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运用所获调查资料拟合三种不同分布型，菜蛾幼虫及蛹在花溪地区甘蓝菜地内主要呈负二项分布，公共Ｋ值Ｋｃ分别为：幼虫１．０６３１蛹０．９８４３；聚集度指标检验结果显示，幼虫、蛹在田间呈聚集分布。负二项分布的理论曲线Ｓ~２＝Ｘ＋Ｘ~２／Ｋｃ与Ｔａｙｌｏｒ式的Ｓ~２＝ａｘ~（－ｂ）曲线接近，与频次分布法检验结果一致。在该调查范围内，幼虫及蛹种群密度小于２．４００头／株、２．５２４３头株时，聚集原因是由环境因素引起，大于此值时，聚集原因是由幼虫及蛹本身习性引起，与调查结果相吻合。
Using the survey data to fit three different distribution patterns, the larvae and pupae of Plutella xylostella were mainly negative binomial distribution in the kale vegetable field in Huaxi area. The public K values were 1.0631 pupae and 0.9843 larva respectively. The test results showed that the larvae and pupae gathered in the field. The theoretical curve of negative binomial distribution S ~ 2 = X + X ~ 2 / Kc is close to the Taylor S ~ 2 = ax ~ (-b) curve, which is consistent with the result of frequency distribution test. Within the survey range, larvae and pupae population density of less than 2.400 head / strain, 2.5243 head strain, the aggregation is caused by environmental factors, greater than this value, the accumulation is caused by the habits of larvae and pupa itself, In line with the findings.