基于地统计学的二点委夜蛾幼虫田间分布及与玉米受害率之间的关系

为明确二点委夜蛾Athetis lepigone在田间的分布特点及其虫口密度与玉米受害率之间的关系,于山东省商河县玉米田采用网格式取样法调查了其发生为害情况,运用地统计学分析法拟合了其幼虫在玉米田的空间变异曲线模型,并利用Arc Gis软件对其空间分布进行插值和模拟,分析了虫口密度与玉米受害率之间的关系。结果显示:二点委夜蛾在田间呈聚集分布,符合高斯模型,空间相关范围(即变程)为4.00 m;在商河田间发生量较大,为48.67头/m2,其田间虫口密度与玉米受害率之间无明显的相关性,二点委夜蛾对玉米的为害具有随机性。表明田间二点委夜蛾幼虫的调查应采取棋盘式(网格式)多样点取样,样点间距大于4.00 m;且田间虫口密度的大小并不能准确预测玉米苗受害率。

Geostatistical analysis on spatial distribution of Athetis lepigone (Möschler) larvae and its correlation with damage rate of maize seedlings

To clarify the spatial pattern of Athetis lepigone (Möschler) larvae in the field and its relationship with the damage rate of maize seedlings, an investigation was conducted in corn fields in Shanghe County, Shandong Province by the grid sampling method. The amount of larvae and damaged maize seedlings were used to fit the space variation curve model following the method of geostatistical analysis, and ArcGIS software was used for Kriging interpolation and output of the simulated diagram. The results showed that the population of larvae exhibited a clumped distribution (Gaussian model) in the field, and the space-related area was 4.00 m. The field population of A. lepigone larvae was 48.67 per m². There was no significant correlation between the population density of A. lepigone larvae and the damage rate of maize seedlings, which indicated that this pest damaged maize seedlings randomly in the field. It was suggested that a grid sampling method would be suitable for the investigation of A. lepigone larvae in the field, with more sampling points, and the distances between two sampling points should be greater than 4.00 m. It would be inaccurate to use the population density of A. lepigone larvae to predict the damage rate of maize seedlings in practice.