›› 2009, Vol. 52 ›› Issue (9): 959-966.

• RESEARCH PAPERS • Previous Articles     Next Articles

Identification of a strain of Heterorhabditis (Nematoda: Heterorhabditidae) from Hebei and its virulence to white grubs

LIU Shu-Sen,LI K B, LIU C Q, WANG Q L, YIN J, CAO Y Z   

  • Online:2009-09-20 Published:2009-09-20

Abstract: Entomopathogenic nematode is a potential factor for biological control of underground pest. A strain of Heterorhabditis isolated from Cangzhou of Hebei province was identified based on the morphological characters and ITS-rDNA sequence analysis, its virulence to white grubs was also determined in the laboratory. Morphological measurement of infective juveniles and males showed that the population was most closely related to Heterorhabditis bacteriophora, while the results of ITS1-rDNA sequences alignment and phylogenetic analysis indicated that the population had the closest genetic relationship with H. bacteriophora. Based on the morphology and biological characters, the population was identified as H. bacteriophora strain Cangzhou. Pathogenicity tests of the nematode to white grubs (2nd instar larvae of Holotrichia oblita, H. parallela and Anomala corpulenta) showed that the mortality of H. parallela larvae was significantly higher than that of the other two scarabes (P<0.05) after infection of 72 h. After 120 h, the mortality of H. parallela and A. corpulenta larvae were 93.3% and 80.0%, respectively, without significant difference (P>0.05), suggesting that the nematode has strong virulence against them. Virulence tests of different nematodes to larvae of H. parallela indicated that the larvae which were infected by H. bacteriophora strain Cangzhou had higher mortality than those infected by Steinernema feltiae and S. longicaudum after infection of 96 h (P<0.05), suggesting that the virulence of H. bacteriophora strain Cangzhou is significantly higher than the other two nematodes.

Key words: Heterorhabditis bacteriophora, white grubs, taxonomic status, morphological characters, ITS-rDNA analysis, virulence