Editor's note: This article originally appeared in the Waxahachie Daily Light on Sept. 6, 2016. It has been updated throughout with additional information.


For months, Mary Thundercloud has meticulously worked to manicure her lawn. There was growing, healthy green grass in areas where they had not been previously — partly due to the resident dogs no longer present and part due to her diligent use of her newfound green thumb.

Then it rained. And it then rained some more.

The Waxahachie resident initially thought the rain would further benefit her yard on Dunn St. She was not aware, however, of the downfall from the rainfall — Spodoptera frugiperda, or the fall armyworm.

It did not take long, a couple of days at most, before the once bermudagrass oasis was a barren lot.

According to Ellis County AgriLife Extension Agent Mark Arnold, fall armyworms are common pests of bermudagrasses, sorghum, corn, wheat and ryegrass, as well as several other crops in north and central Texas.

"Fall armyworm outbreaks in pastures and hay fields often occur following rain which creates favorable conditions for eggs and small larvae to survive in large numbers," Arnold said. "Hayfields with a dense canopy and vigorous plant growth are often more susceptible to armyworm infestations than less intensely fertilized and managed fields.

"[Residents should] look for fall armyworm larvae feeding in the crop canopy during the late evening and early morning and during cool, cloudy weather. During hot days, look for armyworms low in the canopy or even on the soil surface where they hide under loose soil and fallen leaves."

Arnold noted armyworms are "very small" at first, about 1/8 of an inch, and cause very little damage during the early growing periods, which often leaves infestations unnoticed. After the armyworms feed for 2-3 weeks, they reach one to one-and-a-half inches in length and can damage an entire pasture in a matter of three days,

Arnold said the key to managing the outbreak of fall armyworms is to catch the infestation early. Once the larva has grown larger than three-quarters of an inch, the armyworm can consume 80 percent of the total foliage of their lifespan during the final two-to-three days of feeding.

"The density of armyworms sufficient to justify insecticide treatment depends on the stage of crop growth and value of the crop," Arnold noted. "Seedling plants can tolerate fewer armyworms than established plants. Infestations of more than two to three armyworms one-half-inch or longer per square foot may justify an insecticide application. If practical, apply insecticides early in the morning or late in the evening when armyworm larvae are most active and therefore most likely to come into contact with the insecticide spray. If the field is near harvest, an early harvest, rather than an insecticide treatment, is an option."

The following insecticides can be used to treat or control armyworms. However, Arnold said to always make sure to read and follow all label instructions before use.

Suggested insecticides include Karate Z, Lambda-Cy, Mustang Max, Tombstone Helios, Warrior II, Baythroid XL, Dimilin 2L, Prevathon, Besiege, Sevin 4F, Sevin XLR, Sevin 80S, Generic Carbaryl, Malathion, Intrepid 2F, Tracer.

For further information, contact Mark Arnold, County Extension Agent-Agriculture and Natural Resources, by phone at 972-825-5175 or by email wmarnold@ag.tamu.edu. The AgriLife office is located at 701 S Interstate-35E in Waxahachie.