TABLE 2.

Logit regression and time-to-death analysis for the SfB, Sfbac, S29null, and Sf29null-repair bacmids compared with the SfWT isolate in second-instar Spodoptera frugiperda larvae

Virus	Logit regressiona					Time to deathb
	LC50 (OBs/ml)			Relative potency	P	Mean (h)	95% Confidence limit
	Mean	95% Confidence limit
		Low	High				Low	High
SfWT	2.9 × 104	1.7 × 104	4.8 × 104	1.0		110 a	105	116
SfBc	9.3 × 104	5.5 × 104	1.1 × 105	0.31	<0.001	120 a	114	125
Sfbac	1.0 × 105	6.1 × 104	1.7 × 105	0.28	<0.001	123 a	116	130
Sf29null	1.5 × 106	8.2 × 105	2.9 × 106	0.02	<0.001	157 b	147	167
Sf29null-repair	2.1 × 105	1.2 × 105	3.5 × 105	0.13	<0.001	132 a	125	140

^aLogit regressions were fitted using the GLIM program with a common slope of 0.7847 ± 0.0695 (mean ± standard error). A test for nonparallelism was not significant (χ² = 6.374, df = 4, P = 0.173). Relative potencies were calculated as the ratio of effective concentrations relative to the SfWT isolate. P values were calculated by a t test of the differences between regression intercepts compared to that of the SfWT isolate.

^bMTDs were estimated by Weibull analysis (8). MTDs labeled with different letters were significantly different.

^cSfB data are from reference 48.