The antibacterial effect of the thuringiensin preparations in the microbiology assay by way of using the Sarcina flava, Micrococcus aureus, Agrobacterium tumefaciens and Pseudomonas fluorescens was compared with the toxic response of the thuringiensin preparations in the bioassay using the larvae of the housefly. 用黄色八叠球菌、金色微球菌、根癌农杆菌和萤光假单胞杆菌作指示菌,同时用家蝇幼虫作指示昆虫,对产苏云金素的4株苏云金杆菌发酵物的毒力进行了测定。