Corn earworm (CEW) and feeding on corn ear tip. Image credit: Rachel Milliron.
Corn earworms (CEW) are pests that can be found in corn as well as tomatoes, sorghum, alfalfa, tobacco, and other hosts. During our Crop Tour last week, a couple of educators found CEW and feeding in field corn.
As an adult, the corn earworm takes form as a moth in the Noctuidae family. Moths are buff-colored with olive shading, and a wavy dark band near the edge of wings in younger specimen. The University of Missouri provides excellent pictures showcasing the variation of coloring and markings of adults. Here in Pennsylvania, we don’t typically see overwintering CEW, but adult moths can fly long distances and are found flying during the night.
In corn, female moths are attracted to fresh silks and can lay anywhere from 500 to 3,000 eggs on individually on silks. When corn silks are not available, they will lay eggs on other plant tissues or hosts. Larvae will hatch within 2-4 days during summertime. These larvae take the form of a caterpillar and will feed at the ear tip.
CEW larvae can grow to be 1-1/2inches long and varies in color, ranging from light green to tan, brown, pink, or nearly black. CEW larvae have many small, black spines along their back and sides, which can distinguish the CEW from other striped larvae with four abdominal prolegs, like the Western Bean Cutworm.
Western Bean Cutworm eggs were easily found in vegetative stage corn earlier in August and larvae can also be found feeding on the developing corn kernels. Larvae are dark brown with a faint diamond-shaped marking on their back. As they mature they will lighten in color and turn gray to pinkish brown. Older Western Bean Cutworms have dark brown stripes behind the head.
To learn more about CEW or Western Bean Cutworm check out the following resources: