The sod web worm does its damage at night any time between spring and fall, but all year round in Florida. Silk webbing seen in the morning dew and moths swarming above the turf surface are signs of an infestation. Damaged lawns will have irregular patches of chewed or notched grass blades. Sod web worms only eat the grass leaves, leaving the root system intact. As a result, the grass can recuperate if prompt action is taken.