Pre-introductory risk assessment studies of Gonatocerus ashmeadi (Hymenoptera: Mymaridae) for use as a classical biological control agent against Homalodisca vitripennis (Hemiptera: Cicadellidae) in the Society Islands of French Polynesia

Homalodisca vitripennis (Germar) ( H. coagulata [Say]) (Hemiptera: Cicadellidae) invaded French Polynesia in 1999. A classical biological control program against H. vitripennis was initiated in 2004 aiming to introduce the exotic egg parasitoid Gonatocerus ashmeadi (Girault) (Hymenoptera: Mymaridae) to the Society Islands archipelago. Prior to any release, two risks were assessed: (a) continued uncontrolled H. vitripennis spread and proliferation in French Polynesia, and (b) non-target impacts by G. ashmeadi on indigenous French Polynesian cicadellids. The primary risk of H. vitripennis is its potential to vector the lethal plant bacterium, Xylella fastidiosa. While the presence of X. fastidiosa in French Polynesia has not yet been demonstrated, the presence of uncontrolled H. vitripennis greatly elevates the risk of a disease outbreak and thus represents a major threat for numerous plant species. Assessing the risk of G. ashmead