Abstract
In Qinghai Province, China, the wild rose ( Rosa multiflora Thunb) has been identified as a critical host for a virulent strain of Diaporthe eres , which is implicated in the causation of the catastrophic black mold disease. A plant specimen, manifesting intense symptoms indicative of black mold, underwent a meticulous diagnostic process. Employing a combination of morphological assessments and nucleotide sequencing of key genetic markers—Internal Transcribed Spacer (ITS), Translation Elongation Factor 1-α (TEF1-α), Tubulin 2 (TUB2), Histidine biosynthesis (HIS3), and Calmodulin (CAL)—the pathogenic fungus was unequivocally identified as Diaporthe eres . The reisolation of this strain, adhering to the principles of Koch’s postulates, substantiated its etiological role in the black mold disease affecting wild roses. This study represents the inaugural documentation of Diaporthe eres infection and its pathological consequences in wild roses within the Chinese context, providing critical insights into the pathogen’s potential impact on native vegetation and shaping prospective strategies for disease management.