TABLE 1.
Responses of resistant (GipBtR and GlenBtR) and susceptible (GipS and GlenS) strains of T. ni to native toxins (Cry1Ab and Cry1Ac), modified toxins (Cry1AbMod and Cry1AcMod), and formulations (DiPel and Agree)
| Toxin or formulation | Strain | No. of larvae | LC50 (95% FL)a | Slope ± SE | Resistance ratiob |
|---|---|---|---|---|---|
| Cry1Ab | GipBtR | 400 | 180 (59-2,900)c | 0.41 ± 0.09 | 580 |
| GipS | 376 | 0.30 (0.21-0.41) | 0.56 ± 0.06 | ||
| Cry1AbMod | GipBtR | 400 | 3.4 (2.6-4.6) | 0.52 ± 0.05 | 5.5 |
| GipS | 375 | 0.62 (0.51-0.75) | 0.99 ± 0.09 | ||
| Cry1Ac | GipBtR | 600 | 54 (35-110)d | 0.50 ± 0.07 | 1,400 |
| GipS | 1,450 | 0.038 (0.031-0.046) | 0.44 ± 0.02 | ||
| Cry1AcMod | GipBtR | 600 | 5.1 (4.4-5.8) | 0.85 ± 0.06 | 9.3 |
| GipS | 1,145 | 0.55 (0.47-0.64) | 0.60 ± 0.03 | ||
| DiPel | GipBtR | 125 | 66 (21-420,000)e | 0.43 ± 0.17 | 370 |
| GipS | 125 | 0.18 (0.08-0.27) | 0.73 ± 0.16 | ||
| Agree | GipBtR | 300 | 4.9 (3.6-7.7) | 0.81 ± 0.12 | 9.9 |
| GipS | 300 | 0.49 (0.42-0.57) | 1.4 ± 0.14 | ||
| DiPel | GlenBtR | 150 | 3.2 (2.7-3.9) | 1.9 ± 0.27 | 26 |
| GlenS | 125 | 0.13 (0.05-0.17) | 1.5 ± 0.44 | ||
| Agree | GlenBtR | 300 | 2.0 (1.7-2.4) | 1.2 ± 0.12 | 5.9 |
| GlenS | 295 | 0.34 (0.29-0.39) | 1.4 ± 0.17 |
a
Concentration that killed 50% and its 95% FL in mg protoxin per cm2 diet for toxins and mg formulation per ml of diet for DiPel and Agree.
b
LC50 of the resistant strain divided by the LC50 of the related susceptible strain for each toxin or formulation.
c
Total of 17% mortality at the highest toxin concentration tested (17 mg protoxin/cm2 diet).
d
Total of 35% mortality at the highest toxin concentration tested (23 mg protoxin/cm2 diet).
e
Total of 24% mortality at the highest toxin concentration tested (15 mg DiPel/ml diet).