The Dreaded Armyworm
August 25, 2021
Homeowners in Oklahoma are all abuzz about a summer invader that’s destroying lush green lawns nearly overnight. The dreaded armyworms.
Armyworm attacks usually occur in late summer and early fall. And believe us, this worm (which is actually a caterpillar) can destroy your lawn in a heartbeat. Their appetite is voracious, and they’re not picky eaters. Bermuda grass seems to be a favorite fodder, but they also feed on buffalo grass, fescue, ryegrass and bluegrass, as well as some veggie plants.
How to identify them in your lawn
- Caterpillars are light green or tan in their early growth stage and dark green or brown in later stages.
- Full-grown larvae are 1-2 inches long and almost hairless.
- They can be identified by a series of green, yellow or brown stripes down the length of their bodies.
Spotting the damage
- The first sign of trouble may be tell-tale brown patches in your lawn with grass blades chewed or completely eaten. With a large infestation, blades may be completely sheared to the ground.
- You may also notice an increased presence of birds in your yard. Birds will eat the worms, but they won’t get enough of them to make your lawn healthy again. Skunks, rodents, ants and some beetles also feed on armyworm grubs.
Treat early for best control
Armyworms feed on the surface and can be easily controlled by insecticides if identified early enough. In a small to moderate infestation, even though grass blades may be chewed, the crowns are not damaged by the feeding and grass blades can recover if the damaged area is kept well fed and watered. The most severe damage occurs when armyworms attack during hot, dry weather.
The long-term health of your grass is usually not affected and will recover with proper care. But in some severe cases, overseeding or re-sodding may be needed to repair the damage to your lawn.
Tips for spotting armyworms
- Using a 5-gallon bucket, add 1 cup of Dawn dishwashing liquid and fill with water. Mix.
- Pour the solution heavily over a section of your yard and wait 15 minutes.
- If present, the worms will crawl out of the ground.
Tips for treating your lawn for armyworms
- Mow the grass short and water it well to move the armyworms “into the light,” so to speak.
- Spray the grass with a liquid insecticide specifically targeted for armyworms. Granular insecticides are generally less successful with this pest.
- Leave your lawn alone for at least three days without mowing or watering, giving the insecticide a chance to work.
If you discover an armyworm infestation, you can try spraying insecticide yourself. Just be prepared to go on the hunt for product in your local hardware/home improvement stores; many stores are sold out at the moment. Or call in a professional as soon as possible to help remove them.