I've only ever seen one of these in the 30+ years I have lived near the Rockies. They are indeed creepy but recently I read they turned into the sphinx or hummingbird moth, which is the most beautiful creature ever. I saw one of those one summer, only once. For that reason, I'm going to leave any future ones I see alone. However, I don't have many to contend with.

Heather --- They've never been a problem for us either, and I tend to leave even the one or two unparasitized ones I see. But we have plenty of parasites to eat them up! Some gardeners report that their plants become totally defoliated by hornworms.

I have found about eight in my tomato patch this year. All but one of them was completely covered by these parasitic wasps. It is really nice to see that my efforts in planting flowers that attract these wasps has paid off. http://earthhomevt.blogspot.com/2012/08/who-is-eating-my-tomatoes-hornworms.html

I don't know what attracted to wasp to my garden - perhaps it's the marigolds - but I'm glad to see the eggs all over that hornworm that I found.

Ruth --- Isn't it wonderful when the garden ecosystem takes care of itself?