Yes I read about Agasphaerops nigra attacking bulbs and underground stems Sue, but the person answering on extension.org thought it could be Agasphaerops nigra. I guess they tunnel up the stem, or down it, need to do more research on it.
I see you've done more research on it Leslieray.
The white may be pith, which suggests something has bored it's way in or out of the stem. It reminds me of woodworm which push chewed up wood out of the hole which happens I think when they escape but I need to refresh my memory on that.
