水稻生育期对稻水象甲成虫种群空间格局影响及抽样技术

Effect of rice growth period on population spatial pattern of rice water weevil and sampling technique

【目的】明确四川省西南浅丘稻区稻水象甲成虫种群在水稻不同生育期的空间格局及抽样技术,为获取准确稻水象甲虫情调查资料和制定有效的综合防控措施提供理论依据。【方法】调整水稻播栽时间,错开2组试验田水稻的生育期,用聚集度指标法、回归模型法和频次卡方检验法分析稻水象甲成虫种群的空间格局及水稻生育期对空间聚集特性的影响,并对田间序贯抽样技术和抽样方法进行研究。【结果】不同田块稻水象甲成虫平均密度为0.48~5.83头·丛^-1,分蘖期水稻田虫口密度显著高于抽穗期。稻水象甲成虫在不同水稻生育期稻田间呈负二项聚集分布,基本成分为个体群,个体间相互吸引,聚集强度随种群密度的升高而增加。当种群密度较低时,其聚集由环境因素引起;种群密度较高时,其聚集为其自身的聚集习性与环境因素共同引起。双对角线抽样法是稻水象甲成虫田间抽样的最佳方法,当稻水象甲成虫防治指标为1头·丛^-1时,Iwao序贯抽样模型为T 1(n),T 0(n)=n±1.96■2.286n,结合Kuno序贯抽样模型建立了用于田间抽样的复序贯抽样图。【结论】稻水象甲成虫在不同水稻生育期稻田间呈负二项聚集分布,分蘖期水稻田虫口密度显著高于抽穗期,双对角线抽样法是稻水象甲成虫田间抽样的最佳方法。

【Aim】In this paper,the spatial pattern of Lissorkoptrus oryzophilus adult populations were examined through the use of different sampling techniques and timing of rice planting in the shallow hilly rice area of Southwest Sichuan Province.The results aimed to provide a scientific basis for obtaining accurate survey data of rice water weevil and formulating effective comprehensive control measures.【Method】The growth periods of rice in two experimental fields were staggered by adjusting their planting time.The spatial pattern of L.oryzophilus adult populations and the effect of rice growth period on the spatial aggregation characteristics were analyzed by the methods of aggregation index,regression model and frequency chi square test.The sequential sampling technique and double diagonal sampling method were also tested in the field.【Result】The average density of L.oryzophilus adults in different fields was 0.48-5.83 heads/clump,and the population density at the tillering stage was significantly higher than that in heading stage.The adult populations of L.oryzophilus had an aggregated spatial pattern and fit to negative binomial distribution in rice fields of different growth periods.The basic component of distribution was individual group,which attracted each other,and the aggregation intensity increased with the increase of population density.The aggregation was associated with environmental factors at low population density,while at high population density,aggregation was associated with the habit of the pest and environmental factors.The double diagonal sampling method was the best method for field sampling of L.oryzophilus adults.The Iwao′s sequential sampling model was T 1(n),T 0(n)=n±1.96■2.286n,combined with Kuno′s sequential sampling figure,the multiple sequential sampling figure for field sampling was established,under control threshold of L.oryzophilus l adults with 1 head/clump.【Conclusion】The adult populations of L.oryzophilus had an aggregated spatial pattern and fit to negative binomial distribution in rice fields of different growth period,and the population density in tillering stage was significantly higher than that in heading stage.The double diagonal sampling method was the best method for field sampling of L.oryzophilus adults.