bacillus thuringiensis - spray your plants when young and when you plant them in the soil... Another way is to put bird feeders around the garden. birds come in to feed and see a big fat juicy horn worm and cant resist it... 1 last option i can think of is to use up-side-down gardening techniques.. use fresh soil thats not from your garden.. These thing can eat like theres no tomorrow.. i had them where i used to live.. good luck.