Sod Webworm (Herpetogramma licarsisalis) is a relatively thin caterpillar up to 25 mm long, with a pale green-brown body that is marked with characteristic dark spots along its length.
When mature the adults become a slender-bodied moth with a wingspan of 2.5 cm. Their wings are grey with black spots and transverse dark, wavy lines.
Female sod webworm moths drop their eggs onto turf while flying at night. The eggs fall into the thatch and hatch within 10 days, depending on temperature. Peak hatching occurs in early summer and continues throughout the summer months. The eggs tend to be oval or elliptical in shape with longitudinal ridges on the surface that run from pole to pole.
Upon hatching larvae burrow into the thatch and conceal themselves. These larvae remain concealed during the day and wander out at night to feed.
By late spring or early summer the young adult moths emerge and fly just above the turf. These moths are active at dusk. The entire life cycle generally takes about six weeks, and in most regions this pest has two to three generations per year.