灰斑古毒蛾幼虫空间分布及防治指标序贯抽样模型

Spatial Distribution of Larvae of Orgia ercae Germar and Sequential Sampling Model of Controlling Index

灰斑古毒蛾幼虫在沙冬青、杨柴和花棒上呈聚集型分布,聚集度较大,且聚集度随着种群密度的升高而增加。灰斑古毒蛾幼虫分布为聚集型分布,属一般负二项分布,分布的基本成分是个体群,个体间相互吸引。根据Iwao(1975)得出理论抽样数模型为N=3.8416(2.1698/m+0.7206)/D2。并建立防治指标序贯抽样数模型和抽样数表,对提高种群密度估计精度、指导林间调查和判断防治决策,具有一定的实践指导意义。

The larvae of Orgia ercae Germar take the aggregation distribution in Ammopiptanthus mongolicus,Hedysarum mongolicum and Hedysarum scoparium in a high aggregation degree,which has risen with the increase of population density. The distribution of larvae of O. ercae Germar belongs to a general negative binomial distribution,the individual group is basic component in its distribution and the individuals attract each other. According to Iwao（ 1975）,the theoretical sampling model was N = 3. 8416（ 2. 1698/m ＋ 0. 7206）/D^2. It is helpful to establish the model and table of sequential sampling number of controlling index for improving the estimate precision of population density,guiding the investigation in forest and judging the control decision.