Fall Armyworms Pose Potential Threat to Tennessee Lawns and Farmland

UT Entomologist Shares Latest Control Strategies

NASHVILLE, Tenn. – As reports of fall armyworms continue across Tennessee, an entomologist with the University of Tennessee Institute of Agriculture encourages residents to monitor their land for this migratory pest.

“Fall armyworms travel north from Texas, passing right through Tennessee and neighboring states every year,” says Midhula Gireesh, assistant professor and UT Extension entomologist. “With the number of reports we are seeing, landowners should regularly ‘scout’ their property for signs of an infestation, especially these next few weeks.”

Gireesh says one of the first indications is grass with a “frosted” appearance resulting from newly hatched armyworms eating the underside of the plant leaf. Other signs include dead plants, brown patches in lawns and even large congregations of birds gathering to eat the worms.

“It is important that we scout every few days to identify infestations quickly. If armyworms are present, it is recommended that you begin control strategies immediately,” says Gireesh.

Available at farm supply and lawn and garden stores, chemical treatment options can effectively eliminate most infestations. However, these solutions are not preventative measures and should only be applied if worms are already present. Many insecticides could also pose a risk to beneficial insects and other organisms, Gireesh encouraging applicators to always follow the label and to contact your local UT Extension office prior to application if you have any questions.

The armyworm is the caterpillar of the fall armyworm moth that feeds primarily on grass, fresh sod, hay fields and, on rare occasion, summer and fall crops. An armyworm’s life span is about 30 days, with late-stage caterpillars consuming the most amount of food.

Gireesh says residents should remain calm despite the ongoing reports. “The severe infestations we saw in 2021 were a rare incident, and we must remember that this is a yearly migration. While warm-season grasses like bermudagrass can be susceptible to significant injury by fall armyworms, feeding will generally not result in the death of established lawns. Many grass varieties in our area have rhizomes, or belowground stems, which makes recovering from damage more likely. Armyworms can be controlled if identified early, so remain diligent in scouting and don’t be afraid to seek assistance if needed.”

To learn more about armyworms and available treatment options, please contact your local county Extension office.

The University of Tennessee Institute of Agriculture is comprised of the Herbert College of Agriculture, UT College of Veterinary Medicine, UT AgResearch and UT Extension. Through its land-grant mission of teaching, research and outreach, the Institute touches lives and provides Real. Life. Solutions. to Tennesseans and beyond. utia.tennessee.edu.