In order to identify the pathogen responsible for Hedera nepalensis leaf blight and investigate effective biocontrol strategies, samples were collected from 10 significantly infected areas at Southwest Forestry University
four to six infected leaves were gathered from each area, followed by the isolation and purification of strains from the infected plant leaves using tissue isolation and hyphae-purification techniques. We conducted an examination of the biological characteristics and compared the inhibitory effects of different concentrations of Phomopsis sp. (50%, 25%, 16.7%, 12.5%, and 10%) with 20 µg/mL of synthetic fungicides (Mancozeb, Carbendazim, Polyoxin, and Hymexazol) on the pathogen, while also assessing the control efficacy of Phomopsis sp. against the pathogen in the greenhouse. The internal transcribed spacer (ITS) region, β-tubulin (TUB), and translation elongation factor 1-alpha (TEF) analysis revealed that the highly virulent strain causing H. nepalensis leaf blight was Apiospora intestini. Additionally, it was found that 25% Phomopsis sp. significantly inhibited Apiospora intestini when compared to synthetic fungicides, and Phomopsis sp. supernatant possesses both protective and curative effects against the plant diseases caused by Apiospora intestini. The results of this study serve as a reference for the prevention and treatment of H. nepalensis leaf blight.