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.
On this page:
- What you can do
- Identifying myrtle rust
- Risk to NZ
- What MPI is doing
- Find out more
1 May 2018 – New approach being taken to manage myrtle rust
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
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.
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.
List of plants in the myrtle family [PDF, 477 KB]
Symptoms to look out for
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
Videos on YouTube featuring 'Bug Man' Ruud Kleinpaste
All myrtle species in New Zealand are at some risk from myrtle rust infection, but there are actions you can take to give your myrtle plants the best chance.
Planting and restoration programmes
If you are planning large-scale planting and restoration programmes using myrtle plants, follow the advice in Managing native plants susceptible to myrtle rust: Guide for large-scale planting and restoration programmes. This guide was developed in collaboration with the Department of Conservation and Council representatives.
Specific groups that may have contact with myrtle species
Our information sheet has specific advice for:
- feijoa growers
- other orchardists
- nursery owners
- home gardeners
- walkers and trampers.
Download the information sheet [PDF, 522 KB]
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.
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 is vital as it will result in a better understanding of myrtle rust that could help us limit the impact on our myrtle plants for future generations. MPI has commissioned a comprehensive research programme made up of more than 20 specific projects and valued at over $4.5 million. A bid for further research will be requested from Cabinet later in 2018.
The projects will be done over 2 years to June 2019.
Summary of research projects
New Zealand Plant Producers Inc. is scoping and developing a plant production biosecurity scheme for nurseries and garden centres.
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.
Plant & Food Research, in collaboration with Scion Research, Manaaki Whenua Landcare Research, Kew Gardens, and Australian myrtle rust researchers, also has several inter-linked research projects underway including
- the identification of native and important exotic host species susceptibility to myrtle rust, including variability within species
- identification of asymptomatic periods
- assessment of the risk of introduction of other myrtle rust biotypes to New Zealand
- initial identification of genetic markers linked to resistance
- resistant plants and their potential relationship with endophyte populations
- A. psidii de novo genome sequencing; and, a national seed banking and germplasm research strategy.
Plant & Food Research is also investigating seed storage methodologies and protocols for non-orthodox myrtle species, which cannot be stored by conventional methods. The research explores whether seeds or other tissues can be stored using cryopreservation methods and then subsequently propagated successfully.
Karin van de Walt at Wellington Gardens is undertaking a PhD on non-conventional preservation techniques for swamp maire/maire tawake (Syzygium maire), supported by Plant & Food Research. She is also undertaking a trial cryopreservation conservation initiative for Bartlett’s rata/rata moehau (Metrosideros bartlettii), in collaboration with Otari Native Botanic Garden, Te Papa and Auckland University. Wellington Gardens is studying the seed characteristics and seed storage behaviours of ramarama (Lophomyrtus bullata) and NZ myrtle/rohutu (L. obcordata), to ensure that these fleshy-seeded species are stored at optimal conditions.
MPI, in collaboration with the New South Wales Dept. of Primary Industries, is investigating alternative fungicides and possible non-target impacts from the current fungicides being used for the treatment/control of myrtle rust infections.
Completed research projects
Lincoln University completed a non-market value impact assessment, of the potential losses to biodiversity and ecosystem values under low-, medium-, and high-impact disease outbreak scenarios.
The NZ Institute of Economic Research completed an economic impact assessment of the potential economic impact of myrtle rust on industry sectors on mainland
NIWA (National Institute of Water and Atmospheric Research), in association with Plant & Food Research, developed a climate model of the potential risk of myrtle rust spreading from Australia and Raoul Island, and around New Zealand.
MPI's Plant Health and Environment Laboratory and the Food and Environment Agency (UK) developed a rapid field monitoring tool that has been used in the myrtle rust response on mainland New Zealand.
Plant & Food Research completed an assessment of myrtle rust spore transmission risk via bees and beehives. The research shows that myrtle rust spores can survive for some time within beehives, but more research needs to be done to understand any potential risk that bees might pose to the spread of the fungus.
The research does not provide enough evidence to justify widespread restrictions on the movement of beehives, which would have significant financial implications for beekeepers, the honey industry and primary industries that rely on bee pollination.
- Media releases for myrtle rust from 2017 and 2018
- Subscribe to myrtle rust updates
- Myrtle rust A4 Poster [PDF, 724 KB]
- Read more about myrtle rust
- Download the myrtle rust fact sheet [PDF, 1.5 MB]
- Myrtle rust – DOC website
Who to contact
If you have questions about myrtle rust, email email@example.com
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