Stop Hornworms in Your Garden

Tomato hornworms can strip plants bare overnight. Learn how to protect your crop.
Identifying the Pest
Hornworm larvaSphinx moth adult on bergamot

Tomato and tobacco hornworms are large green caterpillars (up to 4 inches long) that feed on tomato plants. Tomato hornworms are more common in the North, while tobacco hornworms are more likely in the South. In addition to tomato, they feed on closely related plants, including tobacco, eggplant, pepper, and potato.

Identifying the Pest

Hornworms get their name from the prominent "horn" on their rear end. The tomato hornworm has a black horn and eight yellow or white V-shape marks on its side. The tobacco hornworm has a red horn and seven angled white stripes on its side. Because they are green and blend in with plant foliage, gardeners often don't see hornworms until they have grown large and caused significant defoliation from their feeding. They usually eat leaves, but may chew on developing fruits, too.

The adult is a brownish moth, variously known as a hummingbird moth, sphinx moth, or hawk moth. If you see grayish brown moths with thick bodies hovering over plants, be on the lookout for eggs and small larvae. Eggs are oval and light green to white. Young larvae look just like older worms, except they are smaller.

Continued on page 2:  How to Control Hornworms