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Occurrence of Gray Mold Caused by Botrytis cinerea on Okra in Korea
Res. Plant Dis. 2018;24:302-307
Published online December 31, 2018
© 2018 The Korean Society of Plant Pathology.

JangNam Choi1, InYoung Choi2*, KuiJae Lee3, JungNo Lee4, SeongWan Cho5, HyeonDong Shin6*, and Victor Galea7

1Department of Agricultural Biology, Chonbuk National University, Jeonju 54896, Korea
2Jeollabuk-do Agricultural Research and Extension Services, Iksan 54591, Korea
3Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 54596, Korea
4Department of Bionanometerials, Biocampus of Korea Polytechnics, Nonsan 32943, Korea
5Department of Pharmaceutics & Biotechnology, Konyang University, Daejeon 35365, Korea
6Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea
7School of Agriculture and Food Sciences, The University of Queensland, QLD 4343, Australia
*I.Y. Choi Tel: +82-63-290-6182 Fax: +82-63-290-6198 E-mail: choiiy21@korea.kr
H.D. Shin Tel: +82-2-3290-3063 Fax: +82-2-925-1970 E-mail: hdshin@korea.ac.kr ORCID https://orcid.org/0000-0002-7778-2747
Received August 26, 2018; Accepted September 14, 2018.
cc This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
From 2014 to 2016, approximately 5% of okra fruit were observed displaying gray mold symptoms at the research field of Jeollabuk-do Agricultural Research and Extension Services, Korea. The symptoms observed were water-soaked, brown or gray spots, and abundant mycelial with conidia appearing on the infected fruit. Initial infection commenced from the base of fruit and gradually moved to the pod, where it finally resulted in collapse. Colonies on potato dextrose agar were gray to grayish brown, felted and cottony expanding 65-80 mm after one week. The fungus formed several black sclerotia ranging 1.0-3.5×0.5-3.0 mm on the Petri dish after two weeks. The conidia were one-celled, ellipsoidal or ovoid, colorless or pale brown, and 6.2-15.4×5.0-10.4 µm. Conidiophores arose solitary or in groups, straight or flexuous, septate, with an inflated basal cell brown to light brown, and measured 85-450×10.0-40.0 µm. On the basis of the morphological characteristics and phylogenetic analyses of internal transcribed spacer rDNA, the fungus was identified as Botrytis cinerea Pers. Pathogenicity of a representative isolate was proved by artificial inoculation, fulfilling Koch’s postulates. To our knowledge, this is the first report on the occurrence of B. cinerea on okra in Korea.
Keywords : Abelmoschus esculentus, Botrytis cinerea, Gray mold, Okra


December 2018, 24 (4)