Author(s): AK Jain and Ravindra Depale

Abstract: Stem end rot (SER) is one of the most frequently occurring post-harvest disease of mango in all parts of the world including India affecting quality of mango fruits. Three fungi namely Botryodiplodia theobromae, Colletotrichum gloeosporioides and Alternaria alternata were isolated from naturally infected mango fruits showing SER symptoms with maximum frequency of B. theobromae (68.8%) followed by C. Gloeosporioides (20.0%) and A. alternata (9.3%). Significant variations in mycelia growth of B. theobromae was recorded in six culture media, six carbon sources, four temperatures and five pH levels. Maximum mycelia growth of the fungus was recorded in oat meal agar (66.7mm) followed by potato dextrose agar (55.3 mm) and mango leaf extract agar (45.7mm). Dextrose (79.2 mm) and glucose (78.0 mm) supplemented potato agar media supported the highest mycelia growth of B. theobromae. Highest mycelia growth was recorded in potato dextrose agar (PDA) incubated at 30 °C (79.7 mm) temperature followed by 25 °C (65.5 mm) and lowest growth was at 20 °C (32.3 mm). Mycelia growth of the fungus was maximum in PDA adjusted at pH 6 (59.5 mm) followed by pH 6.5 (55.8 mm) and pH 7 (49.5 mm). Pathogenic potential of B. theobromae was assessed in five popular mango varieties namely Fazali, Langra, Chousa, Neelam and Dashahari. Significant variation in lesion area (cm2), physiological loss in fruit weight (PLW %) and total soluble solids (TSS) content were found in all the varieties. Maximum lesion area (73.7 cm2) was recorded in Chousa followed by Neelam (69.9 cm2). Physiological loss in fruit weight (PLW %) and reduction in TSS content were 9.6to 19.0% and 5.1 to 25.3%, respectively in five varieties of mango with maximum in Neelam followed by Chousa. On the basis of these characters Dashahari was resistant, Fazali was moderately resistant, Langra was moderately susceptible. Whereas Chousa and Neelam were susceptible to SER.

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