Morpho-cultural, molecular characterization and identification of the pathogen of the burning of leaf and cashew fruit

Abstract

The cashew tree (Anacardium occidentale L.) is one of the most important fruit trees cultivated in the semi-arid regions of tropical climate in the world. However, this crop is affected by numerous diseases throughout its production cycle. The burning of the leaf and fruit of cashew is a relatively new disease in Mozambique and is characterized by causing necrotic lesions in fruits and leaves. Thus, the present work was carried out with the objective of isolating and making the morphological and molecular characterization of the fungus responsible for burning the leaf and fruit of the cashew tree and determining its taxonomic identity. The study was based on laboratory tests with the aid of the optical microscope and polymerase chain reaction (PCR). In PDA, cultures of spongy dark coloration were often isolated and distinguished; abundant orange and white and, spongy, typified as Neofusicoccum spp., Colletotrichum spp. and Pestalotiopsis spp., respectively. Molecularly, the results confirmed that at least these genera of fungi are involved in the disease of leaf burning and cashew fruit. No Cryptosporiopsis spp. isolates were isolated. However, it is recommended to evaluate the interactive/synergistic effect of the different isolates obtained from samples with symptoms of leaf burning and cashew fruit in the different stages of host tissue development.