I'm not quite sure what eats tulip bulbs, but I seem to have hit on a

solution. The first year we had our country weekend place I planted

tulips and saw not a single one in the following spring. Whatever it was did not eat or burrow through the daffoldils or the bearded iris I planted.

Last year I decided to try again and planted a circle of daffodils shoulder to shoulder around each clump of five tulips. This involved opening a 12-14" diameter hole of the appropriate depth so that all bulbs could be deployed at the same time at the same depth. I covered them all up and when I was up to the appropriate depth, I put in aconite, muscari and crocus. Everything arrived in its turn this spring. The burrowing creatures at the bottom of the garden--moles or voles or likely both--almost killed Madame Isaac Periere by tunneling right under her this year, but avoided the chionadoxa planted in little clumps between the roses. I'm thinking they are planted at just about the same depth as the tunneling denizens of the lower yard and I am going to try tight phalanxes of such things around the ornamentals down there, making sure I have something planted at every depth I've seen the tunnels. It's the catskills, you don't go too deep before you hit rock and the rock attracts the earthworms and the excavations I hog out to put in ornamentals like the roses make easy ground for burrowing creatures.

Don't know if this sort of defensive planting will work in this case, but the iris and daffodils I planted that first year are still there after four years in the middle of mole/vole metropolis. The iris are planted deeper there than I would have done down in Virginia where I come from because of the hard winters, so you'd think they would be subject to mole damage, but I've never found any tunnels under them. They thrive and grow enormous in the mountain climate and I have not seen any rhizome rot issues even though they do have to be covered with about an inch or two of earth.

My suggestion: I'd try the repellant you use and some defensive planting.

Other things down there that have never shown any sign of tunneling damage are coneflower and black-eyed susan, daylilies, peonies and shasta daisies.

The garden backs up against a rather boggy bit of meadow that slopes down to our pond and nothing in that meadow seems bothered and the main residents are an assortment of grasses as well as Joe Pye weed (pink eupatorium) and it's cousin, White Snake Root, white turtle heads further down, solidago in several varieties, blue vervain, elderberry, both the early purple and the later red, cuckoo flower (cardamine p.), false solomon's seal, Canadian Mayapple, an assortment of asters and daisy fleabane, blue cohosh and trout lily at the higher dryer part, wild strawberries and other things too numerous to mention that grow and bloom and contribute to the lovely tumble. More cultivated things that were planted before we arrived up at the dry part where tunneling has been observed are russian sage, creeping phlox and lamium, Mallow and butterfly weed also persist as well as chives. The clump of chives the former owners left behind is now a five foot swath. Onion like plants might be a clue.

Hope there's something useful here.