First Report of Colletotrichum kahawae Causing Anthracnose on Buckwheat (Fagopyrum tataricum) in China and Biological Characterization of the Pathogen

Buckwheat (<i>Fagopyrum tataricum</i>) is native to Yunnan, China, and as a miscellaneous grain crop with high nutritional value, it has received increased attention from farmers and enterprises in recent years. In June 2024, we observed severe anthracnose in the buckwheat cultivation area in Malu Township and Jiache Township, Huize County, Qujing City, Yunnan Province, China. In this study, six isolates (SM01-SM06) of anthracnose with similar morphology were obtained using the tissue isolation method, which was due to the fact that this disease is highly pathogenic to buckwheat. The strain SM02 was selected as a representative isolate for biological characterization and molecular phylogenetic analysis, and a phylogenetic tree was constructed based on the <i>ACT</i>, <i>CHS</i>, and <i>ITS</i> genes to determine its taxonomic status. The selected SM02 isolate was further identified as <i>Colletotrichum kahawae</i>. Biological characterization showed that the representative strain SM02 exhibited optimal growth for in vitro cultivation under a photoperiod, temperature, pH, carbon source, and nitrogen source of 12L:12D, 25 °C, pH 7.0, glucose, and beef extract, respectively. Host range testing demonstrated that <i>C. kahawae</i> might infect important field crops, including maize, wheat, oats, and potatoes. In conclusion, <i>C. kahawae</i> causes buckwheat anthracnose in China, which might hinder the production of buckwheat. This study provides insight into anthracnose disease in buckwheat and provides a basis for further investigations to assess and implement effective disease management strategies.