“Worms” in Corn Ears

I’ve had a few calls as well as personnel observations regarding “worms” and their damage in corn ears. European corn borer seems to be making a bit of a comeback. Although these reports have been locally heavy, they have not been widespread. Western bean cutworm complaints have certainly increased from previous year, especially on traited corn. Fall armyworms, which migrate to Wisconsin, had a surprisingly early migration and their damage can mimic injury caused by other ear feeding insects. Finally, corn earworm is another one of those late-season migrants which arrived in very heavy numbers at some locations during the 2016 growing season. Normally it is not a field corn pest but when migrating populations are this high, field corn can be a host. One clue that you have an infestations of corn “worms” can be significant bird damage to the ears. Diagnosis of the injury can be important when planning for the future. However, diagnosis of injury symptoms can be a little tricky and not always definitive based on symptoms. Below is a quick synopsis that can be used for identification of both the larvae as well as type of damage.