My Adansonia looked fine Tuesday. Yesterday a lot of the leaves had turned yellow, and today there are lots of black spots on the yellow leaves, and some on the green leaves. I can't find anything that looks like bugs on them, just lots of black spots. Is this some kind of fungus or something?

Weather here has been rain every day. Usually I water it every other day, because they like to dry out. It has been doing fine with that, even in the heat around here. Now, for days it has been soaked. Is that the problem? The forecast is little to no rain for the next week or so, so maybe that problem will solve itself.

Looks like mildew, indeed.
I have not found an efficient remedy yet (Then again, I hardly ever have had to deal with it either).

Ventilation, ensureing lots of air movement can help. And of course, spraying with an anti-mildew product.

After saying no rain in sight we got about an inch and a half.

It is outside and had plenty of air movement, so if it will stop raining it should help. Then spraying it won't wash off. Maybe sun shine will help.

I went to the local hardware super store, picked out what appeared to be a good mildew spray, and read the directions.

It had the usual cautions, etc., and then said I should spray every two weeks, beginning two weeks before the mildew infection is expected to appear.

Shoot, I missed that one.

Ivan wrote:

..beginning two weeks before the mildew infection is expected to appear..

hahahahahah!
"Bend the trunk till just before it breaks."

We need a haha button.

Ivan wrote:

We need a haha button.

Yessssssss!!

Yes, they look like a mildew only. Well, Conditions that favor mildew formation include dry foliage, high humidity, low light and moderate temperatures. I had also found similar powdery mildew on my flower plants, I was also confused about what type of powered it is, then after inspection, I got to know that this powder mildew was caused because of tiny bugs on the plants. After discussing this problem with one of my neighbors they suggested me to contact Best bed bug exterminator NYC or any other and take useful content from them. If Yours is powdery mildew than One of the most common active ingredients used for controlling it is chlorothalonil.

Reviving this one, all the yellow leaves with brown spots fell off, and the rest stopped turning yellow. Now the tree has new growth appearing all over and looks great.

I am wondering if we got it wrong and this was just the end of a short dormant period. Just about six months ago a very similar thing happened and most of the leaves fell off, but there were defsplder mites all over the tree then.

Should have done repotting, etc., a couple of weeks ago? Is the dormant period over?

Elms, crepe myrtles, etc., are very plain about when the dormant period is. How do I tell with the tropicals?