Lessio Federico, Alma Alberto
Di Va PRA, Entomologia e Zoologia applicate all'Ambiente C Vidano, University of Turin Grugliasco (TO), Italy.
J Econ Entomol. 2006 Apr;99(2):578-82. doi: 10.1603/0022-0493-99.2.578.
The spatial distribution of the nymphs of Scaphoideus titanus Ball (Homoptera Cicadellidae), the vector of grapevine flavescence dorée (Candidatus Phytoplasma vitis, 16Sr-V), was studied by applying Taylor's power law. Studies were conducted from 2002 to 2005, in organic and conventional vineyards of Piedmont, northern Italy. Minimum sample size and fixed precision level stop lines were calculated to develop appropriate sampling plans. Model validation was performed, using independent field data, by means of Resampling Validation of Sample Plans (RVSP) resampling software. The nymphal distribution, analyzed via Taylor's power law, was aggregated, with b = 1.49. A sample of 32 plants was adequate at low pest densities with a precision level of D0 = 0.30; but for a more accurate estimate (D0 = 0.10), the required sample size needs to be 292 plants. Green's fixed precision level stop lines seem to be more suitable for field sampling: RVSP simulations of this sampling plan showed precision levels very close to the desired levels. However, at a prefixed precision level of 0.10, sampling would become too time-consuming, whereas a precision level of 0.25 is easily achievable. How these results could influence the correct application of the compulsory control of S. titanus and Flavescence dorée in Italy is discussed.
应用泰勒幂法则研究了葡萄黄化病（葡萄韧皮部杆菌，16Sr-V）的传播媒介——黄斑叶蝉（同翅目叶蝉科）若虫的空间分布。研究于2002年至2005年在意大利北部皮埃蒙特的有机葡萄园和传统葡萄园中进行。计算了最小样本量和固定精度水平的停止线，以制定合适的抽样计划。通过样本计划重采样验证（RVSP）重采样软件，利用独立的田间数据进行模型验证。通过泰勒幂法则分析，若虫分布呈聚集型，b = 1.49。在害虫低密度时，32株植物的样本量在精度水平D0 = 0.30时足够；但为了更准确的估计（D0 = 0.10），所需样本量需要292株植物。格林固定精度水平停止线似乎更适合田间采样：该抽样计划的RVSP模拟显示精度水平非常接近期望水平。然而，在固定精度水平为0.10时，采样会变得过于耗时，而精度水平为0.25则很容易实现。讨论了这些结果如何影响意大利对黄斑叶蝉和葡萄黄化病强制防治措施的正确应用。
