Biology and Nutritional Indices of The Fall Army Worm Spodoptera Frugiperda (J E Smith) on Maize

Lifecycle, progressive growth of larval head capsule, and nutritional indices of Spodoptera frugiperda (J E Smith) on maize (Co-H6) were studied at the Department of Agricultural Entomology, TNAU, Coimbatore during 2018-19. Incubation, total larval, and pupal periods were observed as 2-3, 13-20, and 7-11 days, respectively. The total lifecycle of male and female was 33-46 and 35-47, respectively. The head width was observed to be 0.34, 0.60, 0.89, 1.32, 1.86, and 2.36 mm from the first to the sixth instars, respectively. Linear regression analysis showed a significant relationship between larval instars and head capsule width (R²=0.0979); and geometric progression ratio was observed as 1.48. Nutritional indices were also studied for the third and fifth instar on the maize plants. Consumption index (CI) and approximate digestibility (AD) increased with larval age, while efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) were inversely related to age. These values for the third and fifth instar were- CI= 2.30 and 2.31; AD=35.7 and 40.29; ECI=18.33 and 12.21; ECD=51.33 and 30.3, respectively.