Biological control agents
We explain what biological control agents are, how they work, and our role in ensuring they are safe for Aotearoa New Zealand.
We explain what biological control agents are, how they work, and our role in ensuring they are safe for Aotearoa New Zealand.
Biological control (biocontrol) uses one living organism to control another. It is a way to control weeds and pests by introducing a natural enemy or predator into the environment.
The number of introduced plant species have dramatically increased over the years. Some of these plants are already weeds or becoming weeds. Weeds invade sensitive or native habitats, or productive land. Similarly, many insects hitchhiked to New Zealand with the development of trades, and some species negatively impact the primary industries and the native environment.
Different organisms such as beetles, wasps, mites and fungi can be used as biocontrol agents to stop introduced weeds and insects from damaging natural habitats, taonga species, and farms in an environmentally friendly way.
The underlying principles of biocontrol are safety, self-sustainability, and cost-effectiveness.
Biocontrol can be cheap over the long term and is the least damaging way to target weeds and pest insects over a long period of time. They are effective over widespread areas, and in areas that are hard to reach like hilly, bush-covered terrain. However, the action of a biocontrol agent is unlikely to fully eliminate a weed or a pest insect. Normally a combination of control methods is necessary.
Most plants and insects introduced into New Zealand do not have the same natural enemies that they have at home. This means they can flourish here, as there is nothing to naturally keep them under control. Over time they can turn into weeds, pests or predators.
Most organisms considered as potential biocontrol agents are specific to their hosts, making them unlikely to damage non-target plants and animals. In comparison, agrichemicals are generally less specific and can also kill non-target plants and animals.
A lot of research goes into testing biocontrol agents before they are released. Safety of the people and the environment is paramount. Research of new biocontrol agents can take 5 to 10 years, and can be costly to undertake.
Researchers usually only consider biocontrol agents that are the natural enemies of target weeds and pests, so it is unlikely the biocontrol agent will attack and harm non-target plants and animals. Researchers assess the risk of damage to non-target plants using procedures endorsed internationally.
These before and after pictures show how effective biocontrol agents can be. The first set of pictures shows biocontrol success in Tongariro National Park – the weed is heather (Culluna vulgaris) and the agent is the heather beetle (Lochmaea suturalis).
Biocontrol success in Tongariro National Park. Image credit: Manaaki Whenua Landcare Research
The second set of pictures shows the success story of a fungus (Kordyana brasiliensis) that attacks the weed Tradescantia (Tradescantia fluminensis).
Success story of a fungus that attacks the weed Tradescantia. Image credit: Ben Wolf, Waikato
Our approval is required to release a new biocontrol agent into the environment. Applicants should make a case to the EPA addressing all the pros and cons.
The investigative process is long and rigorous. We invite the public to participate in this process by making submissions and attending hearings (if a hearing is needed). We also incorporate mātauranga Māori into our decision-making as Māori believe in kaitiakitanga – preserving the environment for future generations.
Our risk assessment weighs up environmental, economic, societal, human health, and cultural values into our decision-making framework.
If we grant approval, biocontrol agents first come into a containment facility where they are bred in a controlled environment.
Our approval is also required to introduce biocontrol agents into a containment facility, or to release them into the environment.
Read about approvals to release biocontrol agents on the Manaaki Whenua Landcare website
Any approval to import a plant or animal for release or to release an organism from containment lapses 5 years after the date of the approval, unless the organism is already released into the environment, or an extension of the time limit is granted.
Check with us or the applicant to confirm whether an organism has been released yet before using any of these approvals.
The biocontrol agents in the table below fall under one of the three approval statuses.
