苹果园山楂叶螨9-11月种群空间分布

为了研究苹果树冠9-11月山楂叶螨种群分布格局及空间方位关系,探明这一时期苹果园山楂叶螨种群数量及越冬趋势,在陕西省扶风县果园,选取富士和嘎啦苹果树各5株,将立体树冠划分为20个资源单位,每个资源单位随机抽取5片叶,调查统计叶螨数量。应用聚集度指标、Iwao回归分析法、Taylor幂法则及Brayr Curtis Measure系数对数据进行分析。结果表明,山楂叶螨在苹果两个品种上的数量分布不同,富士品种上叶螨总量是嘎啦的2.03倍。山楂叶螨在两品种上均呈聚集分布,但在富士植株上聚集的原因为种群中个体间相互排斥,而嘎啦上则为个体内相互吸引。种群差异度表现为,在水平方向上,富士品种4方位无显著差异,内、外侧差异极显著,嘎啦上均无显著差异;在垂直方向上,富士树冠上、中、下3层之间的差异性均达极显著水平,嘎啦仅上层与中、下层差异极显著,中层与下层之间无明显差异。该螨在两品种树冠上的分布构成不同层次的种群亚层结构。因此,当地苹果园山楂叶螨种群分布更偏向于富士品种,应重点防治,以减少来年螨源;方位上趋向于西侧越冬,且多分布于树冠内侧中、下层,这是翌年果园喷药管理的重点部位。

The Population Spatial Distribution of Tetranychus viennensis in Apple Orchards from September to November

In order to make a study of the population distribution pattern and spatial orientation of Tetranychus viennensis in apple trees during Sept. Nov., ascertain the population size and overwintering trends, in the orchards of Fufeng, Shaanxi province, we selected five strains from each Fuji and Gala apple trees, divided the crown into 20 units from which five sample leaves were selected in each resource units randomly. Through this way, we could collect statistics of wintering mites populations. The Aggregation Indices, Iwao of Regression Analysis, Taylor Power Law and Brayr Curtis coefficient were applied to analyze the data we got. The results indicated that the distribution of T.viennens on the two varieties was different. In the Fuji variety, the total mites was 2.03 times that of the Gala; the mites on two varieties displayed in an aggregated distribution, while the reason of aggregated distribution on the Fuji variety was inter individual mutual exclusion, for the Gala variety, it was mutual attraction. Besides, the population difference in the two species shows: horizontally, the population of T. viennens on Fuji was no significant differences in the four directions. However, there was an extremely significant difference between the inner side and outside, while for the Gala, no notable difference in any direction. Vertically, the population of T. viennensis in the upper, middle and lower part of the Fuji revealed significant differences and that of the Gala had the same results only except the subtle difference between the middle and lower part. The distribution of T. viennensis on crowns of those two varieties constituted population sub layer structure at different levels. Therefore, the Fuji variety had more attraction for T. viennensis in local apple orchards. Hence, we should focus on prevention to reduce the population in the coming year; the hawthorn spider mites tended to overwinter in the west side of crowns, and were distributed mainly at the middle and lower part of the inside of the crown, where should be the focus for spraying pesticides of orchard management in the next year.