By Maggie Lawrence
Alabama farmers have been battling fall armyworms in their pastures since July, and now the pest is giving homeowners headaches. Dr. Dave Han, a turf specialist with the Alabama Cooperative Extension System, says 2016 is an above average year for fall armyworms in lawns and turfgrasses.
“They attack a wide variety of plants, including home turf,” said Han. “Bermudagrass is far and away the favorite host for fall armyworms.
“They can eat other grasses, but it’s unusual to see them on zoysia, centipedegrass or St. Augistinegrass lawns.”
He adds while fall armyworms eat grass leaves and stems, they do not feed on roots or rhizomes.
“Because they eat only the upper portion of grasses, they are not the disaster for turf that they are in pastures. When the pest eats its way through a pasture or hayfield, they are eating the farmer’s crop.”
Dr. Kelly Palmer, an entomologist with the Alabama Integrated Pest Management program says the fall armyworm problem may last longer than homeowners and farmers would like.
“We often see 5 to 6 generations of fall armyworms each year,” said Palmer. “It takes about a month for a female fall armyworm to develop from an egg to the point where she, as an adult moth, is ready to lay an egg of her own.”
She adds that while most Alabama farmers are used to scouting for these pests when the weather turns hot and dry, it’s not second nature to most homeowners.
“They may not notice a fall armyworm infestation until older larvae are present,” she said. “This can be a big problem. Larger caterpillars are much more difficult to control and consume a greater quantity of food.”
Palmer says damage may be first noticed along lawn edges as well as areas that are around lights. The armyworms will migrate from surrounding fields and lawns once they eat most of the available food.
“Homeowners that live near pastures, hay fields and other agronomic crops should be extra vigilant to prevent infestations in their lawns and gardens.”
Inspect dead patches in lawns and scout vegetable gardens daily if possible for the armyworm larvae. Fall armyworms feed all day but are easier to spot in the early morning and late afternoon.
Han says most of the readily available lawn insecticide products sold in retail stores will control fall armyworms. Consult individual product labels to see if the product is effective against fall armyworms and for application rates and other instructions.
Palmer offers these tips for homeowners battling fall armyworms.
1. Cutting turf prior to treatment aids in control because the insecticide will not have to penetrate as far to reach the armyworms.
2. Irrigate lightly prior to treatment. It has been shown to help in some cases because it may increase the larval activity.
3. Apply treatments in the early morning or late afternoon when they are most active.
Han adds that there is still time for lawns to bounce back from ravenous armyworms.
“Bermudagrass lawns this time of year can be expected to recover in 3 to 4 weeks after treatment,” said Han. Homeowners should watch for another generation of the pest so treatment can be made early.
“There’s less time left in the growing season for recovery when turf is defoliated later in the season,” he said. “In those cases, winter weeds will probably be a problem due to the reduced turf canopy.”