search for


Effects of Dryness, Moisture Interruption, and Temperature on Germination of Diaporthe citri Pycnidiospores on Yuzu
Res. Plant Dis. 2018;24:132-137
Published online June 30, 2018
© 2018 The Korean Society of Plant Pathology.

Sung-Jun Hong and Sung-Chul Yun*

Department of Pharmaceutical Engineering and Biotechnology, Sunmoon University, Asan 31460, Korea
Tel: +82-41-530-2282
Fax: +82-41-530-2393
Received May 11, 2018; Revised May 31, 2018; Accepted May 31, 2018.
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.
Melanose caused by Diaporthe citri is a serious disease on yuzu fruits. Moisture is the most important to infect after the pycnidiospores are released. In order to understand how dryness and moisture interruption affect on germination, the conidial suspensions on slide glass were dried for 0-48 h. For the moisture interruption experiment, moisture was supplied for 10 h then interrupted for 0-6 h depending on the treatments. Germinations on the treatments with longer than 15 h of dryness were less than 10%. And those with longer than 3 h of moisture interruption were less than 30%. Compared with other fungal phytopathogens, D. citri was xero-sensitive. Germination on yuzu feel medium was measured under 15, 20, 25, 30, 35°C with 3, 6, 9, 12, 15, 18, and 24 h of wetness. The minimum wetness periods achieving 10% and 50% germinations were 4.5 and 13 h, and the optimum temperatures were 29.1°C and 29.2°C, respectively. From the yuzu medium study, the regression equations to be required wetness period achieving 10% and 50% germinations on various temperatures were Wh50% = 0.1093 × T2 - 6.3762 × T + 106.08 and Wh10%=0.082 × T2 - 4.8025 × T + 74.861.
Keywords : Melanose, Optimum temperature, Regression of germination, Xero-sensitive, Yuzu feel medium

June 2018, 24 (2)