Archive for the ‘Biosecurity’ Category

Kauri dieback fungus may have been in NZ for longer than previously believed

Phytophthora agathidicida (PTA), the fungus-like organism that causes kauri dieback, has been in New Zealand much longer than previously thought, a study led by Bio-Protection Research Centre researchers based at Massey University suggests.

Plant geneticist Dr Richard Winkworth and collaborators have been using genome sequencing to investigate when PTA arrived and how it has changed since arriving.

“It had been suggested that PTA arrived in New Zealand not long before the first diseased trees were found in the early 1970s,” Dr Winkworth says.

“However, our results suggest PTA was diversifying in New Zealand kauri forests around 300 years before that. It must have arrived even earlier. Humans may have brought it here – perhaps the pathogen was carried to New Zealand by Polynesian settlers or the earliest European explorers – or it may even have been here before humans arrived.”

The researchers have sequenced and analysed complete mitochondrial genomes of 17 PTA samples collected from sites across the geographical range of the disease.

“The samples we have collected suggest several genetic subgroups within PTA,” Dr Winkworth says.

“To better understand the history of spread through the kauri forests we need to increase our sample size. However, we do see, for example, that several genetic subgroups are present in the Waitākere Ranges, perhaps as the result of human activity.”

These results raise an important question: If PTA has been in New Zealand for at least the last 300 years, why has it only recently become a significant problem?

“The results suggest that the relationship between PTA and its host may have changed,” Dr Winkworth says.

There are several ways this might have happened. One is that genetic changes to PTA have made it more virulent. “It is a possibility, but our results suggest it is not as simple as a single pathogenic form evolving and spreading through the forest,” Dr Winkworth says.

An alternative is that environmental changes have resulted in the disease emerging. The research results are consistent with this possibility.

“Since humans arrived, we have been altering New Zealand environments. Perhaps the combination of heavily fragmenting the kauri forests together with ongoing human-mediated disturbance and climate change has led to emergence of the disease. Perhaps we introduced another pathogen that, in combination with PTA, results in disease.

“If we are to fight back effectively we need to better understand the relationship between when PTA arrived, its pattern of spread, and the emergence of kauri dieback disease,” Dr Winkworth says. “Identifying why kauri dieback disease emerged might help us to move beyond containment to managing and controlling it.”

The research team has also been developing a cheap, robust DNA test that is simple enough for community groups to use in the field, but that is as accurate as laboratory-based testing.

“We are hoping to evaluate the test in field trials in the next few months.” Dr Winkworth says. “We hope that this will make it easier to monitor where PTA is, both for the purposes of management but also to enable further research.”

This Massey University-led research has been largely funded by the Bio-Protection Research Centre, and has involved researcher contributions from Manaaki Whenua Landcare Research, Toi Ohomai Institute of Technology, Scion, and the University of Auckland.

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Biosecurity Minister disappointed by further findings of Mycoplasma bovis

Agriculture and Biosecurity Minister Damien O’Connor says he’s “deeply disappointed’’ by the detection of cow disease Mycoplasma bovis on farms near Hastings and Winton.

The Ministry for Primary Industries has identified four new properties as positive for the bacterial cattle disease and strongly suspects it is present on one further property.

One of the latest infected properties is in the Hastings district, the other three are within a farming enterprise in Winton.

The suspect property is near Ashburton.

“The fact the disease has been found in the North Island is disappointing to me and, no doubt, will be for farmers too,’’ Mr O’Connor says.

Mr O’Connor says officials are working hard to track the disease.

“We are still unable to identify the source of the disease and that concerns me.”

Mr O’Connor says he will meet with officials to discuss the next steps in dealing with the outbreak.

“I understand this is tough for farmers, people working on these properties and people in these close-knit communities, but everyone is working hard to find solutions.’’

The Hastings and Ashburton properties were identified through MPI’s tracing programme and the Winton property was identified through the industry milk testing programme.

All of the movements were prior to July 21, when the disease was first detected and notified to MPI.

The Hastings and Winton properties were placed under a Restricted Place Notice under the Biosecurity Act. This effectively places them in quarantine lockdown – restricting the movement of animals and other risk goods on and off the farm.

The suspect property is under voluntary movement controls until its status is confirmed.

Mr O’Connor says it is possible further infected properties could be found.

The bacteria can spend some time in an animal before it is found or they show signs of the disease, which makes our job harder, he says.

