https://scholars.lib.ntu.edu.tw/handle/123456789/606115
標題: | Stemphylium Leaf Blight of Welsh Onion (Allium fistulosum): An Emerging Disease in Sanxing, Taiwan | 作者: | Wang C.-H Tsai Y.-C Tsai I Chung C.-L Lin Y.-C Hung T.-H Suwannarach N Cheewangkoon R Elgorban A.M CHIA-LIN CHUNG TING-HSUAN HUNG |
關鍵字: | Disease management;Fungicide evaluation;Leaf wetness;Phylogeny;Allium;Ascomycetes;genetics;onion;phylogeny;Taiwan;Ascomycota;Onions | 公開日期: | 2021 | 卷: | 105 | 期: | 12 | 來源出版物: | Plant Disease | 摘要: | Welsh onion (Allium fistulosum L.) is one of the main and oldest vegetable crops grown in Taiwan. A severe epidemic of leaf blight in Welsh onion caused by a Stemphylium-like pathogen was found in Sanxing, Taiwan, from 2018 to 2020. However, correct species identification, biology, and control of Stemphylium leaf blight (SLB) of Welsh onion are not well-established. Therefore, the main objective of this study was to investigate the causal agent of SLB in Sanxing and evaluate the in vitro sensitivity of Stemphylium-like pathogen to commonly used fungicides. A phylogenetic analysis based on combining the internal transcribed spacer (ITS) region and glyceraldedyhe-3-phosphate dehydrogenase (gapdh) and calmodulin (cmdA) gene sequences together with morphological features identified that S. vesicarium is associated with SLB in Sanxing. When inoculated onto Welsh onion leaves, the isolates caused symptoms identical to those observed in the field; therefore, S. vesicarium was reisolated and Koch’s postulates were confirmed. We observed a higher incidence of SLB symptoms on the oldest leaves compared with younger leaves. The maximum and minimum temperatures for in vitro mycelial growth and conidial germination (%) of S. vesicarium were 20 to 30_C and 5_C, respectively. Sixteen fungicides were tested for their effectiveness to reduce the mycelial growth and conidial germination of S. vesicarium in vitro. Boscalid plus pyraclostrobin, fluopyram, fluxapyroxad, and fluxapyroxad plus pyraclostrobin were highly effective at reducing mycelial growth and conidial germination in S. vesicarium. However, strobilurin fungicides (azoxystrobin and kresoxim-methyl) commonly used in Welsh onion production in Sanxing were ineffective. This study discusses the emergence of SLB caused by S. vesicarium in the foliar disease complex affecting Welsh onion and the management of the disease using fungicides with different modes of action in Taiwan. The research will support the sustainable management of SLB in Sanxing, Taiwan; however, further field assessments of the fungicides are warranted ? 2021 The American Phytopathological Society |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122001053&doi=10.1094%2fPDIS-11-20-2329-RE&partnerID=40&md5=0ec8a572ff6023b2ef08573de2ba8c57 https://scholars.lib.ntu.edu.tw/handle/123456789/606115 |
ISSN: | 01912917 | DOI: | 10.1094/PDIS-11-20-2329-RE |
顯示於: | 植物病理與微生物學系 |
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