Severe infestations resemble drought stress since damage progresses from the bottom of the plant up. Webbing is initiated near the midribs of the host plant and gradually envelopes the plant as the population increases. C. Caterpillars that bore into the whorl, stalk, or ear. All larvae described in this section have three pairs of legs near the head and five pairs of prolegs. When fully grown, this larva is green, reddish, or brown with pale, longitudinal stripes and scattered black spots.
Early instars are cream colored or yellowish-green with few markings.
Larval instars vary from 1.5 to 44 mm in length and have five pairs of prolegs. As injured leaves unfurl, they display ragged holes and soggy, brown frass. This worm also feeds on the tip kernels of the ear. Round emergence holes are sometimes evident in the shuck. Its boring into the stalk weakens the plant and causes tassel and stalk breakage, ear dropping, and small ears.