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Corn Earworm

Helicoverpa zea (Boddie) is a sub tropical Noctuid moth species attacking many crops and food plants including sweet corn. It is a cosmopolitan pest.

In the past, H. zea reinvaded the PNW intermountain region each year to infest sweet corn. It is a major PNW corn pest, requiring treatment.

Recent mild winters have allowed over wintering and the pest  appears earlier and more severely than in the past.  Ears are damaged by the feeding larva resulting in the top of the ear being eaten, moldy, smelly, and full of frass (see photo of larva).

This is the season for “why is my corn all moldy and black” questions followed by “how do I manage this”?

The secret is to apply an insecticide treatment at TASSEL DROOP when the SILK appears (see photos). When the silk emerges from the husk, the tassel droops to shed the pollen that falls into the silk pollinating the corn. At this time, adult moths fly through the corn flipping eggs  right into the ear while the husk opens to allow silking and pollination of the ear.

Spraying or rather “dusting” at this time will manage most of the damage. Once the ear tightens after pollination, it is too late for anything but regrets!