Oklahoma wheat producers should check for fall armyworms now

Monday, October 6, 2014

Oklahoma State University’s Division of Agricultural Sciences and Natural Resources is recommending state wheat producers examine their pastures for the presence of fall armyworms.

“I checked a field of wheat this past weekend that exhibited significant damage from fall armyworms and found an average of six to seven fall armyworms per square foot,” said Tom Royer, OSU Cooperative Extension Integrated Pest Management coordinator.

Producers should scout for fall armyworms by examining plants in five or more locations in the field. The presence of “window paned” leaves – where the green tissue has been scraped off, leaving a clear membrane – or chewed leaves is a tipoff a fall armyworm problem may exist.

Fall armyworms are most active in the morning or late afternoon. Take care to count all sizes of larvae. Examine plants along the field margin as well as in the interior because fall armyworms sometimes move in from road ditches and weedy areas.

“The caterpillars were widely distributed in the field I checked, suggesting they were the result of a large egg-lay from a recent adult moth flight,” Royer said. “The suggested treatment threshold is two to three larvae per linear foot of row in wheat with active feeding.”

For control suggestions, consult the newly updated OSU Extension Fact Sheet CR-7194, “Management of Insect and Mite Pests of Small Grains,” available online at http://osufacts.okstate.edu and through all OSU Cooperative Extension county offices, usually listed in telephone directories under “County Government.”

Oklahoma will not get relief from fall armyworms until the first killing frost of the year, since they do not overwinter in the state.