枣瘿蚊幼虫在设施枣树上的空间分布型及抽样技术

【目的】近年来,枣瘿蚊(Dasineura jujubifolia)在陕西榆林设施枣树基地危害严重,造成巨大经济损失。研究枣瘿蚊幼虫在设施枣树上的空间分布型及抽样技术,掌握枣瘿蚊在寄主上的发生情况和生物学特性,为该虫的监测预报和防治提供参考。【方法】2020年4—5月,在陕西省榆林市佳县柳树会村,选取枣瘿蚊幼虫危害严重的设施枣树样地。采用五点抽样法、双对角线抽样法、棋盘式抽样法、平行线抽样法和“Z”形抽样法抽取受害枣树,运用全株调查法(全查法)统计每株枣树上枣瘿蚊幼虫的数量。5种抽样方法与全查法之间进行t检验、误差率和变异系数比较,筛选出最适合的抽样方法,然后应用7种聚集度指标、Iwao的m^*-m回归分析法和Taylor幂法则对枣瘿蚊幼虫在设施枣树上的空间分布型进行研究。【结果】5种抽样方法均适合设施枣树枣瘿蚊幼虫的调查,其中平行线抽样法为最适合的抽样方法。调查表明,枣瘿蚊幼虫在设施枣树上的空间分布型呈聚集分布,分布的基本成分为个体间相互吸引,密度越大,个体群聚集度越高;其聚集分布由个体的聚集习性引起。依据Iwao的m^*-m回归分析确定了枣瘿蚊幼虫的最适理论抽样公式为N=3.841 6/D²(2.878 3/m+0.176 5),当枣瘿蚊幼虫的防治阈值设置为4头/株,序贯抽样模型公式为$T_{(n)}=4 n \pm 7.4214 \sqrt{n}$。若调查100株设施枣树,当枣瘿蚊幼虫数量累计大于474头时,需要进行防治。【结论】枣瘿蚊幼虫在设施枣树上的最适调查方法为平行线抽样法,其空间分布型为聚集分布,为该虫在设施枣树上的防治提供了基础资料。

Spatial distribution patterns and sampling techniques of Dasineura jujubifolia larvae on facility jujube trees

【Objective】 Dasineura jujubifolia is an important pest on jujube trees. In recent years, this pest has caused serious economic losses at the jujube base facility in Yulin City, Shaanxi Province. Understanding the spatial distribution pattern and sampling technique of jujube gall midge larvae on protected jujube trees are of great practical significance for the monitoring, prediction and control of this pest. 【Method】 Facility jujube sample plots displaying serious damage by jujube gall midge larvae were selected from April to May 2020 in Liushuhui village, Jia County, Yulin City, Shaanxi Province. First, the damaged jujube trees were examined using methods such as five-point sampling, double diagonal sampling, checkerboard sampling, parallel line sampling and Z-shaped sampling. Then, the number of jujube gall midge larvae on each facility jujube tree was counted using the whole plant survey method, and the suitability, representativeness and variations among these five methods were compared using t-test. After determining the most suitable sampling method, the spatial distribution of jujube gall midge larvae on facility jujube trees was studied using seven aggregation indexes, Iwao’s m^*-m regression analysis, and Taylor power law. 【Result】 Although all five sampling methods were suitable for the investigation of jujube gall midge larvae in facility jujube trees, the parallel line sampling method was the best performing one. The spatial distribution pattern of jujube gall midge larvae on protected jujube trees was of the aggregation type. The basic component of distribution is the mutual attraction between individuals. The greater the density, the higher the aggregation of individual groups. The larvae of jujube gall midge were clustered on facility jujube trees, caused by the joint action of environmental factors and the aggregative habit of individual larvae. According to Iwao’s m^*-m regression analysis, the optimal theoretical sampling formula for jujube gall midge larvae was obtained as: N = 3.841 6/D² (2.878 3/m + 0.176 5). When the control threshold of jujube gall midge larvae was set at four inds/plant, the formula of sequential sampling model was obtained as: $T_{(n)}=4 n \pm 7.4214 \sqrt{n}$. If 100 facility jujube trees are investigated, and the cumulative number of jujube gall midge larvae is greater than 474, they need to be controlled. 【Conclusion】 The parallel line sampling method was determined to be the most suitable investigation method for jujube gall midge larvae on facility jujube trees. The spatial distribution of jujube gall midge larvae on facility jujube trees is of the aggregation type, which provides a theoretical support for the prevention and control of jujube gall midge larvae in facility jujube trees.