Early stage fall armyworm larva
Whorl-stage corn injury from fall armyworm
Dark spots (tubercles) on dorsal surface arranged in "trapezoid" or when near the tail, in a "square" pattern. Spots are darkened in photo for emphasis.
Fall armyworms can be distinguished from similar corn caterpillars by 2 physical characteristics:
Similar caterpillar species found on corn (left-right): armyworm, fall armyworm
and corn earworm. The fall armyworm has an inverted "Y" pattern on the front of a dark head.
An inverted "Y" pattern on the front of a dark head identifies the fall armyworm.
Dark spots (tubercles) on dorsal surface arranged in "trapezoid" or when
near the tail, in a "square" pattern. Spots are darkened in photo for emphasis.
Photos and Text
Marlin E. Rice; Reviewed by Susan Moser, Herb Eichenseer and Laura Higgins
Reference
Bessin, Ric. 2003. Fall armyworm in corn. University of Kentucky Cooperative Extension Service. ENTFACT-110.