马铃薯块茎蛾幼虫致病黏质沙雷氏菌的分离鉴定及杀虫活性

Isolation, Identification and Insecticidal Activity of Pathogenic Serratia marcescens from Potato Tuber Moth Larvae

从马铃薯田自然罹病马铃薯块茎蛾幼虫上,分离到1株对马铃薯块茎蛾幼虫具有较强致病作用的菌株ML-1,通过形态及16S r RNA序列测定分析,确定该菌株ML-1为黏质沙雷氏菌Serratia marcescens。采用饲喂法分别测定了该菌株ML-1菌悬液、发酵液及发酵上清液对马铃薯块茎蛾初孵3日龄幼虫的毒力。结果表明,用ML-1菌悬液、发酵液及发酵上清液饲喂后第7 d时,马铃薯块茎蛾3日龄幼虫的累积校正死亡率分别为63.16%、80.70%和49.12%,在3.0×109 cfu/m L浓度下的LT50分别为4.71、3.04和6.47 d,在发酵液处理后第3、5和7 d的LC50分别为9.784×1010、1.855×108和5.434×105 cfu/m L。综上所述,黏质沙雷氏菌ML-1菌株对马铃薯块茎蛾幼虫有较强的毒力,在马铃薯块茎蛾绿色防控中具有一定的开发潜能。

A strain ML-1 showing strong pathogenicity to larvae of potato tuber moth was isolated from the natural diseased larvae of potato tuber moth collected from potato fields.The strain ML-1 was identified as S.marcescens by morphological observation of pathogens and 16S rRNA sequencing analysis.The virulence of the strain ML-1 suspension,fermentation broth and fermentation supernatant to the 3-d-old larvae of potato tuber moth was determined by feeding method.The cumulative corrected mortalities were 63.16%,80.70%and 49.12%on the 7th day after feeding,respectively,and the LT50 were 3.04,4.71 and 6.47 d at 3.0×109 cfu/mL,respectively.The LC50 at the 3rd,5th and 7th day after treatment with fermentation broth were 9.784×1010,1.855×108 and 5.434×105 cfu/m L,respectively.In summary,S.marcescens ML-1 strain has strong virulence to potato tuber moth larvae and has good prospective for development of biological control agents against the pest.