or yard debris pick-up, which will cause it to spread), and you might find that the same spot if you plant a new one might be susceptible again - but if you are willing to stay on top of it, you can keep it at bay.
Maybe this is not the situation, but you are not far from the Keys, and what you describe sounds a lot like it - sudden and rapid death with no clear cause. First it will look like slight wilting, like the plant is a little thirsty. Then it goes from yellow to brown in like a day or two, with the new growth starting out brown, and before a week is over it's dead, hard and dried up all the way down through the roots, with nothing salvageable at all.
This problem has cost me thousands of dollars and a ton of my time in the last few years. You can see signs of it around usually, in other plants in the area - where suddenly one will go brown and completely die, or branches will, in the midst of a bunch of plants that are fine. New transplants are especially susceptible, but it can kill plants that have been healthy for years, too. Seagrapes will look fine, but they have stems that look charred, and if you look very closely they will have tiny webbing - they never ever get to the point of producing grapes, because the mite kills them as soon as they start to grow, but the seagrape leaves are tough and hard to penetrate so the trees live. I notice it is in at least 60% of the seagrapes I've seen, throughout the entire 110+ miles of Monroe County. I seems to spread via bees or the wind, and definitely by plants that touch each other with their branches - they crawl I guess from one to the other, but whatever it is exactly is so tiny I have never seen it with the naked eye.
If none of the other explanations people have offered sound like the answer to you, cut off a dead piece of branch and look closely, assuming the crazy storm conditions lately didn't destroy all the evidence already. It might be "the plague."
Topic: Help: Sudden annona squamosa (sugar apple) decline/death (Read 1843 times)