PHYSIOLOGICAL ATTRIBUTES OF FUNGI ASSOCIATED WITH STEM END ROT OF MANGO (MANGIFERA INDICA L.) CULTIVARS IN POSTHARVEST FRUIT LOSSES

Abstract

Stem end rot majorly contributes in post-harvest losses of mango during storage conditions. Maximum disease incidence (70%) was recorded in Sindhari cultivar, followed by Chaunsa (64%), Fajri (62.5%) and 50% in both Langra and Anwar ratol. In vitro studies were carried out to identify fungal pathogens responsible for rotting and decaying mango fruits during storage along with isolation and testing their pathogencity on healthy fruits. Results revealed that all selected commercial mango varieties infected by stem end rot. Colletotrichum gloeosporioides, Lasidodiplodia theobromae, Alternaria alternata, Aspergillus niger, Dothiorella domonicana were identified from Sindhri mango fruits, in which of C. gloeosporioides was found the most prevalent. Phomopsis mangiferae, Botryodiplodia theobromae, Altrnaria spp., Aspergillus niger, A. flavis were found in Chaunsa and Phomopsis mangiferae was most prevalent, while Botryodiplodia theobromae caused infection to locally consumed Fajri variety. Effect of abiotic factors like pH, temperature, light intensity and carbon sources were tested against these isolates. The most efficient carbon source was glucose, which supported the maximum growth of the P. mangiferae and L. theobromae, while C. gloeosporioides had maximum growth on lactose. All fungi had maximum growth at pH range of 6-6.5 and temperature range of 25-30o C on PDA medium. Alternate cycles of 12hr light and 12 hr darkness resulted maximum mycelial growth as compared to the 24 hour continuous exposure to either dark or light. Susceptibility of fungi with cultivars and intensity of spread under specific abiotic conditions provides basic information in this paper to minimize stem end rot of mango in field and storage conditions.