Several releases of 20,000 and 40,000 individuals of Trichogramma cacoeciae were made at a central point in a vineyard in order to follow the dispersal of trichogrammes and the distribution of parasitism on Ephestia kuehniella egg-cards. The dispersal of trichogrammes essentially occurred along the release row and over the nearest rows, since the vine rows formed a plant screen that channelled their dispersion. The daily captures of trichogrammes increased with the number of trichogrammes released and decreased over time. It increased with minimal temperature and solar radiation, but did not depend on other meteorological factors. The number of parasitised egg-cards decreased with the distance from the release point and increased with the amount of wind received at the control points. The doubling of the number of trichogrammes released influenced parasitism by increasing both the discovery rate and the exploitation rate of egg-cards.