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How to Control Cutworms and Armyworms on Your Lawn

Sprinklers watering the grass

Armyworms and cutworms are the larvae of various species of night-flying moths. These immature moths love feeding on young plants and turfgrass leaves and stems, often causing brown patches and dead spots on the lawn. Here are tips on how to control armyworms and cutworms infestations.

Cultural control

Good cultural practices can help a healthy lawn withstand a moderate armyworm or cutworm infestation. Cultural practices that can help control the caterpillars include:

– Proper fertilization and watering schedules – These minimize the appearance of caterpillar feeding damage to the grass. Healthy grass can also outgrow moderate injury by the caterpillars. However, an overly maintained yard can encourage adult female moths to lay their eggs on your grass. Consult a lawn care service provider in Utah about the appropriate way to keep your plants healthy without attracting moths.

– Scouting – In early spring, scout for moths moving to your turfgrass. Talk to a lawn care professional about useful moth monitoring and sampling tools. In the summer, monitor for caterpillars with the soap flushing method.

– Regular mowing and clipping collection – Adult moths lay their eggs on overgrown grass. Daily mowing and discarding of the collected clippings a safe distance away can help remove the eggs from the lawn and prevent re-infestation.

– Predation – Several birds and parasitic wasps and flies love feeding on caterpillars. Facilitate this predation to reduce armyworm and cutworm populations.

Insecticidal control

Cutworms and armyworms’ damage in turfgrass is usually erratic. Accordingly, preventative pesticide treatments are typically unnecessary. However, when cultural practices and natural enemies are not sufficient or effective, insecticide applications may be warranted. Consider spot treatments using reduced-risk insecticides instead of blanket applications of broad-spectrum products.

Although adult cutworms and armyworms do no damage to lawns, their caterpillars can be significantly destructive.  Implement integrated pest management strategies to reduce caterpillar feeding and potential damage to plants. Use recommended insecticides to control moths and their larvae when chemical control becomes necessary.