Corn Earworm
Helicoverpa zea
Chewing Insects High Risk 25-40 mm
📖 Description
The corn earworm is one of the most costly agricultural pests in North America, attacking a wide range of crops beyond corn. Larvae feed on fruit, kernels, and buds, contaminating produce with frass and opening wounds for fungal and bacterial infections. In corn, they typically enter at the silk channel and feed on developing kernels at the ear tip. In tomatoes and peppers, they bore into the fruit, causing rapid rotting. This pest is highly adaptable and has developed resistance to many insecticides, making integrated pest management essential.
⚠️ Symptoms to watch for
- Chewed kernels at the tips of corn ears,Round entry holes in tomato and pepper fruits,Frass and silk webbing inside ear tips or fruit cavities,Damaged buds and flowers with feeding holes,Larvae visible inside fruit or ear tips when pulled back,Premature fruit drop or rotting in damaged areas
🩹 Treatment
- Apply Bt (Bacillus thuringiensis) to corn silks and plant tips (organic),Apply mineral oil to corn silk tips to suffocate larvae (organic),Release Trichogramma wasps to parasitize eggs (organic),Spray with spinosad-based insecticide (organic),Apply carbaryl (Sevin) dust to silk channels (chemical),Use pyrethroid-based insecticide spray (chemical)
🌿 Organic treatments
- Apply Bt (Bacillus thuringiensis) to corn silks and plant tips,Apply mineral oil to corn silk tips to suffocate larvae,Release Trichogramma wasps to parasitize eggs,Spray with spinosad-based insecticide
🧪 Chemical treatments
- Apply carbaryl (Sevin) dust to silk channels,Use pyrethroid-based insecticide spray
🛡️ Prevention
- Plant corn varieties with tight husks that resist earworm entry,Apply mineral oil to silk tips 2-3 days after silking begins,Use pheromone traps to monitor adult moth flights,Rotate crops and destroy crop residue after harvest,Release beneficial insects early in the season,Harvest sweet corn early before larvae cause significant damage
🪴 Affected plants
- Corn,Tomatoes,Cotton,Peppers,Beans
🦋 Natural predators
- Trichogramma Wasps,Green Lacewings,Birds
🌱 Host plants
- Zea mays,Gossypium spp.,Solanum lycopersicum
🔄 Lifecycle
- Moths lay single eggs on silk, buds, or fruit surfaces.
- Eggs hatch in 2-5 days.
- Larvae feed for 2-4 weeks through 5-6 instars, then drop to soil to pupate.
- Pupation takes 10-25 days depending on temperature.
- Adults emerge, mate, and begin laying eggs within 2-3 days.
- Multiple generations per year, with 3-4 generations common in warm climates.
- Overwinters as pupae in soil in southern regions.
📅 Season
- Late Spring to Fall (peak in mid-summer)
🔎 Appearance
- Larvae vary in color from green to brown to pink with alternating light and dark stripes along the body.
- They have a pale head capsule and sparse dark hairs.
- Adults are tan or olive-green moths with a wingspan of about 30-40 mm.
💥 Damage level
- High
🔁 Reproduction rate
- Rapid
🗺️ Geographic regions
- North America
- South America
- Africa
- Asia
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