我国南北方土壤中苏云金芽孢杆菌的分布及杀虫特性

DISTRIBUTION OF BACILLUS THURINGIENSIS IN SOILS OF NORTH AND SOUTH OF CHINA

从我国南部和北部地区12省的1491份土样中分离出苏云金芽孢杆菌(Bacillus thuringiensis,以下简称为 Bt)221株。经鉴定,属于已有血清型(H_1～H_(45))中的24个血清型。此外尚有部分自凝型和未知血清型菌。东北和内蒙古地区的出菌土样率为12.6％,出菌率为17.2％,优势血清型为H_4、H_(10)、H_3、H_(13)、H_5及H_(29),其中以黑龙江省土壤Bt菌最丰富,出菌土样率和出菌率分别达21.4％和29.4％,还分离出H_(43)型菌2株;西北地区的出菌土样率和出菌率分别为6.6％和7.1％,远低于东北、内蒙古地区,优势血清型为H_4、H_5、H_(19)、H_(10)及H_3;南部4省土壤中的优势血清型为H_3及H_5,Bt菌的平均分出率高,但地区分布极不均衡,湖南、江苏的出菌土样及出菌率均在4.8％～4.9％,广东珠江三角洲土壤中分别高达77.8％和129.6％,湖北长江沿岸冲积土中则未分离出Bt菌。毒力初测结果表明:北部地区的Bt分离株中仅有1.6％对棉铃虫(Heliothis armigera)高效,1.1％对柳蓝叶甲(Plagwdera versicolora)高效,98.0％以上的菌株对两种昆虫无效或低效。出自南部地区土壤的Bt菌株,5.3％对棉铃虫高效,未发现对柳蓝叶甲有效的菌株。菌株H27-05自黑龙江省土壤中分离,对棉铃虫毒力极高,对柳蓝叶甲有中等毒效。

221 isolates of Bacillus thuringiensis were isolated in 1491 soil samples from North and South of China. H-serotypes and larvicidal characters of all Bt isolates have been identified. The rate of Bt-harbouring soil sample and the rate of Bt isolates in Northeast and Neimeng were in 12.6% and 17.2% respectively. Predominant serotypes were H4, H10, H3, H13, H5and H29.The most fertile Bt-harbouring area was the Heilongjiang Province with rate of Bt-harbouring sample of 21.4% and rate of Bt isolate of 29.4%. Rate of Bt-harbouring sample and rate of Bt isolate in Northwest area were 6.6% and 7.1% respectively. Main serotypes were H4, H5, H19, H10and H3.In four provinces of Southern China, both rates above were 18.6% and 29.5%, but frequency of Bt distribution was varied seriously in different distinct. Predominant serotypes in soils from Southern China were H3and H5.Results of bioassay showed that the percentage of strains high active to Heliothis armigera and Plogioidera vcrsicolora were 1.6% and 1.1% in soils from North of China.In contrast to North of China, Bt strains active to H. armigera were 5.3% and none of Bt was effective to P.versicolora in South of China. A strain H27-05 was high toxic to H.armigera and showed temperate toxicity to P.versicolora.