Corn Earworm (Tomato Fruitworm)

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PestControlBasics Editorial Team

Reviewed by Derek Giordano · Updated 2026

Illustrated identification guide — PestControlBasics.com

🔍 Identification

Larvae: 40mm at maturity; highly variable coloring — tan, green, brown, or pink; distinctive alternating dark and light stripes along the side; pale head capsule. Found at the silk tip of corn ears or burrowing into tomatoes and peppers. Adults are medium-sized brownish moths.

🧬 Biology & Behavior

Cannot overwinter above the frost line — migrants from the Gulf Coast reinvade northern states each summer, identical to fall armyworm. This means resistance management in the Southeast affects populations throughout the US. Multiple generations per year; continuous production in South Florida. Pheromone traps monitor adult flight timing.

⚠️ Damage & Health Risk

In corn: silk tip damage and tunneling into ears; in tomatoes: entry hole at the stem attachment point with tunneling into the fruit; in peppers and beans: similar direct fruit penetration. Secondary fungal infection of damaged tissue.

🔧 DIY Treatment

In gardens: apply Bt or spinosad spray to corn silks every 3-4 days during silking period. Mineral oil or vegetable oil applied to corn silk tip after pollination prevents larval entry. Bacillus thuringiensis injected into ear tip at silk emergence.

👷 When to Call a Pro

Commercial corn production uses Bt transgenic corn varieties (Cry protein expression), which has been extremely effective but has also driven resistance evolution in southern populations.

❓ FAQ

How do I get rid of corn earworms in my garden?

Apply Bt spray to corn silks every 3-4 days when silks are fresh. After pollination is complete (silks brown), put 2-4 drops of mineral oil into the tip of each ear — this smothers young larvae that have just hatched. Both approaches together give excellent control for a small garden.

Is a corn earworm the same as a tomato fruitworm?

Yes — Helicoverpa zea attacks both corn ears and tomatoes (and many other crops). It's the same species called different common names depending on the crop attacked. The larva found boring into a tomato is genetically identical to the one found in a corn ear.

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 🐛 Corn Earworm

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.

🐛 Corn Earworm