Don't Let Armyworms March All Over Your Turf

When summer heat rolls in, so do destructive lawn pests like armyworms and cutworms, both of which can rapidly devastate a healthy yard. Armyworms—actually the larvae of moths—are particularly aggressive, especially the fall armyworm (Spodoptera frugiperda), which thrives in warm climates. These caterpillars march across lawns in large numbers, feeding voraciously on grass blades and leaving behind large, patchy dead zones overnight. Cutworms, such as the black cutworm (Agrotis ipsilon), are nocturnal feeders that chew through young grass stems at the soil surface, effectively “cutting” them down—hence the name.

These pests feed mostly during dusk and nighttime hours, often going unnoticed until the damage is widespread. Armyworms skeletonize the grass by feeding on the leaves, while cutworms attack the base of the plant, causing irreversible injury. Both pests prefer well-watered, fertilized lawns, which provide the lush, green blades they thrive on. Infestations often increase following heavy rains or irrigation, and if left untreated, these caterpillars can reduce a thriving lawn to a brown, chewed-up mess in a matter of days.

To combat these pests, insecticide treatment is essential—especially during peak summer months when infestations escalate. Products containing bifenthrin, carbaryl, or spinosad are commonly recommended for effective control. Timely treatment not only kills the active larvae but also prevents future generations from hatching and spreading. For homeowners and property managers, early detection and intervention can mean the difference between maintaining a vibrant lawn and facing costly reseeding or sod replacement. Regular inspection, especially after spotting moths or birds feeding on your lawn (a telltale sign), can help catch infestations early and ensure your turf stays healthy all summer long.

We offer protection from armyworms and cutworms with our Organo Lawn Pro+ Program.