By Donna Reynolds
The turf at both Jordan-Hare and Bryant-Denny looks immaculate as fall approaches. The end zones at each field are painted and yard lines are numbered. Most importantly, the bermudagrass turf is trimmed and green. Meanwhile, homeowners have battled one of the worst infestations of fall armyworms in the past decade. Armyworms are destroying manicured lawns everywhere.
It would be easy to infer that turf managers taking care of vaunted top-dollar fields have advanced techniques to deal with armyworms, while homeowners have limited choices. According to Alabama turf specialist Dr. Dave Han, however, the methods used by the athletic turf managers are simple and accessible.
Fall armyworm moths make their way into Alabama each summer from Central America and South Florida. The moths prefer dry and hot conditions. Their offspring spend two to three weeks in the larval stage, progressing from eggs to pupae as caterpillars. The younger caterpillars do not eat much grass; however, in the sixth and final stage of growth, armyworm caterpillars eat more than they have during the rest of their lives combined. For this reason, damage to bermudagrass lawns from armyworms often seems to happen overnight and prevention can be tricky.
“The major thing is aggressively scouting,” Dr. Han advised. “Once you know the armyworms are active in a neighborhood, go out and look for them.” This is easy enough for the turf managers at Jordan-Hare and Bryant-Denny, who mow and work on the fields every day. For homeowners, there are a few tricks to finding and thwarting armyworms before they have a chance to ruin a lawn.
Fall armyworms prefer to lay their eggs on a flat, light-colored surface. On a football field, this may mean a goalpost. For a homeowner, this may be a porch or a mailbox. Adult moths also have a distinctive flight pattern. They zigzag back and forth as they fly, which Dr. Han calls a dead giveaway. He also suggests a homeowner or pasture farmer keep an eye on the natural predators of armyworms–birds.
“If you see a big flock of birds descending on a pasture,” he said, “you should probably go check it out.”
Scouting and identifying the problem is one thing. Correcting it before disaster strikes is another issue entirely. The trained turf managers at Jordan-Hare and Bryant-Denny know to use synthetic pyrenthroid or organophosphate insecticides as soon as armyworm eggs hatch. They are trained to use these products and have easy access to them. Homeowners have options as well.
“Almost all commercially available turf insecticides work [against fall armyworms],” he explains. “Pyrenthroids are the active ingredient.”
Han notes that some smaller high school fields and other less actively managed athletic fields may have dealt with armyworm infestations this year. He said, even if a field is defoliated completely, there are still solutions. Since armyworm caterpillars only eat the leafy part of the grass, the roots and rhizomes are unaffected. This is what provides footing for players, so the fields are safe to play on. The fields also can be fertilized, watered and treated like newly sprigged fields. For a field that must be played on immediately, a solution could be early overseeding.