Spatial heterogeneity and population risk analysis of cotton bollworm, Helicoverpa armigera, in ChinaKey words spatial characteristics, spatial pattern, semivariance, population management, geostatistics, Helicoverpa armigera, population regulation

In this study, semivariance was used to quantitatively measure the spatial heterogeneity for the egg population of cotton bollworm during a growing season. The typical characteristic parameters of theoretical semivariance models against lag distances were applied to measure components of spatial heterogeneity： trend, range, spatial dependence, and the strength of spatial dependence. Then, kriging interpolation was used to evaluate the population risk of cotton bollworm exceeding economic thresholds. From early June through early September, the population densities were sampled 10 times in the study field. Results showed that the spatial patterns were related to population density. For its low-density population, the spatially heterogeneous trends were usually of spherical shapes; but for highdensity ones, the trends shifted to Gaussian shapes. The spatial dependence appeared at varied distances ranging from 52 meters to 936 meters, and the spatial dependence was in the range of 0.39-288.60, which changed with population densities. While having high heterogeneity, the strength of spatial dependence became much stronger. Results of population risk analysis showed that there was a high risk during its early stages, especially in mid-June. In August, population risk was so low that it did not need to be controlled.

在这研究，半变化习惯于份量上在生长期期间为棉花一种蛾的幼虫的鸡蛋人口测量空间异质。理论半变化模型对的典型典型参数落后距离被使用测量空间异质的部件：空间依赖的趋势，范围，空间依赖，和力量。然后， kriging 插值被用来评估超过经济阀值的棉花一种蛾的幼虫的人口风险。从通过早 9 月的早 6 月，种群密度在学习领域里被取样 10 次。结果证明空间模式 werer 鼓舞了到种群密度。为它的低密度的人口，空间地异构的趋势通常具有球形的形状；要不是高密度的，趋势变了到 Gaussian 形状。空间依赖在从 52 米到 936 米的改变的距离出现了，并且空间依赖在 0.39 的范围—288.60，它随着种群密度变化了。Whilehaving 高异质，空间依赖的力量变得强壮得多。人口风险分析的结果证明在它的早阶段期间有高风险，特别 inmid6 月。在 8 月，人口风险是那么低的它不需要被控制。