about 2 years ago, i germinated a silk floss tree seed and now have a tree about 20" tall. It has been doing well for its whole life - the trunk is thickening nicely and the tree is a nice green color. There have always been lots of leaves, most of which fall off, but lots of new ones come out so it's all good.

It's planted in a ceramic pot with no drainage holes on the bottom. it's been in there for over a year with no problems. I have been watering it about once every 7-9 days or so. it does great.

I went out of town a few weeks ago for about a week and came back to find that most of the leaves had dropped off and only one small one was left. In addition, a new one was emerging from the middle of the plant. Both of these leaves were black on their tips. A few days later, the whole leaves were black. A couple days after that, one leaf shriveled to black and fell off and the one growing out of the center was also shriveled. The top half inch of the plant is now starting to shrivel and get soggy almost to the point where it's bending a tiny bit. Today, a little more of the top of the plant is shriveled and it seems to be moving down the length of the tree.

Incidentally, I also have a large silk floss tree with a top canopy of leaves and then a lower canopy of leaves. After being in some hot sun here in phoenix, the leaves on both growth levels started to turn black and fall off, just like on the baby tree. The lower area regenerated just perfectly and is quite healthy now, but the canopy on top is all black-tipped and shriveled, on virtually every growth tip. No new growth is visible.

I'm very concerned, primarily about the younger tree, since i grew it from a seed and it is special to me. I don't know what to do to preserve it. I'm tempted to cut off the bad area, down to where there's solid (not soggy) tree, but maybe this isn't the right thing to do. I may have fungus gnats, or even whiteflies, as i've seen some things flying around. Should I cut it? Should I get some fungicide instead?

Any ideas? Here's a picture: