Characterisation and Pathogenicity of Botryosphaeriaceae Species Associated With Avocado in South Africa

ABSTRACT

Botryosphaeriaceae fungi are important pathogens of woody plants, including fruit and nut crops such as avocado, macadamia and mango, yet their diversity and pathogenicity are often uncharacterised. This study characterises the Botryosphaeriaceae species associated with avocado in South Africa and evaluates the pathogenicity of selected isolates. Sampling symptomatic and asymptomatic avocado tissues from major production regions yielded 249 isolates. All isolates were characterised using culture morphology and ITS sequencing, while a representative subset of 32 isolates underwent multilocus phylogenetic analyses using rDNA ITS, tub2 and tef‐1α , with rpb2 additionally analysed for selected Neofusicoccum isolates. Phylogenetic analyses revealed a diverse assemblage of 11 species, including Botryosphaeria dothidea , Diplodia pseudoseriata , five Lasiodiplodia and four Neofusicoccum species. This investigation documents the first peer‐reviewed report of Lasiodiplodia gilanensis and Lasiodiplodia plurivora on avocado. Pathogenicity tests of three selected species confirmed that Neofusicoccum parvum , Lasiodiplodia theobromae and Neofusicoccum australe induced necrotic lesions on avocado stems, with aggressiveness varying among cultivars and trials. These findings highlight the diversity of Botryosphaeriaceae associated with avocado in South Africa and provide baseline data for future studies of their epidemiology and management.