Diversity of <i>Colletotrichum</i> species associated with torch ginger anthracnose

Anthracnose caused by <i>Colletotrichum</i> species is one of the most important diseases of torch ginger. The disease leads to loss of aesthetic and commercial value of torch ginger stems. This study aimed to characterize <i>Colletotrichum</i> species associated with torch ginger anthracnose in the production areas of Pernambuco and Ceará. A total of 48 <i>Colletotrichum</i> isolates were identified using molecular techniques. Pathogenicity tests were performed on torch ginger with representative isolates. Phylogenetic analyses based on seven loci—DNA lyase (<i>APN</i>2), intergenic spacer between DNA lyase and the mating-type locus <i>MAT1-2-1</i> (<i>APN</i>2/<i>MAT</i>-IGS), calmodulin (<i>CAL</i>), intergenic spacer between glyceraldehyde-3-phosphate dehydrogenase (<i>GAPDH</i>) and a hypothetical protein (<i>GAP</i>2-IGS), glutamine synthetase (<i>GS</i>), and β-tubulin (<i>TUB</i>2)—revealed that they belong to five known <i>Colletotrichum</i> species, namely, <i>C. chrysophilum, C. fructicola, C. siamense, C. theobromicola</i>, and <i>C. tropicale</i>, and three newly discovered species, described here as <i>C. atlanticum, C. floscerae</i>, and <i>C. zingibericola</i>. Of these, <i>C. atlanticum</i> was the most dominant. Pathogenicity assays showed that all isolates were pathogenic to torch ginger bracts. All species are reported for the first time associated with torch ginger in Brazil. The present study contributes to the current understanding of the diversity of <i>Colletotrichum</i> species associated with anthracnose on torch ginger and demonstrates the importance of accurate species identification for effective disease management strategies.