Table 2. Probit regression and time to death analysis for SfNIC-Bpif1, SfNIC-Begt and SfNIC-Bp10 recombinant viruses compared with the SfNIC-B parental virus in Spodoptera frugiperda second instars.
| Viruses | Intercept ± S.E. | LC50 (OBs/ml) | Relative potency | Fiducial limits (95%) | Mean time to death (h) | Fiducial limits (95%) | ||
| Low High | Low High | |||||||
| SfNIC-B | −4.592±0.427 | 7.25×104 | 1.00 | - | - | 124a | 121 | 127 |
| SfNIC-Bpif1 | −5.296±0.467 | 6.22×104 | 1.17 | 0.71 | 1.93 | 121a | 118 | 124 |
| SfNIC-Begt | −5.056±0.509 | 3.60×105 | 0.20 | 0.11 | 0.37 | 100b | 98 | 103 |
| SfNIC-Bp10 | −5.435±0.584 | 7.33×105 | 0.10 | 0.05 | 0.19 | 99b | 97 | 101 |
Probit regressions were fitted using the PoloPlus program [25]. A test for non-parallelism was not significant (χ2 = 2.61, d.f. = 3, P = 0.456). Lines were fitted with a common slope of 0.927±0.099 (S.E). Relative potencies were calculated as the ratio of effective concentrations relative to the SfNIC-B virus. Mean time to death (MTD) values were estimated by Weibull survival analysis [26]. MTD values labelled with different letters were significantly different (P<0.05). The hazard function (α) was 5.0577.