No. 13 Article 3/July 2, 2010

Wheat Head Armyworm Moths Caught in Some Fall Armyworm Pheromone Traps in Illinois

Kelly Estes, state survey coordinator with the Illinois Cooperative Agricultural Pest Survey (CAPS) Program, indicated to me recently that some of her cooperators are capturing wheat head armyworm moths in their fall armyworm pheromone traps. The wheat head armyworm, Faronta diffusa (Walker), is typically not a significant pest of wheat.

Some Kansas State University entomologists (J.P. Michaud, P.E. Sloderbeck, and R.J. Whitworth) have constructed an excellent fact sheet on the wheat head armyworm. They indicate that infestations are typically not noticed until wheat is downgraded after harvest due to the damaged kernels by the first generation of the insect. They indicate that no economic thresholds have been established for wheat head armyworms. It remains unclear why more captures have been reported in 2010 than in other years.

With regard to fall armyworms, the larvae of this migratory and tropical insect species can cause injury to corn by feeding on the tassel, ear, and upper leaves. The economic threshold for fall armyworms is to consider a rescue treatment when 75% of plants have whorl damage and larvae are present and feeding. Fall armyworms are typically much more significant a threat to corn production, especially sweet corn, in the southeastern portion of the United States. With the increased use of Bt corn hybrids over the past decade, I've received fewer reports of significant injury caused by fall armyworms in Illinois.--Mike Gray

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