Persistence of Toxic Activity of Fermentation Extracts from Bacillus thuringiensis var. israelensis after More Than Three Decades of Storage

Table 1

Dead larvae counted every 6 hours after exposure to the extracts.

Treatment	Dead larvae
	Concentration (ppm)/time (h)
	0.01					0.1					1					10					100					1000
	1	6	12	18	24	1	6	12	18	24	1	6	12	18	24	1	6	12	18	24	1	6	12	18	24	1	6	12	18	24
	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
2858	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3826	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3859	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
3350	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	2
3549	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	3	4
3553	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	4	5
3356	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	4	6
3824	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	3	6	8
3552	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	2	6	10
3825	0	0	0	0	0	0	0	0	1	3	0	0	2	4	5	0	0	2	3	6	0	1	2	5	9	0	3	5	8	12
3299	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	8	14	19	23
3779	0	0	0	0	0	0	0	0	1	1	0	0	1	4	5	0	1	3	7	11	4	11	17	21	24	8	20	25	25	25
3353	0	0	0	0	0	0	0	0	0	0	0	0	1	1	2	0	2	6	9	10	0	6	15	22	25	11	23	25	25	25
3691	0	0	0	0	0	0	0	0	3	5	0	0	1	4	13	0	4	12	19	24	2	12	22	25	25	23	25	25	25	25
3505	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	4	5	8	20	25	25	25	25	25	25	25	25
3857	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	0	0	0	1	2	14	24	25	25	25	25	25	25	25	25
3756	0	0	0	0	0	0	0	0	1	1	0	0	2	4	5	4	9	18	21	24	13	25	25	25	25	25	25	25	25	25
3696	0	0	0	0	0	0	0	0	1	4	0	0	3	5	8	0	5	14	19	23	9	25	25	25	25	25	25	25	25	25
3501	0	0	0	0	0	0	0	0	2	6	0	2	6	10	13	14	24	25	25	25	25	25	25	25	25	25	25	25	25	25
3260	0	0	1	3	3	2	8	10	10	13	16	25	25	25	25	23	25	25	25	25	25	25	25	25	25	25	25	25	25	25
VA	16	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
VC	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25

indicates average of four replications in three separate experiments; indicates distilled water. VA: activated VectoBac; VC: commercial VectoBac.