A Study on the Overwintering of Cucumber Downy Mildew Oospores in China |
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| Authors: | Yan‐ju Zhang Zi‐jing Pu Zhi‐wei Qin Xiu‐yan Zhou Dong Liu Li‐ting Dai Wen‐bo Wang |
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| Institution: | 1. Authors’ address: College of Agriculture, Northeast Agricultural University, Harbin, China;2. College of Horticulture, Northeast Agricultural University, Harbin, China (correspondence to Z.‐W. Qin. E‐mail: zwqin727@hotmail.com) |
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| Abstract: | Oospore formation of Pseudoperonospora cubensis was investigated in 10 Chinese locations: Mohe, Harbin, Changchun, Shenyang, Beijing, Liaocheng, Yinchuan, Xining, Yangling and Haikou. Oospores were observed in all but Haikou. Oospore viability was monitored from 10 January to 10 July 2009, in Harbin. Percentages of activated oospores increased from 10 April with a peak in late May (14.0% on 25 May 2009), and then decreased. This is in accordance with the usual time of downy mildew appearance in Harbin, 20–30 May. Inoculation tests using the oospores overwintered in Harbin, whether in the greenhouse or outdoors, showed that these were viable, with a disease occurrence of 26.6–95.0%. Oospores overwintering locally could be primary infection sources of downy mildew in cool temperate northern China. |
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| Keywords: | Pseudoperonospora cubensis oospore plant debris soil viability |
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