What Are Armyworms
Armyworms are caterpillars (larvae of the Spodoptera moth) that feed on grass blades, primarily at night. They’re called armyworms because they move across lawns in large groups like a marching army, consuming everything in their path. A severe infestation can strip a lawn down to bare soil in 1 to 2 nights. Fall armyworms are the most destructive species for lawns and typically arrive in late summer to early fall.
How to Identify Armyworms
Check your lawn at dusk or early morning with a flashlight. Armyworms are 1 to 1.5 inch caterpillars, green to brown with light stripes running lengthwise. During the day, they hide in the thatch layer. Another sign: flocks of birds feeding aggressively on your lawn means there’s something in the turf they’re eating. A soap flush test confirms: mix 2 tablespoons of dish soap in a gallon of water, pour over a 2 sq ft area, and watch for larvae coming to the surface within 5 minutes.
