Morphological characteristics to identify fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) from common polyphagous noctuid pests for all instar larvae in Japan

The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the most important pests, which was first found in Japan (Kagoshima Prefecture) in 2019. This study reports the morphological characteristics of all the larval instars in order to identify S. frugiperda among common polyphagous noctuid pests in Japan. In general, several larval characteristics of S. frugiperda are rudimentary or indistinct in early instars larvae, yet sufficiently distinguishable from the larvae of other species apart from the first instar. This stage shows considerable overlap among different species in the proportion of D1 and D2 pinacula widths to the spiracle on 8th abdominal segment, cuticle texture and prothoracic L setae arrangement.