A plea for help: this white crusty substance is killing my jasmine plants which I have brought inside for winter. It forms on the stems and winds up drying the leaves and eventually the whole plant dies. I've already lost one (it was the oldest), now the second to oldest is succumbing, the younger one has some on it. I notice that the other young one I have in the opposite end of the apartment is just fine, though. I'm afraid to bring the one that only has a little near it! Any ideas?