Myrtle rust

Myrtle rust is a serious fungal disease that affects plants in the myrtle family. Plants in this family include the iconic pōhutukawa, mānuka and rātā as well as some common garden plants such as ramarama and lilly pilly.

If you think you've seen myrtle rust, don't touch it, take a photo, and call 0800 80 99 66.

UPDATE

1 May 2018

A new approach is being taken to manage myrtle rust in New Zealand.

Background

– Myrtle rust on ramarama (Lophymyrtus bullata)
Myrtle rust on ramarama (Lophomyrtus bullata)

Myrtle rust (Austropuccinia psidii) has been found in 11 North Island regions – Auckland, Thames-Coromandel, Waikato, Bay of Plenty, Taranaki, Taupo, Gisborne, Manawatu, Wellington and Tasman. It is also widespread on Raoul Island in the Kermadec group north-east of Northland.

The fungus attacks plants belonging to the Myrtaceae family, also known as the myrtle family. It is found in many parts of the world including New Caledonia and all along Australia's eastern seaboard.

Spores can spread easily

Upper and lower surface of same leaf of pohutukawa (Metrosideros). Red/brown lesions with pustules on top, orange/yellow pustules underneath
Upper and lower surface of same leaf of pōhutukawa (Metrosideros). Red/brown lesions with pustules on top, orange/yellow pustules underneath

Myrtle rust spores are microscopic and can easily spread across large distances by wind, or via insects, birds, people, or machinery.

Evidence suggests the fungus arrived in New Zealand carried by strong winds from Australia where it is well established all down the eastern coast.

The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC), with the help of local iwi, the nursery industry, and local authorities ran a year long operation to attempt to contain and control myrtle rust and determine the extent of its spread.

What you can do

Look out for signs of myrtle rust. If you think you see the symptoms of myrtle rust:

  • don't touch it
  • call the MPI Exotic Pest and Disease Hotline immediately on 0800 80 99 66
  • if you have a camera or phone camera, take clear photos, including the whole plant, the whole affected leaf, and a close-up of the spores or affected area of the plant.

Remember, don't touch it or try to collect samples as this may increase the spread of the disease.

Do not attempt to self-treat trees and plants with fungicide, either for a cure or to try to prevent myrtle rust infection. We are still building a picture of whereabouts the disease is present nationally, and if people use preventative sprays, it could suppress symptoms, and prevent us from making the best management decisions for the country.

Identifying myrtle rust

List of plants in the myrtle family [PDF, 477 KB]

Lower and upper surface of same pohutukawa (Metrosideros) leaf. Red/brown lesions with pustules on top; orange/yellow pustules underneath
Lower and upper surface of same pōhutukawa (Metrosideros) leaf. Red/brown lesions with pustules on top; orange/yellow pustules underneath

Symptoms to look out for

Raised yellow pustules and red/brown lesions on lilly pilly (Syzygium)
Raised yellow pustules and red/brown lesions on lilly pilly (Syzygium)
Raised yellow pustules and red/brown lesions on bottle brush (Callistemon) leaves and stem
Raised yellow pustules and red/brown lesions on bottle brush (Callistemon) leaves and stem.

It generally attacks soft, new growth, including:

  • leaf surfaces
  • shoots and buds
  • flowers, and fruit.

Symptoms to look out for on myrtle plants are:

  • bright yellow powdery eruptions appearing on the underside of the leaf (young infection)
  • bright yellow powdery eruptions on both sides of the leaf (mature infection)
  • brown/grey rust pustules (older spores) on older lesions.
  • grey, 'fuzzy' spore growth on undersides of leaves.

Some leaves may become buckled or twisted and die off.

Pictures of some types of trees that may be affected

Myrtle family plants
Five examples of plants out of the 104 species in the myrtle family that grow in New Zealand. Clockwise from top left: pōhutukawa, mānuka, bottlebrush, ramarama and blue gum.

Videos on YouTube featuring 'Bug Man' Ruud Kleinpaste

Advice for specific groups

Our information sheet has specific advice for:

  • beekeepers
  • feijoa growers
  • other orchardists
  • nursery owners
  • home gardeners
  • walkers and trampers.

Download the information sheet [PDF, 522 KB]

Risk to New Zealand

Myrtle rust could affect iconic New Zealand plants including pōhutukawa, mānuka, rātā, kānuka, swamp maire and ramarama, as well as commercially-grown species such as eucalyptus.

Severe infestations can kill affected plants and have long-term impacts on the regeneration of young plants and seedlings.

It is not yet known how this disease will affect New Zealand species. Overseas its impacts have varied widely from country to country and plant species to species.

