Biology and Morphometric Characteristics of Invasive Pest Spodoptera frugiperda (J.E.Smith) on Maize for Two Successive Generations

Abstract

Maize commonly known as the "Queen of cereals," is the second most frequently grown crop in the world. It is grown in tropical, subtropical, and temperate climates. Spodoptera frugiperda is a big problem because of its infamous and polyphagous behavior. It is currently the main bug causing significant yield losses in maize. The biological and life history parameters of fall armyworm, Spodoptera frugiperda, through successive generations on maize were studied during 2021-22 under laboratory conditions at the Agricultural Research Station, Mudhol, Karnataka. The females laid an average of 1237.50 and 1150 eggs in the first and second generations, respectively. Only a trivial difference was observed between successive generations. The incubation, larval, pupal, pre-ovipositional, ovipositional, and post-ovipositional periods ranged from 2-3,15-19, 12-15, 3-4, 3-4 and 4-5 days, respectively. The total life cycle duration of males and females was recorded as 36-46 and 39-49 days, respectively, in the first generation, and 42-46 and 41-50 days, respectively, in the second generation. The findings showed that during generation I, the average length and breadth of the first instar were 1.70 mm and 0.20 mm, respectively; 2.30 mm length and 0.30 mm breadth for the second instar; 6.70 mm and 0.70 mm for the third instar; 13.90 mm and 1.90 mm for the fourth instar; 19.30 mm and 2.90 mm for the fifth instar; and 27.02 mm and 3.90 mm for the sixth instar. There was no significant difference in larval length and breadth in generation-II, which ranged from 1.74 to 27.20 mm in length and 0.22 to 3.90 mm in breadth.