Fall armyworm

Spodoptera frugiperda (J. E. Smith)

(Insecta: Lepidoptera: Noctuidae)

Adult moths have a wingspan of 32 to 40 mm with grayish-brown, mottled forewings and silver to white, iridescent hindwings. The forewings of males show characteristic triangular white spots at the tip and in the center. First instar larvae are green with a black head capsule. Later instars either remain green or turn brown dorsally with lateral white lines and dorsal, elevated, spine-bearing spots. Their heads capsules are orange or brown marked with a light inverted Y. Larvae grow from 1.7 mm (first instar) to 34.2 mm (sixth instar).

Depending on the season, the life cycle is completed in 30 days (summer) to 90 days (winter). Each female produces on average 1,500 eggs that she deposits onto foliage in masses of 100 to 200 and covers with grayish scales. The egg stage and the six instars each last two to four days. Pupation occurs in the soil within a loose cocoon.

Spodoptera frugiperda is native to the tropical regions of the western hemisphere and survives the winter in the United States in southern Florida and southern Texas. During the summer, adults migrate to virtually all states east of the Rocky Mountains.

Preferred hosts are grasses such as Bermudagrass, corn, sorghum, and grassy weeds. During periods of high abundance, however, larvae disperse and consume almost all encountered vegetation including field, vegetable and fruit crops and flowering plants.

Images 

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Larva of fall armyworm, Spodoptera frugiperda (J. E. Smith) on Bermudagrass, lateral view

(Photographer: Lyle Buss, University of Florida)

Larva of fall armyworm, Spodoptera frugiperda (J. E. Smith) on Bermudagrass, dorsolateral view

(Photographer: Lyle Buss, University of Florida)

Female adult of fall armyworm, Spodoptera frugiperda (J. E. Smith)

(Photographer: Lyle Buss, University of Florida)

Male adult of fall armyworm, Spodoptera frugiperda (J. E. Smith) with typical white spots at the tip and center of each forewing

(Photographer: Lyle Buss, University of Florida)