Fall armyworm (FAW) can appear throughout much of the Midwest in the mid to late summer months. Unable to handle Midwestern cold winter months, FAW moths move progressively north with each generation in the summer from southern states. Each generation can move up to 300 miles.1
The FAW larva can be identified by shades of green and brown and have a characteristic inverted white “Y” between their eyes (Figure 1). Because several species of larvae can be found feeding on plant tissue in the fall, the “Y” is a defining characteristic for identification.
Moderate to severe outbreaks can occur, especially in warm years when multiple generations can mature. Late planted crops are attractive because of the tender foliage. During the 2021 growing season, several areas in the Midwest had infestations feeding on alfalfa, soybean, and corn. A unique feature of FAW is the ability to thrive in nearly all crops with more than 60 different plant species recognized as a potential FAW host.3
Cultural, biological, and chemical control measures exist for managing FAW. General management practices include:
1 Fall armyworm. Combatting an invasive pest exacerbated by climate change. Bayer Global. https://www.bayer.com/en/news-stories/fall-armyworm-combatting-another-invasive-pest-amidst-the-pandemic/.
2 Reynolds, C., Merchant, M., and Reynolds, D.S. Fall armyworms – identification and control. Texas A&M AgriLife Extension. Texas A&M University. https://agrilifeextension.tamu.edu/library/landscaping/fall-armyworms-identification-and-control/.
3 Flanders, K.L., Ball, D.M., and Cobb, P.P. 2019. Management of fall armyworm in pastures and hayfields. Alabama A&M & Auburn Universities Extension. Alabama Cooperative Extension System. https://www.aces.edu/blog/topics/farming/management-of-fall-armyworm-in-pastures-and-hayfields/?cn-reloaded=1/.
4 Fall armyworm. Spodoptera frugiperda Smith. 2009. Field Crops IPM. Purdue University. https://extension.entm.purdue.edu/fieldcropsipm/insects/fall-armyworm.php/.
Web sources verified 6/27/22