Histopathology of Colletotrichum sp. in infected mango (Magnifera indica L.) fruits

Abstract

Postharvest losses as a result of anthracnose infection remain a serious threat to mango producers. Hence, histopathology of mango fruits after being artificially infected with spores of Colletotrichum sp. was investigated. Fruits at the physiologically mature stage were wounded (cut) in the peels and inoculated with a spore suspension of Colletotrichum sp. (8.04 ? 103 conidia m1-1) and incubated at 28?2?C for five days to allow pathogen establishment. The infected peel was then carefully cut with a razor blade and dehydrated in series in different grades (50, 70, 80, 90 and 100%) of ethyl alcohol for 1? hours each. Histopathological studies were carried out on the infected peel tissue excised from inoculated fruits using standard procedures while unwounded peels of fruits that were not artificially inoculated served as control. Sections were examined by light microscopy to observe histopathological differences between the infected and non-infected fruits. Results from this study revealed that only the wounded peel showed symptoms of anthracnose infection as a result of the artificial inoculation, but the unwounded peel showed no disease symptoms. This showed that the fungus infected the mango fruits through the peel wounds. Besides, the disorganization of the cells and the rupture of the cell walls were observed microscopically, thus indicating disease establishment in the infected fruits. Therefore, mango producers should avoid mechanical damage to fruits during harvesting since this work confirms that the fungus infects mango fruits through wounds.