Council seeks release of weevils to combat invasive plant
Posted on Thursday, 10 November 2011 12:02 p.m.
Environment Southland and the National Biocontrol Collective are pursuing the release of two Chilean weevils to help stop the advance of the invasive plant Darwin’s barberry.
Environment Southland Senior Biosecurity Officer Randall Milne said the council will make an application to the Environmental Protection Authority in January for the introduction and release of the weevils because the plant was deemed a significant threat to indigenous plant life.
The plant can also invade pastoral areas impacting on productivity, he said.
Darwin’s barberry was originally introduced to New Zealand as an ornamental plant but has spread because birds disperse its seeds.
It can be found on Stewart Island, where an eradication programme has been in progress since 2001, and it has also spread out to all points of the compass in Southland.
In native shrublands and forests the plant grows and spreads aggressively, outcompeting native species, Mr Milne said.
As part of the joint effort between Environment Southland and the National Biocontrol Collective, the Council will make an application to the Environmental Protection Authority to allow for the introduction of the weevils to halt its advance.
The weevils target the flower buds and seeds reducing the distribution capabilities of Darwin’s barberry.
“They won’t kill the plants but they can heavily reduce seed production, affecting future spread,” Mr Milne said.
Experiments conducted in Chile have proven the weevils to be specific to Darwin's barberry and the application indicated that there was no significant risk to other species in New Zealand, Mr Milne said.
The EPA will weigh up the risks and benefits of introducing the weevils into New Zealand, and call for public submissions on the proposal.
- Darwin’s barberry is an evergreen shrub with small shiny dark green leaves that have small spines.
- It has bright yellow/orange flowers in spring followed by green fruits that turn purple/black.
For more information, or to discuss the proposal, please contact Richard Hill who is preparing the application on behalf of Environment Southland and the National Biocontrol Collective.
He can be contacted at richard.hill@plantandfood.co.nz or by phone at 021 1376 919.
For more information on Darwin's barberry in Southland contact Randall Milne at Environment Southland.
Environment Southland is the brand name of Southland Regional Council.