AUSTIN (KXAN) — If you work hard to keep your lawn looking green, heads up! There may be something eating away at it right now, undoing all your hard work.

Our wet and cooler summer weather has been great for keeping our lawns looking healthy, but that weather might just be their undoing.

I recently spotted several creatures crawling on the grass in my back yard and took video of them to ABC Home and Commercial Services Entomologist Dr. Santos Portugal.

“So, those do look like armyworms, probably fall armyworm, so probably what they’re doing is they’re growing, they’re eating,” said Dr. Portugal.

These so-called “armyworms” aren’t worms at all, they’re caterpillars eating away at your lawn before they turn into moths.

Dr. Portugal added, “They’re called armyworms because if they get in high enough numbers, they’ll actually almost line up side-to-side and just march down a lawn and leave a path of destruction in their wake.”

They’re most active at dusk and dawn, and while they prefer Bermuda grass, any grass will do.

“They’re going for that green leafy part so that’s really what they’re going for and it’s usually at the top of the grass,” said Dr. Santos.

While they don’t kill your lawn, they will take out the green, leaving brown patches or lines of dead-looking grass.

At ABC, it’s been their busiest season in 15 years for armyworm calls, and they’ve had to spray liquid treatment on yard after yard over the past few weeks. 

Dr. Santos Portugal explains the weather we’ve been having is largely to blame for their increased number, “It’s a combination of factors you know we’ve had a really mild year temperature-wise. I think we’ve had seven or eight days above 100 degrees and then we’ve had a good level [of] precipitation. We’re just making perfect breeding conditions for them.”

So, when do the armyworms go away? Well, it’s not an answer that you’ll like. We have to wait until the first frost until they, at least temporarily, disappear, until they return next year.

Armyworm season is mid-summer and into fall. If you want to prevent them from arriving in your yard, turn off the lights.

“The moths are attracted to light and the moths are what lay the eggs, so one of the ways you can prevent them potentially or at least reduce their number is try to keep those exterior lights off this time of year,” Dr. Santos suggested.

That way those moths will lay eggs in someone else’s yard.