This armyworm and all his/her buddies are causing havoc to lawns in Sumner County. 

Editor’s note: They’re back! The army worms have taken over munching Wellington lawns – the worst case since 2021. This story was originally written on Aug. 17, 2021. Time for a revisit.

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by Tracy McCue, Sumner Newscow — The war is over, and we have lost. 

No, we aren’t talking about Afghanistan. This war concerns those one-inch caterpillars called armyworms. They have taken over yards and have destroyed the lawns. 

The worm has been around forever. But nobody remembers it being this prolific as it has been this month. 

As a result, Wellington retailers like Orscheln’s (now Tractor Supply) and Mill Creek Lumber can’t keep pesticides on the shelves long enough. Lawn care businesses like Hawkins Lawn Care have been working around the clock, spraying people’s yards, hoping to contain the little critters. 

But to no avail, these military-like worms come in and consume the plants, turning a lush lawn into a gray, dead wasteland in a matter of days.

The armyworms, aptly named, attack like they are in the army and can devastate a lawn in less than three days. They won’t stick around long – heading to the next batch of lawn, traveling in herd-like fashion.

For you lovers of the cool-season plant Fescue, this has been even more disheartening. Armyworms devour Fescue especially the irrigated kind. Grass seed is sure to be on sale at your favorite garden retailer this fall. 

So how do you get rid of them? Here is an exert from Brian Jervis, a Master Gardner for the Tulsa World: 

“Armyworms are caterpillars on their way to becoming a moth. These moths will migrate south later this year in search of the warmer climates of the Gulf Coast, Texas or Mexico, only to return to Oklahoma (and Kansas) in June next year. Until they leave, they can be quite destructive.

When the armyworm moths return in June, the female moth can lay up to 1,000 eggs in smaller groups of 50 to several hundred. These eggs hatch in July as tiny caterpillars and begin to eat, and they can eat. They can do quite a bit of damage to your lawn or plants, not so much individually, but you can imagine what it would be like if 100 or so females each laid 1,000 eggs in a concentrated area. A hundred thousand armyworms could do some damage.

The good news is that they don’t have a long feeding season — only about two to three weeks. After this feeding frenzy, they go down into the soil to pupate. Two weeks later, the next generation of adult armyworm moths emerge. There can be several generations all the way into October or even November. With this relatively quick life cycle, it’s easy to see how their numbers can build up quickly. Their preferred food is turf grass, but they will really eat anything. 

So what to do? 

If you suspect you have armyworms eating your turf, there is a quick and easy test you can perform to confirm their presence. Just mix up about an ounce of dish detergent with a gallon of water and pour that solution in about a square yard of turf. The soap will serve as an irritant and the armyworms will come to the surface to getaway. If you find five to 10 armyworms in the test area, you should consider treatment.

One of the safest ways to treat armyworms is to use an organic pesticide called bacillus thuringiensis, or BT for short. Spray BT on the turf of the plant experiencing the issue. The armyworms will eat the pesticide and die. One good thing about BT is that it is only effective on caterpillars, so this minimizes potential damage to any beneficial insects as long as you are careful where you spray.

With large infestations, you might want to consider getting a product containing bifenthrin such as Ortho Bug-B-Gone among others. These are available in containers you attach to the end of your hose to spray. The challenge with this strategy is that this type of pesticide does not discriminate and will kill any insect it comes in contact with, even the good ones.

Since their feeding frenzy only lasts two to three weeks, if your lawn or garden can take the hit, you might choose not to do anything about it. Yes, there will likely be some damage to your turf, but Bermuda and Zoysia will grow back. Fescue will likely be damaged, but it’s almost time to re-seed fescue anyway. Good luck.”