Corn earworm Larvae range in color from light green, brown to almost black, with light and dark stripes running lengthwise of the body. The head capsule is usually orange. Damage may be caused by corn earworm, fall armyworm, and southwestern corn borer. All of these may be in the same field at the same time. Whorlworm damage to the whorl often appears as ragged shot-hole damage.
Plants can stand a considerable amount of whorlworm damage.
When worms infest young plants shorter than 24 inches high, the center of the plant may be killed. Economic Threshold Control of fall armyworm and other whorlworm infestations is critical on young plants less than 15 inches high and on plants approaching heading. Between these two stages, the plant can withstand considerable defoliation or leaf loss. Ground application, using 20 gallons of water per acre, has given the best results. Control is needed when an infestation averages one worm or more per plant.