When the eggs hatch, they begin to feed on the tomato hornworm internally. Once mature, the larvae chew their way out of the hornworm, spin a small cocoon and pupate. When the adult wasps emerge from their cocoons, the hornworm dies.
So if you see a tomato hornworm covered in small white cocoons, just leave it because it is hosting a new batch of parasitoids that can help rid your future garden of hornworms in about the most nature-friendly way we have. And I think most gardeners would call that a good thing.
Paper wasps are ones that most of us are probably familiar with, as they build those paper-like umbrella-shaped nests you have probably seen under the eaves of your homes or any number of other places. While they can sting if disturbed, they are mainly out there looking for food for themselves and their young. These wasps can