With the dramatic upswing in fall armyworm moth captures last week in Princeton, sweet corn producers should monitor their late plantings closely. Fall armyworm (FAW) can attack the leaves and, when available, will move to the developing ear of sweet corn. Ragged holes in the leaves emerging from the whorl and course, sawdust-like frass are characteristic of fall armyworm (Figure 1).
Sweet corn lines with Bt traits will help to manage FAW. While corn earworm will typically restrict its feeding to the tip of the ear, FAW can attack any part of the ear. With whorl stage sweet corn, sprays for FAW should be directed from over the plant down into the whorl leaves. As the ears form, sprays should be directed to the middle third of the plant to protect the ear.
By Ric Bessin, Extension Entomologist