Ursula, there could be other things causing or contributing to your baby bulbs' disappearance. I think botrytis helps weed out the weak among mine, but add things like getting too dry then too wet, too hot, too cold, competition for nutrients and light, animals... whether they like the water and potting mix I'm using, pH....
If the leaves have been healthy before dormancy but then foliage doesn't return, I don't think botrytis would be the cause. I don't think it attacks the bulb underground.
