Leaf Spot of Choerospondias axillaris Caused by Pestalotiopsis choerospondicola sp. nov. in China

ABSTRACT Choerospondias axillaris is an important edible and wood plant in China. In 2023, leaf spot was observed on C. axillaris in Yongxiu County, Jiangxi Province, China, with a disease incidence of approximately 50%. To identify the etiologic agent of the disease, the fungal isolates were obtained using the tip hyphae picking method. Based on colony and conidial characteristics, 66.7% of the isolates were identified as Pestalotiopsis sp. Phylogeny analysis of combined sequences from the internal transcribed spacer (ITS), beta‐tubulin ( TUB 2) and elongation factor 1‐alpha ( TEF ) loci strongly supported a monophyletic clade, with posterior probability and bootstrap values of 1.00 and 97, respectively. Further morphological examination confirmed the establishment of a new species, which was described as Pestalotiopsis choerospondicola sp. nov. Koch's postulates were fulfilled by inoculating C. axillaris seedlings in the field, confirming the pathogenicity of the fungus. The sensitivity of the pathogenic strain Y1‐2 to eight fungicides was assessed, revealing that 8% compound sodium nitrophenolate (CSN), carbendazim and tebuconazole exhibited high toxicity to Y1‐2, with effective concentration inhibiting 50% (EC 50 ) of mycelial growth measured at 0.3395, 0.5417 and 0.7680 mg/L, respectively. In summary, P. choerospondicola sp. nov. was identified as the causal agent of leaf spot on C. axillaris . CSN, carbendazim and tebuconazole are recommended for disease management.