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本文报导1974—1980年间利用苏云金杆菌(Bacillus thuringiensis)的几个变种对菜青虫(Pieris rapae L.)的毒力测定和田间防治试验结果。室内菌效试验结果指出,不同菌剂的1×10~8/ml孢子、晶体混合液处理后2天可获90％以上死亡率,某些菌剂的1×10~7/ml悬液2天内可获55—100％死亡率。室内毒力测定结果看出,HD-1和B-Hm-18对3龄幼虫毒力随菌剂浓度递减相应减低,致死中浓度(LC_(50))随作用时间增长而降低。田间防治实践所用浓度不宜过低。对菜青虫的毒力直线回归的斜率b值经多次测定范围为0.44—2.65。田间防治试验结果表明,1×10~8/ml的菌液浓度一般可使虫口减退90％以上,以B-Hm-18效果较好。0.1×10~8/ml菌液的防治效果与80％敌敌畏1:800药液防治效果相同,0.4×10~8/ml菌液防治效果显著高于敌敌畏。同浓度的HD-1(美国高效菌种)和B-Hm-18(我院分离菌株)菌剂间防治效果无显著差异。结果指出利用苏云金杆菌可以在生产上有效地防治菜青虫。
This article reports the results of the toxicity test and field control test of Pieris rapae L. using several varieties of Bacillus thuringiensis from 1974 to 1980. The results of indoor bacteriostasis test indicated that the mortality of 1 × 10 ~ 8 / ml spores and crystal mixture of different antibacterial agents could reach over 90% 2 days after the mixture was treated, and 1 × 10 ~ 7 / ml suspension 2 55-100% mortality rate within days. The result of indoor toxicity test showed that the virulence of HD-1 and B-Hm-18 to 3rd instar larvae decreased correspondingly with decreasing concentration of bacteriocin, and the lethal concentration (LC 50) decreased with the increase of lavage time. The concentration used in field control practices should not be too low. The linear regression of cabbage worm toxicity b value by multiple determination of the range of 0.44-2.65. Field control test results show that the bacterial concentration of 1 × 10 ~ 8 / ml can generally reduce the population more than 90%, B-Hm-18 better. The control effect of 0.1 × 10 ~ 8 / ml bacterium liquid was the same as that of 80% dichlorvos 1: 800 liquid. The control effect of 0.4 × 10 ~ 8 / ml bacterium solution was significantly higher than that of dichlorvos. There was no significant difference in the control effect between the same concentration of HD-1 (American high-efficiency strain) and B-Hm-18 (our hospital isolates). The results indicated that the use of Bacillus thuringiensis in the production of cabbage can effectively control insects.