甜菜褐斑病发生时间动态规律研究

Dynamic Rule of Sugar Beet Cercospora Leaf Spot Occurrence Time

在摸清甜菜褐斑病发生时间动态规律的前提下,确定甜菜褐斑病化学防治时期,为科学治理甜菜褐斑病提供理论依据。2016—2017年,采用田间定期调查甜菜褐斑病病情指数的方法,探讨甜菜褐斑病发病程度随时间变化规律。结果表明:2016年病害发展时间曲线有4个高峰日,分别为7月25日、8月24日、9月3日、9月18日,病情指数分别为:9.33、42.5、55.92、61.46;2017年,病害发展时间曲线经过8月14日、8月19日、8月24日、8月29日4次升高点一直到9月3日,病害发展达到第1个高峰期日9月3日,病情指数分别为7.86、10.75、30.56、36.53、42.88。发病前期(7月上中旬),降雨是甜菜褐斑病发生蔓延的决定性因子。9月中旬以后,温度是甜菜褐斑病发生蔓延的决定性因子。第一个高峰期或上升点日期之前为最佳打药时期,2016年应在7月25日前喷洒杀菌剂,2017年应在8月14日前喷洒杀菌剂。

Based on dynamic rule of sugar beet Cercospora leaf spot(CLS) occurrence time, the period of CLS chemical control is determined to provide a theoretical basis for the scientific management of CLS. From 2016 to 2017, the author used the method of field survey, to study the dynamic rule of CLS disease index and occurrence time. The results showed that the disease development time curve had four peaks in 2016, which were July 25, August 24, September 3 and September 18, and their disease indexes were 9.33, 42.5, 55.92 and61.46, respectively. In 2017, the disease development time curve showed that August 14, August 19, August24 and August 29 were four high points up to September 3,which was the first peak day of disease development, and disease indexes were 7.86, 10.75, 30.56, 36.53 and 42.88, respectively. At the early stage of disease(early and middle of July), rainfall was the determining factor of CLS spreading. The first fastigium and before rising point is the best time to spray fungicides, the time for spraying fungicides should be before July25 in 2016 and before August 14 in 2017..