稻茎毛眼水蝇幼虫田间分布型及抽样技术

根据14丘稻田稻茎毛眼水蝇幼虫调查资料．对其幼虫分布型进行了分析。结果表明；用I、CAm／m、Iσ四种聚集指标法测定，64．3％的田块呈随机分布．28．4%为均匀分布．7．3%为聚集分布。用Iwao平均拥挤度和Taylor幂法则测定．其田间分布型符合随机分布。用频次拟合法测验，50%的田块同时符合渡松、奈曼和负二项分布三种分布型；35．7%的田块同时符合2种分布型。根据该虫田间分布型的特点．制定了相应的序贯抽样技术。

THE DISTRIBUTION AND SEQUENTIAL SAMPLING TECHNIQUE FOR THE LARVAE OF HYDRELLIA SASAKII

According to the investigating data of the larvae of Hydrella sasakii obtainedfrom 14 piecies of rice fields. the distribution patterns of the larvae of H. sasakii were analysed.It showed that the larvae of H. sasakiiin 64.3% sampling fields belong to therandom distribution. 28.4% fit intotheeven distribution and 7.3% is the aggregationdistribution. The distribution patterns. when tested with the index of mean crowding of Iwao and power law of Taylor. all the larvae in 14 sampling fields belong to the randomdistribution. While tested with frequency comparing methods. 50%of the larvae in 14fieldsconform to Poisson. Neyman and Negative binomial distributions simultaneously. 35.7% of which conform poisson and Negative binomial distributions or Neyman and Negativebinomial distributions.Based on the these distribution patterns. the sequential samplingtechnique of H. sasakii set up as well.