Table 2.
Summary of the lethal concentrations to kill 20% (LC20) and 50% (LC50) of the insect population, and their 95% confidence intervals (95% CI) for each of the four insecticides determined in 20-day larvae of T. castaneum (Georgia-1 strain).
| Insecticides | LC20, μg/mL (95% CI) | LC50, μg/mL (95% CI) | Slope a | Intercept a | χ2 | p b |
|---|---|---|---|---|---|---|
| Cypermethrin | 2.27 (1.6–3.0) | 7.77 (6.5–9.4) | 3.66 ± 0.67 | 1.94 ± 0.94 | 5.13 | 1 |
| Lambda-cyhalothrin | 1.76 (1.6–3.3) | 4.24 (3.6–5.0) | 3.49 ± 0.40 | 2.98 ± 0.32 | 7.16 | 0.85 |
| Permethrin | 23.73 (15.3–32) | 77.46 (63.6–94.9) | 3.51 ± 0.80 | 1.63 ± 1.25 | 41.86 | 0.08 |
| Imidacloprid | 14.25 (12.0–16.5) | 48.65 (44.9–53.4) | 1.80 ± 0.49 | 2.02 ± 0.84 | 28.48 | 0.15 |
a Slope and intercept were derived from the logarithm of concentration-probit mortality curve that generated by probit analysis; b p-Value > 0.05 indicates a significant fit between the observed and expected regression lines in a probit analysis.