Crambus tutillus

Turfgrass lawns, golf courses, and managed grasslands; larvae inhabit the thatch layer and root zone of soils.

North America: recorded from British Columbia and Oregon.

Adults emerge mid-May, with reproductive peak in early June and activity ending by July; larvae overwinter as diapausing eighth instars.

Grass roots and crowns; primarily feeds on turfgrass species.

Univoltine with nine larval instars. Eggs hatch in approximately 10 days. Larvae develop slowly through summer, reaching seventh instar by autumn. Short daylengths during seventh instar induce molt to eighth (diapausing) instar. Diapause requires short days and cool temperatures for normal development; long days and warm temperatures terminate diapause, allowing completion of ninth instar, pupation, and adult emergence. Adults live 10–14 days.

Nocturnal flight activity with attraction to light. Larvae construct silken tunnels in thatch and soil. Early instar growth rate increases as daylength decreases, an adaptation believed to match developmental timing to seasonal food availability.

Pest of managed turfgrass; larval root and crown feeding causes characteristic dead patches in lawns.

Economic pest of turfgrass in lawns and golf courses; management concerns focus on larval damage to grass root systems.

• Crambus spp. (other sod webworms)Similar larval habits and turfgrass damage; distinguished by specific photoperiod responses and geographic range.
• Other Crambinae turf pestsShared habitat and feeding ecology; C. tutillus identified by its univoltine cycle and Pacific Northwest distribution.

• sod webworm
• turfgrass pest
• univoltine
• photoperiod adaptation
• Pacific Northwest
• diapause
• Crambidae
• Lepidoptera
• pest management
• grassland ecology

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• Catalogue of Life
• ENVIRONMENTAL BIOLOGY OF A SOD WEBWORM CRAMBUS TUTILLUS (LEPIDOPTERA, CRAMBIDAE)1