Rationale for release of the Irish strain of Microctonus aethiopoides for biocontrol of clover root weevil

Abstract

A European biotype of Microctonus aethiopoides was identified as the best candidate biocontrol agent for Sitona lepidus a serious New Zealand pasture pest A Moroccan biotype was already present throughout the country and hence there was no requirement to obtain Hazardous Substances and New Organisms (HSNO) Act approval to release new biotypes However as research had shown mating between the two biotypes produced hybrids with poor efficacy against target hosts and that the Moroccan biotype attacked several native weevil genera serious reservations were held about introducing the European biotype Concerns were overcome with the identification of a parthenogenetic strain of European M aethiopoides from Ireland which has little risk of hybridisation and a narrower host range than the Moroccan biotype Following regulation of M aethiopoides as a risk species this strain was considered to be a new organism Approval was sought and gained under the HSNO Act to release the strain