Table 1. Responses to Cry1Ac of two susceptible strains (LF and 96S) and a resistant strain (LF60) of H. armigera.
| Strain | Form of Cry1Ac | LC50 (95% fiducial limits) (µg Cry1Ac per ml diet) | Resistance ratio* |
|---|---|---|---|
| LF | protoxin | 0.009 (0.002–0.020) | 1.0 |
| 96S | protoxin | 0.021 (0.008–0.036) | 2.3 |
| LF60 | protoxin | 12.4 (8.0–17) | 1400 |
| LF | activated toxin | 0.008 (0.002–0.014) | 1.0 |
| 96S | activated toxin | 0.013 (0.007–0.021) | 1.6 |
| LF60 | activated toxin | 9.15 (5.8–13) | 1100 |
*LC50 of each strain divided by the LC50 of the susceptible LF strain.