Purpose To clarify the pathogen and biological characteristics of Hansenia weberbaueriana leaf spot disease, providing theoretical basis for prevention and control of the disease.
Methods Diseased leaves of H. weberbaueriana planting base in Yulong Naxi Autonomous County, Lijiang City, Yunnan Province were used as research materials, the pathogen was isolated, purified, and identified by morphology; and ITS sequence phylogenetic analysis, pathogen determination and biological characteristics research were carried out.
Results Morphological identification showed that the colony of isolated pathogen was round, covered with white mycelium on the front, dark brown on the back, with concentric rings; mature conidia were rod-shaped, with 2-3 septa, and the spore size was (10.52-20.54) μm×(3.24-4.32) μm. Based on ITS sequence alignment and phylogenetic analysis, the strain was identified as Phoma insulana. The pathogenicity test of pathogen confirmed the pathogen could cause H. weberbaueriana leaf spot disease. The results of biological characteristics showed that PDA medium, pH 7.0, 25 ℃ and all dark culture conditions were conducive to strain growth and conidia formation. The sporulation quantity was the highest when glucose was used as carbon source, and the mycelial growth was the fastest when sucrose was used as carbon source. When peptone was used as nitrogen source, sporulation and mycelial growth were the most significant.
Conclusion P. insulana is the pathogen causing H. weberbaueriana leaf spot. The culture conditions of pH 7.0, 25 ℃ and darkness are suitable for pathogen growth and conidia formation.
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