Performance of <i>Aphis gossypii</i> on <i>Bt</i> and non-<i>Bt</i> cotton varieties (n = 24 to 30).

Bioassays were performed at 25°C±1°C day/20°C±1°C night, 70%±10% r.h. and a 16-h photoperiod. Printed estimate refers to median and variability to first to third quartile in case of Cox-proportional hazard analysis, and to 95% confidence interval of the mean otherwise. a(rm) intrinsic rate of increase (days); (FD) number of nymphs produced during D; (DF) daily fecundity; (TF) total fecundity; (D) nymphal developmental time (days); (AL) adult longevity (days); (TL) total longevity (days). bbootstrap percentile method. c3-way ANOVA with experiment, cotton variety and Bt-transformation as factors. dCox-proportional hazard analysis with experiment, cotton variety and Bt-transformation as factors. eF = Test statistic for F-distribution; W = Wald test statistics.