Morphology and phylogeny of three Colletotrichum species causing cacao anthracnose in Peru

Abstract

Colletotrichum spp. cause anthracnose diseases in a wide range of host plants worldwide. However, anthracnose of cacao in Peru has been poorly studied. In August 2022, a phytosanitary survey of cacao plantations in the province of Bagua, Amazonas revealed a high incidence of cacao anthracnose in pods and leaves. Fourteen, Colletotrichum spp. isolates were obtained and morphologically and molecularly identified. The molecular identification was based on a seven-loci concatenated phylogenetic analysis, which supported an accurate phylogenetic identification of three species belonging to Colletotrichum gloeosporioides species complex: C. siamense, C. fructicola , and C. tropicale . Koch’s postulates were fulfilled after inoculation of cacao pods and leaves with conidial suspensions from representative strains of the three species, the development of similar symptoms as those observed in the field, and re-isolation of the strains. The present study enriches our knowledge about the C. gloeosporioides species complex affecting cacao in Peru.

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