Neocosmospora caricae sp. nov. and N. metavorans, two new stem and trunk canker pathogens on Ficus carica in Iran

Abstract

During 2018–2021, a survey was conducted in rainfed fig (Ficus carica L.) orchards throughout the Fars Province of Iran to investigate the occurrence of canker diseases, and to identify the causal organisms. Morphological and cultural characteristics, as well as multilocus phylogenetic analyses of the internal transcribed spacer (ITS) region of rDNA, RNA polymerase II second largest subunit (RPB2), and the translation elongation factor 1-alpha (TEF1), revealed that the recovered isolates from the infected fig trees clustered in clade 3 of Neocosmospora (Nectriaceae), including N. metavorans, and a new taxon described here as N. caricae sp. nov. Neocosmospora caricae is characterised by falcate, multiseptate, gently dorsoventrally curved macroconidia with poorly developed foot-shaped basal cells, ovoid, aseptate microconidia that cluster in false heads, and abundant terminal or intercalary chlamydospores. Pathogenicity tests indicated that isolates of both Neocosmospora species were pathogenic, causing stem canker and wood discolouration on fig saplings of “Sabz” and “Shah Anjeer” cultivars. The present study adds to existing knowledge on the aetiology of fig stem and trunk canker, and may provide essential information for developing effective integrated management strategies against canker diseases affecting fig orchards in Iran.