none Listronotus bonariensis; CONTROL-BY; Microctonus hyperodae (Hymenoptera); HYMENOPTERAN-PARASITES; Microctonus hyperodae; Parasite introduction for control; NEW-ZEALAND; Hymenopteran parasite introduction for control Microctonus hyperodae; CONTROL-OF; Listronotus bonariensis (Coleoptera); REARING-TECHNIQUES; Mass rearing for introduction & control of coleopteran host; COLEOPTERAN-HOSTS; Listronotus bonariensis; Parasite introduction for control; INTRODUCTION-; Coleopteran host control relations, records of establishment; NEW-ZEALAND; Establishment after introduction for control of coleopteran host. The method whereby equal numbers of seven ecotypes of the parasitoid Microctonus hyperodae Loan (Hymenoptera: Braconidae, Euphorinae) were reared and released is described along with the reasons for doing so. This was achieved by variably intense rearing effort depending on the number of founder females in that particular ecotype. The parasitoid was released in three regions of New Zealand as a control agent of the Listronotus bonariensis Kuschel (Col.: Curculionidae), a severe pest of New Zealand pastures. It was later recovered from all three regions.