Armyworm feeding has been observed in several fields in northeast and southeast Iowa. Most of the fields with the feeding had cereal rye planted last fall and were terminated this spring.
Now is the time to be scouting for armyworms. Look for feeding on leaves. The larvae will typically begin eating on the lower leaves first. They start on the outer edges of the leaf and work their way in, leaving just the midrib. You may also find their frass pellets in the whorl of the plant.
Note that if you are scouting during the daytime you may not see the armyworms actively eating, as they like to hide beneath residue or clods of soil.
Armyworm less than 1/4" in size found in a corn field in SE Iowa that had cereal rye planted last fall. Photo by: Cody Schneider, Ag Specialist Southeast Research and Demonstration Farm (taken 5/28/17).
Armyworm feeding on a young corn plant in SE Iowa. Photo by: Cody Schneider, Ag Specialist Southeast Research and Demonstration Farm (taken 5/28/17).
For more information and management thresholds, check out this ICM News article “True Armyworms Defoliating Corn Seedlings.”
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- Field Agronomist in EC/SE Iowa