Detecting myrtle rust in New Zealand

This timeline follows the discovery of the fungal disease myrtle rust and its spread throughout New Zealand.

This timeline follows the discovery of the fungal disease myrtle rust (Austropuccinia psidii) and its spread throughout New Zealand. As of July 2018, the disease was present in all regions of the North Island apart from Hawke’s Bay. It is also present in the Tasman region of the South Island. A full transcript is underneath the timeline.

Transcript

Chronology of events

A brief sequence of events that follows the discovery and spread of myrtle rust.

Science collaboration

Scientific investigations often involve a range of organisations. Myrtle rust has environmental, commercial, cultural and societal impacts.

Chronology of events

4 April 2017 – Myrtle rust found on Raoul Island

Myrtle rust is found on Kermadec pōhutukawa trees. Raoul Island, in the Kermadec Islands, is part of New Zealand but its location is more than 1,000 km northeast of Northland. Access to the island is strictly controlled.

Image: Kermadec pōhutukawa. Tangatawhenua, iNaturalist, CC BY-NC 4.0

3 May 2017 – Myrtle rust found in New Zealand

Myrtle rust is found on mainland New Zealand for the first time. Tests confirm five pōhutukawa seedlings at a Kerikeri nursery have the disease. Experts use fungicide spray and restrict the movement of plants and people.

Image: MPI Biosecurity staff bury potting mix at an infected Kerikeri nursery. Department of Conservation, CC BY 4.0

17 May 2017 – Taranaki nursery discovery

A plant nursery in Waitara tests positive for the disease. MPI suggests that nurseries are the first to find myrtle rust due to careful monitoring.

20 May 2017 – More sites confirmed in Taranaki

Additional private and commercial properties in the region are infected. MPI considers the infectious spores have been carried in by the wind from Australia.

Image: Yellow spore clusters on a ramarama tree in Taranaki. Ministry for Primary Industries and licensed by MPI for reuse under the Creative Commons Attribution 4.0 International licence

23 May 2017 – Te Kūiti plant nursery tests positive

Plants from an infected nursery had been sold to a King Country nursery, spreading the disease. Restrictions are in place to prevent the on-sale of infected plants.

13 June 2017 – Private garden in Te Puke

Experts find the disease in a 25-year-old ramarama plant. There is no connection to the Northland or Taranaki sites, and no new plants have been put into the garden. This strengthens the windborne infection proposal.

21 June 2017 – 52 infection sites

MPI confirms 52 sites are infected with myrtle rust – 39 in Taranaki, four in Northland, seven in the Bay of Plenty and two in the Waikato. MPI continues to work with the Department of Conservation, local iwi, Te Puni Kōkiri and local councils to control the movement of plants, trees, fruit and garden waste from infected areas.

Image: Myrtle rust awareness poster. Ministry for Primary Industries and Department of Conservation – Te Papa Atawhai

8 September 2017 – Ōtorohanga detections

Ramarama trees on two Ōtorohanga properties test positive. Once again, there are no connections to plant nurseries or infected locations. As in other cases, the plants are destroyed and experts check all myrtle plants within a 500 m radius.

23 November 2017 – First Auckland find

Myrtle rust is found on hundreds of ramarama plants in a commercial property in West Auckland. MPI reports that ramarama and pōhutukawa appear to be the most susceptible species in New Zealand.

Image: Lower and upper surface of infected pōhutukawa leaves found in Northland. Ministry for Primary Industries and licensed by MPI for reuse under the Creative Commons Attribution 4.0 International licence

1 December 2017 – Myrtle rust detected in Lower Hutt

A 2 m high row of ramarama plants have their foliage sealed to prevent spore drift. After removal, the plant matter is deeply buried.

1 March 2018 – Department of Conservation land affected

Infected ramarama plants and large rātā trees are discovered on Department of Conservation land for the first time. The land is in northern Taranaki.

Image: Northern rātā tree. jacqui-nz, iNaturalist, CC BY-NC 4.0

19 March 2018 – Palmerston North infection

The disease is found in the Manawatū region for the first time. This brings the total number of identified properties to 409 across the North Island.

7 April 2018 – First South Island location

The Tasman region confirms two locations are infected. Authorities are not surprised as climate models identified the region at high risk from windborne spores from Australia. Myrtle rust has now been detected on 547 properties across nine regions.

1 May 2018 – A new approach

MPI announces it will adopt a new approach. Eradication is no longer considered feasible so the focus moves to managing the disease. The new emphasis will be on research to treat myrtle rust, boost resistance and improve collection for seed banking.

Image: Ramarama leaves, flowers and seeds. Engraving by Walter Hood Fitch for Curtis’s botanical magazine, 1854. Public domain.

9 October 2018 – Beehive movement restrictions

The Department of Conservation puts restrictions on all beehive movements on Public Conservation Land. Research indicates that bees may be a vector for myrtle rust.

14 January 2019 – Teliospore stage

Biosecurity New Zealand reports local myrtle rust produces a teliospore stage. This indicates the fungus is capable of sexual reproduction. It increases the risk to the country as it allows the fungi to adapt to new environments and possibly affect new hosts.

