Sod Webworm Identification and Management

Diagnosing Sod Webworms

Pencil-sized holes with browning grass indicate sod webworm infestation. The holes are bird feeding marks (starlings, robins probing for larvae). Confirm by:

• Birds congregating on lawn
• Silk-lined tunnels in thatch
• Tan moths flushing during mowing (adults)
• Greenish caterpillars with brown heads in thatch

Cultural Management

1. Water deeply (1 inch weekly) to reduce stress
2. Mow at 3 inches minimum
3. Frequent mowing (≤1/3 blade removal)
4. Dense turf resists infestation better

Treatment Resources

• Ohio State: Sod Webworm Management
• Colorado State: Control Options
• Kansas State: Identification & Biology

Biological Control

Beneficial nematodes (Steinernema carpocapsae) applied to moist soil in evening provide organic control. Bacillus thuringiensis (Bt) kurstaki effective on young larvae.