Need for growing non-Bt cotton refugia to overcome Bt resistance problem in targeted larvae of the cotton bollworms, Helicoverpa armigera and Pectinophora gossypiella

Egyptian Journal of Biological Pest Control

Table 1 Median lethal concentration of Bacillus thuringiensis protein against the target insect pest species

Target larvae	Variety	LC₅₀^a (ppm)^b	95% FL^c	Slope (± SE^d)	χ^2e	df^f	P^g
Pectinophora gossypiella	FH-142	8.91	4.16–12.2	0.6 (± 0.21)	1.45	3	0.83
	MNH-886	13.4	6.21–20.7	0.76 (± 0.49)	0.46	3	0.92
	IR-3701	14.0	3.20–25.3	0.70 (± 0.43)	0.87	3	0.83
	FH-Lalazar	36.4	22.04–50.7	0.65 (± 0.2)	0.39	3	0.94
Helicoverpa armigera	FH-142	5.91	3.26–7.2	0.8 (± 0.41)	0.45	3	0.93
	MNH-886	4.04	1.23–7.2	0.52 (± 0.22)	0.34	3	0.95
	IR-3701	2.37	0.15–4.8	1.47 (± 0.17)	3.94	3	0.27
	FH-Lalazar	8.26	4.18–12.35	0.5 ± (0.25)	0.08	3	0.97