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An application to release the beetle Freudeita cf. cupripennis (Chrysomelidae) as a control agent for moth plant was approve in May 2019.

Image – Carolyn Lewis

The EPA decision document and other application documents can be found on EPA's website. 

Background

The application will be submitted by Waikato Regional Council, acting on behalf of the National Biocontrol Collective, a consortium of regional councils and the Department of Conservation. The Collective funds the development of weed biocontrol programmes in New Zealand. Landcare Research is the science provider for this development.

In its native range moth plant is considered to be an ornamental, industrial and medicinal plant but in its exotic range these benefits are heavily outweighed by its environmental impact. In New Zealand moth plant climbs over shrubs and small trees, smothering and breaking them down. It also spreads over the ground, shading out regenerating seedlings and low native vegetation. Moth plant is known from intact and disturbed forest and forest margins, tracks, coastline, cliffs, riparian margins, shrublands, mangroves, inshore and offshore islands; almost any frost-free habitat.

Both fruits and stems exude a caustic milky sap when broken.  This white latex is sticky, and causes skin or eye irritation in susceptible people.  The latex is poisonous (Landcare Research accessed 2011) and ingestion of the foliage of Araujia hortorum can cause gastrointestinal symptoms such as nausea, vomiting and diarrhoea. Other plant parts including seeds have been reported as toxic to poultry and cattle in Australia, though it is not often eaten and cases of poisoning are not common.

For more information about moth plant see:

The moth plant beetle is the second agent to be developed for this weed.  EPA approved the release of the moth plant rust Puccinia araujiae in 2015.  The larvae of the moth plant beetle feed on the roots of the weed, and this attack will complement the rust fungus which damages the leaves and stems. The rust has not yet been released.  The fly Toxotrypana australis is also being considered as a control agent. Larvae of this species destroy seeds developing in moth plant pods.

Identification and assessment of risks, costs and benefits

The potential risks, costs and benefits resulting from biological control of moth plant and the introduction of the beetle were formally identified and addressed in 2011 when the application to introduce Colaspis argentinensis was presented.  That application can be found on EPA's website.

The same information will be provided to EPA in this application. The significant effects that will be addressed in detail in the application are highlighted in this file:

The key potential adverse effects are the risk of:

  • direct damage to valued garden ornamentals especially tweedia
  • direct damage to native plants
  • indirect effects on flora and fauna as a result of disruption of ecological relationships

Moth plant belongs to the sub family Asclepiadoidieae of the family Apocynaceae. This was previously a separate family Asclepiadaceae.  There are no native species in this sub-family, and the application will present evidence that no native species will be at risk from this rust. Several ornamental species are related to moth plants, notably tweedia (Oxypetalum coeruleum).  This is particularly valued by those fostering butterflies such as monarchs.  Tests indicate that this plant could be at risk from incidental attack by Freudeita cf. cupripennis.  The social and economic costs associated with possible attack on tweedia were canvassed and addressed in the previous application, and in the EPA decision. The results of that consultation will be repeated in this application.

Because the beetle is almost host specific, population densities capable of interacting significantly with other plants or animals will only be found in close proximity to moth plant. Mechanisms for interaction are limited. As a result, no significant disturbance of ecological relationships is expected in New Zealand.

Pre-application consultation with Iwi

Consultation was undertaken before Freudeita cupripennis was first approved for release in 2011 (as C. argentinensis). No additional consultation has been undertaken for this re-application. The outcome of previous consultations will be presented in the new application. Members of Te Herenga, the EPA's national network, were contacted in July 2018, and informed of the National Biocontrol Collective's plans to re-apply to EPA to introduce the beetle for biological control of moth plant.

EPA convened a reference group from Te Herenga to meet and discuss the issues surrounding the proposed applications.  The reference group's report to EPA will be found here, and the findings will inform the application.

Pre-application consultation with other organisations

Other organisations were consulted in the course of preparing the successful 2011 (C. argentinensis) and 2015 (P. araujiae) applications.  No further consultation is planned to support this application. Those consulted in 2011 and 2015 included:

  • Nursery and Garden Industry New Zealand
  • Regional Councils
  • Royal Forest and Bird Protection Society of New Zealand
  • Department of Conservation staff
  • QEII National Trust
  • NZ Landcare Trust

Summary of responses:

Key documents

Reports on host-range determination

Safety issues are paramount in the minds of biocontrol of weeds researchers. Researchers rigorously test all proposed agents to assess the risk of damage to non-target plants. A set of procedures helps researchers choose a suitable shortlist of test plants, and this methodology is now well-accepted internationally. The results of host range testing conducted on the moth plant rust will be fully discussed in the application. The report of these results can be found here:

The unpublished report by will be peer reviewed and that review will be provided to EPA.

Cited references

Waipara, N.W., Winks, C.J., Gianotti, A.F., Villamil, C.B., Villamil, S.C., Delhey, R., Kiehr, M., Traversa, M.G., Carpintero, D.L. (2006) Surveys for potential biocontrol agents for moth plant in New Zealand and Argentina. New Zealand Plant Protection 59: 1-6.

Winks C.J., Fowler, S.V., (2000) Prospects for biological control of moth plant, Araujia sericifera Asclepiadaceae). Landcare Research Contract Report LC9900/100. Landcare Research, Lincoln, New Zealand. 18 p.

Key contact