They are nocturnal, eating at night and sleeping during the day. The first four larval stages only feed on the upper part of the grass blades, so the damage is often overlooked, but mature sod webworms can chew entire sections off the leaf blade, quickly making a lawn look like it was scalped. You can tell if you have sod web worms in a few different ways. First, if you notice portion of your grass is lower than the rest, and is brown, as if that portion was scalped by a weed eater. Second, If you notice that the blades of your grass are looking ragged, as if they’ve been chewed, or the blades have holes in them, Third, if you walk through your grass, brushing it with your feet, and you see brown moths flying out of it. The moths are laying eggs, which turn into sod web worm caterpillars, which eventually turn back into moths. If you see lots of tan moths flying out from an affected area, you typically have an advanced infestation. Forth, you can mix 2 tablespoons of liquid dish soap, like dawn, in two gallons of water, then pour the mixture over a section where you suspect sod web worms have invaded. The sod web worms don’t like the soap and will usually surface where you confirm their existence. You’ll need to get on your knees and look closely using this method.