Influence of maturity stage of grape berries on the development of Lobesiabotrana (Lepidoptera : Tortricidae) larvae

Larvae of Lobesia botrana Denis & Schiffermueller were reared on grape berr ies of different stages of maturity. The berries belonged to 5 grape variet ies: 'Soultanina', 'Muscat Ambourg',.Razaki', 'Italia', and 'Xinomavro'. Th e berries were collected every 8-10 d from 1 wk before the stage of veraiso n until grape maturity. Larvae were reared individually on the grape berrie s of each collection day to observe their development. The larvae were allo wed to develop on berries of the same variety and maturity stage until pupa tion. Rearing cups were examined daily to observe the condition of the berr ies and the larval development. The percentage of adults that emerged was c ounted as well. Larval development was faster on midmature or mature berrie s depending on the variety. In all varieties and ail stages of maturity, ma le larvae developed faster than female. The fastest development was observe d on Razaki. The percentage of adult emergence was the largest on the matur e berries although there were no differences among the emergence of adults from larvae on berries of different varieties. The observed differences wer e associated with differences in the sugar content and acidity during the p rocess of berry maturity, although other unmeasured factors are likely to b e important.