Oviposition site preferences of fall armyworm moth, Spodoptera frugiperda J. E. Smith (Lepidoptera: Noctuidae) on selected crops under a no-choice scenario

Abstract

ABSTRACT

The fall armyworm (Spodoptera frugiperda) is a destructive invasive pest threatening food security across Sub-Saharan Africa, especially maize-based systems. This study assessed the oviposition preferences of female fall armyworm moths on maize, cowpea, and okra – crops commonly intercropped by Nigerian smallholder farmers – under no-choice laboratory conditions. Two-week-old seedlings of each crop were individually exposed to mated female moths in sleeve cages for 72 hours, and egg masses were examined for quantity, position on plant, and distribution across leaf surfaces and regions (distal-, mid- and proximal- portions of the leaf). Results showed maize and cowpea were significantly more preferred than okra, with maize receiving the highest total number of egg masses and eggs. Interestingly, cowpea had the highest number of eggs per mass, suggesting its potential as a viable secondary host. Okra received the fewest eggs and was associated with a high proportion of off-plant oviposition. Across all crop types, females consistently preferred to lay eggs on the abaxial and distal portions of leaves rather than stems or adaxial surfaces. These findings highlight that while female fall armyworm moths may not strictly follow the preference–performance hypothesis at the plant species level, they exhibit marked discrimination at the microhabitat scale.