Well, first things first: it's a Dracaena fragrans. I think. The reason why it hasn't attempted to grow back any of the lost leaves is because it can't. All you can do when you're a Dracaena is get taller or branch, and branching would only be likely if it had grown mostly horizontally for a period of time, or if it had flowered. So it gets taller. Is there a way to regrow? Well, kinda. You could cut the plant back, at which point it would be forced to sprout new growing tips. Or you could air-layer (.pdf file) and start over again with the tops of the plants. The more interesting question to me is why you're losing so many leaves in the first place. Granted, keeping your plant alive for two years is an accomplishment in and of itself, but the leaf drop looks like a fairly extreme case of something or another, too. It would like more light, though that's not why it would be dropping leaves. Soil breakdown is a possibility, as is over- or under-watering, fertilizer buildup, and temperature. Pests are an outside possibility, but these aren't really known for having pest problems, and most pest problems would have progressed well beyond obvious by now. So. When you water, do you pour water in until it starts running back out, or do you only add a little bit at a time? Does the plant ever have to stand in a saucer full of water? Is the plant in a draft? Is the plant in the path of an air conditioning or heating vent? How long has it been since the plant got new soil? Is the water in your area naturally high in fluoride? How do you decide when it's time to water? (by schedule? by feeling the top couple inches of soil? by weight of the pot? whenever you remember?) Are there roots coming out of the bottom of the pot? I'm going to go ahead and bet $10 on soil compaction and/or rootbound: that's a lot of plant for the size of the pot it's in. Unlike saucer, I think I would go up a pot size unless you're planning to cut it back, and if it's as potbound as I suspect it is, I might move it up to the next largest size regardless. If it were my plant. Which it is not. Look at the roots first, like saucer said.

If, under magnification, you have no reason to think it's related to a living organism, it might simply be dissolved solids left behind from an exudate - sort of like the limey deposits often seen of tea kettles or plumbing. Sometimes, either by the process of guttation or through mechanical injury sites, sap is forced from the plant under pressure. When the water in the exudate evaporates, whatever was dissolved or suspended in the water - sugar, mineral salts, resins, ....... is left behind. Al

How is your drainage? Is the soil staying soggy? Don't fertilze it yet; repot it in some African violet soil mixed with course sand and just a little nitrogen and Phosphorous 1-0-1 and a little chelated iron-half-strength, and trim any diseased roots. Trim the blooms; the blooms take away energy needed for recovery. Keep it a semi-shaded location out of the rain and cold. Water just to keep the soil damp as a sponge. Trim as much top growth as you do roots. Don't fertilize again until you see vast improvement, then use a good citrus fertilizer and gradually acclimate it to full sun. Good luck

That's interesting--most years when it's dry we have trouble with the fig leaves turning brown and yellow and falling off. This year with all the rain they're staying beautifully green. I think it's a fungus, but somebody I believed (but I don't remember who!) told me not to worry about it, that it wouldn't hurt the trees and spraying would be expensive and not very effective. For what it's worth----