Comparative toxicity of transgenic cotton CEM-33, Bt-906 varieties, and Annona squamosa L., seed extract against biotic potential of Spodoptera litura (Fab.)

The research studies were conducted to determine the effects of Custard Apple ( Annona squamosa L). (Seed extract) and transgenic cotton CEMB-33, BT-906 varieties against larval mortality, pupation, adult emergence, fecundity and fertility of Spodoptera litura Fab. The study was conducted under laboratory conditions 27.5 ± 5 °C and relative humidity 65 ± 5%, at (MAHQ) Biological Research Centre, University of Karachi. Toxicity of A. squamosa (SE) as seed extract was determined against sixty S. litura fifth instar larvae, treated with 0.90, 1.10, 1.30, 1.50 and 1.70% concentrations each of A. squamosa (SE) seed extract. After 72 h of treatment, mortality was recorded and LC 50 value found to be 1.32%, by probit analysis. When sixty, fifth instar larvae of S. litura were treated with LC 50 of A. squamosa (SE) and the same number of larvae fed with fresh leaves of transgenic cotton CEMB-33 and BT-906. Larval pupation was recorded 43.33, 79.17, and 81.25% from which only 26.25, 50.00 and 57.08% pupa emerged as adults. Male and female moths’ were paired (T♀ × U♂) and showed relative fecundity 57.40, 34.70, and 29.45% while relative fertility was recorded 55.78, 21.02, and 19.81%. Moths’ paired as U♀ × T♂ showed relative fecundity 61.64, 43.02, and 36.71% while relative fertility 65.03, 29.29, and 28.18%, similarly S. litura moths paired (T♀ × T♂) showed relative fecundity 84.02, 59.09 and 53.62% while relative fertility 70.88, 35.47 and 32.91%. A. squamosa (SE) and crystal protein Bacillus thuringiensis (Bt) present in transgenic cotton affect the biotic potential of S. litura with significant margins as compared to the control. Both may be employed against S. litura larvae.