YANG Huai-wen; ZHANG Zhi-ming; YANG Xiu-fen; JIAN Heng
HE Hong;CAI Xue-qing;HONG Yong-cong;GUAN Xiong;HU Fang-ping
30 strains of Bacillus thuringiensis were isolated from 858 samples of dryland, vegetable garden and rice soils in different ecological regions of Hunan province. One was selected from them as original strain7012c typical of B. thuringiensis. By means of multiple mutagenesis of UV and double NTG+LiCl and through microscopic examination of smear dyeing, it was first found that the insecticidal activity of B. thuringiensis closely related with the shape, size and number of the crystal protein and the proportion of spore and crystal protein. One high toxic mutation, strain 4.0718, was selected, and its toxicity to the larval of Plutella xylostella was 7.5 times higher than that of strain7012c and the lethal rate reached to 20%, 97% and 100% respectively after treatment of 6, 12 and 24 h. The virulence of 4.0718 did not change after transferation of ten generations.
JIANG Ying-hua;HU Bai-shi;LIU Feng-quan
Two isolates i.e. Pseudomonas putida type B1 strain P-91 and Bacillus subtilis strain B-916 were compared with Jinggangmycin in their ability to control rice sheath blight at field plots during 1992-1994. Performance test of B-916 of biocontrol on sheath blight was carried out during 1994-1995 at three sites. Results showed that ferment product of B-916 possessed a good control effect of 50.0%-81.1% against rice sheath blight infection under field conditions.
Chinese Journal of Biological Control
Supported by: Beijing Magtech
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