Pest Profile

True armyworm
Pseudaletia unipuncta
  • True armyworm caterpillar
  • True armyworm caterpillar

Pest Description

When nearing maturity, armyworm larvae are 1½ to 2 inches long. The head capsules have honeycomb-like markings, and the body lacks obvious hairs. Overall body coloration varies, but is usually some shade of greenish-black with two alternating dark and orange stripes running lengthwise down each side plus a light or faint white line on the back. Adults frequently deposit their eggs where grass is very lush, often in low-lying areas on wheat or pasture ground. Field margins or fields with dense growths of grassy weeds also are preferred egg-laying sites. Problems develop when the larvae consume the grasses or the grasses dry (wheat matures) and the larvae move to corn to survive.

Source of information

Pest photo source

Phil Sloderbeck, KSU Entomology