Over-wintering larvae distribution pattern and sampling techniques of Obolodiplosis robiniae
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Key Words:Obolodiplosis robiniae, spatial distribution pattern, sampling techniques, over-wintering larvae
Abstract: 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.