Fungi Associated with Leaf Spot Diseases of Potato in Guizhou Province, China

Since 2016, the leaf spot disease in Guizhou Province has become increasingly serious. This study aimed to identify and characterize the pathogenic fungi causing leaf spot disease in Qingzhen, Zunyi, Sandu, and Libo, the four main potato production areas in Guizhou Province, China. Fourteen isolates of pathogenic fungi were obtained from potato leaf spot samples collected from the four areas between 2020 and 2021 and were identified through morphological, phylogenetic, and pathogenicity analyses. These 14 isolates belonged to the four species Alternaria alternata, Colletotrichum chlorophyti, Nigrospora oryzae, and Pestalotiopsis clavispora. Among these, A. alternata accounted for the largest proportion, 64.3%, of the pathogenic fungal isolates. In summary, this study identified multiple pathogenic fungi associated with potato leaf spot disease in Guizhou Province, China, and first reported the infestation of C. chlorophyti, N. oryzae, and P. clavispora on potato leaves.