【摘要】 蛴螬混合种群于白芍生长后期在田间呈聚集分布。进行X~2检验结果表明:当蛴螬虫口密度为2.5—8头/米~2时,符合负二项分布。本文还导出在不同置信度t、不同虫口密度(?)(头/株)和不同允许误差D下的理论抽样数n,对蛴螬混合种群在轻度发生(1头以下/米~2)、中度发生(2—3头/米~2)、严重发生(4—6头/米~2)和特大发生(6头以上/米~2)等不同情况下的序贯抽样模型也进行了推导。更多还原

【Abstract】 The spatial distribution pattern of mixed populations of white grubs was aggregated at the late growing stage of Paeonia Lactiflora in the field. The further x~2-test indicates that 6 groups of experimental data all agree to negative binomial distribution. As a result, a model for theoretical sampling number is established, which differs with confidence degrees, insect population density and adoptable errors. Based on the sequential sampling method for negative binomial distribution, a sequential sampling model is concluded for the mixed white grub population at different population levels.更多还原