Fall armyworm

Spodoptera frugiperda

Damage to plants

  • Foliar, whorl, ear and tassel damage.
  • Stems cut at the base.


  • 'Window pane’ feeding damage caused by newly emerged larvae, which feed by scraping the leaf surface without perforating it.
  • Burrowing damage on the ear through the husk.
  • Ragged leaf appearance from the edge of the leaf inwards, due to larvae feeding.
  • Yellow-brown frass (feces) within whorls, on leaves and around base of plant.
  • Cutting of the stem base.
  • Presence of larvae on foliar tissue and masses of larvae migrating to adjacent fields.

Factors favoring insects / pest development

  • Cold, wet springs reduce effectiveness of natural predators thus favoring the fall armyworm.
  • Late planted and late maturing maize is more vulnerable to damage.

Geographic distribution

  • Fall armyworm is one of the most important pests of maize in the Americas. Distribution of the pest ranges from northern Argentina to southern Canada and includes the Caribbean.