Lawn Moth Larva (also known as a Sod Webworm)
Scientific Name: Crambus spp. (e.g., Pediasia trisecta)
Order & Family: Order: Lepidoptera, Family: Crambidae
Size: 1/2 inch to 1 inch (12 mm to 25 mm) in length when fully grown
Natural Habitat
Thatch layer of lawns, golf courses, and grassy fields; they often reside in silk-lined tunnels at the soil surface.
Diet & Feeding
Herbivorous; they feed on the leaves and stems of various grasses including Kentucky bluegrass, fescue, and bentgrass.
Behavior Patterns
Larvae are primarily nocturnal feeders that retreat into silken burrows during the day. They go through several instars before pupating in the soil and emerging as adult snout moths.
Risks & Benefits
They are considered a lawn pest as large populations can cause brown patches and significant damage to turfgrass. They provide an ecosystem benefit as a food source for birds and predatory insects.
Identified on: 1/1/2026