Sod webworms and fall armyworms can devastate a lawn. They hatch from groups of eggs and eat their way through your lawn slowly at first and then rapidly as they grow. Worm damage shows as a slight browning in irregular patches and resembles drought damage. Look at the leaf edges and if there are uneven margins and the leaf edge is no longer smooth then you have worms. You may also see the worms themselves or small green balls in bunches near the soil. Treat with a contact insecticide at least twice seven days apart to keep the worms at bay. The presence of white moths will let you know that the worms have matured and you will most likely see more worms in 3-4 weeks as new eggs hatch. Do your best to get ahead of their life cycle and it will make them significantly easier to control.