Defeating the Armyworm

Caterpillars!  Watching them develop into moths and butterflies can be fascinating.  In small numbers they are harmless.  Large numbers feeding on your turf can damage your lawn.  Armyworms feed on the leaves of the grass. In large infestations, they can eat the turf down to the soil. While typically bermudagrass can recover, cool season grasses can receive permanent damage from these attacks.

Armyworms are the larvae caterpillar stage of a light brownish gray moth.  Their name comes from their feeding habits.  They move in groups, consuming all the grass in one area before moving to the next location.  Fall armyworms are not a constant issue in our area, but when they do attack, it can be devastating to a lawn. They are most commonly associated with late summer or fall damage to bermudagrasses, but also feed on fescue, ryegrasses, bentgrasses, bluegrass, and other turfs.



lawn damage from an armyworm infestation

 Since typically these caterpillars feed at night, it can be difficult to explain the brown patches in your bermudagrass at first. There are a few tell-tale signs of armyworms, though. If you have flocks of birds feeding in your turf, you must have something that they are feeding on and this can be an early sign of armyworms. To determine if you have them, inspect the grass for the caterpillars. If you find more than 1 per square foot, you may need to treat for them. In addition, you can do a soap flush to bring the larvae to the surface to make identification easier.

Treatment for the pests is usually effective. A sprayable lawn insecticide can be applied to kill them. Treat in late afternoon when the caterpillars are more likely to be feeding. It’s best to mow before you spray. Then hold off on mowing or irrigating for several days afterward to allow the insecticide to work.

If you think you have an issue with armyworms, give us a call and we can come out and evaluate your lawn and set up a treatment plan for you. As long as you stay on top of the problem you can avoid any cataclysmic results.

Thanks,
The AA Tex Lawn Team