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Pests in the Northeastern United States

Editors: W.T. Wilsey, C.R. Weeden, and A.M. Shelton

Corn Earworm
(Helicoverpa zea)
- Life Cycle
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The adult is a yellowish-brown moth with a wingspan of 1 1/2 inches (37 mm). The moth belongs to the same group as the common armyworm moth, which it resembles. The moths vary in color; in general the front wings are a light tannish brown, marked with dark gray irregular lines and a dark area near the tip of the wing. The irregular lines often shade into an olive green. The hind wings are whitish with some irregular dark markings. The eyes are a light green color.
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Corn Earworm Adult
Eggs are laid at night, deposited individually on the underside of leaves by the first generation or in the cornsilks by the second generation. They are white, hemispherical in shape and about one-half the diameter of a pin head. Depending on temperature, eggs hatch in 2-10 days.
The larvae has a tan head and is 1 1/2 inches (37 mm) long when fully grown. Prominent alternating light and dark stripes run lengthwise of the body. The larvae vary greatly in color from a light green or pink to brown or nearly black and are lighter on the underparts. The skin of the insect is somewhat coarse and has many small thorn-like projections. The corn earworm larva should not be confused with the European corn borer larva which seldom exceeds 1 inch (25 mm) in length and is a dirty white color with dark brown or black head.
When the larvae are full grown they leave the corn ears and drop or crawl to the ground where they burrow. The larva excavates a small, smooth-walled cell, usually 3-5 inches in the soil, then transforms into the resting or pupal stage. The moth will emerge 10-25 days later depending on temperature. The development from egg to adult usually takes about 30 days in midsummer.

Damage inflicted by corn earworm on corn or on beans

Some information on this page taken from Insects of Corn: Cornell Cooperative Extension factsheet number 139VCFS791.00 authored by A. A. Muka.

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Maintained by Jason D. Plate. Last updated Mar. 8th, 2007.