This guideline describes a standardised form of extended laboratory test for evaluating the effects of plant protection products on the parasitic wasp, Aphidius rhopalosiphi (De Stefani-Perez) (Hymenoptera, Braconidae), both in terms of acute treatment effects (i.e. mortality over a 48 h exposure period) and sub-lethal treatment effects (i.e. changes in the reproductive capacity of surviving wasps). The test method involves the treatment of a 3-dimensional test substrate (barley seedlings), over which the test insects (laboratory-bred female wasps, less than 48-hold) are confined for 48 h. Surviving wasps are then individually confined over untreated aphid-infested plants for 24 h and the numbers of parasitised aphids in which wasp pupae subsequently develop are recorded. Acute mortality after 48 h and the mean number of 'mummies' (the pupal stage of the wasps) produced per female are used as assessment endpoints for the test.