Plant Protection Bulletin (Taipei) (2000) 42, 125-134

S.S. Kao, C.H. Shih, M.S. Chang and J.L. Ko (2000)
Screening of indigenous thuringiensin-producing Bacillus thuringiensis isolates
Plant Protection Bulletin (Taipei) 42 (2), 125-134
Abstract: Specimens of stored-grain materials from different locations around Taiwan were collected. Islation and identification of Bacillus thuringiensis (Bt) isolates were made. Five hundred and seventy-four isolates were selected for thuringiensin screening by HPLC. Results indicated that 321 out of 574 Bt isolates produced thuringiensin. The best 14 isolates of this collection were isolates BPD1-BPD14 which produced 6.79 to 9.62 mg/ml thuringiensin. The relative amount of thuringiensin production was 1.02 to 1.45-fold as compared to reference strain B. thuringiensis darmstadiensis HD199 (6.6 mg/ml). The high thuringiensin-producing isolates BPD1, BPD2, BPD3, were serologically classified as B. thuringiensis kenyae of H-antigen 4a, 4c, while BPD5, BPD6, BPD7 and BPD8 were serologically classified as B. thuringiensis tolworthi of H-antigen 9. Isolates of B. thuringiensis kenyae were found to be a novel thuringiensin producing serotype. In another screening test of mutation, UV was tested against 8 thuringiensin-producing isolates. The quantity of thuringinsin produced by UV1-3 (UV mutant of B. thuringiensis darmstadiensis HD199) was 1.7-fold as compared with the parental strain (HD199). The LC₅₀ values of 8 high thuringiensin-producing isolates against Musca domestica (CMA080192) were between 2.39 ± 0.19 and 7.83 ± 0.17 ppm. Pupation rate of M. domestica was 85.25% when treated with low concentration of thuringiensin (6.7-30 ppm), however, pupation rate decreased significantly down to 60.15% at higher concentrations (>53.6ppm). Emergence rate was drastically declined to 23.33% even at the concentrations of 6.7-30ppm. The percentage of malformed adults reached to as high as 7.84%.
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Database assignments for author(s): Suey-Sheng Kao

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
control - general
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Musca domestica		Taiwan
Bacillus thuringiensis var. kenyae (entomopathogen)			Taiwan
Bacillus thuringiensis var. tolworthi (entomopathogen)			Taiwan