Food consumption and utilization pattern of fall armyworm (Spodoptera frugiperda J. E. Smith)in different genotypes of cotton

Abstract

Fall army worm (FAW), Spodoptera frugiperda (J. E. Smith), a native species of tropical and subtropical regionsof the America invaded into India quite recently. A study was conducted to know the food consumption and utilizationpattern of fall armyworm (FAW) in cotton under laboratory conditions. Highest consumption indices (CI-1.18,GR- 0.23 mg/day, ECI-17.50 %, ECD-42.81 % and AD-51.32 %) were indicated by larvae when fed with leaves of anon-Bt cotton genotype DHH-11. S. frugiperda Bt revealed the lowest consumption and utilization indices when fed onleaves of cotton hybrid Bindas BG II (CI-0.21, GR- 0.07mg/day, ECI-7.32 %, ECD-18.44 % and AD-22.44 %).When larvaewere fed with squares of non-Bt cotton genotype DHH-11 showed highest indices (CI -0.87, GR- 0.27 mg/day, ECI-38.51 %,ECD-53.37 % and AD-64.55 %) while lowest indices recorded on Bindas BG II Bt (CI -0.30, GR- 0.09 mg/day, ECI-17.57 %,ECD-22.53 % and AD-31.52 %). Similar effect was noticed when larvae fed with cotton bolls Non-Bt cotton genotypeDHH-11 could lead to highest indices (CI - 0.87, GR-0.46 mg/day, ECI-38.80 %, ECD-59.44 % and AD-74.31 %) whereasBindas BG II Bt cotton genotype was not well accepted by the larvae and led to the lowest food intake, utilization andassimilation indices (CI-0.16, GR-0.10 mg/day, ECI-22.49 %, ECD-28.41 % and AD-40.22 %). Among non-Bt genotypesSuvin indicated the lowest value for all the parameters. Among leaf, square and boll fed to the larvae the highest CI (1.18)was noticed for leaves and lowest (0.16) for boll. But highest GR (0.46 mg/day) was indicated when larvae were fed on thebolls followed by squares (0.27 mg/day). Hence, bolls and squares found to be more nutritious than leaves to larvae ofS. frugiperda