Table 1.
Comparative toxicity of the four Bt endotoxins tested against D. plexippus larvae on artificial diet
| Toxin | Instar | n | LC50 (95% FL)* | EC50 (95% CI)† |
|---|---|---|---|---|
| Cry1Ab | 1st | 318 | 3.3 (2.2–4.8) | 0.8 (0.6–0.9) |
| 2nd–3rd | 141 | 35.1 (30–100) | 9.6 (6.0–15) | |
| 3rd–4th | 125 | >100‡ | 18.3 (9.4–40) | |
| Cry1Ac | 1st | 192 | 13.8 (3.0–26) | 0.9 (0.9–1.0) |
| Cry9C | 1st | 164 | 316 (203–428) | 34.9 (22–55) |
| Cry1F | 1st | 62 | >30,000‡ | 5,220 (2930–8520) |
*
Nanograms of Cry1Ab per milliliter treated artificial diet. FL, fiducial limit.
†
Concentration of Cry1Ab that produces 50% growth inhibition relative to untreated controls. Calculated by nonlinear regression fitted to a probit model. CI, confidence interval.
‡
Highest concentration tested.