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More Armyworms (07/16/20)

High densities of big (2 inches long), mature armyworms are being found in wheat, barley fields located in Bottineau, Cavalier, Traill, Nelson, Grand Forks and Wells counties.

High densities of big (2 inches long), mature armyworms are being found in wheat, barley fields located in Bottineau, Cavalier, Traill, Nelson, Grand Forks and Wells counties. Unfortunately, these armyworms are mature and done feeding. Larvae will be pupating soon (a non-feeding stage where it transforms into the adult moth). So, no insecticide application is warranted, since the cost of the insecticide and application is not likely to provide an economic return.

The economic threshold for armyworms in small grains is when two or more worms per square foot are present, head clipping and smaller worms <¾ to 1¼ inches long present. Please see Crop and Pest Report (Issue 8, 06-25-20) for more information on scouting and IPM. Check preharvest intervals (PHI) if the treatment is close to the crop harvest. For more information, read the NDSU Extension publication The Armyworm and the Army Cutworm E830.

Janet J. Knodel

Extension Entomologist

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