fall armyworm late instar MER copy.jpg

Fall armyworm moth

Description

  • Adult: Gray and brown moth with triangular white spots on each forewing and a wingspan of 1½".
  • Larvae: Smooth-skinned caterpillar, ranging in color from light tan or green to black with three light yellow stripes down the back. Distinguishing feature is a white inverted "Y" marking on the front of its brown head. Grows to about 1½".
  • 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, giving the mass a moldy appearance. 
     

Timing of damage: All growing season

Type of damage: Leaf and pod feeding; sometimes fall armyworms will cut the stems of seedlings.

Scouting: Examine whole plants in rows, use a sweep net or shake the plants onto a drop cloth. 

Economic threshold: Eight caterpillars per row-foot, or if the number of cut seedlings is putting the field below the recommended stand density.

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