Morphology and phylogeny of Calonectria elaeocarpi sp. nov., a new foliar pathogen of Elaeocarpus sphaericus (Gaertn.) Heer from India

Elaeocarpus sphaericus is one of the most important medicinal species in the ancient Indian system of medicine. In 2023, leaf spots were observed on E. sphaericus trees in Dehradun, India. Morphological features and phylogenetic analyses of combined partial actin, calmodulin, histone, internal transcribed spacer, translation elongation factor 1-alpha and β-tubulin regions confirmed the association of a new fungal species of Nectriaceae, which is illustrated and described as Calonectria elaeocarpi sp. nov. In pathogenicity tests, this species caused disease symptoms on the healthy leaves of E. sphaericus and successfully re-isolated, thus fulfilling Koch’s postulates. This study is the first confirmed report of a new Calonectria species causing foliar symptoms on E. sphaericus in India. Future studies are warranted to monitor its natural host range and understand cross infectivity potential. [Display omitted] •This study reports Calonectria elaeocarpi sp. nov., a new foliar pathogen of Elaeocarpus sphaericus (rudraksha) in India.•Identification was based on microscopic features and multi-locus phylogenetic analyses.•Koch's postulates for the new taxon as a foliar pathogen of rudraksha were fulfilled.•Further studies on the species diversity of Calonectria fungi are imperative.