southwestern corn borer larva 5 copy.jpg

Southwestern corn borer moth


  • Adult: Dull white moth with a snoutlike mouth.
  • Larvae: Initially very light gray with a brown head and rows of dark spots. Over time, the spots fade and the larvae turn yellow-white.
  • Eggs: Greenish-white at first but within a few days develop three red transverse lines. 

Timing of damage: First generation: V6 to VT. Second generation: V12 to R6.

Type of damage: First generation: Leaf feeding, tunneling into the midvein and boring into stalks. Second generation: Leaf feeding and boring into stalks, tassels, ears and shanks. Larvae are known to bore into the stalk and tunnel down through it.

Scouting: Inspect 20 plants in five locations. First generation: Record whorl feeding. Second generation: Record eggs and live larvae in the ear zone.

Economic threshold: When 35% of the whorls show fresh feeding and larvae are present. Timing is critical; once in the stalk, borers cannot be controlled.

Similar Pests

Ask an Agronomist

The material and content contained in the Greenbook label database is for general use information only. Agworld and Greenbook do not provide any guarantee or assurance that the information obtained through this service is accurate, current or correct, and are therefore not liable for any loss resulting, directly or indirectly, from reliance upon this service. This label database does not replace the official manufacture issued label. Users of this database must read and follow the actual product label affixed to the container before use of the product.