European corn borer
- Adult: Moth with alternating wavy yellow and brown lines across each wing.
- Larvae: Beige with black heads and two brown spots on each abdominal segment.
- Eggs: The size of a pinhead, white and are laid in clusters of up to 60.
Timing of damage: First generation: V6 to VT. Second generation: V12 to R6. Third generation: R2 to R6.
Type of damage: First generation: Leaf feeding and tunneling into the stalk. Second and third generations: Leaf feeding and tunneling into stalks, tassels, ears and ear shanks.
Scouting: Inspect five sets of 20 plants. First generation: Look for fresh whorl feeding. Second and third generations: Count eggs and larvae in the ear zone.
Economic threshold: First generation: Decide whether yield loss might occur before treating. Second and third generations: Treat when eggs are hatching or about to hatch.