Research Article Open Access

The First Report of Fusarium sacchari Causing Yellow Leaf Spot Disease on Rhynchostylis gigantea Orchids in Thailand

Kanokwan Dekham1 and Krieng Kanchanawatee1
  • 1 Chulalongkorn University, Thailand
American Journal of Agricultural and Biological Sciences
Volume 15 No. 1, 2020, 68-74

DOI: https://doi.org/10.3844/ajabssp.2020.68.74

Submitted On: 24 February 2020
Published On: 15 May 2020

How to Cite: Dekham, K. & Kanchanawatee, K. (2020). The First Report of Fusarium sacchari Causing Yellow Leaf Spot Disease on Rhynchostylis gigantea Orchids in Thailand. American Journal of Agricultural and Biological Sciences, 15(1), 68-74. https://doi.org/10.3844/ajabssp.2020.68.74

Abstract

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.

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Keywords

  • Fusarium sacchari
  • Rhynchostylis gigantea
  • Yellow Leaf Spot Disease