The gall-forming wasp would lay its eggs in the Sydney Golden Wattle flower buds, inducing abnormal growths (galls) that prevent flowers from forming and seed production. Photo / Supplied
The gall-forming wasp would lay its eggs in the Sydney Golden Wattle flower buds, inducing abnormal growths (galls) that prevent flowers from forming and seed production. Photo / Supplied
A decision on whether to introduce a species of wasp to control the spread of an invasive plant on Whanganui and New Zealand coasts is pending.
Horizons Regional Council submitted an application in August to the Environmental Protection Authority (EPA) to import and release the gall-forming wasp as biological control agents (BCA) for the Sydney golden wattle.
The Australian native plant was introduced to New Zealand before 1897 and has since spread invasively in some areas, including Whanganui coastlines.
EPA general manager of hazardous substances and new organisms Dr Chris Hill said the EPA had robust processes to assess and manage the risks of introducing new organisms into New Zealand.
"We have carefully considered social, cultural, economic and environmental risks and benefits and have recommended this application be approved," Hill said.
Horizons applied for the approval and release of the wasp on behalf of the National Biocontrol Collective, a group of regional and district councils from across New Zealand, and the Department of Conservation.
"Extensive testing has been carried out on the bud-galling wasp's behaviour and impact on native species in various countries, and this wasp only attacks three specific kinds of wattle," Hill said.
The wasp lays its eggs in flower buds, inducing abnormal growths (galls) that prevent flowers from forming and seed production.
Hill said based on this evidence, the EPA concluded the wasp would not significantly impact any native or valued species.
The EPA released a report last month summarising its findings on the potential effects of releasing the wasp.
Horizons Regional Council has applied to release the gall-forming wasp to control the spread of an invasive plant on Whanganui coasts. Photo / Supplied
"We found the BCA is highly likely to improve biodiversity by reducing Sydney golden wattle to the benefit of native flora, which in turn will attract native fauna and restore the soil composition," the report said.
"The BCA will facilitate access to previously infested areas and by increasing biodiversity."
The EPA identified no direct or tangible risks to public health from the release of the wasp, the report said.
The assessment said the benefits from the release of the wasp would likely allow native species to gradually replace the wattle.
The application was open for public submissions in September.
The EPA received 49 submissions, 31 of which supported the application, two neither supported nor opposed and 16 opposed the application.
An opposed submitter from Wellington said "when are we going to learn that introducing non-native species ends up having a negative effect on our ecosystem?"
Another opposed submitter from Canterbury expressed concern, as someone who grew wattle and foliage for a living, about damage the wasps could do to other plant species.
Hill said the decision-making committee was considering all the information received for the application, including submissions from the public, and would release its decision no later than December 14.
The decision-making panel was appointed by the EPA Hazardous Substances and New Organisms Committee and, for this application, members were Greg Percival (chairman), Dr Ngaire Phillips and Dr Derek Belton.
