Posts Tagged ‘Myrtle rust’

Climate model gets the measure of myrtle rust’s behaviour under NZ conditions

Plant & Food Research scientist Dr Rob Beresford spent the month of June poring through research articles, crunching data and creating mathematical formula to better gauge what myrtle rust may mean for New Zealand.

The end result was the Myrtle Rust Risk Model, specifically designed to understand and predict how myrtle rust will behave under New Zealand conditions.

The Ministry for Primary Industries is using it to help inform its responses, such as targeted surveillance for the disease.

“The model has three key attributes,” says Dr Beresford.

“It warns when the weather is suitable for any spores in the air to infect susceptible plants; it predicts the time from when infection occurs to when rust symptoms may appear; and it assess the suitability of conditions for spores to be produced from infected plants that are showing symptoms.”

With no history of myrtle rust in New Zealand until its arrival in May, developing the model was not easy because of a large number of unknowns.

Dr Beresford’s first step was to dig deep into scientific literature and record observations from countries where the disease is already established, such as Brazil, the US (Hawaii) and Australia.

“Although the overseas research is tremendously useful, you can’t assume that myrtle rust will behave in New Zealand in ways observed in other countries with similar climates,” says Dr Beresford.

“New Zealand has its own seasonal weather patterns. Moreover, the genetic differences between plant species in the myrtle family could influence susceptibility, just as there can be differences in the strains of the rust pathogen itself. So, it’s very complex.

“All these things have to be calculated and factored in to the model, with mathematical parameters set to represent things such as plant susceptibility, temperature range and humidity.

“Essential to doing this well is having a good understanding of the biology of the disease and host plant species.”

The risk model is distinctive in simulating the biology of the disease at a fine scale of time and space. Additionally, thanks to NIWA’s sophisticated weather analysis and prediction maps in combination with its climate-data mapping skills, the NIWA data can be factored into the model hourly, allowing for day-to-day measurability and reporting.

This model can work in conjunction with other climate models developed for myrtle rust that take a more general, broad-brush climate matching approach or rely on long-term weather data.

“The next step to further refine the model is to do more in-depth research into host plant susceptibility,” says Dr Beresford. “This means we can tweak the model from reporting relative risk to something even more definitive.”

Funding for the development of the model came from the Ministry for Primary Industries.

Plant & Food Research is currently collaborating with NIWA on mapping the risk of myrtle rust infection in different regions.

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Ministry urges continued monitoring by the public in Myrtle rust update

The Ministry for Primary Industries says it is continuing to encourage people to keep an eye out for the harmful plant disease myrtle rust and report any signs of the disease.

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. So far in New Zealand, the infection has been mostly found on pōhutukawa (Metrosideros) and ramarama (Lophomyrtus).

MPI, in partnership with the Department of Conservation and with the support of local mana whenua and councils, has been working to manage the disease since it was first found in Kerikeri in early May this year.

Since then, the disease has been found on 123 individual properties, mostly in private gardens. The majority of these affected locations are in Taranaki, principally around Waitara, and there is a second significant area of infection in Te Puke in the Bay of Plenty. There have been small detections in Northland and Waikato that were immediately removed and there has not, as yet, been any recurrence.

In Taranaki, as part of the work to try to contain the disease, MPI has put legal controls restricting the movement of myrtle plants and plant material (for example, cuttings, garden waste) out of the Taranaki region.

To date, the focus has been on trying to contain the disease and remove any infection found. Myrtle rust eradication has never been achieved anywhere in the world and rusts are notoriously difficult to treat. The next phase in tackling this issue may be to aim at protecting specific areas and trees while developing scientific solutions around treatments and building resistance.

By learning where myrtle rust is in New Zealand, the ministry expects to make better decisions about the most appropriate way to manage it in the future.

 

Ministry calls for proposals for research on Myrtle Rust

The Ministry for Primary Industries has posted a Request for Proposals (HERE) for its 2017/18 Myrtle Rust Research Programme.

It advises interested parties that in March this year a response was initiated to a myrtle rust incursion on Raoul Island. This was extended to mainland New Zealand when the rust was discovered in Northland, Taranaki, Waikato and the Bay of Plenty.

