首次报道：广东省发现由黄曲霉菌（Podosphaera xanthii）引起的广东木兰（Sphagneticola × guangdongensis）白粉病

Abstract

Powdery mildew, a globally pervasive and destructive disease of angiosperms, is caused by fungi within the Erysiphaceae family. Podosphaera xanthii , an obligate plant pathogen, is recognized as a major causative agent of powdery mildew in Cucurbitaceae crops. Sphagneticola × guangdongensis , a hybrid of Sphagneticola trilobata and the indigenous Sphagneticola calendulacea (L.) Pruski, belongs to the Asteraceae family and the Heliantheae tribe. In January 2024, a severe outbreak of powdery mildew was documented on Sphagneticola × guangdongensis in Shenzhen, with a disease incidence rate approaching 90%. P . xanthii was identified as the pathogen through morphological characterization, phylogenetic analysis using the Internal Transcribed Spacer (ITS) region and 28S ribosomal DNA (rDNA), and beta-tubulin ( TUB2 ) sequences, and pathogenicity tests of the representative isolate SGZML. This study presents the first report of P . xanthii inducing powdery mildew in Sphagneticola × guangdongensis within China.