pathogens Communication Fusarium elaeidis Causes Stem and Root Rot on Alocasia longiloba in South China Yunxia Zhang 1 , Chao Chen 1 , Jingpeng Zhao 1 , Cantian Chen 1 , Jieying Lin 1 , Ruvishika S. Jayawardena 2,3 , Meimei Xiang 1 , Ishara S. Manawasinghe 1, * and Chunping You 1, *   Citation: Zhang, Y.; Chen, C.; Zhao, J.; Chen, C.; Lin, J.; Jayawardena, R.S.; Xiang, M.; Manawasinghe, I.S.; You, C. Fusarium elaeidis Causes Stem and Root Rot on Alocasia longiloba in South China. Pathogens 2021, 10, 1395. https://doi.org/10.3390/ pathogens10111395 Academic Editors: Lawrence S. Young and Kevin D. Hyde Received: 31 July 2021 Accepted: 18 October 2021 Published: 28 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Innovative Institute for Plant Health, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; zhangyunxia@zhku.edu.cn (Y.Z.); Chenchao_cc98@163.com (C.C.); jingpeng-zhao@yahoo.com (J.Z.); 18825187974@163.com (C.C.); linjieying178@163.com (J.L.); mm_xiang@163.com (M.X.) 2 Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand; ruvishikajay@mfu.ac.th 3 School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand * Correspondence: ishara9017@gmail.com (I.S.M.); cpyou@zhku.edu.cn (C.Y.); Tel.: +86-2089-0031-92 (I.S.M. & C.Y.) Abstract: Alocasia longiloba is a popular ornamental plant in China, however pests and diseases associated with A. longiloba reduce the ornamental value of this plant. From 2016 to 2021, stem and root rot has been observed on A. longiloba in Guangdong Province, China. Once the disease became severe, plants wilted and died. A fungus was isolated from the diseased stem and identified as Fusarium elaeidis using both morphological characteristics and molecular analysis of DNA-directed RNA polymerase II subunit (rpb2), translation elongation factor-1α (tef1) gene and β-tubulin (tub2) sequence data. The pathogenicity test showed the fungus was able to produce typical symptoms on A. longiloba similar to those observed in the field. The original pathogen was reisolated from inoculated plants fulfilling Koch’s postulates. This is the first report of Fusarium elaeidis causing stem rot on A. longiloba. These results will provide a baseline to identify and control diseases associated with A. longiloba. Keywords: Fusarium rot; first report; ornamental plants; pathogenicity; Nectriaceae 1. Introduction The ornamental plant industry has become a high demanding industry with the increased interest in modern architecture. The values of ornamental plants are based on the appearance of the plant. However, they are susceptible to several diseases including wilts, rots and leaf spots which reduce the economical values of the plants [1]. In addition, the ornamental plant industry is the main global source of planting material exchanges. Thus, it is possible to introduce a new pathogen to a new locality via these planting materials which can affect already established plants as well [2] Therefore, the identification and characterisation of phytopathogenic genera on ornamental plants are crucial. Four Alocasia species are grown in China: A. cucullata, A. hainanica, A. longiloba and A. macrorrhiza. Alocasia longiloba is a perennial herb belonging to the Araceae (L). It is native to tropical Asia and in China this plant is mainly distributed in Hainan, Yunnan and Guangdong provinces. Among these A. longiloba is widely cultivated in Guangdong Province as an ornamental plant due to its distinctive ‘elephant ear’ foliage. There are several diseases and pests associated with Alocasia spp., including fungal diseases [3,4]. Alternaria alocasiae and Ceratocystis fimbriata have been reported to cause leaf spots [4] and leaf blight [5], respectively, on A. macrorrhiza in China [4]. In addition, anthracnose of A. macrorrhiza caused by Colletotrichum karstii [3], root rot on Alocasia sp. caused by Pythium sp. and Rhizoctonia solani in Florida, USA [6] are among reported diseases. Most of these Pathogens 2021, 10, 1395. https://doi.org/10.3390/pathogens10111395 https://www.mdpi.com/journal/pathogens