棉叶螨在棉株上的垂直分布及其二阶抽样技术研究

Study on Vertical Distribution and Subsample of Cotton Red Spider Mites on the Cotton Stems

根据田间调查结果分析，在棉花苗期，棉叶螨的垂直空间分布格局呈聚集分布，且具有明显的层次性，主要分布在倒１至倒５叶上，约占总螨量的９０％左右，不同田块之间差异不显著。应用Ｉｗａｏ根据Ｍ＊－ｍ关系提出的二阶抽样模型估测，在Ｄ达０．１０、０．１５、０．２０精确水平时，调查顶１叶至倒５叶层螨量所需抽查的棉株数平均分别为１０９．６、４８．９、２７．５株。置信度取９５％时，区间估计ｐ上为０．９３８６～０．９６７４，ｐ上为０．９５３０；ｐ下为０．０３７４～０．０６１８，ｐ下为０．０５１８。

According to the analysis of fields research during the cotton seedling stage, the vertical spacial distribution pattern of cotton red spider mites is a gathering distribution and cotton mites mainly distribute from the last leaf to the last but fifth, the number of which accounts 90% in total. There isn′t much difference about the distributive numbers in the different fields. With the application of Iwao and M -m under the condition of D=0.10, 0.15, 0.20 respectively to assess about the number of leaf mites from the last leaf to the last but fifth, the average number for sampling are 109.6, 48.9 and 27.5 respectively. While taking 95% degree of confidence, estimation of larger interal is P up (0.9386～0.9674), up =0.9530; smaller interal is p down (0.63074～ 0.0618 ), down =0.0518.