(Ostrinia nubilalis)
The European corn borer is one of the most destructive pests of corn. It also feeds on tomatoes, potatoes, and peppers. Early plantings are the most severely affected. The borer survives the winter in corn plants, pupates in the spring, and emerges as an adult moth in early summer. The moth, which is tan with dark wavy lines on the wings, lays clusters of about 20 white eggs on the undersides of the lower corn leaves. The borers that hatch from these eggs feed first in the whorl of leaves, riddling the leaves with shotholes. Later they bore into stalks and the bases of ears. This feeding results in broken stalks and tassels, poor ear development, and dropped ears. The borers continue feeding for a month, pupate, and emerge as moths to repeat the cycle. Cool, rainy weather in the early summer inhibits egg laying and washes the hatching larvae from the plants, reducing borer populations. Very dry summers and cold winters also reduce borer populations.
Treat ear shoots and centers of leaf whorls at the first sign of borers or when 10 percent of the ears show silk with an insecticide containing carbaryl or rotenone. Repeat at weekly intervals until borers are no longer seen. Destroy the plants at the end of the season. Avoid early planting.
Plant Care for Corn