蚜虫病原细菌的分离鉴定及其对褐飞虱的杀虫活性初探

为寻找有效防治褐飞虱的病原微生物,采用平板划线法和稀释涂布法,从感病死亡的蔷薇蚜虫体中分离筛选出一株对褐飞虱具有较高致病性的菌株JSA1;通过形态学特征、生理生化特性及16S r DNA序列分析,对菌株JSA1进行了初步鉴定;采用盆栽法和稻苗浸渍法,对其杀虫活性进行了测定。鉴定结果显示菌株JSA1为铜绿假单胞菌Pseudomonas aeruginosa。杀虫活性测定结果表明:菌株JSA1对褐飞虱具有杀虫作用,且致死率随菌液浓度的升高和作用时间的延长而提高,但致死率低于40%;菌株JSA1发酵液的上清液和沉淀破碎液对褐飞虱3龄若虫均具有致病力,72 h后的校正死亡率分别为30.72%和82.53%,表明铜绿假单胞菌JSA1在褐飞虱的生物防治方面具有一定的应用前景。

Isolation and identification of an entomopathogenic bacterium from aphids and preliminary study of its efficacy against Nilaparvata lugens

In order to obtain effective pathogenic microorganisms against Nilaparvata lugens, a highly virulent strain JSA1 was isolated from naturally infected cadavers of Rosa aphid by using the plate dilution coating method and flat crossed separation method. The strain JSA1 was primarily identified on the basis of its phenotypic, physiological and biochemical properties and 16S rDNA sequences analysis. Insecticidal activity of strain JSA1 was determined by using pot planting method and rice seedling dipping method. The results showed that strain JSA1 was primarily identified as Pseudomonas aeruginosa, and it exhibited insecticidal activity against N.lugens at different concentrations. The mortality of N.lugens increased as the concentration of strain JSA1 increased and the treatment time prolonged, but the mortality was less than 40%. The supernatant of fermentation broth and suspension of sonicated cell pellet of strain JSA1 showed significant insecticidal activity against the 3rd instar nymphs of N.lugens, with corrected mortality reached 30.72% and 82.53% after 72 h treatment, respectively. The results indicated that the strain JSA1 has potential in biological control of N.lugens.