2021 army worm takeover begins

Future Brown
Herald Democrat
army worm larvae

Each morning when you step outside, if you noticed your driveway seems to have been taken over by army worms, know that you are not the only one. The army crawl has started for the 2021 season, and there is little you can do about it.

The small caterpillar-like moth larvae are attracted to grass, so if the lawn is flourishing, the army worms will be too.

Texas Master Naturalist David Parsons said the region will probably see three generations of the army worm moths which have a lifecycle of about four weeks.

Army worms made their debut in July for the 2021 season.

"Considering how relatively mild and wet the weather has been so far you can expect perhaps 3 generations and they'll go into late summer," the master entomologist and arachnologist who helps out at the Grayson AgriLife Extension said in an email this week.

Mid-to-late July is the normal time for the moth larvae to arrive. The worms like to skip the Fourth of July fireworks, but enjoy July because of the warm Texas weather.

And, this time of year is perfect for the worm's favorite food...grass of all types. Though they are more visible on driveways and other flat outdoor surfaces, it is guaranteed that they are flourishing in the grass.

Army worm moth

"But they aren't particularly picky," Parsons said. "They will eat grass down to the soil. That isn't really a big deal unless you have a delicate import like St. Augustine or Zoysia because most grasses tend to fully recover without much help. Non-natives you will probably need to care for their recovery based on whatever cultivar you have in your yard."

So what can we do to make them less attracted to our yards or make our yards less of a breeding ground for them year to year? The answer is nothing really. The armyworm larvae love grass so unless you want a lawn without grass, the moths will find a way to thrive.

"The moths are, obviously, flying insects so there isn't a whole lot you can do as far as a physical barrier goes," Parsons email said. "You can apply an insecticide called Spinosad once you see that the armyworms are on the march. Spinosad is an appropriate pesticide for most homeowners. If you are raising crops or livestock you will need to check with Agrilife about appropriate Integrated Pest Management protocols."

As for harm, armyworms are harmless. They will not affect pets, squirrels, birds or other animals that may also enjoy being outdoors during Texas summers. 

"No, they are neither poisonous nor venomous," Parsons said. "They are just kinda gross and squirt-y if you squish them."

But even if you squish them, next year's batch are very likely. Parsons said that like most insects, they hatch when it is warm and summer warmth is never in short supply in North Texas.

An army worm sits on a house post in Texoma on July 23.