Studies on Post Harvest Diseases of Mango With Special Reference to Stem End Rot
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Date
2016-06
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University of Agricultural Sciences, Dharwad
Abstract
Mango (Mangifera indica L.) is the one of the most important fruit crop of India. It is being affected by several post harvest diseases. Among them stem end rot caused by Botryodiplodia theobromae (Pat.) Griffon and Maubl. cause drastic reduction in yield as well as market value.
A study on post harvest diseases of mango was conducted. It included isolation, identification and proving pathogenicity test. Anthracnose (Colletotrichum gloeosporioides (Penz.) Penz. & Sacc)., stem end rot (Botryodiplodia theobromae ) and Alternaria rot ( Alternaria alternate) were the major diseases which causes for the post harvest losses. Three districts were surveyed. Maximum per cent diseases index was recorded in Dharwad market. Among the varieties, Alphanso showed maximum per cent diseases index. The conidia of Botryodiplodia theobromae was initially unicellular, hyaline and thick-walled. Mature conidia were uniseptate, cinnamon to fawn colored and often longitudinally striate.
Cultural studies revealed that among solid media, potato dextrose agar proved to be the best for good growth of the fungus. Among the seven liquid media, potato dextrose broth supported the maximum mycelial dry weight of the pathogen. Physiological studies revealed that optimum pH of 8.0 was favourable for growth and sporulation of the pathogen. Maximum colony diameter and dry mycelial weight of the fungus was recorded at the temperature 30 0C.
Under in vitro evaluation of bio-rationals, clove oil (1 %) was found to be effective against B. theobromae. Among the salts tested, potassium bicarbonate was found to be effective at all three concentration (5, 7.5 and 10 %). Under in vivo evaluation of bio-rationals and salt, minimum per cent disease index was observed in neem oil at 1 per cent and potassium bicarbonate at 5, 7.5 and 10 per cent.