Armyworms are light brown to dark tan, mostly hairless caterpillars (moth larva) with a yellow or brown stripes that runs the length of their 1½ to 2 inch long bodies.
They are formidable feeders, especially of lawns and young vegetable seedlings. As their name suggests, they will decimate one area, then move in mass to another area in search of additional food. Young lawns are particularly susceptible.
Armyworms mainly migrate to a food source in the cool of night, so they can be hard to detect until they begin to inflict damage by eating leaves. Young seedlings are often eaten at the base, causing them to fall over, similar to cutworm damage. To detect armyworms, examine plants at night with a flashlight or douse lawn with soapy water, which will bring pests to the surface.
Armyworms are found throughout the Southwest and Southeast and somewhat North. They are most damaging in spring and early summer.