Missouri Pest Monitoring Network Southwestern Corn Borer I.D.
Identification of moth (stage attracted to and captured in traps)
Moths are dull white with prominent snoutlike mouthparts.
Identification of larvae (damaging stage)
Southwestern corn borer larvae initially have a reddish color but develop the characteristic off-white coloration and black spots by the second- or third-instar stage.
Full-grown larvae are 1 to 1 1/4 inches long and pupate within the stalk.
Larvae of the second or third generation tunnel down into the base of the corn stalk to hibernate in late August to early October in southeastern Missouri. These larvae are pale yellow with no spots and eventually construct a hibernation cell within 6 inches to the soil surface.
Identification of Eggs
Eggs are generally laid in groups of two to five overlapping like fish scales.
They are initially creamy white but develop three red transverse bars within 36 hours of being laid, and these bars remain until the larva's emergence.
Eggs are generally deposited on the leaf surface but may also be found under leaves and on the stalk.