Sphinx Moth Caterpillar

Q: Is the large green caterpillar on my grapevine a hornworm?

Probably a grape sphinx (Darapsa myron) — green with white diagonal stripes and a blue-green horn, found specifically on grapes and Virginia creeper. Same management as tomato hornworm if control is needed.

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PestControlBasics Editorial Team

Reviewed by Derek Giordano · Updated 2026

Illustrated identification guide — PestControlBasics.com

🔍 Identification

Tomato Hornworm (Manduca quinquemaculata): Green, diagonal stripes, black horn on tail. On tomatoes, peppers, eggplant.

Tobacco Hornworm (Manduca sexta): Green, C-shaped lateral markings, red horn. On tobacco and tomatoes — very similar to above.

Whitelined Sphinx (Hyles lineata): Variable — green, yellow, or black with yellow spots and orange/red horn. On portulaca, grapes, evening primrose.

Grape Sphinx (Darapsa myron): Green with diagonal white stripes; blue horn. Specifically on grapevines and Virginia creeper.

Snowberry Clearwing: Bumblebee mimic as adult; caterpillar green or yellow-green. On snowberry and honeysuckle.

🧬 Biology & Behavior

All sphinx moth caterpillars are the larval stage of large, fast-flying 'hummingbird moths' that hover at flowers. Most species have just one generation per year. Larvae pupate in soil. Adults feed on nectar — beneficial pollinators.

⚠️ Damage & Health Risk

Defoliation of host plants, but most host plants tolerate feeding by 2-3 large caterpillars without lasting harm. The braconid wasp parasitism that's so valuable for tomato hornworm control applies to all sphinx caterpillars.

🔧 DIY Treatment

Hand-pick if numbers are large and plants are being significantly defoliated. Bt spray if necessary. Leave any parasitized individuals (white egg mass attached). Most sphinx caterpillars on appropriate host plants can simply be left alone — they complete development and become valuable pollinators.

👷 When to Call a Pro

Never warranted for most sphinx caterpillar species.

❓ FAQ

Is the large green caterpillar on my grapevine a hornworm?

Probably a grape sphinx (Darapsa myron) — green with white diagonal stripes and a blue-green horn, found specifically on grapes and Virginia creeper. Same management as tomato hornworm if control is needed.

What do sphinx moths look like as adults?

Sphinx moths are large, streamlined moths that hover at flowers like hummingbirds — this is why they're called 'hummingbird moths.' Some species are active at dawn and dusk; some are strictly nocturnal. They're important pollinators of deep-throated flowers.

Factor	Details
U.S. Range	All or most U.S. states
Regional Detail	Distribution varies — consult your local extension service for regional prevalence data.

Factor

Details

U.S. Range

All or most U.S. states

Regional Detail

Distribution varies — consult your local extension service for regional prevalence data.

📅 Treatment Timing Guide

Treating at the right time dramatically improves results. Pest control timed to the life cycle uses less product and achieves better long-term control.

Period	Action
Spring	Inspection and perimeter treatment before pest season starts.
Summer	Active monitoring and targeted treatments as needed.
Fall	Preventive treatment before overwintering pests seek entry.

Period

Action

Spring

Inspection and perimeter treatment before pest season starts.

Summer

Active monitoring and targeted treatments as needed.

Fall

Preventive treatment before overwintering pests seek entry.

💰 Professional Treatment Costs

Service Type	DIY Cost	Professional Cost
Initial inspection	Free (self-inspect)	$75–$150 (often credited to treatment)
One-time treatment	$30–$100 in materials	$150–$500
Annual service contract	N/A	$400–$900/year
Severe infestation	Often ineffective alone	$500–$2,500+

Service Type

DIY Cost

Professional Cost

Initial inspection

Free (self-inspect)

$75–$150 (often credited to treatment)

One-time treatment

$30–$100 in materials

$150–$500

Annual service contract

N/A

$400–$900/year

Severe infestation

Often ineffective alone

$500–$2,500+

Prices vary by region, property size, and infestation severity.

❓ Common Questions About 🐛 Sphinx Moth Caterpillars

How do I confirm I actually have this pest (not something similar)?

The most reliable confirmation is a physical specimen — capture one and compare to reference images on this page. For cryptic pests (bed bugs, termites), look for secondary signs: frass, shed skins, mud tubes, or bites with a specific pattern. When uncertain, a professional inspection is faster than months of misidentification.

Can I treat this myself or do I need a professional?

DIY is effective for small, accessible infestations caught early. Professionals are worth the cost when: the infestation is inside wall voids or structural elements, multiple rooms are affected, you have health-risk pests (hantavirus, venomous species), or DIY has already failed twice.

How long until the infestation is completely gone?

Expect 3–8 weeks for most infestations with proper treatment. Insects with dormant life stages (pupae, eggs) extend the timeline because those stages are impervious to most insecticides. Follow-up treatments at 2 and 4 weeks catch each new cohort as they emerge.

What's the most common mistake people make treating this pest?

Treating only the visible pest population while ignoring the harborage site, entry point, or breeding location. Killing adults provides temporary relief but the population rebuilds from hidden egg cases, pupae, or new arrivals through unaddressed entry points.

🐛 Sphinx Moth Caterpillars