Corn Borer

Ostrinia nubilalis

Also known as European Corn Worm, European Corn Borer, European High-flyer

Corn borer damaging corn [Credit: NY State IPM at Cornell University]

Corn borer moth [Credit: gailhampshire]

Host Plants:

On Crops: Corn, millet, peppers

Where Found:

Worldwide in temperate climates

Description:

Small caterpillars with dark heads and faint dark spots on their bodies tunnel into the main stalks of young corn plants, and then move to the silks and ears as the plant matures. The most common sign that borers are present are round holes that have been chewed into corn stalks, usually when the corn is more than waist high. Corn borers are the larvae of a beige moth. Late-season peppers are also a common target.

Damage:

Corn borer feeding weakens plants and slows their growth. Severely damaged plants often snap off and fall over. When peppers or mature corn ears are damaged, they are prone to rot.

Preventing Problems:

Corn borers have numerous natural enemies, including wasps, lady beetles, lacewings and other common beneficial insects, so growing flowers that attract borer predators is quite effective with this pest. In a large planting of sweet corn, intercropping with buckwheat, dill and coriander can prevent corn borer problems. Pupae overwinter in corn stalks, so add them to a compost pile and make sure they're actively composting by late spring.

Managing Outbreaks:

Spray plants with a Bt or spinosad-based insecticide near where you see damage, and be sure to cover the leaf undersides while avoiding spraying the tassels. Many beneficial insects gather corn pollen from corn tassels.

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