Most likely hornworm caterpillars. That is what it sounds like as they do like eating buds before they open. They might be hiding as they are green and blend in with the leaves or already gone.(check to see if more damage occurs) I raise butterflies and moths and really love all butterflies and moths but my experience with hornworms is limited. Post this on the butterfly garden forum and ask them what you could do to find the cats and where you could transfer them to. Hope this helps Mike

Let the remaining stem and leaves go dormant just like the rest of you lilies and they will be just fine for next year. In fact, they will be larger and have more flowers than the others--all because they didn't flower this year. Flowering is very stressfull and these now will be able to put all their energy into making a larger bulb for next year.

The type of damage and the droppings point to an insect larva and not a slug or a snail (snails tend to graze across a leaf or bud, leaving holes surrounded by undamaged leaf). Since you haven't found any caterpillars it's probably a sawfly larva or something similar. These look like caterpillars, but hide in the soil near the plant during the day. If you go out with a flashlight just after it gets dark you should be able to spot them. If there aren't too many you can handpick them & dispose of them, otherwise I'd suggest a systemic insecticide (and perhaps a preventative spray early next season before the damage gets done).

From the pic I'm not sure if that's a rose slug or some type of caterpillar? Our curled Rose Slug does munch alittle on buds and I find them inside the petals once in awhile but not often... -------------------------------------------------------------------------------------------------------- How can you tell the difference between a sawfly larva and a caterpillar? Count the prolegs. Caterpillars may have up to five pairs of abdominal prolegs (seeparts of a caterpillar diagram), but never have more than five pairs. Sawfly larvae will have six or more pairs of abdominal prolegs*. Another notable difference, though it requires a closer look, is that caterpillars have tiny hooks called crochets, on the ends of their prolegs. Sawflies don't. Another, less obvious difference between caterpillars and sawfly larvae is the number of eyes. Caterpillars almost always have 12 stemmata, 6 on each side of the head. Sawfly larvae usually have just a single pair of stemmata.