We’ve gotten our first reports of fall armyworms (FAW) in the state for this year. FAW are one of our major turf pests in North Carolina and can cause damage starting in July and ending in mid-late October. FAW in North Carolina can attack many turf species like bermudagrass, fescue, ryegrass, and bluegrass but are capable of causing damage in any turf if populations are high.
FAWs are 1-1/2 inch long caterpillars and come in a variety of colors including green, mottled brown and brown-black. They are often recognized by the distinct, upside-down “Y” marking on the head capsule (pic) but, unlike other turf insect pests, the damage itself can easily be diagnosed.
FAWs crawl across the turf surface during the day and will create distinct lines in the turf between damaged and undamaged areas. Larvae are active for 2-3 weeks then will dig into the soil to pupate and emerge as adult moths. Moths are attracted to lights at night so be sure to keep a close eye on turf areas near light fixtures. Newly-installed sod or turf that has been mechanically disruptive is often more susceptible to damage than established turf.
The key to minimizing FAW damage is to correctly identify the problem as early as possible before considerable damage occurs. Insecticides are generally ineffective against large larvae so be sure to note the size of the armyworms before making an application. Large larvae are likely to finish feeding and burrow into the soil to pupate so only treat if larvae are relatively small. Pyrethroids (particularly lambda-cyhalothrin) and carbamates (carbaryl), will provide effective control against smaller larvae. Chlorantraniliprole will also control turf-feeding caterpillars, if applied very early.
For more information on FAW and specific control recommendations, check out the pest info sheet on Turffiles.