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The Lawn Disappeared Overnight: Armyworms

Grass disappearing fast? It's likely an Armyworm invasion. Learn the soapy water test and how to stop the 'march' before your lawn is destroyed.

November 28, 2025 1 min read

Striped armyworm caterpillar crawling on a blade of grass

It sounds like an exaggeration. "I went to bed, and when I woke up, the grass was gone."

It's not a joke. It's Armyworms.

These are the caterpillars of a nondescript moth. They get their name because they move in a massive line, like an army, eating everything in their path.

The "March"

They don't just nibble. They eat the grass blade down to the dirt. A healthy green lawn can turn brown and dead in 48 hours.

The Soap Test

Not sure if it's drought or bugs?

Mix a bucket of water with lemon dish soap. Pour it over a 2x2 foot patch of healthy grass near the dead line. Wait 5 minutes.

If you have Armyworms, the soap irritates them, and they will come wriggling to the surface. If you see 5 or more, you need to treat immediately.

Speed is Key

You can't wait until the weekend. If you confirm Armyworms, apply a curative insecticide (like a pyrethroid liquid) that evening. Granules work too slow. You need a contact killer to stop the march before they eat the whole yard.