A Case Report of Apical Necrosis in a Mango (Mangifera indica L.) Plantation Established under Colombian Dry Caribbean Conditions

Abstract

Bacterial apical necrosis of mango (Mangifera indica L.) is an acute disease reported mainly in Southern Europe, characterized by the generation of necrotic lesions in buds and leaves that spread through the petioles towards the stems. Its incidence results in significant economic losses due to a decrease in production. Known causative agents of this disease are the bacteria Pseudomonas syringae and Pantoea spp., which survive as epiphytes on plant surfaces. In a two-year-old mango cv. Keitt orchard, established at the Colombian Corporation for Agricultural Research (AGROSAVIA), Motilonia Research Station, mango trees exhibited symptoms of necrosis in buds, leaves, and branches. The mango plants were affected downwards, causing their death 30 days after the first symptoms. Five samples of affected leaf tissue and petioles were taken to isolate the causative agent and make a diagnosis to manage the disease properly. The samples were superficially disinfected and incubated in a humid chamber and culture media for three days. After incubation, hyphae, exudates, and bacterial colonies were plated on solid culture media. The isolates obtained were characterized morphologically and biochemically. The results showed the presence of bacteria identified as Pantoea spp. by amplifying and sequencing the region coding for the 16S subunit of rRNA. In vitro pathogenicity tests preliminarily suggest Pantoea spp. as the causative agent of the disease. This work is the first report of apical necrosis by Pantoea spp. in mango for Colombia.