Largely found in the South, especially on bermudagrass, armyworms can infest lawns and cause severe damage. The first sign of trouble is small patches of brown grass with the edges of the blades chewed. Some blades may be completely eaten. You can protect your lawn from these invading bugs by applying Ortho® Bug-B-Gon MAX® Insect Killer for Lawns. or Scotts® Turf Builder® with SummerGuard®.
Armyworms generally can't survive freezing temperatures, but adult armyworm moths sometimes ride storm fronts into the North. The adults are tan or brown moths less than an inch long, with a white spot in the middle of each forewing. The egg-laying females prefer to attach masses of eggs on tree leaves. As the larvae move into a lawn, their damage usually becomes apparent starting close to the edges.
Armyworms are surface feeders and are easily controlled by insecticides when identified early enough. Consider using an insecticide control for armyworms when you find 4 to 5 small, healthy armyworms per square foot of lawn. Although the grass blades may be chewed, the crowns are not damaged by the feeding and can recover if the damaged area is kept well fed and watered. The most severe damage occurs when armyworms attack during hot, dry weather.
Armyworms are the larvae of moths. The caterpillars are light green or tan in their early growth stage and dark green or brown in later stages. Full-grown larvae are 1 ½ to 2 inches long and almost hairless. They can be identified by a series of green, yellow, or brown stripes down the length of their bodies. They eat grass blades, and large infestations can completely defoliate a lawn in a few days.
