著者

Kandai Yoshida Shunsuke Asano Yuka Sumikawa

出版者

The Kansai Plant Protection Society

雑誌

関西病虫害研究会報 (ISSN:03871002)

巻号頁・発行日

vol.61, pp.79-84, 2019-05-31 (Released:2019-09-01)

参考文献数

11

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In 2017, chrysanthemum downy mildew, which has not been reported in Japan since 1980, severely affected chrysanthemum production in Nara Prefecture, Japan. We investigated the occurrence of the disease at the fields in Nara Prefecture and the control efficacy of thermotherapy and fungicides against it. In the field survey, over 95 % of plants were diseased in seven cultivars, while no plants with the symptoms were observed in the other six cultivars. This suggests that some chrysanthemum cultivars had resistance to downy mildew. Chrysanthemum cuttings were treated with thermotherapy (treatment with hot water and hot air). The disease prevalence in both treatments was significantly lower than that in the non-treated. Severely diseased plants were sprayed with three fungicides (azoxystrobin, manzeb, and tolfenpyrad). While azoxystrobin and manzeb reduced the disease severity compared with non-treated, its efficacy was not so high. We concluded that the use of resistant cultivars and the application of thermotherapy can effectively control chrysanthemum downy mildew.