Hornworms are categorized as large caterpillars that mainly cause insignificant damage with the exception of the tomato hornworm. All caterpillars in this genus transition into moths known as ‘hawk moths,’ to lay more eggs mid-summer.
They appear as giant caterpillars with a flexible ‘horn’ that is for show.
The relatively harmless white lined spinx worm turns into a hummingbird moth (see picture below) which hovers near tubular flowers with an extended proboscis!
- Attracted to
- Level of Concern
- Can be a serious problem
- What months
- May–Aug
- Treatment / Useful Links
Defoliated plants and large areas of leaves missing are good indicators of predation.
Look for rolled leaves near the tops of plants to find clusters of translucent green eggs or young caterpillars which are often camouflaged.
Manually remove or destroy critters with fingers. Sometimes it might make sense to remove whole leaf.
Ducks, chickens, birds, and reptiles may feed on removed caterpillars.
For more information:
CSU Extension Spanish: https://extension.colostate.edu/docs/pubs/spanish/05517.pdf
CSU Extension English: https://extension.colostate.edu/topic-areas/insects/hornworms-and-hummingbird-moths-5-517/