Tobacco hornworm vs Catalpa sphinx
These two are easy to mix up. Here's how to tell a tobacco hornworm from a catalpa sphinx, and whether either one bites or stings.
Tobacco hornworm
Manduca sexta
Catalpa sphinx
Ceratomia catalpae
≠The key differences
Tobacco hornworm is usually found on solanaceous plants (tomato, tobacco) and has larger diagonal white stripes and a red horn rather than the catalpa worm's coloration and host choice.
⚖︎Side by side
| Tobacco hornworm | Catalpa sphinx | |
|---|---|---|
| To humans | Non-toxic | Harmless |
| Size | 9-12 cm wingspan | 6.5-9.5 cm wingspan |
| Colours | Green, Pale cream, Red (horn), Gray-brown | Green, Yellow-green, Gray-brown, Cream |
| Family | Sphingidae | Sphingidae |
| Habitat | Gardens, agricultural fields and wild areas where host plants (Solanaceae) grow; adults visit nectar-rich flowers at night. | Where catalpa trees grow: woodland edges, urban and suburban yards, planted streets and parks. |
| Range | Widespread in North, Central and South America; common across the United States where host crops are grown. | Eastern and central North America; closely tied to the distribution of planted and native Catalpa species. |
| Active | Spring to autumn (multiple generations in warm areas); caterpillars feed mainly by day while adults are primarily nocturnal. | Larvae mainly late spring to summer (generations vary by region); adults fly at dusk and night. |
| Pest? | Yes | Yes |
🔍How to spot a tobacco hornworm
- Large green caterpillar with diagonal pale stripes on each segment and a conspicuous rear horn that is usually red.
- Full-grown larvae reach 8-10 cm and have smooth skin without hairs.
- Adult moths are robust with a 90-120 mm wingspan, gray-brown mottled forewings and a long proboscis.
🔍How to spot a catalpa sphinx
- Look for smooth yellow-green caterpillars marked with black (a black back stripe or rows of black side spots) and a black rear horn, feeding in groups on catalpa leaves.
- Adult is a sphinx moth with a 6.5-9.5 cm wingspan and gray-brown forewings with wavy dark lines.
- Clusters of chewed leaves or noticeably skeletonized catalpa branches during late spring or summer indicate catalpa worms.
?Frequently asked questions
What is the difference between a tobacco hornworm and a catalpa sphinx?
Tobacco hornworm is usually found on solanaceous plants (tomato, tobacco) and has larger diagonal white stripes and a red horn rather than the catalpa worm's coloration and host choice.
Is a tobacco hornworm or a catalpa sphinx more dangerous?
Tobacco hornworm: Non-toxic. Catalpa sphinx: Harmless. Neither the caterpillars nor adults are venomous. Caterpillars are not venomous, have no stinging hairs and do not bite or sting people.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.