Table 1. Toxicity of 5 Bt toxins against the Asian corn borer strains ACB-BtS and ACB-FR.
| Bt toxin | ACB-strains | na | LC50 (95%FL) (μg/g) | RRb (95%FL) | Slope±SE | χ2 | df (χ2) |
|---|---|---|---|---|---|---|---|
| Cry1F | ACB-BtS | 672 | 0.57 (0.36–0.83) | - | 2.76 ± 0.36 | 11.5 | 10 |
| ACB-FR | 1248 | >1000 | >1754 | ndc | nd | 22 | |
| Cry1Ab | ACB-BtS | 672 | 0.23 (0.14–0.33) | - | 2.76 ± 0.40 | 16.9 | 10 |
| ACB-FR | 672 | 5.13 (4.12–6.27) | 22.8 (16.9–30.9) | 2.51 ± 0.40 | 5.1 | 10 | |
| Cry1Ac | ACB-BtS | 768 | 0.18 (0.06–0.33) | - | 1.11 ± 0.17 | 12.8 | 12 |
| ACB-FR | 672 | 4.88 (3.91–5.97) | 26.9(15.7–46.0) | 2.44 ± 0.38 | 4.4 | 10 | |
| Cry1Ah | ACB-BtS | 672 | 0.21 (0.12–0.31) | - | 2.56 ± 0.40 | 15.9 | 10 |
| ACB-FR | 576 | 0.78 (0.38–1.34) | 3.7 (2.3–5.9) | 1.27 ± 0.20 | 7.7 | 8 | |
| Cry1Ie | ACB-BtS | 672 | 1.69 (0.41–2.46) | - | 0.9 ± 0.25 | 5.6 | 10 |
| ACB-FR | 576 | 1.03 (0.78–1.26) | 0.6 (0.4–1.0) | 0.96 ± 0.13 | 4.6 | 8 |
a n, number of larvae tested.
b RR, resistance ratio
c nd, not determined, indicates that the Probit regression line could not be determined because the range of Cry1F concentrations needed to cause significant response exceed the range tested.