Development of a Novel Isolation, Preservation and Characterisation of Native Powdery Mildew Isolates in Cucurbita moschata

Powdery mildew is a major foliar disease affecting Cucurbita moschata , caused by obligate biotrophic fungi of the order Erysiphales . Despite its economic importance, research on its causal agents remains limited due to the challenges associated with maintaining viable isolates for experimentation. Traditional isolation and conservation rely on the Pathogen‐Leaf system (Path‐I), which has been widely used but presents limitations in sustaining isolates over time. In this study, we developed and evaluated an alternative system, namely the Pathogen‐Seedling (Path‐II), designed to optimise pathogen isolation and maintenance. Path‐II proved to be the most effective method, ensuring higher recovery rates and prolonged viability of powdery mildew isolates compared to Path‐I. Furthermore, long‐term conservation methods described in the literature, including tissue‐free approaches, were unsuccessful in maintaining viable isolates. To confirm taxonomic identity, we combined morphological and molecular approaches, optimising a direct‐PCR protocol targeting the ITS region of rDNA. Both techniques consistently identified Podosphaera xanthii as the predominant causal agent among the isolates obtained from C. moschata in this study. By simplifying pathogen isolation and maintenance, this study enhances the feasibility of powdery mildew research and provides valuable tools for breeding programmes focused on disease resistance.