From https://extension.umn.edu/yard-and-garden-insects/tomato-hornworms
Caterpillars
- Hornworms are among the largest caterpillars in Minnesota and can measure up to four inches in length.
- Small tomato hornworms are yellow to white in color with no markings.
- Large caterpillars develop eight white, V-shaped marks on each side.
- Tomato hornworms have a black projection or “horn” on the last abdominal segment.