Pasture Webworm (Hednota spp.) larvae grow to about 18 mm long and are smooth bodied with shiny dark brown heads. They are light to dark brown and may have a tinge of the green gut contents showing through the skin. Older larvae have darker raised patches on each segment. Young larvae live in silken tubes among leaf blades and older larvae in web-lined tunnels beneath the ground. Larvae feed at night on leaves or whole young plants, which they scatter on the ground or pull into their tunnels near the base of plants. Continued chewing will kill plants. In pasture, the grass component may be removed.