Okay, well I'll be honest....I'm not much for separating pups from plants. Usually I don't have anything large enough or enough of them to even bother. So the other day, I was watering one and happened to move my hand quickly past the pseudostem of my super dwarf cavendish and accidentally broke off a small pup that was growing off the side of the corm.
The story behind this pup was that the main plant in this pot stopped growing over the winter and died back to the soil (and was cut off just above the soil). The plant was replaced by a pup and grew into a new main plant. From the side of the old pstem (about an inch remained firm above the soil line) grew a new pup.
Anywho....it was really too small to transplant off, but I broke it off and it had NO ROOTS. But, rather than toss it, I figured, I'd try to keep it going. So I placed it in a shot-glass with water in it till I figured out what I was going to do to it. I kinda forgot about it for a week or so....didn't do anything with it except make sure it had water in the shot-glass. So I pulled it out and low and behold it has a bunch of roots now! Totally ready to be planted now....and I have no doubt it will be just fine!
So for anyone who has a prematurely separated pup with no roots (or very few)....just place it in a glass with some water and forget about it. I've heard a lot of people that have lost pups when they were separated too early, and apparently they root just fine in plain water (had nothing added whatsoever). I guess give it a try...I'm kinda surprised it didn't rot, but no rot at all.
Here are some pics of the pup before:
Pup that got broken off is at the bottom of the pic growing off the old pstem (the kinda sunburnt-looking one).
Here's a more recent pic of the pup before it got broken off (on the left).
And here's what it looks like now:
