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

## TL;DR

This study identifies twelve Fusarium species causing white mold disease in cultivated morels in China, with F. verticillioides being the most common.

## Contribution

The first comprehensive identification of twelve Fusarium species responsible for white mold disease in morels.

## Key findings

- Twelve Fusarium species were identified as causing white mold disease in morels, with F. verticillioides being the most prevalent.
- All twelve identified Fusarium species were confirmed to be pathogenic to morel ascocarps through pathogenicity assays.
- Most isolates were recovered from northern China, highlighting regional differences in pathogen distribution.

## Abstract

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