摘要
根据10个样地100株粟树8452茶果枝剪枝标实象（CyllorhynchitesursulusRoelofs）为害状调查数据，分析为害状的空间分布格局。结果显示：东、南、西、北四个方向为害程度差异不显著。树枝顶部为害程度显著低于下部各个方向，达1．05倍。样地间差异也达到极显著水平，而且这种差异与样地的管理水平相一致。该种群为害状空间分布的基本成份为个体群，总体为聚集分布。用Iwao回归法分析，得出理论最适抽样数（n）回归式为：n=（1.67／X＋0．07）／D2，式中X为粟枝平均被害率，D为允许误差。在防治指标定为果枝被害率10％时，序贯抽样的累积被害率上下限（T’（0））为：T’（0）=10×9．54×。每平方米土壤虫口密度和树上虫口密度相关性式为：Y＝3．9883×P－0．3016，相关系数为0．95。式中Y为P分别为剪枝粟实象树上成虫密度与土壤中幼虫密度。这说明可用土壤中幼虫密度估计成虫密度。
By the data collected from the field invetigation the space pattern of symptom caused byweevil (Cyllorhynchites ursulus Roelofs) on its host plant ( Castanea mollissima Bl. ) branches wasanalyzed in this paper. The differenes of the damage symptom among the branches in different di-rections was significant . The damage on the top portion of host plant canopy was much lowr thanthe other directions. The differece among different sampled fields was also significant.This differ-ence was coinidence with the management levels. The spece pattern belonged to the aggregatedtype. By lwao regression model the formulae of optimum sample units (n)was:n=(1.67/x +0.07)/D2 where X was the mean of the damage rate of plant branches, D was relative errors. Whenthe control index was 10% of the branches damaged, the upper or lower limits functions of accumu-lated damage rate (T(0) ) to judge whether the insecticides were used or not were: T(o) = 10 × n9.54 ×n , where n was the number of sample units. lts adult lived on the tree canopy, its larvaelived in the soil under tree canopy . By the densities of the adult and the larvae the relationship be-tween them was analyzed with the ther regression model . The model was Y = 3.9883 × P-0.3016,where Y was the adul density, P was the larvae density. The regression coefficient was 0. 95. Thisindicated by the be density in soil the adult density could been estimated.
出处
《昆虫天敌》
CSCD
1999年第2期65-69,共5页
Natural Enemies of Insects
关键词
板粟
剪枝栎实象
空间格局
抽样技术
Weevil(Cyllornchites ursulus oelofs)Host plan (Castanea mollissima Bl.)spatial pattern,Sampling technique
