Armyworms in moth form will often hatch in the spring or early summer. If you notice greater than usual numbers of these ash-gray, two-toned moths around lights and other attractive surfaces, you should begin to watch your grassy areas for armyworm damage. You may also notice more birds than usual gathering on your lawn to feed on armyworm larvae.
Natural predators will be the most likely eliminator of these moths, but they may still have time to lay clusters of up to 200 tiny eggs on plants, structures, or landscaping elements. Here are some suggestions on how to lessen the appeal of your lawn to armyworm invaders.
Reduce Excess Thatch
Army worms often find their first temporary shelter in loose thatch on a lawn. There is a chance that minor early damage can be spotted before the larvae move on to the grass under their feet.
Removing thatch around your lawn with a rake will eliminate daytime shelter for hungry caterpillars and make it easier for you to do a thorough inspection for army worms. The worms will be easier to see when they're taking shelter near the soil if there is less thatch on the ground.
When cooler weather arrives in the fall, consider aerating or turning your soil before winter. This will help to expose army worm pupae that may be staying overwinter in the soil of your lawn. Birds and other beneficial predators will eagerly feed on the surfaced cocoons that appear.
Maintain Your Lawn
Keeping a healthy lawn is always a great way to reduce the risk of an insect pest takeover. Properly maintained turf has a better chance of withstanding and rebounding from armyworm damage, and will add visual appeal to your property as a bonus.
Keep your lawn watered at a conservative level--avoiding overwatering or unnecessary watering during heavy rains. Armyworm larvae prefer warmer, dryer soil, so keeping your turf at a consistently damp (but not soaked) level could make it less appealing to a young batch of armyworm larvae looking for their next meal.
Keep your lawn mowed to its recommended height without cutting it too short to reduce stress on the turf. Recommended grass height is usually between two and three inches.
For more advice on how to keep your lawn healthy year-round, read our lawn care schedules.
Apply a Preventative Insecticide
A product with a long residual effect can offer early protection against army worm infestations if applied during the spring and summer. Check out our recommended products for army worm control below, and always consult the label of your selected product to confirm application rates and other details.
Learn More About Army Worms
The other parts of this lawn pest treatment guide can help you confirm you have army worms and learn where army worms like to live to make sure your prevention efforts are as effective as possible.