none Sphecophaga vesparum burra (Cresson) (Hymenoptera: Ichneumonidae) has been released at seven sites in New Zealand as a biological control agent for wasps (Vespula spp.). Between 1996 and 1998, more than 35 000 overwintering cocoons were released nationwide, more than half of them at two South Island sites: Binser Track in Arthur's Pass National Park (13 200 cocoons) and Tennyson Inlet in the Marlborough Sounds (13 660 cocoons). Monitoring at these two climatically and altitudinally disparate sites revealed that over 5000 adult parasitoids emerged at each site over the 4 years. More than 300 wasp nests were dug and inspected for attack by S. v. burra, but there was no evidence of establishment. Animals and man; Control; Biological control; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Zoogeography; Dispersal; Means of dispersal; Land and freshwater zones; Australasian region Sphecophaga vesparum burra (Ichneumonidae); Control of; Vespula (Hymenoptera); Hymenopteran hosts; Vespula; Introduction; Establishment success, implications for control of hymenopteran host; New Zealand; South Island; Binser Track & Tennyson Inlet; Parasite establishment after introduction, implications for comtrol of hymenopteran host Vespula (Vespidae); Control by; Sphecophaga vesparum burra (Hymenoptera); Hymenopteran parasites; Sphecophaga vesparum burra; Parasite establishment after introduction; New Zealand; South Island; Binser Track & Tennyson Inlet; Hymenopteran parasite establishment after introduction, control relationships