The first thing that comes to mind is Xanthopastis timais the Spanish Moth or the Convict Caterpillar. I have never seen caterpillars that large but they sure can mow down Hymenocallis as well as Hippeastrum and Crinum. I have seen them eat scapes as well as developing seed and seen them eat the upper portions of the the bulbs even in native patches of Hymenocallis occidentalis. The colony of Hymenocallis recovered as the bulbs resprouted from the bulb plates but it took two years for them to do it fully. -- Alani Davis