Table 1.
Response of Myzus persicae clones 4106A (susceptible), 5191A (moderately resistant) and FRC (highly resistant) to imidacloprid and thiamethoxam using two bioassay methods, with and without pretreatment with piperonyl butoxide (PBO)
| Micro-application | Spray application | ||||||
|---|---|---|---|---|---|---|---|
| Treatment | Clone | LC50 1(mg l-1) | 95%CL | RF2 | LC50 (mg l-1) | 95% CL | RF2 |
| Imidacloprid | 4106A | 0.99 | 0.9-1.4 | 0.14 | 0.11-0.17 | - | |
| 5191A | 31.1 | 7-69.7 | 31.4 | - | - | - | |
| FRC | 28% at 1000 mg l-1 | n/c | n/c | 235.02 | 142.33-476.29 | 1679 | |
| Imidacloprid+PBO | 4106A | 0.1 | 0.07-0.15 | 0.03 | 0.01-0.10 | - | |
| 5191A | 1.55 | 0.56-2.55 | 14.9 | - | - | - | |
| FRC | 30% at 1000 mg l-1 | n/c | n/c | 7.03 | 1.77-37.91 | 234 | |
| Thiamethoxam | 4106A | 0.64 | 0.54-0.79 | 0.48 | 0.42-0.55 | - | |
| 5191A | 19.7 | 14.87-25.74 | 30.8 | - | - | - | |
| FRC | 10% at 1000 mg l-1 | n/c | n/c | 107.84 | 69.52-185.36 | 225 | |
| Thiamethoxam+PBO | 4106A | 0.27 | 0.18-0.32 | 0.19 | 0.09-0.41 | - | |
| 5191A | 1.06 | 0.77-1.45 | 3.93 | - | - | - | |
| FRC | 216 | 110.25-483.48 | 800 | 4.86 | 2.03-14.91 | 26 | |
5191A was only tested by micro-application of insecticide.
1Calculated concentration to kill 50% of individuals. If unobtainable, % mortality at the highest concentration applied
2 Resistance factor (LC50 resistant/LC50 susceptible). n/c = not calculable