Abstract
<title>Abstract</title> <p> During 2021 to 2023, Komatsuna ( <italic>Brassica rapa</italic> var. <italic>perviridis</italic> ) plants exhibited symptoms including leaf chlorosis, reduced root development, and root or stem rot occurring across several fields in Tokyo, Japan. Fungi isolated from the symptoms were identified as <italic>Neocosmospora falciformis</italic> , <italic>Fusarium nirenbergiae</italic> , and <italic>Fusarium</italic> sp. 1 reported by Crous et al. (2022), based on morphological and molecular characteristics. Representative isolates of each species reproduced the original symptoms on the inoculated komatsuna plants. This is the first report of <italic>N. falciformis, F. nirenbergiae</italic> and <italic>Fusarium</italic> sp. 1 as a causal agent of root and stem rot of komatsuna. </p>