There have been a few reports of armyworms clipping heads in wheat.  This behavior is not always predictable and can occur even when infestation are not that impressive.  The typical recommendation to treat when there are 6-8 larvae per square foot does not apply at this late stage of crop maturity, and treatment should be based on the amount (or potential amount) of head clipping.  Keep the following points in mind before pulling the trigger.

• Application plus insecticide costs will be at least $8/acre (more if applying by air).  This assumes a mid-rate of a synthetic pyrethroid is used.
• If spraying by ground, wheel tracking may cause 1-2% yield loss (depending on wheel spacing and boom size).   This may be minimized if you can follow previous tracks made when putting out a fungicide.

Thus, the cost of spraying can be as high as 2-3 bushels of wheat per acre.  On a crop of 70 bushels per acre, head clipping levels would ultimately need to exceed at least 3-4% to justify application.  Keep this figure in mind and consider infestation levels before making an application.   Also consider that the additional cost of aerial application may be “paid for” by reducing wheel tracking.