Three New Records of Pathogens Causing Stem Blight on Vaccinium corymbosum in China

Stem blight is a significant disease affecting blueberries worldwide, caused by various pathogens. This study investigated stem blight disease in Ji'an, Jilin Province, China. Fungi isolated from diseased stems were identified as <i>Colletotrichum temperatum</i>, <i>Curvularia austriaca</i>, and <i>Diaporthe unshiuensis</i> based on morphological characters and multi-locus phylogenetic analyses using the internal transcribed spacer (ITS) region, glyceraldehyde 3-phosphate dehydrogenase (<i>gapdh</i>), chitin synthase (<i>chs</i>), actin (<i>act</i>), β-tubulin (<i>tub2</i>), the translation elongation factor 1-alpha (<i>tef1-α</i>), calmodulin (<i>cal</i>), and histone 3 (<i>his3</i>) regions. Pathogenicity test was conducted on detached green blueberry shoots, all shoots inoculated by mycelium plugs presented necrotic lesions with dark brown margins, while the control (PDA plugs) group did not show any symptoms. Koch's postulates were confirmed by re-isolating the inoculated pathogen from the disease symptoms. The study provides three new host-pathogen records of fungi associated with blueberry stem blight.