Integrated Pest Management
Sod Webworms and Cranberry Girdler
Crambus spp.; Chrysoteuchia topiaria
Adult cranberry girdler (Andy Reago & Chrissy McClarren, Wikimedia Commons)
Common sod webworm larva (Samuel Abbott, Utah State University)
Sod webworm damage to turf (Steven Arthurs, University of Florida Institute of Food and Agricultural Sciences)
Pest Description
- complex of multiple species of moths
- adults: 3/4 inch wingspan; snout protruding forward; forewings dull colored and striped with silver, gold, yellow, brown and black
- larvae: 3/4 – 1 inch; vary in color (beige, gray, brown or green); most are covered with dark spots and coarse hairs; typically associated with green frass and webbing
Host Plants, Diet & Damage
- larvae feed on a number of grasses
- larvae clip grass blades at night just above the crown leaving areas of turf thinning
- subterranean sod webworm larvae, specifically, feed on crowns and roots causing similar damage as white grubs
- severe infestations can cause irregular turfgrass patches
Biology, Life Cycle & Damaging Life Stage
- overwinter as larvae in silk-lined chambers in thatch
- larvae become active in spring
- one or two generations depending on species
- moths may emerge summer through fall
- subterranean sod webworms have one generation and moths emerge late spring to early summer
- female moths drop eggs over turfgrass in the evenings
- larvae are the damaging life stage
IPM Recommendations
- Monitor larvae with a soapy-water flush, and adult flights just above the turfgrass in the evenings.
- Avoid drought-stressed turf and consider endophyte-enhanced turfgrass.
- Apply a biopesticide containing entomopathogenic nematodes or Bacillus thuringiensis to suppress populations.
- Apply a pesticide (carbamate; pyrethroid; organophosphate) when larvae are present.