Influence of host-plant alteration on the oviposition performance of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Abstract

The study evaluated the influence of larval host-plant nutrition and subsequent host-plant alteration during oviposition on the reproductive performance of fall armyworm, Spodoptera frugiperda. Larvae were reared on six host plants viz., maize, teosinte, sorghum, cowpea, pearl millet, and Napier bajra hybrid and adult females were either allowed to oviposit on their larval host or transferred to an alternative host. Fecundity and egg hatching varied significantly among various host-plant. In case of same larval and oviposition host plants, highest number of eggs per plant (496.00 ± 25.01) were laid on maize, followed by those on teosinte (311.50 ± 13.75). Egg hatching was highest on maize (70.96 ± 6.28%) followed by sorghum (67.99 ± 4.00%) and teosinte (66.95 ± 6.10%). When maize-reared females were offered alternative hosts for oviposition, teosinte supported the highest fecundity (200.60 ± 15.39 eggs) and egg hatching (69.20 ± 7.91%). Conversely, when females reared on alternative hosts were offered maize for oviposition, the highest egg production occurred in females reared on teosinte (198.60 ± 5.12 eggs) that was followed by sorghum (116.40 ± 13.58 eggs). These results indicate that maize was the most suitable host among the various plants tested, irrespective of the host plants on which the larvae were fed. However, teosinte and sorghum also supported oviposition and egg development. Thus, these hosts may contribute to the persistence of S. frugiperda populations when preferred hosts are less available especially in more suitable habitat of sub tropics offering this polyphagous pest a varied agricultural landscape.