云斑白条天牛幼虫肠道致病菌的分离鉴定及杀虫活性研究

Isolation and Identification of Bacteria from Batocera lineolata and Determination of Its Insecticidal Bioactivity

应用传统微生物鉴别方法并结合分子技术对自然罹病死亡的云斑白条天牛幼虫肠道内1株产红色色素的菌株(BS-1)进行分类鉴定;采用饲喂法观测该菌株BS-1菌悬液对云斑白条天牛5龄幼虫的毒力及致病症状。结果表明,该菌株BS-1为粘质沙雷氏菌。以基础培养基培养时,其余成分种类及添加量为蔗糖1%、酵母粉6%及NaCl 1%时最适,且最佳体外培养条件为35℃、pH=7、240 rpm、培养时间为16 h。使用1.17×10^(11)cfu/mL的菌悬液处理新鲜铁核桃树树皮饲喂云斑白条天牛幼虫,被感染虫体身体逐渐变红且仅肠道异常,15 d的校正累计死亡率为100%。从自然罹病死亡的云斑白条天牛幼虫肠道内筛选的菌株BS-1为粘质沙雷氏菌,具有杀虫活性。该研究结果为云斑白条天牛的生物防治提供了依据。

A red pigment-producing strain(BS-1)in the intestinal tract of Batocera lineolata,which died from natural diseases,was classified and identified by traditional microbial identification method and molecular technology;the virulence of the strain BS-1 suspension to the 5-d-old larvae of B.lineolata was determined by feeding method.The findings revealed that the strain BS-1 was identified as Serratia marcescens.On the basis of basal medium,the type and amount of other ingredient are sucrose 1%,yeast powder 6%and NaCl 1%.The best in vitro culture conditions are 35℃,pH 7,240 rpm,and the culture time is 16 hours under the medium defined.The fresh bark of an iron walnut tree which was treated with 1.17×10^(11) cfu/mL BS-1 suspension was fed to the larvae of B.lineolata,the infected body of B.lineolata gradually turned red and only the intestinal tract was abnormal.Finally,the corrected cumulative mortality rate was 100%after 15 days.The strain BS-1 in the intestinal tract of B.lineolata larvae which died from natural diseases was identified as S.marcescens,and the strains with insecticidal activity to its larvae.The results suggest that S.marcescens BS-1 which provide a basis for biological control of B.lineolata.