The First Report of Fusarium sacchari Causing Yellow Leaf Spot Disease on Rhynchostylis gigantea Orchids in Thailand
- 1 Chulalongkorn University, Thailand
Published On: 15 May 2020
Copyright: © 2020 Kanokwan Dekham and Krieng Kanchanawatee. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Yellow leaf spot disease was observed on Rhynchostylis gigantea orchids on an orchid farm in the Nonthaburi province of Thailand. Symptoms started with yellowish patches lacking definitive borders on the leaves of the orchids. The patches slowly expanded and merged, creating larger patches; a brown spot or black necrotic area then emerged at the center of some of the patches. R. gigantea leaves exhibiting these symptoms were used as the source for isolation studies. Based on the morphological characteristics of the fungal isolate (colony appearance, macroconidia, microconidia, conidiophore and chlamydospore structures), phylogenetic analysis of translation elongation factor-1α sequence and fulfillment of Koch’s postulates, the causative pathogen was identified as Fusarium sacchari. To our knowledge, this study is the first to report F. sacchari as a pathogen of R. gigantea.
- Fusarium sacchari
- Rhynchostylis gigantea
- Yellow Leaf Spot Disease