From the Vine – Fall Armyworms

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In recent days there have been widespread and numerous reports of fall armyworm infestations and damage to pastures across southeast North Carolina. Some of those sightings have been local to Sampson County. Fall armyworms not only damage pastures and agricultural crops, but also home lawns and gardens.

Feeding may occur for a week or more before being noticed, as newly hatched armyworms are light feeders. However, damage may appear “overnight” as these worms grow and begin to feed more heavily. Grass rapidly thins out and brown spots develop resembling drought damage. Since armyworms cross the turf surface as a group, they create a noticeable line between damaged and undamaged turfgrass. Usually damaged areas will originate around a site where egg masses can be easily laid (signposts, buildings) and radiate outward. Although fall armyworms do not have many specific preferences, newly-installed sod is more attractive and more susceptible to damage.

Normally, natural enemies such as birds can keep fall armyworm populations in check. If you happen to see more bird activity in your lawn, investigate to see if armyworms are present. Fall armyworms are approximately 1 – 1.5 inches in length, and can vary in colors from green to brown to black. They will have a wide lateral black stripe running down each side of their bodies. They also have an upside-down “Y” marking on their head capsule.

If you discover fall armyworms in your lawn, try to let the birds keep them in check. If there aren’t enough birds to do the job, then you can resort to chemical control. A biological control is spinosad A+D (Conserve). Pyrethroids (particularly lambda-cyhalothrin) and carbamates (carbaryl), will provide somewhat effective control against smaller larvae. Other pyrethrin controls include Menace, Talstar, and Tempo. Chlorantraniliprole will also control turf-feeding caterpillars, if applied very early.

If you are unsure what may be causing problems in your lawn, you can call the Extension Master Gardener℠ volunteers of Sampson County Plant Clinic at 910 592 7161.

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