刺槐叶瘿蚊越冬幼虫空间格局及抽样调查技术

本文采用聚集指标法分析了刺槐叶瘿蚊Obolodiplosis robiniae(Haldemann)越冬幼虫的空间分布格局,结果表明:刺槐叶瘿蚊越冬幼虫在林间呈聚集分布;其聚集的原因与刺槐叶瘿蚊自身的行为习性有关或由刺槐叶瘿蚊本身与环境的异质性共同作用所造成。采用"z"字型、平行线、棋盘式、大五点、对角线5种抽样方法估计林间刺槐叶瘿蚊越冬幼虫虫口密度,确定对角线法调查15样方为最佳抽样方法。对土壤不同深度土层中越冬幼虫数量调查,明确最适取样深度为3cm。同时利用Iwao回归建立了理论抽样数量模型:n=t2/D2(1.1957/x珋+0.8905)。利用过筛手检和过筛水漂2种方法检数土中幼虫,对检出刺槐叶瘿蚊越冬幼虫虫量及检虫时间进行了对比分析,结果表明过筛水漂法检虫较为可取。

Over-wintering larvae distribution pattern and sampling techniques of Obolodiplosis robiniae

Five aggregation degree indices,the Taylor method and the Iwao method,were used to test the spatial distribution pattern of Obolodiplosis robiniae （ Haldemann ） in fields. The results indicate that O. robiniae had an aggregated distribution due to innate behavioral and environment factors. Over-wintering larval population density was measured by 5 sampling methods; ＂Z＂shape,parallel lines,‘checkerboard’,twin- diagonal lines and ‘big five points’,and 5,10 and 15 samples obtained by each method compared through simulating sampling. The results show that collecting 15 samples using the twin-diagonal lines method was the best sampling regime. 3cm proved a feasible soil depth to collect larvae. A theoretical sampling model n = t2 / D2 （1. 1957 / ＋ 0. 8905） was developed. A comparison of the efficiency of collecting larvae from soil by hand and rinsing them from soil with water indicated that rinsing was superior.