Probability distribution, sampling unit, data transformations and sequential sampling of European vine moth, Lobesia botrana (Lepidoptera: Tortricidae), larval counts from Northern Greece vineyards

Larval densities of the second and third generation of Lobesia botrana on half-vine and entire plants of wine and table cultivars were investigated from 2003 to 2004. No insecticide treatments were applied to plants. The distribution of L. botrana larvae can be described by a negative binomial. This reveals that the insect aggregates. A common value for the k parameter of the negative binomial distribution of kc=0.6042 was obtained using maximum likelihood estimation. The advantages and cases of use of a common k are discussed. The best transformations for L. botrana larval counts were calculated. An entire vine is recommended as the sampling unit for research purposes, whereas a half-vine which is suitable for grape vine cultivation in northern Greece is recommended for practical purposes. We used these findings to develop a fixed precision sequential sampling plan and a sequential sampling program for classifying the pest status of L. botrana larvae.