Wasps and hornets strike fear in many, but with Terro® wasp and hornet killer, you can kill these dreaded pests on contact. Terro® wasp and hornet killer is an entrapping foam spray that coats nests for a complete kill. The entrapping foam not only kills wasps and hornets inside the nest, but it also remains on the nest and kills unsuspecting insects that have the misfortune of returning.