The developmental morphometry of head capsule width in fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on different genotypes of maize

The objective of this study was to examine the morphometric differences in head capsule of each instar of larvae of fall armyworm, when they are grown in two different genotypes (viz., fodder and sweet corn) of maize crop. The larvae were raised in the controlled laboratory condition (25 ± 1 and 70% RH) until the final moult, and head capsule were counted and measured. The width of head capsule of first, second, third, fourth and fifth instar larvae was 0.36 ± 0.003, 0.46 ± 0.003, 0.76 ± 0.003, 1.31 ± 0.003 and 2.01 ± 0.003 mm, respectively when they are reared in sweet corn, while it was reported 0.34 ± 0.003, 0.43 ± 0.003, 0.74 ± 0.003, 1.29 ± 0.003 and 1.99 ± 0.003 mm, respectively when reared in fodder corn. The comparative study for the head capsule measurement revealed that each instar was found better developed when they are reared on sweet corn as compared to fodder corn.