青贮玉米锈病空间分布研究

Spatial Distribution Pattern of Rust Insilage Maize

采用田间调查试验,对青贮玉米普通型锈病的空间分布规律进行了分析研究。结果表明:青贮玉米锈病在田间发病初期呈聚集分布,随后聚集程度逐渐变小,至发病后期表现为随机分布或均匀分布;锈病的严重程度(X_i)与距菌源区距离(d_i)的最佳模型关系为指数模型,顺风向传播梯度可用指数方程X_i=42.579exp(-0.049di)表示,侧风向传播梯度可用X_i=59.732exp(-0.058d_i)表示,在全田大面积发病情况下,青贮玉米锈病在1个月内顺风向传播距离约为80~90m,侧风向传播距离约为40~50m;空中锈病病斑数随叶片距地面高度的增加呈先增加后降低的趋势,可用多项式方程Y=-0.0014X^2+0.1997X+6.9915表示;夏季锈病在高海拔(900~1 200m)区域发生严重,低海拔(300~600m)和中海拔(600~900m)区域发生较轻,发病率和病情指数都显著低于高海拔区域。

This paper analyzed the spatial distribution law of eolmnon rust in silage maize by field experiments. Results showed that the silage maize rust was distributed gathered in the early onset in the field, then the aggregation degree became small, to the late onset, it presented random distribution or uniform distribution. The best model of relationship between the severity of rust （xi ） and the spacing distance （di） to the rust source was exponential model. The gradient with the wind to spread, could be expressed by index equation Xi =42. 579exp （ -0. 049di）., The gradient side wind to spread could be expressed by index equation Xi =59. 732exp （ -0. 058di）. In the condition of whole field widespread disease easing, the propagation distance of silage maize rust was about 80 - 90 m in one month, the side wind propa- gation distance was about 40 - 50m. The number of plaques of rust increased with the increasing of the blade distance to the ground, then it decreased, it could be expressed by polynomial equation Y = -0. 0014X2 ＋0. 1997X ＋6. 9915. In the summer, the rust disease occurred seriously in the high altitude （900 - 1200m） area, in the low altitude （300 -600m） and the middle elevation （600 -900m） area it was relatively lighter, and the incidence and severity of disease were significantly lower than that in the high altitude area.