AUTHOR=Liu Yayong , Tan Xiaoqian , Zhao Juan , Niu Yajie , Hsiang Tom , Yu Zhihe , Qin Wentao 

TITLE=Diversity of Colletotrichum species associated with anthracnose on Euonymus japonicus and their sensitivity to fungicides

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1411625

DOI=10.3389/fpls.2024.1411625

ISSN=1664-462X

ABSTRACT=<p>As an evergreen shrub, <italic>Euonymus japonicus</italic> plays a crucial role in urban landscape construction, and its growth is affected by severe foliar anthracnose caused by <italic>Colletotrichum</italic> spp. However, the biodiversity of <italic>Colletotrichum</italic> species associated with anthracnose on <italic>E. japonicus</italic> remains undetermined. This study involved a two-year collection of <italic>E. japonicus</italic> leaf samples with typical anthracnose symptoms from 9 districts in Beijing, China. A total of 194 <italic>Colletotrichum</italic> isolates were obtained, and eight <italic>Colletotrichum</italic> species were subsequently identified using morphological characteristics and molecular identification with the <italic>ACT</italic>, <italic>GADPH</italic>, <italic>CHS</italic>, <italic>TUB2</italic>, and <italic>CAL</italic> genes, as well as the rDNA-ITS region. These species included <italic>Colletotrichum aenigma</italic>, <italic>C. fructicola</italic>, <italic>C. gloeosporioides</italic>, <italic>C. grossum</italic>, <italic>C. hebeiense</italic>, <italic>C. karstii</italic>, <italic>C. siamense</italic>, and <italic>C. theobromicola</italic> with <italic>C. siamense</italic> being the most prevalent (57%), followed by <italic>C. aenigma</italic> and <italic>C. theobromicola</italic>. Furthermore, <italic>C. fructicola</italic>, <italic>C. grossum</italic> and <italic>C. hebeiense</italic> are reported for the first time as causal agents of anthracnose on <italic>E. japonicus</italic> worldwide, and <italic>C. karstii</italic> is newly reported to be associated with <italic>E. japonicus</italic> anthracnose in China. Pathogenicity tests revealed that all tested isolates exhibited pathogenicity in the presence of wounds, emphasizing the need to avoid artificial or mechanical wounds to prevent infection in <italic>E. japonicus</italic> management. The EC<sub>50</sub> values of five fungicides, namely difenoconazole, flusilazole, tebuconazole, hexaconazole, and prochloraz, were found to be less than 10 mg/L, indicating their strong potential for application. Notably, the EC<sub>50</sub> of prochloraz was less than 0.05 mg/L for <italic>C. theobromicola</italic>. These findings offer valuable insights for the management of anthracnose on <italic>E. japonicus</italic>.</p>