玉米弯孢菌叶斑病田间流行动态研究

通过对玉米弯孢菌叶斑病（Curvularia lunata（Wakker）Boed）时间（季节）流行动态和空间流行动态的系统研究,绘制出时间流行曲线和空间流行曲线。研究结果表明,相同菌株在不同玉米品种上及不同菌株在相同玉米品种上的致病性和发展速度有差异,并随着调查时间的延后,病情指数有增加趋势,流行曲线经过升高—平稳的循环过程达到高峰值,8月下旬至9月初各个品种均达到发病高峰。玉米弯孢菌叶斑病以中心传播方式进行传播,随着距菌源中心距离的增大,东、西、南、北各个方向的病情指数均有降低趋势。不同发病时期每个距离调查点的不同方向病情指数存在差异,距菌源中心较远处,东向比西向发病重,而发病前期和发病中期南向比北向发病重,发病后期距菌源中心近处各个方向无差异。

Study on Field Epidemical Dynamics of Maize Curvularia Leaf Spot(Curvularia lunata)

The temporal epidemic curves and space epidemic curves of maize curvularia leaf spot（Curvularia lunata （Wakker）Boed）were protracted through systemically researched the temporal（season）epidemic dynamics and the space epidemic dynamics. The results showed that there were difference,the same strain in the different maize varieties or the different strains in the same maize variety, in the pathogenicity and the disease tempo and there was increasing trend of disease index with carry-forward of investigating times. The epidemic curves reached pinnacle value pass through the cycle course of hoist-smooth and the disease index of every varieties all reached pinnacle at the time of the last ten-day of August to early September. The spreading mode of maize curvularia leaf spot was center spread. The disease index in four directions of east, west,south and north all play down with the augmenting of distance from the center of fungus fountain. There were differences of disease index in four directions of east,west,south and north,with the investigation spot of every distance in the different period of disease. The disease was more serious in east than in west at the distance far from the center of fungus fountain. The disease was more serious in south than in north at the prophase and metaphase stage of disease,and there were no differences of disease index in every direction at the distance near by the center of fungus fountain at the anaphase stage.