RALEIGH, N.C. — Currently, there are widespread reports of fall armyworm damage in pastures across North Carolina. In this area, fall armyworms are most numerous in late summer or early fall.
The fall armyworm is a chronic pest in the Southeast and can cause severe damage to grass and forage crops alike. The caterpillars feed on variety of turf and forage species including: bermudagrass, tall fescue, alfalfa, corn, and sorghum sudan grass. Damage varies in appearance and severity according to the type of forage and management practices.
Even though feeding usually occurs for a week or more before being noticed, fall armyworm damage is said to appear “overnight” due to the light appetite of small early instars. It is not until later instars that the caterpillars begin consuming large amounts of forage. The grass rapidly thins out and brown spots develop, resembling drought damage.
An easily detectable sign of armyworms is the presence of birds, especially crows, in your fields. Closely examine the areas where most of the birds are congregating. Also, check in areas where grass is brown or patchy.
Scouting pastures can help detect fall armyworms before they cause economic damage. The economic threshold for Fall Armyworms is 3 or more per sq. ft. If infestations higher than 3 are found it is recommended to treat with insecticides.
–Ryan Adams, N.C. State University