Green Caterpillars: Identifying and Controlling Tomato Hornworms
What Is the Green Caterpillar on My Tomato Plants?
The most common green caterpillar found on tomato plants is the tomato hornworm (Manduca quinquemaculata). It is a major pest in home gardens, feeding on leaves, stems, and fruit. The tobacco hornworm, a closely related species, also targets tomato plants.
Key Characteristics of Tomato Hornworms
Bright green body with a smooth texture
Diagonal white stripes along its sides
A curved horn-like tail at the rear
Can grow up to 4 inches long
Found on tomatoes, peppers, and other host plants in the nightshade family
While their green color helps them blend into foliage, spotting them early is essential to prevent serious damage.
The Difference Between Tomato Hornworms and Tobacco Hornworms
Both species look similar but have distinct markings:
FeatureTomato Hornworm (Manduca quinquemaculata)Tobacco Hornworm (Manduca sexta)Body ColorBright greenBright greenStripesDiagonal white stripesStraight white linesTail HornDark blue or blackRed
Knowing the difference can help you correctly identify the pest and choose the best control method.
How Tomato Hornworms Damage Plants
Tomato hornworms are among the most destructive pests in vegetable gardens. Both the larvae and adult moths cause damage:
Larvae (Caterpillars) – Eat leaves, stems, and fruit, causing defoliation and reduced yields.
Adults (Sphinx Moths) – Lay eggs on the underside of leaves, leading to more caterpillars.
Without control, an infestation can strip a plant of its leaves within days.
How to Get Rid of Tomato Hornworms
1. Handpicking and Removing Caterpillars
Check plants daily and remove any green caterpillars by hand.
Drop them into soapy water to prevent them from returning.
2. Introduce Natural Predators
Braconid wasps lay eggs inside caterpillars, killing them naturally.
Birds and beneficial insects, like ladybugs, also help control populations.
3. Use Organic Sprays
Bacillus thuringiensis (Bt) is a natural insecticide that targets caterpillars without harming beneficial insects.
Apply neem oil to deter adult moths from laying eggs.
4. Maintain Healthy Plants
Rotate crops each season to disrupt the pest’s life cycle.
Keep weeds and host plants under control to limit egg-laying sites.
Final Thoughts: Protecting Your Tomato Plants
Tomato hornworms can devastate your tomato plants, but early detection and natural control methods can help prevent damage. Regular inspection, handpicking, and attracting natural predators are the best ways to keep these green caterpillars in check.
Key Takeaways:
✔ Look for diagonal white stripes to identify tomato hornworms.
✔ Handpick caterpillars and destroy them before they spread.
✔ Encourage natural predators like wasps and birds.
✔ Use organic sprays like Bt for long-term control.
With the right approach, you can keep your home garden healthy and thriving.