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First report of septoria steviae causing stevia leaf spot in Thailand
Author(s) -
Termsung Natthida,
Cheewangkoon Ratchadawan,
Kunasakdakul Kaewalin
Publication year - 2021
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12983
Subject(s) - septoria , biology , leaf spot , stevia , azoxystrobin , internal transcribed spacer , stevia rebaudiana , chlorothalonil , botany , mycelium , mancozeb , fungicide , horticulture , ribosomal rna , gene , genetics , medicine , alternative medicine , pathology
Stevia leaf spot is present in stevia production fields in Chiang Mai, Thailand. The disease was characterized by distinct lesions with angular chlorotic halos that result in defoliation. Based on morphological characters and sequence analysis of the rDNA internal transcribed spacers (ITS1‐5.8S‐ITS2 = ITS), rDNA 28S subunit (LSU) and RNA polymerase II second largest subunit (RPB2) genes, the pathogen was identified as Septoria steviae . Pathogenicity tests proved Koch's postulates, supporting S. steviae as the causal agent of stevia leaf spot in Stevia rebaudiana Bertoni. Mancozeb, chlorothalonil, difenoconazole and azoxystrobin significantly inhibited mycelial growth of S. steviae under in vitro conditions at label the recommended concentrations. To our knowledge, this is the first report of Septoria leaf spot disease on stevia caused by S. steviae in Thailand.