Influence of some environmental conditions on stability and activity of Bacillus thuringiensis formulations against the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae)

Egyptian Journal of Biological Pest Control

Table 5 Activity of Bacillus thuringiensis formulations against neonate and 2nd larvae of Spodoptera littoralis at different storage conditions

Bioinsecticides	Conditions	LC₅₀ (mg/L)	LC₉₀ (mg/L)	x ²	Slope ± SE	Toxicity index
Neonate larvae
Dipel 2×	0	948.18	9067.25	3.37	1.307 ± 0.12	100
	1	3156.95	24,948.50	4.53	1.428 ± 0.16	30.03
	2	3460.22	28,855.13	2.86	1.391 ± 0.22	27.40
Protecto	0	1577.92	33,715.81	1.16	0.935 ± 0.11	100
	1	4233.44	37,038.06	1.07	1.422 ± 0.19	37.27
	2	4504.29	38,769.82	2.88	1.371 ± 0.19	35.03
2nd larvae
Dipel 2×	0	931.99	17,905.98	6.97	0.998 ± 0.11	100
	1	2069.06	10,281.37	1.26	1.841 ± 0.12	45.04
	2	4067.42	24,013.61	8.34	1.662 ± 0.19	22.91
Protecto	0	1530.31	59,547.43	0.56	0.806 ± 0.11	100
	1	4051.99	25,819.24	6.67	1.593 ± 0.19	37.77
	2	5000.50	71,826.85	1.02	1.107 ± 0.22	30.60

0—zero time where each mg contain 31,289 IU for Dipel 2× and 30,155 IU for Protecto
1—storage at 35 ± 2 °C for 12 weeks where each mg contain 29,156 IU for Dipel 2× and 26,379 IU for Protecto
2—storage under direct sunlight for 2 days where each mg contain 24,889 IU for Dipel 2× and 23,610 IU for Protecto