Sod webworms are the lawn-damaging larvae of several moth species known as snout moths, lawn moths or grass moths. These caterpillars grow 3/4 to 1 inch long. Depending on the species, their bodies range in color from gray to green to pinkish-brown. They have dark heads and dark spots along their length.

Sod webworm moths are typically off-white, brown or gray, with a pair of prong-like projections by their mouths. When held together, the prongs look like one long snout. The moths zigzag across lawns and hang on grass blades with snouts pointed downward. When not in flight, they roll their 1/2-inch wings tightly against their bodies.


Sod webworms usually strike sunny lawn areas hardest. These pests are most active at night. By day, they hide in silky, weblike tunnels in the thatch layer of sod. Sod webworms chew grass off at the thatch line. Then they eat the grass and take it back to their tunnel for later.

Unlike the large, scattered brown patches caused by chinch bugs, sod webworm damage arrives as baseball-sized spots of very short grass that go straight from green to brown. As damage continues, the spots grow and merge into large areas of dead, dying grass. Dig into the thatch layer in affected areas, and you'll find sod webworms and their silky "webs."


Snout moths produce multiple generations of sod webworms each year. Effective control starts with early treatments to kill sod webworms and prevent new generations. To maximize results, treat lawn areas late in the day — right before sod webworms come out to feed. Amdro brand offers several highly effective products to kill sod webworms and moths:

  • Amdro Quick Kill Lawn Insect Killer Granules provides a fast, effective way to reach sod webworms in grass and thatch. Apply the granules with a standard lawn spreader, then water the treated area lightly to release the active ingredient down into the thatch. This product kills sod webworms by contact and keeps working for up to three months.
  • Amdro Quick Kill Ant & Spider Killer Granules offer a convenient, easy-to-use product that's ideal for smaller lawn areas and your home's perimeter. Apply the ready-to-use granules with the resealable shaker bag. Then water the treated area lightly. The fast-acting, deep-reaching formula kills sod webworms by contact and keeps killing for up to three months.
  • Amdro Quick Kill Outdoor Insect Killer, available in ready-to-spray and concentrate formulas, kills sod webworm moths by contact. Use these products to treat lawns, trees, shrubs and flower gardens and keep them protected for up to three months.


Sod webworm infestations often attract large numbers of starlings and other birds. If you notice birds probing your lawn repeatedly, check your thatch for sod webworms, grubs or other turf-damaging pests.

Always read product labels and follow the instructions carefully.

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