长春地区玉米大斑病、灰斑病空间分布型研究

Studies on Spatial Distribution of Northern Leaf Blight and Gray Leaf Spot of Maize in Changchun Region

对长春地区玉米大斑病、灰斑病的病株空间分布型进行研究。结果表明:玉米大斑病病株空间分布型在病害发生前期为随机分布,后期为均匀分布;玉米灰斑病病株空间分布型为聚集分布。用Iwao最适理论抽样模型n=t2/D2×[(α+1)/-X+β-1],计算出两种病害在不同发病程度下的理论抽样数。

The spatial distribution of northern leaf blight and gray leaf spot of maize in Changchun region. The results showed that spatial distribution pattern of northern leaf blight of maize was random at the beginning of the disease developing, and evenness at the last stage. Spatial distribution pattern of gray leaf spot of maize was aggregation. The optimum sampling number of the two diseases were determined under different density according to the optimal sampling formula was built up as n=t^2/D^2×[（α＋1）/-↑-X＋β-1].