Effect of transgenic Bt cotton mature leaves on consumption utilization indices of Helicoverpa armigera (Hubner) and Spodoptera litura (Fabricius) larvae

摘要

Studies on the effect of transgenic Bt cotton leaves on consumption utilization indices of Helicoverpa armigera and Spodoptera litura larvae were carried out in the laboratory, Department of Entomology, CCS Haryana Agricultural University Hisar during2006. Eleven genotypes including five Bt (Ankur 2534 Bt, Ankur 651 Bt, RCH 134 Bt, RCH 317 Bt and MRC 6304 Br) and their corresponding non Bt hybrids with one local hybrid HHH 223 were selected for the study and were grown by adopting recommended package of practices. Fourth instar larvae of H. armigera were used to study various consumption-utilization indices on leaves at an interval of 70, 100 and 130 days of crop age. There was significant reduction in consumption index (CI), growth rate (GR), efficiency of conversion of ingested food (ECI), approximate digestibility or assimilation efficiency (AD/AE) and efficiency of conversion of digested food (ECD) among Bt genotypes at 70 and 100 days of crop age. At 130 days of crop age, no significant effect of Bt was observed on H. armigera larvae. On the other hand, there were no significant differences in CI, GR, ECI, AD/AE and ECD of larvae of S. litura in Bt and non Bt genotypes at 75, 105 and 135 days of crop age.