Abstract:With the aim of improving the dispatches ofEncarsia formosato the agriculturist's greenhouses increasing wasp efficiency, a new method of conditioning by changing the substrate of black pupae was performed.Three groups of parasites to which pupae were glued with or without sugar and compared to a control were studied. This new method of conditioning (pupae were removed from the host‐plant then glued on a cardboard plaquette) did not disturb the wasp's biological potentialities (daily fecundity, longevity) and adding sugar increased the daily fecundit