Table 2. Responses of pink bollworm strains to Bt toxins Cry1Ac and Cry2Ab.

Strain	Date	Gena	nb	LC50 (95% FL)c	RRd	Survival (%)e
Cry2Ab
Bt4-R2	March 2012	F15	240	5,720 (NA)	150,000	85.7
Bt4R-P	May 2012	F19	180	0.0222 (0.013–0.044)	0.58	0.00f
Bt4R	May 2012	F61	180	0.0273 (0.011–0.038)	0.72	0.00f
APHIS-S	May 2012	NA	180	0.0380 (0.014–0.066)	1.0	0.00f
Cry1Ac
Bt4-R2	March 2012	F15	240	9.87 (4.4–18)	28	56.5
Bt4R-P	April 2012	F18	240	143 (93–200)	400	100
Bt4R	March 2012	F59	240	3.79 (1.5–7.1)	11	37.5
APHIS-S	April 2012	NA	180	0.353 (0.094–0.58)	1.0	0.00

^aGeneration tested in bioassays.

^bNumber of larvae tested including controls on untreated diet.

^cConcentration killing 50% with 95% fiducial limits in parentheses (NA indicates limits not available), in μg of toxin per mL of diet.

^dResistance ratio, the LC₅₀ for a strain divided by the LC₅₀ for APHIS-S (susceptible).

^eSurvival at 10 μg of toxin per mL diet (unless noted otherwise), adjusted for control mortality; sample size for each estimate was 30 neonates.

^f10 μg Cry2Ab per mL diet was not tested; adjusted survival was 0% at a lower concentration (1 μg Cry2Ab per mL for Bt4R and APHIS-S; 0.3 μg Cry2Ab per mL for Bt4R-P).