How to Spot and Stop Armyworms and Sod Webworms

If your lawn suddenly looks like it’s been scalped or unevenly mowed, armyworms or sod webworms may be to blame. These hungry caterpillars can move in fast and do major damage in a short amount of time. The good news? If you act quickly, you can stop the infestation and help your lawn recover.

Signs of Armyworm or Sod Webworm Damage

Armyworms and sod webworms feed on the blades of your grass, often chewing them right down to the stem. This feeding frenzy can leave your lawn looking thin, patchy, and discolored, almost like it’s been mowed too short or burned by the sun. Damage typically appears in late summer or early fall, when cooler weather begins to settle in.

Step 1: Apply Insect Control Immediately

Timing is critical. As soon as you spot signs of damage, you’ll need to treat your lawn with an effective insecticide designed for lawn caterpillars. There are two main options:

• Granular Insecticides: These can be applied at any time of day and provide longer-lasting (residual) protection. Be sure to water the granules in after application to activate the treatment. Some formulations even include fertilizer to promote quicker recovery.
• Liquid Insecticides: These are best applied in the early evening, since sunlight can degrade the active ingredients. Liquid options work fast, but don’t provide as much long-term protection as granular products.

Both types are available at most garden centers or hardware stores.

Step 2: Fertilize Damaged Areas

After controlling the pests, apply a high-quality fertilizer to the affected sections of your lawn. This will help your grass bounce back before colder temperatures slow down its growth. Acting quickly gives your turf the best shot at recovering its lush appearance before winter sets in.

Need Help? Grasshopper Can Treat Lawn Pests for You

If you’re dealing with lawn damage and want fast, professional help, the team at Grasshopper can apply targeted pest treatments for armyworms, sod webworms, and other turf pests. We’ll get your lawn back on track with safe and effective insect control, so you can enjoy a healthy lawn without all the guesswork.