9 May 2019 – West Coast infection

The disease is confirmed in Greymouth, the first case found on the West Coast. The Department of Conservation wants the public to help with monitoring in this area as it may help to identify natural resistance in some plants.

7 December 2020 – First mature tree death

The first death of a native mature tree (a ramarama) due to myrtle rust infection is reported. This increases concerns that extinction for some native myrtles could become a reality.

21 January 2021 – Waitākere Ranges infection

Auckland Council announce that mrytle rust has infected one of the country's most highly susceptible native myrtles, Lophomyrtus bullata, commonly known as ramarama in the Waitākere Ranges. The species is nationally threatened, with its conservation status classified as critical.

Science collaboration

5 May 2017 – MPI and DOC co-ordinate response teams

The Ministry for Primary Industries and the Department of Conservation check 800 high-risk sites across the upper North Island. A response team in Wellington makes plans for future efforts.

Image: Biosecurity NZ staff checking for myrtle rust. Ministry for Primary Industries and licensed by MPI for reuse under the Creative Commons Attribution 4.0 International licence

20 May 2017 – Plant producers and industry partner protocols

The nursery industry adopts protocols to try and prevent the spread of myrtle rust. Protocols come from the government and from industry partners such as the New Zealand Plant Producers Incorporated.

13 June 2017 – DNA sequencing and bioinformatic data analysis

Having mapped mānuka’s genetic code in 2015, Plant & Food Research use bioinformatics to obtain more detailed understanding of mānuka’s genetic stocks using samples collected in collaboration with Manaaki Whenua – Landcare Research, the University of Waikato and key Māori partners.

Image: University of Waikato

15 June 2017 – New Zealand-Australia research

The Ministry of Business, Innovation and Employment funds science institutes in New Zealand and Australia to investigate the susceptibility of key species to myrtle rust, explore germplasm storage and develop detection systems.

21 June 2017 – Continued containment and control

The Ministry for Primary Industries continues to work with the Department of Conservation, local iwi, Te Puni Kōkiri and local councils to control the movement of plants, trees, fruit and garden waste from infected areas.

30 June 2017 – Myrtle rust risk model

Plant & Food Research creates a mathematical model to understand and predict how myrtle rust behaves under New Zealand conditions. The model makes use of NIWA weather analysis and prediction maps.

Image: Example of a weekly map generated by the New Zealand Convective Scale Model (NZCSM).

Beresford, R., Turner, R., Tait, A., Paul, V., Macara, G., Yu, Z., Lima, L., & Martin, R. (2018). Predicting the climatic risk of myrtle rust during its first year in New Zealand. New Zealand Plant Protection, 71, 332–347.

1 October 2017 – Short and medium-term monitoring sites

The Department of Conservation sets up four short-term and 40 medium-term monitoring sites on Raoul Island to provide data on the speed of disease transfer and the impacts on mature plants and regeneration.

29 November 2017 – Myrtle rust reporter app

Northland Regional Council, Scion, Envirolink, Te Tira Whakamātaki (Māori Biosecurity Network), Biological Heritage National Science Challenge and the Ministry for Primary Industries develop a bilingual app that allows users to record and monitor potential host plants.

Image: Scion

24 April 2018 – Local and regional councils develop management plans

As the focus shifts from eradication to managing the disease, councils such as the Auckland Council continue to develop plans for how to deal with myrtle rust. Private landowners will likely be asked to self-manage any infections.

22 May 2018 – Seed bank collection

Staff from the Department of Conservation and Auckland Botanic Gardens collect disease-free seeds from myrtle species on Great Barrier Island. The seeds are assessed and prepared by the New Zealand Indigenous Flora Seed Bank (NZIFSB) and banked in the Margot Forde Germplasm Centre at AgResearch in Palmerston North.

Seed banks are important because the seeds can be used should local populations of a species become extinct. They also protect genetic variation.

Image: Botanists from Auckland Botanic Gardens support the Department of Conservation with myrtle family seed collection on Great Barrier Island. Auckland Botanic Gardens.

12 June 2018 – Citizen science challenge

Scion scientist Dr Steve Pawson issues a wero (challenge) to the public to help map the disease by collecting and contributing data.

Image: Scion.

14 Dec 2018 – New test

Bio-Protection Research Centre announces a new test that can detect myrtle rust in 30 minutes. Developed by Dr Richard Winkworth and a team of undergraduate students at Massey University, the test is able to detect the fungus prior to the rust’s appearance. This will allow management to begin before spores are produced. The test is hailed as a cheap, robust game changer.

1 July 2019 – Myrtle Rust Science Plan

The Myrtle Rust Strategic Science Advisory Group (SSAG) releases the comprehensive, longer-term Myrtle Rust Science Plan. The plan was developed in consultation with over 50 scientists, stakeholders and Māori.

19 December 2022 – New RNA-based spray

University of Queensland scientists develop an environmentally friendly RNA-based spray to slow the spread of infection.