Assessment of Post-Harvest Pathogens of Khasi Mandarin (Citrus reticulata, Blanco) from Meghalaya and Evaluation of Most Potent Artificial Inoculation Method to Initiate Penicillium Rot

Abstract

Khasi mandarin is a unique germplasm of North East India owing to its exceptional juice quality, taste and aroma. But the shelf life of the fruit is decreasing due to the post-harvest decay pathogens. The present investigation was carried out in 2023-2024 and 2024-2025 The aim of the study was to investigate post-harvest storage pathogens associated with Khasi mandarin in Meghalaya and to evaluate the most effective method of inoculation to get the highest             infection. Penicillium spp., Fusarium spp., Aspergillus spp., Geotrichum, and Mucor species were isolated as post -harvest associated pathogens with a maximum frequency of 40% against Penicillium spp. followed by Fusarium spp. (20%). Isolated pathogens were characterized morphologically and culturally. Penicillium italicum, being the most dominant post-harvest pathogen of Khasi mandarin, as proved by the pathogenicity test and molecular characterization, was artificially inoculated by four different methods in the fully ripened mandarins. The most efficient inoculation method for disease development was evaluated by calculating disease severity index (DSI) which was found to be highest (63.8%) in the disc inoculation method, followed by injection (38.9%) and spraying (27.8%). Percent seed infection was also calculated by blotter test and found to be highest in disc inoculation method (96%) and lowest in immersion (76%) on 10th day of inoculation. The present investigation evaluates the post- harvest associated mycoflora of Khasi mandarin in Meghalaya and the most potent artificial inoculation method responsible for Penicillium rot.