Fusarium graminearum causes leaf spot disease in Nicandra physalodes in China

Nicandra physalodes is an annual herbaceous plant that belongs to the Solanaceae family. Though native to South America, it is now extensively cultivated in China for medicinal and ornamental purposes. In traditional Chinese medicine, various parts of the plant are used for their therapeutic properties such as sedatives, expectorants, antipyretics, and antidotes. Furthermore, N. physalodes is considered an edible plant, and its seeds contain pectin, which is used in food production. However, recent observations in Hezhang county, Guizhou province, revealed a prevalent leaf spot disease affecting N. physalodes, leading to a decreased yield. In this study, morphological and molecular analyses, pathogenicity assays, and Koch's postulates were used to identify the fungal pathogens responsible for leaf spot disease in N. physalodes. Fusarium graminearum was confirmed as the causative agent based on morphological and molecular analyses, pathogenicity assays, and Koch's postulates, and this represents the first documented case of F. graminearum infection in N. physalodes. These findings underscore the importance of disease management strategies to mitigate the impact of leaf spot disease on the yield of this valuable medicinal plant.