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Abstract. Studies were conducted to investigate the distribution of larvae of the European vine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), a key vineyard pest of grape cultivars. The data collected were larval densities of the second and third generation of L. botrana on half-vine and entire plants of wine and table cultivars in [2003][2004]. No insecticide treatments were applied to plants during the 2-year study. 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, and the advantages and cases of use of a common k are discussed. The and proved to be the best transformations for L. botrana larval counts. An entire vine is k 1 Sinh 1 k x 1/2 k 1 Sinh 1 k x 3/8 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.

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Larνae of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) were reared in laboratory conditions (26°C, 16:8 L:D) and measurements of larval head capsule width, and body weight, were used in order to determine the boundaries of larval instars. Larvae of Η. armigera completed development in 5 to 7 instars. Head capsule width could predict the larval instar only for Ll. The upper boundary of head width for L1 was 0.4mm. Body weight could predict both L1 and L2 larval instars. Boundaries between L1-L2 instars were found to be 1 mg and for L2-L3 5,5 mg. Correlation and regression analysis suggest that a combination of head capsule width and body weight can predict both larval instars and chronological age under constant conditions in the laboratory.