Table 6. Log-dose (mg L–1) probit model fitted to mortality data of Guntur B. tabaci populations collected during 2010 to 2013.
| Population | Sampling year | Genetic group | N | Slope ± SE | χ2 a (df)b | LC50(CI 95%) | RRc |
|---|---|---|---|---|---|---|---|
| Cypermethrin | |||||||
| Guntur | 2010 | Asia-I | 284 | 1.32 ± 0.17 | 9.54 (4) | 25 (5–57) | 1.00 |
| Guntur | 2012 | Asia-I | 253 | 2.27 ± 0.26 | 2.58 (4) | 127 (96–165) | 5.16 (3.05–8.73) |
| Guntur | 2013 | Asia-I | 238 | 2.89 ± 0.51 | 7.08 (5) | 261 (131–383) | 10.60 (6.20–18.01) |
| Triazophos | |||||||
| Guntur | 2010 | Asia-I | 245 | 2.14 ± 0.30 | 4.22 (4) | 167 (99–257) | 1.00 |
| Guntur | 2012 | Asia-I | 246 | 1.26 ± 0.23 | 2.86 (4) | 321 (204–528) | 1.92 (1.11–3.31) |
| Guntur | 2013 | Asia-I | 330 | 1.63 ± 0.22 | 9.54 (6) | 636 (358–1016) | 3.78 (2.46–5.85) |
| Imidacloprid | |||||||
| Guntur | 2010 | Asia-I | 330 | 1.10 ± 0.15 | 10.90 (5) | 11 (2–24) | 1.00 |
| Guntur | 2012 | Asia-I | 254 | 1.90 ± 0.25 | 2.73 (4) | 26 (18–36) | 2.36 (1.31–4.61) |
| Guntur | 2013 | Asia-I | 261 | 1.37 ± 0.13 | 2.78 (4) | 130 (95–183) | 11.81 (6.56–22.73) |
aChi-square test for linearity of the dose–mortality response: ***P < 0.001, ** P < 0.01, *P < 0.05.
bDegrees of freedom.
cResistance ratios (RR) with 95% confidence limits indicating the fold-difference for each insecticide in comparison to the most susceptible population at LC50 (RR = Asia-I populations of 2013 or 2012 divided by most susceptible Asia-I population in 2010). Confidence limits that include 1.0 indicate no significant difference from the susceptible population (Lethal ratio test-Robertson et al.85).