Corn earworm on sweet corn

Corn earworm is the most ubiquitous pest of sweet corn in North America, and the challenge is straightforward: the worm enters through the silk tip of the ear and feeds downward, protected from insecticide contact by the husk. By the time you peel an ear at harvest and find the damage at the tip,.

Corn earworm is the most ubiquitous pest of sweet corn in North America, and the challenge is straightforward: the worm enters through the silk tip of the ear and feeds downward, protected from insecticide contact by the husk. By the time you peel an ear at harvest and find the damage at the tip, the worm has been there for weeks.

I don't grow corn at my Long Island property, so this guide draws on Cornell Cooperative Extension, Penn State Extension, and NC State Extension research.

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The pest

The corn earworm (Helicoverpa zea) is one of the most economically significant pest insects in North America, affecting corn, tomatoes, cotton, soybeans, and many other crops. Per Cornell Cooperative Extension:

• Adults are moths: yellowish-brown to olive with darker wing markings; wingspan approximately 1.5 inches
• Females lay single eggs on corn silk and on the leaves of other hosts
• Larvae (the worm) hatch from eggs on the silk and immediately burrow into the ear tip; they feed downward through the kernels

The corn earworm does not overwinter in the northern US per Penn State Extension. It migrates north each spring from overwintering populations in the South and Southeast. Moths arrive in northern gardens each June–July; the severity of local infestations depends on the size of the migrating population and local moth trapping counts.