Negative effects of strain hybridisation on the biocontrol agent Microctonus aethiopoides

Abstract

Clover root weevil Sitona lepidus remains a threat to New Zealands whiteclover based pastoral production system Unfortunately the New Zealandestablished strain of M aethiopoides (originally from Morocco) active against Sitona discoideus has been found to have no potential as a control agent against S lepidus It was therefore unexpected that a European strain of M aethiopoides was found to be highly active against the weevil This contribution examined the effect of Moroccan x European strain crosses on the value of M aethiopoides as a control agent of S discoideus and S lepidus It was found that such strain hybridisation led to significant reductions in the impact of this parasitoid species as a control agent against either S lepidus or S discoideus The widespread implications of this finding for biological control are discussed