What do I need to do to keep worms out of the corn next year

Lindy Lou · Aug 14, 2011

What do I need to do to keep worms out of the sweet corn patch next season? Thanks

eileen · Aug 15, 2011

Source(s):
Cornell University
North Carolina University
Virginia Cooperative Extension

Organic farmers are using multiple techniques to control European corn worms. Use Trichogramma ostriniae wasps as natural predators that attack the eggs of the European corn borer and an all-season pest, the fall armyworm. Spray Bt(a bacteria toxic only to caterpillars & worms) mixed with soybean oil directly on the corn silks.

Here is some very usefull information from North Carolina University: "Corn earworms are a major pest on corn. The night-flying, light brown- or buff-colored moth lays eggs on the corn silks. In North Carolina, the moth can emerge as early as late March. These tiny, dome-shaped eggs hatch in 1 to 2 days in warm weather or 10 days in cool weather. The small caterpillars move down the silk into the ear, where they feed on the tip. After 12 to 13 days, the caterpillars leave the ears by boring out the side or crawling out the tip. They burrow 3 to 5 inches into the soil to pupate. After about 12 more days, they can emerge to start the cycle again. There can be at least three generations per year, and the pupal stage can also overwinter.

Once earworm caterpillars have worked their way inside the ear, they cannot be controlled. Early plantings often are not affected by earworms, but late plantings can be under serious pressure. Low infestations are often handled by simply removing the damaged ear tip of the corn after harvest. Some growers provide a free "de-silking" of the ears at sale, so the consumer never sees the worms.

Earworm adult moths should be monitored by pheromone traps placed near the corn field. In Oklahoma, Kuepper and colleagues (1991) used oils and oil-pesticide blends to control corn earworm on small acreages. They injected oil into the neck of the ear (where the silk emerges from the husk), with a standard oiling can. To be effective, oil must be applied 2 to 3 days past the full-brush stage (when silks are at maximum extension from the eartip). Addition of Bt or pyrethrum is more effective than the oils alone. Be aware that using Bt with oil is difficult, time consuming, and not always effective. Estimates obtained for costs of these methods, however, are competitive with the conventional pesticide methods.

Fall armyworms can also be a major pest in North Carolina. They overwinter further south and migrate north each year. The female moths are about 1.5 inches across the wings with grayish-white hind wings and dark gray forewings with splotches and white spots near the tips. They deposit clumps of up to 150 pinkish-white eggs on the leaves. In warm weather, these eggs hatch in 3 to 4 days. In 2 to 3 weeks, the armyworms are about 1.5 inches long, light tan or green to almost black with yellow and dark stripes running the length of the body. Their distinctive characteristic is an inverted Y on the front of the head. Fall armyworms will feed on just about any plant, but damage is especially severe in late sweet corn and field corn. They will eat all above-ground parts of the plant and are very messy eaters. The best defense is to plant early so that corn matures in mid-August before armyworms peak in the fall.

Trichogramma wasps may provide some control of European corn borers, beneficial nematodes sprayed on the corn plant and silk may reduce earworm damage, and ladybugs will help control aphid populations."
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What do I need to do to keep worms out of the corn next year

Lindy Lou New Seed

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Houseplant ivy with brown spots, diagnosis needed

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What do I need to do to keep worms out of the corn next year

Lindy Lou New Seed

"Gonna Need An Ocean"

Houseplant ivy with brown spots, diagnosis needed

eileen Resident Taxonomist Staff Member Moderator Plants Contributor

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