Table 1.
Responses to Bt toxins by resistant strains (NO-QA, PEN, and PHI) and a susceptible strain (LAB-P) of diamondback moth
| Strain | Mean mortality, %*
|
|||||
|---|---|---|---|---|---|---|
| Cry1Aa | Cry1Ab | Cry1Ac | Cry1C | Cry1F | Cry1J | |
| LAB-P | 96.1 | 99.0 | 98.0 | 96.8 | 100.0 | 96.1 |
| NO-QA | 0.7 | 0.2 | 0.7 | 73.5 | 0.0 | 0.0 |
| PEN | 0.0 | 1.2 | 0.0 | >90† | 6.8 | <10† |
| PHI | 11.5 | 39.1 | 40.2 | 100.0 | 100.0 | 97.5 |
*
Mortality after 5 days was adjusted for control mortality. The concentration of each toxin was 10 mg toxin per liter except for Cry1C and Cry1F, which were tested at 10 ml formulated toxin per liter. Each test was replicated at least four times. Average total sample size was 142 larvae per toxin per strain.
†
Mortality of PEN in response to Cry1C and Cry1J was estimated from a related study (unpublished) in which artificial diet bioassays with PEN showed no resistance to Cry1C and >1,000-fold resistance to Cry1J relative to a susceptible strain.