草地贪夜蛾Spodoptera frugiperda(J. E. Smith)是一种世界性的重大农业害虫,已于2019年1月侵入中国云南省西部地区,对当地主要经济作物鲜食玉米的生产构成了严重威胁。我们调查了入侵成虫后代幼虫在鲜食玉米田的种群密度和为害情况,分...草地贪夜蛾Spodoptera frugiperda(J. E. Smith)是一种世界性的重大农业害虫,已于2019年1月侵入中国云南省西部地区,对当地主要经济作物鲜食玉米的生产构成了严重威胁。我们调查了入侵成虫后代幼虫在鲜食玉米田的种群密度和为害情况,分析了幼虫种群的空间分布格局。结果表明,草地贪夜蛾幼虫在玉米田呈聚集分布,聚集度随密度的增加而升高,环境是导致聚集分布的主要因素。基于空间分布型的分析结果,进一步研究提出了幼虫密度的理论抽样模型和基于幼虫密度防治指标的序贯抽样技术。本研究明确了草地贪夜蛾幼虫在玉米田的空间分布特征和抽样方法,为通过调查田间种群密度指导幼虫防治工作提供了技术支撑。展开更多
为有效防控食芽象甲Scythropus yasumatsui K8no et Morimoto在陕西榆林地区枣园的危害,在田间调查的基础上,使用Iwao回归分析法、Taylor幂法则和5种常用指标参数,探明了成虫在不同枣园样地中的分布格局、理论抽样数及成虫的序贯抽样方...为有效防控食芽象甲Scythropus yasumatsui K8no et Morimoto在陕西榆林地区枣园的危害,在田间调查的基础上,使用Iwao回归分析法、Taylor幂法则和5种常用指标参数,探明了成虫在不同枣园样地中的分布格局、理论抽样数及成虫的序贯抽样方法。食芽象甲成虫在枣树上的空间格局为聚集型,个体间相互吸引,其聚集性随密度的增大而增加。对成虫进行序贯抽样,当每株成虫达到30头,置信水平为1.96时,序贯抽样进行抽样的防治下限与上限方程分别为:d_0=30n-34.33n^(1/2)和d1=30n+34.33 n^(1/2),当调查10株枣树上的虫数超过409头时,需要进行防治。食芽象甲成虫空间分布型及抽样方法的确定,对于揭示该虫的种群空间结构动态,提高田间测报准确率及防治效果都具有十分重要的意义。展开更多
Xylotrechus namanganensis is a kind of devastating borer to many broad leaved tree species in Xinjiang.Its spatial distribution model has been studied since 1996.The result showed that the number of adult eclosion cav...Xylotrechus namanganensis is a kind of devastating borer to many broad leaved tree species in Xinjiang.Its spatial distribution model has been studied since 1996.The result showed that the number of adult eclosion cavity on the trunk of elm trees with the height of 0～0.5 m,and 0～2.5 m above the ground belonged to assembly distribution model by testing the indexes such as C,I,M *,M */,K and CA .Checking tests by method of Iwao and Taylor also consistently draw out the same conclusion. The sampling numbers of elm trees can be determined by the formulae N=143.26/ +15.78 and N=345.63/ +13.04 respectively if the number of eclosion cavity on the trunk with the height of 0～0.5 m,or 0～2.5 m above ground is to be investigated by Iwao method. On the basis of recognizing that eclosion cavity spatial distribution of Xylotrechus namanganensis on the trunk of elm trees belonged to assembly distribution model,and the economic injury level (EIL) was 2 eclosion cavities on the trunk,the upper and lower limits of sampling number can be calculated by formula T 0(n)=2N±8.179 7N .展开更多
文摘草地贪夜蛾Spodoptera frugiperda(J. E. Smith)是一种世界性的重大农业害虫,已于2019年1月侵入中国云南省西部地区,对当地主要经济作物鲜食玉米的生产构成了严重威胁。我们调查了入侵成虫后代幼虫在鲜食玉米田的种群密度和为害情况,分析了幼虫种群的空间分布格局。结果表明,草地贪夜蛾幼虫在玉米田呈聚集分布,聚集度随密度的增加而升高,环境是导致聚集分布的主要因素。基于空间分布型的分析结果,进一步研究提出了幼虫密度的理论抽样模型和基于幼虫密度防治指标的序贯抽样技术。本研究明确了草地贪夜蛾幼虫在玉米田的空间分布特征和抽样方法,为通过调查田间种群密度指导幼虫防治工作提供了技术支撑。
文摘Xylotrechus namanganensis is a kind of devastating borer to many broad leaved tree species in Xinjiang.Its spatial distribution model has been studied since 1996.The result showed that the number of adult eclosion cavity on the trunk of elm trees with the height of 0～0.5 m,and 0～2.5 m above the ground belonged to assembly distribution model by testing the indexes such as C,I,M *,M */,K and CA .Checking tests by method of Iwao and Taylor also consistently draw out the same conclusion. The sampling numbers of elm trees can be determined by the formulae N=143.26/ +15.78 and N=345.63/ +13.04 respectively if the number of eclosion cavity on the trunk with the height of 0～0.5 m,or 0～2.5 m above ground is to be investigated by Iwao method. On the basis of recognizing that eclosion cavity spatial distribution of Xylotrechus namanganensis on the trunk of elm trees belonged to assembly distribution model,and the economic injury level (EIL) was 2 eclosion cavities on the trunk,the upper and lower limits of sampling number can be calculated by formula T 0(n)=2N±8.179 7N .
