Four Novel Colletotrichum Species Associated with Anthracnose of Ornamental Araceae in Brazil with Insights into Their Host Range

Araceae includes numerous flowering plant species that are cultivated as ornamentals in gardens, pots or by the cut-flower industry. Relatively little has been published on the fungal pathogens attacking these ornamentals, particularly in Brazil. Here we report the results of a study on Colletotrichum spp. found in association with anthracnose and leaf spot symptoms on Aglaonema commutatum, Anthurium andraeanum, Dieffenbachia amoena, Philodendron imbe and Philodendron tripartitum. Nine isolates of Colletotrichum were obtained from diseased tissues. A polyphasic approach was used to identify these isolates as four novel species: Colletotrichum anthuriicola sp. nov., C. araceiphilum sp. nov., C. imbeicola sp. nov. and C. philodendrifolium sp. nov. Cross-inoculation assays were conducted using the plant host species listed above, as well as Epipremnum aureum, and showed that all isolates were pathogenic to at least three of the inoculated aroid species. These findings expand the current knowledge of the genus Colletotrichum and its association with members of the Araceae and highlight the need to consider individual ornamental aroids as potential inoculum reservoirs for infection of other cultivated members, given the low host specificity of aroid-associated Colletotrichum species.