Occurrence, damage pattern and biology of fall armyworm, Spodoptera frugiperda (J.E. smith) (Lepidoptera: Noctuidae) on fodder crops and green amaranth in Goa, India

Abstract

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an economically important polyphagous pest native to the Americas. The pest has recently introduced to India and causing severe damage to maize and other crops. The occurrence of fall armyworm on fodder maize (Zea mays L), Guinea grass (Megathyrsus maximus) (Jacq.), para grass (Brachiaria mutica) (Forssk.) and green amaranth (Amaranthus viridis L) is reported first time from Goa, India. The damage incidence of 16 to 52% was recorded on fodder maize. The other host plants viz., Guinea grass, para grass and green amaranth recorded damage incidences of 9.0, 4.0 and 13.0%, respectively. The pest was identified based on morphological characters and molecular techniques. Phylogenetic analysis of COI gene sequence revealed that fall armyworm on fodder maize from Goa is clustering with the fall armyworm isolates from India, Nigeria, Ghana, Kenya, Canada and Brazil. Goa isolate is aligning with the “Rice” strain of fall armyworm and not with “Corn” strain. Studies on the biology of fall armyworm indicated that longer larval and pupal developmental period (18.6 and 10.7 days) was recorded on Guinea grass and green amaranth, respectively. The highest number of eggs was recorded from fall armyworm population reared on fodder maize as compared to those reared on other host plants. Longer life cycle was recorded on Guinea grass and green amaranth. Shortest larval and pupal period and faster life cycle of fall armyworm was recorded on fodder maize compared to other host plants indicating that fodder maize was the most preferred host for S. frugiperda in India.