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New Downy Mildew Disease Caused by Hyaloperonospora brassicae on Pak choi (Brassica rapa) in Korea
Res. Plant Dis. 2019;25:98-101
Published online June 30, 2019
© 2019 The Korean Society of Plant Pathology.

Hyun Ju Lee1, Jae Sung Lee2, and Young-Joon Choi2*

1Gyeonggido Agricultural Research & Extension Services, Hwaseong 18388, Korea
2Department of Biology, Kunsan National University, Gunsan 54150, Korea
Tel: +82-63-469-4582
Fax: +82-63-469-7421
Received June 14, 2019; Accepted June 18, 2019.
cc This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Pak choi (or a Bok choy; Brassica rapa subsp. chinensis) is a popular brassicaceous vegetable worldwide. In January 2019, a downy mildew symptom on pak choi was found at a farm located in Yongin, Korea. Based on morphological characteristics and molecular phylogenetic inference, the pathogenic oomycete was identified as Hyaloperonospora brassicae. To our knowledge, this is the first report of downy mildew disease occurring on pak choi in Korea. Considering the increasing demand for this crop, this pathogen would be a potentially new threat to the cultivation of pak choi in Korea.
Keywords : Brassica, downy mildew, Oomycota, pak choi, phylogeny

June 2019, 25 (2)