fall armyworm late instar MER copy.jpg

Fall armyworm moth

Description

  • Adult: Gray and brown moth. Forewings are marked with triangular white spots.
  • Larvae: Smooth-skinned caterpillar, ranging in color from light tan or green to black with three light yellow stripes down the back and a white inverted "Y" on the front of its brown head.
  • Eggs: Dome-shaped with a flattened surface and a rounded point at the tip. Female covers the egg mass with a layer of gray scales. 
     

Timing of damage: V12 to R6

Type of damage: Primarily feeding on the leaves and whorl but later larvae will move to the tassel and young ears. 

Scouting: Check for damage on 20 consecutive plants in five separate locations.

Economic threshold: Treat when eggs are on 5% of plants, or when 25% of plants show damage and live larvae are present. Larger larvae burrow deep into the whorl, where they are protected from insecticide.

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