What MPI is doing from 1 May 2018

Myrtle rust has now spread to many parts of New Zealand that have a suitable climate. We also have limited tools available to manage the disease. From 1 May 2018, we have adopted a new approach which involves:

  • scaling back our operations and stopping surveillance in areas that are known to be infected
  • conducting surveillance only in new areas where myrtle rust has not yet become established
  • treating new infections only at sites with isolated low-level infections where we can quickly suppress symptoms and attempt local elimination in the short term
  • lifting movement restrictions in known infected areas
  • allowing landowners with myrtle rust infection on their property to decide how to manage their plants
  • issuing permissions to landowners in known infected areas allowing them to dispose of infected myrtle plant material in local landfills as general waste
  • working with DOC, iwi, the nursery industry, scientists, and local authorities to explore options for future management.

Why are we changing our approach?

It is clear that eradication of myrtle rust from New Zealand is not feasible using the tools we have available. Restricting human activity at this time will not make a significant contribution to slowing the spread of the disease. Focusing our efforts on surveillance in areas where myrtle rust has not been found and undertaking spray and tree removal only at sites with isolated low-level infections will allow us to quickly suppress symptoms and attempt local elimination in these areas in the short term.

At the same time we are investing significantly in scientific research to develop new tools, build understanding of myrtle rust and explore possible treatment and management options. Regardless of where you live, myrtle rust continues to be considered an unwanted organism throughout New Zealand. We continue to encourage landowners to regularly check the health of their myrtle plants.

Our approach in areas where myrtle rust hasn't been found

We encourage residents in these areas who see signs of myrtle rust to call our Biosecurity Hotline (0800 80 99 66).

Our surveillance effort will target areas where myrtle rust has not become established.

Restrictions may still be used where infection levels are extremely low.

Our approach in known infected areas

We’ll be contacting affected owners and giving them self-management packs. The packs will:

  • set out their responsibilities under the Biosecurity Act
  • give advice about maintaining their property to minimise the spread of disease.

Other long-term planning activities

We are engaging with iwi and councils in affected regions to look at ways that MPI can support communities who wish to conduct their own biosecurity activities. We are also developing a programme to provide training to support community-based surveillance for interested groups in their regions. A long-term strategy will be developed over the next 2 years, with input sought from groups including iwi, councils, industry and DOC.

Research programme

MPI has commissioned a $3.4 million research programme made up of more than 20 specific projects. The projects will be done over 2 years to June 2019.

Summary of projects

  • Lincoln University has completed an impact assessment under various outbreak scenarios.
  • NIWA (National Institute of Water and Atmospheric Research) has completed climate modelling on the potential risk of myrtle rust spread from Australia and Raoul Island.
  • MPI's Plant Health and Environment Laboratory and the Food and Environment Agency (UK) have developed a rapid field monitoring tool that has been used in the myrtle rust response on mainland New Zealand.
  • New Zealand Plant Producers Inc is scoping and developing a plant production biosecurity scheme for nurseries and garden centres.

Scion Research projects

Scion Research is working on several projects to:

  • build engagement and social licence through better understanding of potential options around the long-term management of myrtle rust
  • undertake a desktop review of potential disease control tools
  • map myrtle species
  • develop and test possible surveillance and management tools
  • scope a breeding programme for resistant myrtle species
  • develop monitoring approaches to assess environmental, economic, social and cultural impacts over time, and to understand the impact of potential management actions.

Projects yet to start

There are several projects that as at 6 April 2018 have yet to begin. They're on:

  • regular climate modelling to help inform decisions around geographical risks and the deployment of field surveillance teams
  • assessment of spore transmission risk via bees and beehives
  • identification of resistant and susceptible myrtle species and environmental factors that affect susceptibility
  • identification of periods when fungus symptoms are not visible
  • development of  a seed banking and germplasm research strategy
  • assessment of the potential risks that other types of myrtle rust could present to New Zealand
  • investigating the best possible methods to store and preserve myrtle seeds (some myrtle species produce very low amounts of seed that can’t be grown after being  stored).

2018 media releases

19 March 2018

27 February 2018

2017 media releases

1 December 2017

The fungal plant disease myrtle rust has been found in Lower Hutt, north of Wellington.

27 November 2017

A second location of myrtle rust infection has been found in Auckland.

23 November 2017

The fungal plant disease myrtle rust has been found for the first time in the Auckland region.

31 October 2017

MPI continues to encourage people to keep an eye out for the harmful plant disease myrtle rust and report any signs of the disease.

Earlier media releases

8 September 28 June  21 June  13 June
9 June 6 June 2 June 31 May
30 May 29 May 26 May 25 May
24 May 23 May 22 May 20 May
19 May 18 May 17 May 15 May
12 May 11 May 10 May 9 May
8 May (pm) 8 May (am) 5 May 4 April
NZ Government myrtle rust media release (4 May) - Beehive website

Find out more

Who to contact

If you have questions about myrtle rust, email info@mpi.govt.nz

Last reviewed:
Has this been useful? Give us your feedback