By Kim Tungate
The fall armyworm is a chronic pest in North Carolina. The caterpillars feed on a variety of forage and turf species, including: bermudagrass, tall fescue, bahiagrass, sorghum-sudan, and numerous winter annuals. They seem to prefer lush grasses which, in the last few weeks, means a lot of pastures and lawns are susceptible.
As the name indicates, fall armyworms are most numerous in late summer or early fall. Here in Lee County we have been receiving reports of fall armyworms in pastures since last week. They are typically most active in morning, late afternoon and early evening although they will feed throughout the day on tall grass.
Fall armyworm damage often seems to appear “overnight”. The damage may vary in appearance and severity according to type of grass and management practices. In closely grazed fields, the grass may seem to thin out and develop brown spots. These spots look burned or browned out which resembles drought damage.
Established, healthy, bermudagrass is rarely killed by fall armyworms but complete defoliation caused by a severe infestation weakens plants and deprives livestock of pasture or a hay producer of a hay cutting. Other grasses may not fair so well and younger grasses can sustain serious damage if feeding has occurred too far down on these plants.
Scouting pastures and hayfields can help detect fall armyworms before they cause economic 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.
The threshold for fall armyworms is 3 or more per square foot. If infestations are detected treatment with insecticides is recommended. As with other pests, timing is important with treatment. Smaller larvae are much easier to kill than larger ones.
Source:ncsu.edu