Myrtle rust is a fungal disease with the potential to affect multiple ecologically and culturally significant species, as well as species important to industry and the public, on both localised and landscape-scales, across the majority of New Zealand. No country has managed to eradicate myrtle rust from its shores.

Funding has been allocated from August 2017 – June 2018 (Phase 1), for urgent research work focussed on addressing critical knowledge gaps and delivering real-life management tools for myrtle rust.

The funding will be delivered via through a Request for Proposal process. Funded projects will need to ensure there is a focus on high impact research that aligns with, and builds on, research to date in New Zealand and internationally.

The ministry says this is a unique opportunity to be part of a protecting New Zealand’s iconic and culturally significant trees shrubs, and ecosystems.

National management of myrtle rust will be very complex, it says. The disease potentially affects multiple native, iconic, taonga and culturally significant species, as well as species important to industry and the public, on both localised, ecosystem and landscape-scales, across the majority of New Zealand.

There are many unknowns about its long-term impacts under New Zealand environmental conditions, and no effective tools for medium- or large-scale management of the disease.

First new myrtle rust find of the spring is made in Waikato region

The Ministry for Primary Industries (MPI) has found a new area infected with the fungal plant disease myrtle rust.

The fungus has been found on two properties in the Otorohanga township – in both cases on a single ramarama tree. These finds are new positive detections of myrtle rust outside of the known established areas in Taranaki and Te Puke.

The ministry’s myrtle rust response incident controller, Dr Catherine Duthie, says the two properties have no  connection with nurseries or other infected properties in Taranaki.  It would appear these are infections that have occurred by wind dispersal from Australia, like the infections in other regions.

“We located these infected plants through our ongoing checks of areas that we’d identified as at-risk due to prevailing wind direction, the presence of host species and climate.

“Along with the Department of Conservation, we’ve been carrying out surveillance for the disease throughout the winter, even though myrtle rust is generally inactive in colder weather and the symptoms are less obvious.

“We had known that a reappearance of obvious myrtle rust symptoms was likely in spring – so while this is disappointing, it’s not unexpected,” Dr Duthie says.

The two properties are being placed under legal restrictions to stop any movement of plant material off the sites. MPI will  remove and destroy the two affected plants within the next few days.

Teams will then be in the area checking all myrtle plants in a 500 metre radius from the two finds. This could take up to a fortnight.

MPI is continuing  to encourage people to check myrtle species plants – for example, pohutukawa, ramarama, mānuka, feijoa, and bottlebrush.

 

New funding for a joint NZ-Australian project to combat myrtle rust

More details have emerged about Plant & Food Research and Scion winning funds in the latest round of MBIE’s Catalyst Strategic Fund for  a project addressing the threat of myrtle rust to New Zealand.

A media statement posted on the Scoop website (HERE) says the project has three key aims: to establish the susceptibility of key species to myrtle rust, build scientific knowledge for successfully storing germplasm of Myrtaceae species, and develop ‘in the field’ plant pathogen detection and surveillance systems.

“This is very important and timely research now that myrtle rust is present on the New Zealand mainland,” says Plant & Food Research Bioprotection Technologies Scientist and the project’s Principal Investigator Dr Grant Smith.

“This fungal pathogen threatens many species that have environmental, economic, social and cultural importance, including the indigenous pōhutukawa, rātā, kānuka, and mānuka, as well as exotic plant species such as Eucalyptus and feijoa.”

The Catalyst Fund supports international research partnerships and scientific cooperation. In this case, New Zealand scientists will be working closely with colleagues in leading biosecurity organisations across the Tasman, with the research collaboration between Plant Health Australia and New Zealand’s Better Border Biosecurity providing the overarching coordination.

“New Zealand and Australia have much to learn from each other with regards to the invasive species in their respective countries. Myrtle rust is something that Australia has been dealing with for seven years and our experience can really help New Zealand,” says Plant Health Australia Executive Director and CEO Greg Fraser.

The programme reinforces the development of a key trans-Tasman partnership between members of New Zealand’s Better Border Biosecurity network and Australian biosecurity organisations.

“Australia and New Zealand face many of the same issues and opportunities in bio-protection and biosecurity, so high-quality collaborations of this nature are very important. Smart partnerships like this achieve better outcomes than working alone,” says Better Border Biosecurity Director Dr David Teulon.

