Goldson, StephenBarker, GMChapman, HMPopay, AJStewart, Alan V,Caradus, JRBarratt, BIPHesler, L2020-05-222020-04-232020-031536-244232322881 (pubmed)https://hdl.handle.net/10182/11909New Zealand’s intensive pastures, comprised almost entirely introduced Lolium L. and Trifolium L. species, are arguably the most productive grazing lands in the world. However, these areas are vulnerable to destructive invasive pest species. Of these, three of the most damaging pests are weevils (Coleoptera: Curculionidae) that have relatively recently been controlled by three different introduced parasitoids, all belonging to the genus Microctonus Wesmael (Hymenoptera: Braconidae). Arguably that these introduced parasitoids have been highly effective is probably because they, like many of the exotic pest species, have benefited from enemy release. Parasitism has been so intense that, very unusually, one of the weevils has now evolved resistance to its parthenogenetic parasitoid. This review argues that New Zealand’s high exotic pasture pest burden is attributable to a lack of pasture plant and natural enemy diversity that presents little biotic resistance to invasive species. There is a native natural enemy fauna in New Zealand that has evolved over millions of years of geographical isolation. However, these species remain in their indigenous ecosystems and, therefore, play a minimal role in creating biotic resistance in the country’s exotic ecosystems. For clear ecological reasons relating to the nature of New Zealand pastures, importation biological control can work extremely well. Conversely, conservation biological control is less likely to be effective than elsewhere.17 pagesPrinten© The Author(s) 2020. Published by Oxford University Press on behalf of Entomological Society of America.exotic weevil pestsNew Zealand pasturebiotic resistance importation biocontrolconservation biocontrolAnimalsWeevilsWaspsInsect ControlPest Control, BiologicalNew ZealandIntroduced SpeciesJournal Article10.1093/jisesa/ieaa018ANZSRC::070308 Crop and Pasture Protection (Pests, Diseases and Weeds)ANZSRC::050103 Invasive Species Ecology1536-2442ANZSRC::3109 Zoologyhttps://creativecommons.org/licenses/by/4.0/Attribution