Corn Earworm

The corn earworm is a white, green, or red caterpillar with spines. It measures about 1 1/2" long. The adult is a brown moth. The first generation chews the buds and leaves, later generations feed on silks and kernels at the tip of the ear just inside the husk. They overwinter as pupa in the soil.

Most obvious symptoms include damage to buds and young plants. The plants may be stunted. In corn, the ears are destroyed from the tip down. Damp castings may be seen near the silk. Green tomatoes are destroyed from the stem end.

Vulnerable plants include beans, corn, okra, squash, and tomatoes.

The best control strategy is to spray young plants with a light horticultural oil mixed with Bt every 2 weeks. Spray from the time corn is knee-high until ears begin to form. Next, apply a drop of mineral oil to the silks of each ear, after the silk has dried. If the earworm does get access to teh ear of corn, inject Bt into the ear with a hypodermic needle or garden syringe.

Other controls include cultivating the soil in winter to dig up the overwintering pupae and exposing them to the cold. Adults can be trapped with pheromone baits. Smartweed has been found to attract corn earworms and can be used as a trap crop. Pull heavily infested trap crops up and destroy them before it creates it's only pest problem that spread around the garden.

Use hot pepper sprays, bug juice sprays, and other natural sprays to prevent attraction. Use a light horticultural oil during the growing season to control the worms by suffocation.

Use Bt to kill them on contact. Dust Bt on plants every 10-14 days. Cover all parts of the plants. Spray Bt on as a foliar spray every 10-14 days. You can also inject infected ears with Bt into their tips. wait 3-5 days before harvesting infected ears.

Handpick worms. Use pyrethrum and rotenone sprays or dusts. And use a good fall cleanup program to control future infestations. Wait a few days after pulling up old plants to till the soil. Wait 2-3 weeks and till it about 2 inches deep. Plant a cover crop or lay a 4-6" mulch. About 2 weeks before planting, give it another 2 inch cultivation to expose the last few pupae that didn't get caught the first couple times.

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