Scion Research Leader Dr Beccy Ganley says:

“Many biosecurity issues are too large for one organisation or sector to tackle alone. Myrtle rust is a prime example and we are very pleased to receive support from the Catalyst Fund to help reduce the threat this disease poses to our myrtles.”

The project will employ the expertise of Plant & Food Research, Scion, Plant Health Australia, Te Turi Whakamātaki (National Maori Biosecurity Network), the Queensland Department of Agriculture and Fisheries, NSW Department of Primary Industries and the Wellington Botanic Gardens. The project is also linked with scientists at Kew Gardens in the United Kingdom, who have significant expertise in the conservation of Myrtaceae species.

Myrtle rust has now been confirmed in Waikato nursery

A positive detection of myrtle rust has been made in the Waikato region, the Ministry for Primary Industries announced this afternoon.

The fungal plant disease was identified in a small number of plants at a nursery in Te Kuiti. The new location was found as a result of MPI tracing sales of plants from another positive nursery.

MPI has personnel on the ground in Te Kuiti and restrictions have been imposed on the movement of risk goods from the property.

The property will be treated with fungicide.

As with all other finds to date, MPI will continue to search surrounding areas for signs of the fungus.

The new find, along with confirmations on a further three properties in Taranaki, brings the total number of confirmed infected properties to 16 nationally.

Most of the properties are in Taranaki, along with two confirmed in Northland and the latest one in Waikato.

The disease-causing fungus has been found at a mix of properties including nurseries, plant retailers and distributors, an orchard and private gardens.

MPI is receiving unprecedented support from members of the public, with some 420 reports of suspected symptoms to its 0800 number.

Of those reports, a small percentage require sampling and testing. The Ministry is able to distinguish the highest risk reports from photographs.

Myrtle rust only affects plants in the myrtle family. Any rust symptoms on other plants can immediately be discounted.

The ministry has thanked people for their vigilance. Their reports are helping to build a picture of where the rust is present and inform plans being made for the future management of the fungus.

The ministry continues its effort to try to contain the rust at infected properties, but is also realistic that this is a huge challenge and New Zealanders may have to learn to live with it.

People can report suspected signs of myrtle rust to MPI’s Exotic Pest and Disease Hotline on 0800 80 99 66.

The public are urged not to touch the rust or the plant. The location should be noted and photos taken of the symptoms and the plant.

Myrtle rust – MPI reports two more cases confirmed in Taranaki

Two further properties in Taranaki have been confirmed positive with myrtle rust infection today. Both are plant businesses, one a further nursery in Waitara and the other a garden centre in New Plymouth.

This brings the total number of known affected properties to five – a nursery and adjoining property in Kerikeri, two plant nurseries in Waitara and a garden centre in New Plymouth.

The ministry says the new finds are disappointing but not unexpected. It expects to continue to find new locations of infection given the most likely scenario is that the fungal spores entered New Zealand from Australia during a major wind event.

All infected properties are “restricted places”, meaning there are restrictions on the movement of plants or other risk materials off the sites. Locations are being treated with fungicide, risk plants are being safely destroyed, and surveillance is underway in the areas surrounding the properties for signs of the disease.

The ministry says there are two main reasons why the rust is being found in plant nurseries.

* First, growing conditions there are ideal for the fungus with many vulnerable young plants in sheltered, warm and damp environments.

* Second,there has been a large amount of communication with the nursery industry and growers have been particularly vigilant in checking their plants.

Myrtle rust (Austropuccinia psidii) is also known as guava rust and eucalyptus rust.

It is a serious fungal disease that affects plants in the myrtle family, which includes pōhutukawa and mānuka. The first detection of the disease in mainland New Zealand was at a Northland nursery early this month.

The fungus attacks various species of plants in 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.

It is widespread on Raoul Island in the Kermadec group, about 1,100km to the north-east of New Zealand.

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

The spores are thought to be capable of crossing the Tasman Sea from Australia to New Zealand on wind currents.

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, feijoa and guava.

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

Its impacts overseas have varied widely from country to country and plant species to species.

Myrtle rust shows up as yellow bumps and brown patches on leaves.

It generally attacks soft, new growth, including leaf surfaces, shoots, 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.

Some leaves may become buckled or twisted and die off.