Over the last few days I have had several reports of true armyworms showing up in wheat. Most of the calls I have received so far have been numerous worms at the ground level starting to defoliate up the plant but head clipping has been very minimal. Once wheat reaches the dough stage it is very difficult to show any yield benefits from treating armyworms in the absence of head clipping simply from defoliation. However, we have numerous fields that are still in the milk stage and susceptible.
Watch for blackbirds feeding in wheat fields, this is often an indication that armyworms are present. Armyworms are not difficult to control and typically mid-rates of pyrethroids work very well. When scouting for armyworms in the heat of the day it is critical to pull the plants back and search the ground or near the ground for larvae. In Mississippi we recommend treating armyworms in wheat when numbers reach 5-6 per sq. ft. prior to the dough stage or defoliation is reaching the flag leaf prior to dough stage. Treatment after the dough stage is only recommended when head clipping is observed.
Glenn Studebaker at the University of Arkansas just posted a good article on armyworms so I am providing the link to his article as well.
Click on link to read: Arkansas Blog on Armyworms in Wheat