When I have horn worm damage on my tomato plants, I follow the poop. They are usually just above it. And I also flip old poop off so I can follow the new and not waste my time with the old.
Tomato hornworm metamorphs into the Five-Spotted Hawkmoth, aka the Hummingbird Moth - quite the delectable creature.
My avatar is a Hummingbird Moth (from a tobacco hornworm, closely related)
