How to identify
- Caterpillar with a distinct inverted Y on the head
- Longitudinal stripes; dark and light forms
- Frass in corn whorls; ragged leaf feeding
Damage: Rapid defoliation and ear damage in late summer.
Control methods
- Hand-pick on small plantings; check whorls after storms.
- Keep weeds down; armyworms often move in from grassy edges.
- Harvest sweet corn promptly.
What products to use
We list product types and what to check on the label — not brand rankings, prices, or “we tested” claims. Always follow the label for your crop, and prefer the least disruptive option that works.
Bt or spinosad (labeled)
When: Young larvae on foliage
Look for: Fall armyworm or armyworms listed; spray into corn whorls when needed