Preliminary Identification of Microorganisms Associated With Postharvest Decay of Avocado ( Persea americana Mill.) cv. 034 in Lam Dong Province, Vietnam

ABSTRACT Avocado ( Persea americana Mill.) is a high‐value fruit crop with growing demand in Vietnam. However, its postharvest life is severely constrained by microbial decay, and knowledge of causal pathogens in Vietnam remains limited. This study aims to identify microorganisms associated with postharvest spoilage of avocado cv. 034 and to evaluate their effects on fruit quality during storage under experimental conditions. Pathogens were isolated and characterised based on morphological and molecular features, and Koch's postulates were applied to confirm pathogenicity. Three microorganisms were identified as associated with avocado decay, including Enterobacter cloacae , Pectobacterium carotovorum and Lasiodiplodia theobromae . Inoculation assays showed that these pathogens significantly accelerated fruit softening, decreased pH, increased titratable acidity and total soluble solids and enhanced oxidative enzyme activities (polyphenol oxidase and peroxidase). These physiological alterations led to peeling lesions, pulp browning and tissue maceration, resulting in a severe decline in storage quality. Overall, this study provides an initial characterisation of microorganisms associated with postharvest decay of avocado cv. 034 under experimental conditions. It also highlights the need for broader surveys and genome‐based analyses to clarify their epidemiological roles in commercial production systems, thereby informing future research on sustainable management strategies to mitigate postharvest losses and preserve avocado fruit quality during storage.