Table 5. Susceptibility of the second instar S. frugiperda larvae to synthetic insecticides at 24 h post-treatment.
| Fit of probe line | |||||||
|---|---|---|---|---|---|---|---|
| Insecticides | Slope ± SE | chi-sq. (χ2) | df | P value | LC50 (95% CL) (mg L-1) | Reg. equation (y = a + bx) | Toxicity Index |
| Spinetoram | 1.25 ± 0.12 | 0.77 | 3 | 0.89 | 1.41 (1.13–1.69) defg | −0.19+1.27x | 58.59 |
| Spinosad | 1.24 ± 0.12 | 0.23 | 3 | 0.97 | 2.12 (1.76–2.53) cdef | −0.41+1.24 x | 38.88 |
| Lambda-cyhalothrin | 0.97 ± 0.11 | 0.73 | 3 | 0.87 | 1.63 (1.25–2.04) bcde | −0.21+0.98 x | 50.49 |
| Cypermethrin | 0.91 ± 0.11 | 0.46 | 3 | 0.93 | 1.99 (1.53–2.51) bcd | −0.27+0.91 x | 41.54 |
| Bifenthrin | 0.91 ± 0.11 | 0.47 | 3 | 0.93 | 2.12 (1.65–2.68) c | −0.30+0.91 x | 38.86 |
| Abamectin | 0.93 ± 0.11 | 0.20 | 3 | 0.98 | 1.22 (0.88–1.57) ab | −0.08+0.93 x | 67.46 |
| Broflanilide | 0.87 ± 0.12 | 0.95 | 3 | 0.81 | 0.82 (0.52–1.12) a | 0.07+0.88 x | 100 |
SE, df and CL indicate standard error, degrees of freedom and confidence limits, respectively. The LC50 values of each tested insecticide followed by different lower-case letters in the same column indicate significantly different when non-overlapping with each other in the corresponding 95% confidence limits (P < 0.05). Toxicity Index ₌ LC50 of the most effective compound/LC50 of the other tested compound × 100.