Susceptibility of Different Instars of Earias vittella (Fabricius) to Bacillus thuringiensis Insecticidal Proteins

The susceptibility of different instars of Earias vittella (Fabrieius) to Bacillus thuringiensis (Bt) insecticidal proteins (ICP) was studied. The LC 50 of CrylAa, CrylAb, Cry1Ac, CryiC and Cry1E were 108.54, 97.04, 66.62, 1240.83 and 1335.60 ng/cm 2 , respectively to E. vittella neonates. The order of toxicity of different ICPs to second and third instar was Cry1Ac > CrylAb > CrylAa. Overlap 95 per cent fiducial limits at LC 50 of CrylAa and CrylAb showed similar toxicity of these toxins to second and third instars of E. vittella . The possibility of these toxins and toxicity parameters in resistance management is discussed.