Try Mineral Oil As A Trap
Apply half a medicine dropper of mineral oil to the silk on each ear of corn, after the silks have wilted and begun to turn brown (any earlier may interfere with pollination). You can also use an oil can for this process. This will suffocate the worms but will not affect the flavor of the corn. Red pepper, pyrethrum, or BT can be added to the mineral oil. Make two follow-up applications spaced one week apart.

Handpick Corn Earworms
Pulling back the husk at the tip of each ear and remove the worm. Do this only after the silks begin to brown, indicating that pollination has already occurred.

Try Barriers
Clothespins pinched on tops of corn ears will prevent corn earworm from attacking the maturing corn.