关键词: 微生物菌肥, 微生物菌肥, 西瓜, 成活率, 发病率, 枯萎病, 连作障碍, 根肿病

Abstract: The study aims to screen entomopathogenic fungus with pathogenicity against the Lymantria dispar. The infected chrysalises of L. dispar were collected from Harbin Youth Park, the strain was isolated and purified, and identified with morphological characteristics and rDNA ITS sequence alignment analysis. At the same time, the pathogenicity on the L. dispar larvae was studied by spray method. An entomopathogenic fungus was isolated from collected chrysalis of the L. dispar, and named HEB-2016. The colony characteristics were different in different culture media, and the microstructure results were consistent with the characteristics of Aspergillus. The result of rDNA ITS sequencing showed that the obtained fragment length was 595 bp. The comparison result showed that the sequence similarity with Aspergillus ochraceus and A. westerdijkiae was 98%- 100%, and it was identified as A. westerdijkiae by the phylogenetic tree. This strain had strong pathogenicity against the L. dispar larvae. After 7 days of treatment with spores suspension at the concentration of 108 cells/mL, the corrected mortality rate was 80.69%. The sporulation structure of the strain was visible to naked eyes after 10 days. HEB-2016 has pathogenic against L. dispar. The strain can be the candidate strain resource for controlling L. dispar and developing biological pesticides.