This is a photo of a tobacco hornworm, the caterpillar of a Carolina sphinx moth (Manduca sexta) feeding on a tomato plant at Distant Hill Gardens. The tobacco hornworm, is closely related to, and often confused with, the very similar tomato hornworm. Both feed on plants in the Nighshade Family. The tomato hornworm is the caterpillar of the five-spotted hawk moth (Manduca quinquemaculata).
Note the Red horn at the tail end of the caterpillar, and the seven diagonal lines on its side. These identify this as a tobacco hornworm. The tomato hornworm has a Black horn, and eight V-shaped markings in place of the diagonal lines.
This is the same tobacco hornworm seven days later. It is covered with cocoons of Cotesia congregata, a species of parasitic braconid wasp. They lay eggs in the bodies of tobacco hornworms. The eggs hatch inside the hornworm and the larva feed internally, later to emerge from the body to spin their cocoons.
If you find a hornworm with these white cocoons, just let it be. Young wasps will soon emerge from the cocoons and lay their eggs in other unsuspecting tobacco hornworms.
Note: The insect on the body of the hornworm is not a braconid wasp. I'm working on getting a positive ID. Do you know what the insect is?