Sampling plan for Green-Leafhoper (Homoptera: Cicadellidae) in vineyard at Lima Valley

Abstract

The aims of this work were: to study the spatial patterns of nymphal stages of the green-leafhopper Empoasca vitis using the regression models of Taylor's Power Law and Iwao, in vineyard cvs. Arinto and Vinhão in organic farming and integrated production systems; to develop a binomial sampling (presence-absence). The results showed that: i) Taylor's power law was more appropriate to describe the spatial pattern of E. vitis and indicated a random pattern; no statistically differences were detected between varieties and production systems, ii) the sample size required increases with the degree of accuracy, iii) it is possible to simplify the enumerative sampling plan; and iv) the sample size required to estimate population densities of this pest corresponding to the economic thresholds, ranges from 30 to 57 leaves.