Distribution and sampling methods of soft-scale-insects in vineyards

In southwest German vineyards scale insect studies where carried out between the year 1998 and 2005 on the species Parthenolecanium corni and P. persicae. Their phenology was studied and described. The distribution within a plant as well as the distribution within whole vineyards was found to be inhomogeneous and clumped. The negative binomial distribution describes Parthenolecanium species repartition within a vineyard. For P. corni a common k-Value (kc) is probable while for P. persicae it’s not. Usually clumping is so extreme that random sampling doesn’t make sense as the the number of grapevines to be sampled is often higher than the number of grapevines available within a vineyard. Density and population dynamic measurement in plant protection experiences can be achieved by the preevaluation of distinct plants. Parameter free ranking statistics may be usefull to apply, as the number of scale insects between two plants can change within three orders of magnitude.