云南红河流域木薯细菌性枯萎病发生危害动态研究

Occurrence and Epidemic Dynamics of Cassava Bacterial Blight in Honghe Valley of Yunnan

采用定点监测、分级调查法对红河流域不同区域的木薯细菌性枯萎病发生情况进行研究。结果表明:(1)木薯细菌性枯萎病在红河流域进入雨季后(5月)开始发病,整个雨季中(5~9月)病害发生较为严重,尤其是进入夏季后温度满足病原菌的发病条件时,病情指数变化曲线和降雨量曲线出现了同升、同降的现象。(2)同一海拔高度下,病情指数呈现出下游大于上游和中游,而危害率则出现相反的趋势,250~300 m海拔观测点的病情指数大小顺序为下游(2.03)>中游(1.96)>上游(1.77),危害率为下游(64.57%)<中游(66.86%)<上游(70.00%);450~500 m海拔观测点的病情指数大小顺序为下游(2.01)>中游(1.77)>上游(1.76),危害率为下游(64.57%)<中游(66.29%)<上游(69.14%)。(3)同一区域则表现出低海拔地区的病情指数和危害率均高于高海拔地区。

Study of Cassava bacterial blight (Xanthomonas campestris pv.manihotis Starr) was made in different regions of Honghe Valley with Fixed-point monitoring and hierarchical investigation. The result shows. (1) Cassava bacterial blight will begin onset in Honghe Valley when it enter the rainy season (May). Whole rainy season (May-September) is the most serious infection period. Especially, when the temperature is high enough to meeting incidence conditions after entering summer, disease index and precipitation are direct proportion.(2)Under the same altitude, the number of disease index of downstream is more than which of upstream and midstream as the same elevation. The study sites with 250~300 meters above sea level observation show disease index: downstream (2.03)> midstream (1.96)> upstream (1.77), and hazard ratio: downstream (64.57%)< midstream (66.86%) < upstream (70.00%); The study sites with 450-500 meters above sea level show disease index of downstream (2.01) > midstream (1.77)> upstream (1.76), while the hazard rate: downstream (64.57.%)< midstream (66.29%) < upstream (69.14%). (3) The same area show the disease index and hazard rate of the low-altitude are higher than which of high-altitude areas.