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调查了淮北棉田不同时期棉铃虫卵及幼虫在棉株不同叶位间的发生量 ,计算了 5种分布型指数 ,进行了频次拟合优度检验 ,结果表明 ,卵及幼虫在棉田的水平和垂直分布均呈聚集分布 ,其聚集强度随种群密度的改变而变化 ,聚集原因是由于环境因素所致 ;卵及幼虫的垂直分布同时具有聚集、随机和均匀的趋势。建立了卵及幼虫的理论抽样公式和估测种群密度公式
The occurrences of eggs and larvae of H. armigera cotton at different positions in different cotton leaves in Huaibei cotton field were investigated. Five kinds of distributional indices were calculated and tested by frequency goodness-of-fit test. The results showed that the levels of eggs and larvae in cotton field and The vertical distribution showed aggregated distribution, and its aggregation intensity varied with population density. The aggregation was due to environmental factors. The vertical distribution of eggs and larvae had the tendency of aggregation, randomization and evenness. Established the theoretical sampling formula of eggs and larvae and estimated population density formula