Colletotrichum Species Causing Anthracnose in Ipê Trees

Ipê trees (Bignoniaceae), mainly belonging to the genus Handroanthus, are widely used in urban landscaping and reforestation programs in Brazil. Anthracnose, typically associated with species of Colletotrichum, represents one of the major diseases affecting ipê seedlings and ornamental trees. However, the etiological agents involved have not yet been fully clarified using modern phylogenetic tools. In this study, we identified Colletotrichum species associated with anthracnose in ipê trees from Pernambuco, Brazil. A total of 22 isolates were obtained from symptomatic leaves of Handroanthus impetiginosus and H. chrysotrichus. Species identification was based on multilocus phylogenetic analyses using CAL, GAPDH, GS, and TUB2 loci. The isolates were assigned to three species: Colletotrichum siamense, C. tropicale, and C. karsti. Colletotrichum siamense was the most prevalent species (50%), followed by C. tropicale (36.3%), while C. karsti represented 13.7% of the isolates. Pathogenicity tests confirmed that all isolates were pathogenic to both ipê species, producing typical anthracnose symptoms. Aggressiveness differed between hosts, with H. impetiginosus showing higher susceptibility, as indicated by larger lesion development, whereas H. chrysotrichus exhibited lower disease aggressiveness. Thus, our findings represent the first multilocus-based identification of Colletotrichum species causing anthracnose in ipê trees, providing new insights into the diversity and epidemiology of this disease in urban environments.