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

https://entomology.k-state.edu/extension/insect-information/crop-pests/corn/armyworm.html

Pest photo source

Phil Sloderbeck, KSU Entomology