Army worm is a very apt name for those caterpillars that demolish a lawn just like an invading army. Army worms eat grass leaves in an ever-expanding area, leaving behind a brown patch that grows bigger every night. During the day the caterpillars find shelter out of the sun, a characteristic that helps to locate them as the culprits. They’re sometimes found hiding under leaves that are sitting on top of the lawn but they can be trapped even more effectively by placing some damp cardboard on the lawn in the eaten section. Look underneath in the morning to check if the grubs are taking shelter. Once you know they’re about, you can take an appropriate course of action. In Alabama, there may be as many as five to six generations of this pest every summer, so be ever vigilant.