Fall Armyworm

Spodoptera frugiperda

Fall armyworm larvae on corn.
Fall armyworm larvae on corn. Photo courtesy of Frank Peairs, Colorado State University. Licensed under CC BY 3.0.
Fall armyworm larva are known for their voracious feeding habits, moving in large groups at night and decimating whatever crops are in their way. It overwinters in the southern U.S. although it can travel north during the summer.
Adult moths have a wingspan of approximately 1.5" and are greyish-brown in appearance.
Fall armyworm moth
Fall armyworm moth. Photo courtesy of Lyle Buss, University of Florida. Licensed under CC BY 3.0.
Larva are a dark green or brown in appearance with a brown head. They have an inverted Y marking on their head which can be used to distinguish them from other common pests.
Fall armyworm larva
Fall armyworm larva. Photo courtesy of Alton N. Sparks, Jr., University of Georgia. Licensed under CC BY 3.0.
The light grey eggs are laid in a mass and may have a furry or fuzzy appearance.
Fall armyworm egg mass
Fall armyworm egg mass. Photo courtesy of USDA.
Fall armyworm larva can cause significant damage to crops, particularly corn. Besides leaf feeding they will also directly attack the ear resulting in significant yield loss.
Several insecticies are available for controlling fall armyworm. For maximum effectiveness, they need to be applied when the larva are small since mature larva tend to burrow into the plant and are then protected from pesticides. Always read and follow all label instructions.
Some Bt corn hybrids provide partial protection against fall armyworm, although late planted fields should still be monitored and treated with other control methods if necessary.