<i>Boeremia shanxiensis</i> sp. nov.: A newly discovered pathogen causing leaf spot on daylily ( <i>Hemerocallis citrina</i> )

Daylily (<i>Hemerocallis citrina</i>) is a perennial herb cultivated in China and other Asian countries for its nutritional, medicinal, and ornamental values. During the growing season, leaf spot disease was observed on <i>H. citrina</i> plants in Yunzhou District, Datong City, Shanxi Province, China. Isolates JZ-DT1 and JZ-DT2, obtained from the diseased leaf tissues, were identified as <i>Boeremia shanxiensis</i> sp. nov. based on morphological characteristics and multi-gene (<i>tub2</i>, <i>rpb2</i>, ITS, and LSU) phylogenetic analyses. Pathogenicity tests demonstrated that these isolates could infect <i>H. citrina</i> leaves, inducing grayish spots with brown margins encircled by yellowish chlorotic halos via non-wound inoculation. This study is the first to identify and document <i>B. shanxiensis</i> as a novel fungal species and a new pathogen responsible for leaf spot disease on <i>H. citrina</i>. These findings provide crucial guidance for developing disease management strategies for <i>H. citrina</i> leaf spot.