HPIPM:Fall Armyworm FC

Author: Frank B. Peairs[1]

Identification (and life cycle/seasonal history)

Fall armyworm, Spodoptera frugiperda (J.E. Smith), adults are about one inch long, with dark and light gray forewings mottled with light and dark spots. The hind wings are grayish to pinkish-white. Fall armyworm larvae have a white inverted Y-shaped mark on the front of their dark head. They are smooth skinned and vary in color from light tan or green to nearly black, with three yellowish-white hairlines down the back. There is a wider dark stripe and a wavy yellow-red stripe on each side. The larval stage lasts from three to four weeks. Fully developed larvae are about 38 millimeters (1.5 inches) long. Unlike armyworms, fall armyworms feed during the day and night, but are usually most active in the morning or late afternoon.

Plant Response and Damage

Small holes and "window pane" feeding characterize early larval feeding on corn leaves and in the whorl. They may enter the ear and feed on new kernels. Larger larvae may be found deep within the whorl often below a "plug" of yellowish-brown frass. Fall armyworm will feed on corn plants in nearly all stages of development, however later plantings which have not yet silked are preferred.

Management Approaches

Resistant Varieties

Control can be expected with Bt corn hybrids containing the Herculex I event. See Managing Corn Pests with Bt Corn, [2], for details on the use of Bt corn hybrids to control corn pests. See [3] for an excellent summary of currently available traits.

Chemical Control

Due to constantly changing labels, laws and regulations, the sponsors of this web site assume no liability for the suggested use of any chemicals noted in the management section. Contact your local pest management personnel for current information on labeled pesticides that can be used for the intended plant disease, insect pest or weed.