Isolation and Identification of Pathogenic Microorganisms Causing Post-Harvest Disease of Garlic (Allium sativum L.) in Ninh Thuan Province, Vietnam

Abstract

Garlic plays a crucial role in Vietnam's agricultural economy. However, the presence of post-harvest diseases presents considerable obstacles as it reduces the quality and market value of the crop. The objective of this study was to identify the microbial strains responsible for these diseases through isolation and identification. A comprehensive analysis was conducted to identify six pathogenic species that have a significant impact on the quality of post-harvest garlic in Phan Rang, Ninh Thuan province, Vietnam. This analysis involved morphological observations, microscopic assessments, pathogenicity testing and molecular sequencing. Fusarium solani, F. oxysporum and Lasiodiplodia theobromae were identified as the main causes of dry rot, while Macrophomina phaseolina was associated with charcoal rot. Moreover, Aspergillus niger has been associated with black mould, while Pantoea sp. has been identified as the causative agent of soft rot. Re-infection tests following Koch's postulates conducted on garlic bulbs provided confirmation of the isolates' pathogenicity. These findings have significant implications for enhancing our understanding of garlic diseases after harvest, which can contribute to the development of effective control measures in the future.