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昆虫病原线虫是一种有应用潜力的地下害虫生物防治因子。本研究利用形态学特征和ITS-rDNA分析方法对从河北省沧州分离的异小杆线虫一品系进行了鉴定,并在室内测定比较了其对蛴螬的致病力。通过对该线虫侵染期幼虫和雄性成虫主要形态学特征的参数测量,发现其与嗜菌异小杆线虫Heterorhabditis bacteriophora的形态特征最为相近;同时ITS1-rDNA序列比对和系统发育学分析结果显示其与嗜菌异小杆线虫亲缘关系最近。结合形态学和分子生物学特征,确定该线虫为嗜菌异小杆线虫沧州品系。该线虫对蛴螬(华北大黑鳃金龟Holotrichia oblita、暗黑鳃金龟H.parallela和铜绿丽金龟Anomala corpulenta3种金龟子的2龄幼虫)的致病力研究结果表明:处理72h后,暗黑鳃金龟幼虫死亡率显著高于另外两种金龟子幼虫(P<0.05);处理120h后,暗黑鳃金龟和铜绿丽金龟幼虫的死亡率分别达到93.3%和80.0%,二者无显著差异(P>0.05),可见该线虫对它们有较强的致病力。不同线虫对暗黑鳃金龟幼虫的致病力结果显示,嗜菌异小杆线虫沧州品系侵染96h后,幼虫的死亡率显著高于Steinernema feltiae和S.longicaudum两种线虫的处理(P<0.05),说明嗜菌异小杆线虫沧州品系的致病力显著高于另外两种线虫。
Entomopathogenic nematodes are potential biocontrol agents for underground pests. In this study, the isolates of C. elegans isolated from Cangzhou, Hebei Province, were identified by morphological characteristics and ITS-rDNA analysis, and the virulence of the strains was evaluated indoors. The morphological characteristics of Heterorhabditis bacteriophora were most similar to those of H.tritic nematode, and the results of ITS1-rDNA sequence alignment and phylogenetic analysis It has the closest genetic relationship with H. bacterioides. Combined with morphological and molecular biological characteristics, the nematode was identified as C. albicans Cangzhou strain. The virulence of the nematodes to 2 螬 (Holotrichia oblita, H. parallela and Anomala corpulenta second-instar larvae) showed that the mortality of Diabrotica orta larvae (P <0.05). After 120 h of treatment, the mortality of Diabrotidae and Caragana microphylla larvae reached 93.3% and 80.0%, respectively, with no significant difference (P> 0.05) Nematodes have strong virulence to them. The pathogenicity of different nematodes to the black-necked beetle larvae showed that the mortality of larvae was significantly higher than that of Steinernema feltiae and S. longicaudum after 96 h infection (P <0.05) , Indicating that the pathogenicity of C. albicans Cangzhou strain was significantly higher than the other two nematodes.