Skip to content

Biological control

http://www.gw.govt.nz/biological-control

Biological control

Updated 17 March 2020 10:59am

Most pest plants have arrived in New Zealand without their natural enemies that may have kept them in check in their own countries.

Biological control or 'biocontrol' involves bringing some of those natural enemies to New Zealand to help control the plant. Biocontrol organisms are usually insects but can also be animals, rusts or viruses.

Biocontrol agents provide assistance in the control of pest plants that are widespread. It is a very long term approach to pest control.

Before any new organism is brought into New Zealand, strict testing procedures are followed, often over a period of years, to ensure that the new organism poses no risk to valued species.

The biocontrol agent has to be proven to attack only the pest plant and no other plant species.

Buddleia weevil larvae

Manaaki Whenua Landcare Research undertakes the research and trialling of such biocontrol organisms which are then released by either regional council or Department of Conservation (DOC) staff (after approval from the Environmental Protection Authority (EPA)). Release sites are studied further to ascertain the success of the release and to guide future releases.

Greater Wellington contributes towards the biological control collective which includes the majority of regional councils, DOC and several district councils. Greater Wellington biosecurity officers currently release biocontrol agents in the Wellington region. When agent populations are high enough, they may distribute them on to new sites.

Biocontrol agents released in the Wellington Region

Pest plant and biocontrol agents
First released
Total number of known sites
Overall agent status

Boneseed agents

Boneseed leaf roller

2007

8

No evidence of population establishing

Broom agents

Broom gall mite

2009

800+

Agent established

Broom leaf beetle

2009

3

We are unsure if the agent has established a population yet

Broom psyllid

1995

1000+

Now widespread in our region

Broom seed beetle

1994

600+

Now widespread in our region

Broom shoot moth

2008

3

We are unsure if agent has established a population yet

Buddleia agents

Buddleia leaf weevil

2007

100+

Agent established and becoming widespread

Darwin’s barberry agents

Darwin’s barberry seed weevil

2016

4

We are unsure if the agent has established a population yet

Gorse agents

Gorse colonial hard shoot moth

2002

5

Agent failed to establish any populations in our region

Gorse pod moth

1997

abundant

Now widespread in our region

Gorse soft shoot moth

2007

12

We are unsure if the agent has established a population yet

Gorse spider mite

1989

abundant

Now widespread in our region

Gorse thrips

1990

abundant

Now widespread in our region

Japanese Honeysuckle

Japanese Honshu white admiral butterfly

2017

7

We are unsure if the agent has established a population yet

Mistflower agents

Mistflower gall fly

2001

2

Agent established

Mistflower fungus

2009

1

Agent established

Old man’s beard agents

Old man’s beard leaf fungus

1997

3

Agent failed to establish any populations in our region

Old man’s beard leaf miner

1995

abundant

Now widespread in our region

Old man’s beard sawfly

2002

2

Agent failed to establish any populations in our region

Privet agents

Privet lace bug

2015

-

Agent failed to establish any populations in our region

Ragwort agents

Cinnabar moth

2006

abundant

Now widespread in our region

Ragwort plume moth

2012

6

Agent established

Ragwort flea beetle

1988

abundant

Now widespread in our region

Thistle agents

Californian thistle flea beetle

1994

2

Agent failed to establish any populations in our region

Californian thistle gall fly

2006

1

Agent failed to establish any populations in our region

Californian thistle leaf beetle

1993

2

Agent failed to establish any populations in our region

Californian thistle stem miner

2010

2

We are unsure if the agent has established a population yet

Green thistle beetle

2008

229

Established and becoming widespread

Nodding thistle receptacle weevil

1972

9

Now widespread in our region

Nodding thistle crown weevil

1990

4

Agent established

Nodding thistle gall fly

2005

12

Agent established

Scotch thistle gall fly

2005

79

Agent established

Tradescantia agents

Tradescantia leaf beetle

2011

9

Agent established

Tradescantia stem beetle

2012

10

We are unsure if the agent has established a population yet

Tradescantia tip beetle

2013

7

We are unsure if the agent has established a population yet

Tradescantia yellow leaf spot fungus

2018

5

We are unsure if the agent has established a population yet

TOTALS:

 

3000+

 

Biocontrol agents are currently being researched for a wide range of common pest plants including banana passionfruit, wild ginger, Japanese honeysuckle and Darwin's barberry.

For more information contact us on 0800 496 734, email pest.plants@gw.govt.nz or visit the Landcare Research website.