Colletotrichum truncatum causing anthracnose disease of Iris lactea in Beijing, China

Iris lactea is a wide ground cover plant of importance throughout courtyards, trees and roads. From May to September in 2020 and 2021, I. lactea planted in Beijing showed white to yellow spots with black conidiomata and could lead blight expanded down from the tip of leaves. In this study, ninety-six diseased leaves were collected from nineteen regions in Beijing, and a total of fifty-nine Colletotrichum isolates were obtained from the leaf spots. All isolates were identified as Colletotrichum truncatum by polyphasic analyses, combing morphology and phylogeny of combined the internal transcribed spacer of rDNA region (ITS), actin (act), chalcone synthetase (chs), the genes of glyceraldehyde-3-phosphate dehydrogenase (gapdh) and beta-tubulin (tub2). Koch's postulates were confirmed by a pathogenicity test using conidial suspensions (1 x 10(6) conidia/ml) on fresh leaves of the host, re-isolation and identification. Until now, this is the first confirmed report of a new anthracnose disease of I. lactea caused by C. truncatum in China.