Fall Armyworm

Spodoptera frugiperda

Infestations of fall armyworm are most likely to occur in late summer to early fall before frost (September – October). One to two worms per square foot can destroy seedling alfalfa, and populations of 10 to 15 per square foot have been observed to destroy 12- to 14-inch alfalfa. This is a migratory pest that does not overwinter in Kansas.

FAW egg mass

Egg mass.


FAW larva

Larva of fall armyworm
showing distinctive striping and
unique head capsule coloration
with inverted 'Y'.


FAW adult

Adult moths.

Please refer to the most recent version of the Alfalfa Insect Management Guide for specific control alternatives.

Page last updated 4/16/2024 by J.P. Michaud.