Identification and Characterization of Pathogenic Fusarium Species Causing White Mold Disease in Cultivated Morels (Morchella spp.) in China

White mold disease (WMD) is a major constraint to <i>Morchella</i> cultivation in China, leading to significant yield and quality losses. While <i>Fusarium</i> species are recognized plant pathogens, their diversity and role in WMD of morels have been poorly understood. This study aimed to identify and characterize <i>Fusarium</i> species associated with WMD in cultivated morels. Symptomatic ascocarps were collected from 22 cultivation bases across 16 provinces in China. A total of 120 <i>Fusarium</i> isolates were recovered and identified using morphological traits and multi-locus phylogenetic analysis. Twelve <i>Fusarium</i> species were identified, <i>F. acuminatum</i>, <i>F. avenaceum</i>, <i>F. clavum</i>, <i>F. compactum</i>, <i>F. falciforme</i>, <i>F. flocciferum</i>, <i>F. ipomoeae</i>, <i>F. mucidum</i>, <i>F. oxysporum</i>, <i>F. proliferatum</i>, <i>F. subglutinans</i>, and <i>F. verticillioides</i>, with most isolates recovered from northern China. Among them, <i>F. verticillioides</i> was the most common species (22.5%). Pathogenicity assays showed that all twelve of the identified <i>Fusarium</i> species were virulent to morel ascocarps. This is the first comprehensive report of these twelve <i>Fusarium</i> species causing WMD in morels, providing critical insights into pathogen diversity and virulence in <i>Morchella</i> production systems. These findings will support the development of targeted monitoring and management strategies to reduce the impact of WMD in morel cultivation.