稻田灰飞虱种群数量动态和空间结构初步分析

Populational Dynamics and Spatial Structure and Pattern of Small Brown Planthopper,Laodelphax striatellus Fallén on Rice

灰飞虱(Laodelphax striatellus Fallén)是水稻上的重要害虫,近年来对水稻产量的影响逐年加重。2009年至2010年系统调查了沿黄稻区灰飞虱种群的发生特点和数量动态规律,并用聚集度指标法和改进的Iwao回归分析法对稻田灰飞虱种群的空间结构进行了研究。结果表明,沿黄稻区灰飞虱越冬种群主要以少量3、4龄若虫进行越冬;第1代灰飞虱成虫在5月中旬开始从小麦田向水稻秧田迁飞,5月下旬至6月中旬进入第1个发生高峰期,迁入高峰时秧田虫量达483头/m2;灰飞虱种群的第2个发生高峰期出现在8月中旬至9月中旬,其间出现2个小峰值,虫量分别为156和143头/m2;第1代灰飞虱成虫在稻田中空间分布型的聚集性指标大于1,表明其呈现聚集分布特征,在此基础上得出灰飞虱田间调查的理论抽样数模型为N=t2D2(0.23m+0.06),采用m*-m关系的种群序贯抽样Iwao模型为T(1,0)=25±12.9槡n。研究结果为田间灰飞虱的准确抽样调查和有效防治提供了科学依据。

Small Brown Planthopper,Laodelphax striatellus Fallén was a serious pest of rice crops, which resulted in field loss increasing year by year.Based on population dynamics analysis,we studied the spatial structure and pattern systematically between 2009 and 2010 through the methods of assembling indices and advanced Iwao regression in the Yellow River valley of China. The results showed that the population overwintered as a few 3th,4th stage of nymph,the adult of first generation occurred in March and migrated from wheat field to paddy field,then the first population peak occurred during the mid of May and the mid of June,as the maximum was 483 heads/m2,the second peak appeared during the August and September,and the number was 156 and 143 heads/m2,respectively,the distribution pattern of the first-generation adult in the sampled fields was clustered and index of patchiness was more than 1,and so the theoretical sampling equations were established as T（1,0）=25±12.9n,and sequential sampling model was established as N=t2D2（0.23m＋0.06）.These results provided a scientific basis for the reasonable sampling and effective management against the Small Brown Planthopper.