BioControl (2009) 54, 485-495

Jérôme N. Petit, Mark S. Hoddle, Julie Grandgirard, George K. Roderick and Neil Davies (2009)
Successful spread of a biocontrol agent reveals a biosecurity failure: elucidating long distance invasion pathways for Gonatocerus ashmeadi in French Polynesia
BioControl 54 (4), 485-495
Abstract: Invasive species are generally detected in new ecosystems long after their first arrival, making it difficult to elucidate pathways leading to successful invasion. In this study, the dispersal of a classical biological control agent, the mymarid egg parasitoid Gonatocerus ashmeadi, was monitored across ten islands in three major island groups in French Polynesia from the exact moment of its introduction into Tahiti to combat the invasive pest Homalodisca vitripennis. Within 10 months, the parasitoid spread quickly from Tahiti to widely separated islands (up to 1,400 km from Tahiti); presumably through the transportation of plant material containing parasitized H. vitripennis eggs. Gonatocerus ashmeadi thus functioned as a 'biomarker', providing an informal audit of the effectiveness of inter-island quarantine measures designed to curb the accidental spread of noxious organisms. Survey results suggest that invasive organisms, like deliberately released biological control agents, can be unintentionally and rapidly transmitted across vast distances by humans. Furthermore, even remote islands appear to experience relentless pressure from invasive propagules associated with human travel. Implications of survey work documenting the spread and impact of G. ashmeadi are discussed within the context of biological control programs, non-target impacts, and biosecurity initiatives.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Jerome N. Petit, Mark S. Hoddle, George Roderick, Julie Grandgirard

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
classical biocontrol/new introduction
transmission/dispersal

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Homalodisca vitripennis		French Polynesia
Cosmocomoidea ashmeadi (parasitoid)	Homalodisca vitripennis		French Polynesia