椰子木蛾幼虫在椰子树上的空间分布型及抽样技术

Spatial distribution pattern and sampling technique for Opisina arenosella Walker larvae on Cocos nucifera L.

椰子木蛾Opisina arenosella Walker是近年入侵中国的有害生物,严重为害多种棕榈科植物。为了确定椰子木蛾幼虫在椰子树上的空间分布型及抽样技术,2015年12月采用分层随机抽样法在海南省儋州市对椰子树上的椰子木蛾幼虫进行调查,运用聚集度指标法、Iwao回归方程和Taylor幂法则对椰子木蛾幼虫在椰子树上的空间分布型进行了分析,对聚集均数(λ)进行检验,分析幼虫聚集的原因。结果表明:椰子木蛾的幼虫主要在椰子树的中下部叶片为害,有87.17%的幼虫分布在第3层、第4层和第5层叶片上,其中第4层叶片上幼虫数最多,平均每片大叶上有幼虫(22±7.42)头,占总数的42.62%;椰子木蛾的幼虫在椰子树上呈聚集分布,理论分布型符合负二项分布;其种群聚集是由某些环境作用引起的。根据Iwao的回归关系,确定椰子木蛾幼虫的最适理论抽样公式及序贯抽样公式,建立不同密度下的理论和序贯抽样数表。椰子木蛾幼虫主要分布椰子树中下部叶片上并呈聚集分布,本研究为该虫害的准确抽样调查和防治提供理论依据。

Opisina arenosella Walker is an invasive pest of China in recent years,and causes serious harm to a variety of palm plants.This study was conducted to understand the spatial distribution pattern and sampling techniques of the O.arenosellalarvae,and an investigation with stratified random sampling was conducted on the larval number on Cocos nucifera L.in Danzhou,Hainan Province in December 2015.The spatial distribution pattern of the O.arenosellalarvae on C.nuciferaleaves was studied by aggregation indices,the Iwao＇s regression equation and Taylor＇s power law.The reasons for the aggregation of O.arenosellalarvae were analyzed according to estimation by aggregation mean（λ）.The results indicated that O.arenosellalarvae preferred to live in middle and lower leaves of C.nuciferatree.It was observed that 87.17% of the larvae were distributed at the 3rd,4th and5 th leaf layers of C.nuciferatree.In addition,the number of O.arenosellalarvae distributed at the 4th leaf layer was more than at other layers with an average value of 22±7.42 for every sample,accounting for 42.62% of the total.The O.arenosellalarvae presented pattern of aggregated distribution in the field,and it belonged to negative binomial distribution.The reason for the aggregation may be due to some environmental factors.The theoretical and sequential sampling tables of O.arenosellalarvae under different population densities were established by determining the optimum theoretical sampling formula and sequential sampling formula of O.arenosellalarvae according to regression relationship of Iwao.The O.arenosellalarvae were mainly distributed in middle and lower leaves of C.nuciferatree,and were in aggregated distribution.This study may provide the basis for sampling technique and control of the pest.