Etiology of fungi causing postharvest crown rot of Robusta variety banana in Kerala

Deepa R. Chandran, Susha S. Thara

Abstract


Crown rot of dehanded banana is the most important and prevalent postharvest disease of banana leading to heavy economic loss. Survey was conducted during March to May, 2018 in five banana growing districts of Kerala viz., Thiruvananthapuram, Alappuzha, Pathanamthitta, Palakkad and Wayanad to identify the major pathogen associated with crown rot of banana (var. Robusta) in Kerala. All the samples collected from the different locations of Kerala showed incidence of crown rot, indicating 100 per cent prevalence of crown rot in the state. Moreover, varying symptoms were noticed in the diseased fruit samples collected. This denoted the association of different pathogens in crown rot. Pathogens were isolated from the diseased samples collected from different locations surveyed. A total of 32 fungal isolates were obtained from the crown rot affected banana samples. The isolates were initially identified based on morphological characters including cultural as well as microscopic characters. Based on the observations, out of the 32 isolates obtained, there were ten Lasiodiplodia spp, eight Colletotrichum spp, five Fusarium spp, three Aspergillus spp, two each of Cunninghamella and Verticillium and one each of Penicillium and Rhizopus. Pathogenicity tests showed all the isolates to be pathogenic. Different pathogens produced different symptoms when inoculated separately on banana fruits. The pathogenicity test and subsequent virulence rating followed by molecular identification revealed Lasiodiplodia theobromae (GenBank accession number: MN046365) as the major as well as the virulent pathogen associated with the postharvest crown rot disease of Robusta variety banana in Kerala.


Keywords


Crown rot, Lasiodiplodia sp. Postharvest rot, Colletotrichum

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A KAU publication [CODEN: JTAGEI; ISSN 0971-636X; eISSN 0973-5399]