Say Goodbye to Brown Patches: How to Get Rid of Sod Webworms (Grass Moths) for Good!

If you've noticed mysterious brown patches creeping across your otherwise healthy lawn, you might be dealing with a sneaky invader: sod webworms. These tiny caterpillars can do big damage if left unchecked—but don't worry. With the right mix of lawn care and pest control, you can kick them to the curb and reclaim your green paradise.

Here’s everything you need to know about spotting, treating, and preventing sod webworm infestations.

What Are Sod Webworms?

Sod webworms are the larvae of small, tan moths often seen fluttering low over lawns at dusk. These pests love to chew on grass blades, especially in hot, sunny areas. Their feeding habits leave behind unsightly brown patches and weakened grass.

Signs of Sod Webworm Damage:

• Irregular brown or dead patches in your lawn

• Grass blades chewed down to the crown

• Increased moth activity in the early evening

• Silky tunnels in the thatch (a layer of dead grass and roots)

• Greenish larvae with dark heads

Step-by-Step Treatment Plan

1. Lawn Care First (Cultural Control)

A healthy lawn can resist pests better and recover more quickly.

• Mow regularly: Don’t let your grass get too tall.

• Water deeply, but not too often: Encourages deeper root growth.

• Dethatch your lawn: Sod webworms thrive in thick thatch layers.

• Aerate in spring or fall: This improves drainage and grass health.

2. Do a Quick DIY Test

Not sure if sod webworms are to blame? Try this:

Mix 2 tablespoons of dish soap in 1 gallon of water and pour it over a small area (1–2 square feet). If larvae crawl to the surface within a few minutes, you've got sod webworms.

3. Go Natural with Biological Control

Prefer to avoid harsh chemicals? Nature has your back.

• Bacillus thuringiensis (Bt): A bacterium that targets young larvae.

  • Safe for people, pets, and pollinators.

  • Best applied in the late afternoon or evening.

• Beneficial nematodes: Microscopic worms that hunt webworms in the soil.

  • Water them in during cool, moist conditions.

    
    

4. Chemical Options (When Things Get Serious)

If the infestation is heavy or natural methods don’t work, insecticides may be needed.

Look for products with these active ingredients:

• Bifenthrin

• Permethrin

• Carbaryl

• Cyfluthrin

Pro tip: Apply insecticides late in the day, when larvae come out to feed. Lightly water afterward to move the product into the thatch where webworms hide.

When to Treat Sod Webworms

The best times to treat are:

• Late spring to early summer

• Late summer or early fall (if there's a second generation)

  
  

The earlier you catch them, the better—young larvae are much easier to control than mature ones.

Wrap-Up: Keep Sod Webworms Off Your Lawn

Don’t let these hidden lawn pests ruin your summer. With a combination of smart lawn care, natural treatments, and (if needed) strategic insecticide use, you can banish sod webworms and enjoy a lush, green lawn again.

Have questions about your specific lawn or region? Drop a comment below or reach out—we're here to help your grass stay greener!