Pest (Latin name) | Pest type | Biocontrol agent type | BCA's Latin name | Approval date | Approval status |
---|---|---|---|---|---|
Greenhouse thrips (Heliothrips haemorrhoidalis) | Insect | Parasitoid wasp | Thripobius semiluteus | June 2000 | Approved |
Obscure mealybug (Pseudococcus viburni) | Insect | Parasitoid wasp | Pseudaphycus maculipennis | August 2000 | Approved |
Clover root weevil (Sitona lepidus) | Insect | Parasitic wasp | Microctonus aethiopoides | November 2005 | Approved with controls |
Gum leaf skeletoniser (Uraba lugens) | Insect | Parasitic wasps | Cotesia urabae; Dolichogenidea eucalypti; Eriborus species; Euplectrus species | July 2010 | Approved |
Codling moth (Cydia pomonella) | Insect | Parasitoid wasp | Mastrus ridens | June 2012 | Approved |
Tomato potato psyllid (Bactericera cockerelli) | Insect | Parasitic wasp | Tamarixia triozae | June 2016 | Approved |
Brown marmorated stink bug (Halyomorpha halys) | Insect | Parasitic wasp | Trissolcus japonicus | August 2018 | Approved with controls |
Eucalyptus tortoise beetle (Paropsis charybdis) | Insect | Parasitoid wasp | Eadya daenerys | February 2019 | Under approval until 25 February 2024 |
Giant willow aphid (Tuberolachnus salignus) | Insect | Parasitoid wasp | Pauesia nigrovaria | November 2019 | Under approval until 29 November 2024 |
Invasive German and common wasps (Vespula germanica and vulgaris) | Insect | Beetle | Metoecus paradoxus | February 2021 | Under approval until 5 February 2026 |
Invasive German and common wasps (Vespula germanica and vulgaris) | Insect | Hoverfly | Volucella inanis | February 2021 | Under approval until 5 February 2026 |
Mist flower (Argeratina riparia) | Weed | Fly | Procecidochares alani | September 2000 | Approved |
Hawkweed (Hieracium spp.) | Weed | Flies | Macrolabis pilosellae; Cheilosia urbana; C. psilophthalma | June 2001 | Approved |
Boneseed (Chrysanthemoides monilifera subsp. monilifera) | Weed | Moth | Tortrix s.l. sp. chrysanthemoides | February 2005 | Approved |
Buddleia (Buddleja davidii) | Weed | Weevil | Cleopus japonicus | November 2005 | Approved |
Ragwort (Senecio jacobaea) | Weed | Moths | Cochylis atricapitana; Platyptilia isodactyla | December 2005 | Approved |
Broom (Cytisus scoparius) | Weed | Mite | Aceria genistae | July 2006 | Approved |
Broom (Cytisus scoparius) | Weed | Moth | Agonopterix assimilella | July 2006 | Approved with controls |
Broom (Cytisus scoparius) | Weed | Beetle | Gonioctena olivacea | July 2006 | Approved with controls |
Californian thistle (Cirsium arvense) | Weed | Beetles | Cassida rubiginosa; Ceratapion onopordi | April 2007 | Approved |
Wandering willie (Tradescantia fluminensis) | Weed | Beetle | Neolema ogloblini | November 2008 | Approved |
Wandering willie (Tradescantia fluminensis) | Weed | Beetle | Neolema abbreviata; Lema basicostata | June 2011 | Approved |
Wandering willie (Tradescantia fluminensis) | Weed | Fungus | Kordyana sp. | January 2013 | Approved |
Woolly nightshade (Solanum mauritianum) | Weed | Lace bug | Gargaphia decoris | September 2009 | Approved |
Chilean needle grass (Nassella neesiana) | Weed | Rust fungus | Uromyces pencanus | June 2011 | Expired |
Common lantana (Lantana camara) | Weed | Rust fungi | Puccinia lantanae; Prospodium tubuculatum | April 2012 | Approved |
Darwin's barberry (Berberis darwinii) | Weed | Weevil | Anthonomus kuscheli | October 2012 | Under approval until 3 October 2022 |
Darwin's barberry (Berberis darwinii) | Weed | Weevil | Berberidicola exaratus | October 2012 | Approved |
Privet (Ligustrum spp.) | Weed | Lace bug | Leptophya hospita | May 2015 | Approved |
Japanese honeysuckle (Lonicera japonica) | Weed | Butterfly | Limenitis glorifica | August 2013 | Approved |
Japanese honeysuckle (Lonicera japonica) | Weed | Beetle | Oberea shirahatai | July 2015 | Approved |
Moth plant (Araujia hortorum) | Weed | Beetle | Colaspis argentinensis | December 2011 | Expired |
Moth plant (Araujia hortorum) | Weed | Rust fungus | Puccinia araujae | December 2015 | Expired |
Field horsetail (Equisetum arvense) | Weed | Weevil | Grypus equiseti | May 2016 | Approved |
Tutsan (Hypericum androsaemum) | Weed | Moth; beetle | Lathronympha strigana; Chrysolina abchasica | May 2016 | Approved |
Giant reed (Arundo donax) | Weed | Galling wasp; scale insect | Tetramesa romana; Rhizaspidiotus donacis | January 2017 | Approved |
Horehound (Marrubium vulgare) | Weed | Moth | Wheeleria spilodactylus; Chamaesphecia mysiniformis | September 2018 | Approved |
Old man's beard (Clematis vitalba) | Weed | Leaf-galling mite | Aceria vitalbae | October 2018 | Approved |
Moth plant (Araujia hortorum) | Weed | Beetle | Freudeita cf cupripennis | May 2019 | Approved |