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16 February 2006
Clover root weevil has been detected in the South Island near Christchurch
airport by AgResearch during a trap testing programme.
Clover root weevil, which causes significant pasture degradation, is already
very widely spread in the North Island.
Biosecurity New Zealand has commissioned an assessment into the economic
impacts of Clover Root Weevil from the New Zealand Institute of Economic
It looks at a variety of scenarios and concludes that clover damage caused by
Clover Root Weevil could cost the economy between $0.2 billion and $1 billion
annually if it was to spread nationwide. Currently, annual clover production is
estimated to add $3 billion to the national economy.
CRW was first detected on a Waikato dairy farm in 1996, but is thought to
have been in the country much longer. It has since been found in the Bay of
Plenty, Northland, Hawkes Bay, some parts of Taranaki and the Wairarapa. It is
likely to have been in the South Island for some time before discovery. No
eradication tools exist, and were they available, constant re-invasion from the
North Island would be likely and make eradication impractical. Affected farmers
have so far been able to mitigate the impacts principally by supplementary
application of nitrogen.
The Ministry of Agriculture Sustainable Farming Fund is providing $347,000
and other funders $327,000 over the next three years to improve information and
farmer knowledge about CRW. The project will focus on how farmers can maintain
pasture and profitability in the presence of CRW. It will use key people in the
pastoral sector to transfer research findings and solutions developed on-farm.
Research into understanding the impacts of CRW and methods for mitigating the
impacts has been ongoing for some time. That research has established the
biology of CRW in New Zealand, provided an assessment of impacts on pasture, and
assessed the resistance of CRW to a variety of cultivars. It has also resulted
in the identification and release of a promising biopesticide – the tiny
parasitic Irish wasp.
Media contact: Tina Nixon, Senior Communications Adviser, Biosecurity New
Zealand, 027 223 2789.