WSU Extension


Root, stalk, and ear rots 
Seed rot and seedling blight (damping-off) 
Brown marmorated stink bug 
Corn aphids 
Corn earworm 
Cutworms and armyworms 
Spider mites 
Western spotted cucumber beetle 

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Caption: Corn earworm damage
Photo by: A.L. Antonelli
Corn : Corn earworm
(revision date: 3/22/2021)

The corn earworm is the caterpillar of a light to dark brown moth with a 1-1/2" wingspan. The caterpillars are up to 1-1/2" long at maturity. They vary widely in color, but typically have darker stripes along a cream-colored to greenish body. The first generation may feed on the center shoots of the corn, attacking the tender new leaves. Later generations may feed on the silks, preventing pollination. They may also feed in the ear itself, damaging kernels and leaving behind dirty-looking droppings. The droppings may be visible at the tip of the ear. Several generations may occur in one season, as the corn earworm can progress from egg to adult moth in as little as one month during favorable conditions. Corn earworm pupae overwinter in the soil. Peppers, tomatoes, beans, and many other plants are also attacked.
Management Options

Non-Chemical Management
  • Varieties with tight husks (such as 'Country Gentleman', 'Golden Security', 'Silvergent', and 'Staygold') are more resistant to damage.
  • Early-season plantings (before April) are less likely to be damaged.
  • In small plantings, a clothespin placed at the point where the silk enters the ear can prevent earworm access. Place clothespins soon after the first silk is seen.
  • Plow or dig up corn plots in the fall to kill overwintering pupae and prevent emergence of adults in the spring.
  • Encourage natural enemies such as green lacewings, parasitic wasps, and other predators.
Select non-chemical management options as your first choice!

Chemical Management

Apply first application when silks first appear. Follow label instructions on reapplication intervals. Direct insecticide application to silk.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bonide Captain Jack's Deadbug Brew R-T-U [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 4-472
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • This list may not include all products registered for this use.

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Caption: Corn earworm damage
Photo by: A.L. Antonelli
Caption: Corn earworm larva and damage
Photo by: Unknown