Ministry to boost its biosecurity team for the summer rush

Thirty-two new quarantine officers will graduate from their training today, bolstering the Ministry for Primary Industries’ biosecurity defences at the border.

The ministry’s Border Clearance Services director, Steve Gilbert, says half the graduates will assist with biosecurity screening of travellers arriving at Auckland Airport over the summer.

“We’re expecting the busiest summer on record for visitor arrivals at international airports, especially in Auckland.

“The new officers will have a frontline role to protect New Zealand from invasive pests or diseases that could damage our economy or natural environment.”

The graduates include five officers who will work as biosecurity detector dog handlers and five more who will shortly undergo detector dog programme training.

So far this year, the ministry has employed 73 new officers from three intakes.

It now employs around 540 frontline staff, up from 500 last year.

It has also contracted personnel to help with Chinese-language translations and with cleaning shoes and sportswear.

“MPI is quickly becoming the biggest shoe-cleaning operation in New Zealand, and it’s all for biosecurity,” says Mr Gilbert.

He says MPI will be looking for 40 more officers in its latest recruitment drive, starting later this month.

In the year to July 2017, 6.48 million passengers arrived at New Zealand’s five international airports. Under conservative estimates, the ministry is projecting a 2.5 million increase in the number of passenger arrivals over the next five years.

Ministry officials disappointed by discovery of myrtle rust in the Wellington region

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

The Ministry for Primary Industries (MPI) says its laboratory has confirmed positive infection in three ramarama (Lophmyrtus bullata) plants in a Hutt Valley garden.

The two-metre-high plants are in a row and are heavily infected, says the myrtle rust response incident controller Catherine Duthie.

Myrtle rust is a fungus that attacks – and can potentially seriously affect – myrtle species plants, including natives such as pōhutukawa, ramarama, mānuka and rātā.

“This new find, significantly further south of other known infection in the upper North Island, is very disappointing,” Dr Duthie says.

As with other positive finds, the trees are having their foliage sealed to prevent spore drift and are then being removed and deep buried.

“All efforts to date have been to contain infection where it is found. However, we have been planning for the possibility that it turns out to be widespread and are realistic that it won’t be feasible to keep removing all infected trees found long term.

“This new find will see us review our tactics and could signal a move to a longer-term approach to managing it in partnership with others, including local authorities, iwi and hapū, plant production industry, and interested individuals and groups.

“We’ll be keeping people informed about any decisions and will provide the most up-to-date information about best practice in fighting this disease,” Dr Duthie says.

In the meantime, the ministry is encouraging people to keep an eye out for the disease in myrtle species.

“So far ramarama and pōhutukawa are the species we’re finding most affected and these are the ones to look at carefully.

Anyone  who believes they have seen the distinctive yellow fungus are advised not to touch the plant or the rust, because this may spread it. If possible, they should try to get a good photo of the plant and the yellow patches and contact the ministry on 0800 80 99 66.

Ministry for Primary Industries reports second myrtle rust find in Auckland

A second location of myrtle rust infection has been found in Auckland – this time in the city, on ramarama plants at a private property in St Lukes.

Myrtle rust is a fungus that attacks and can potentially seriously affect myrtle species plants including some significant natives such as pōhutukawa, ramarama, mānuka and rātā.

The Ministry for Primary Industries (MPI) says so far it appears ramarama and pōhutukawa are the most susceptible species in New Zealand.

Myrtle rust response controller Dr Catherine Duthie says of the 136 locations now known to be infected, 90% involve infection in ramarama or pōhutukawa plants.

“As with all our previous detections, we’ve placed movement controls on the new property to stop any myrtle plant material being moved off site.
“Our team on the ground will shortly remove all affected plants to contain any risk of spread.”

Dr Duthie says it’s vital that the team knows just how well-established myrtle rust is in the Auckland region to help determine what is feasible in terms of future control.

“Auckland is a big place and we can’t check everywhere. We encourage all Aucklanders to look particularly at ramarama and pōhutukawa plants in their gardens and public areas and report any signs of the distinctive yellow fungus to MPI on 0800 80 99 66.

“It’s important you don’t touch the plant or the rust, as this may spread it. If possible get a good photo of the plant and the yellow patches, and contact us. We’ll look after it from there.

“If you believe you’ve found it, don’t touch the plant or the rust, as this may spread it.”

Dr Duthie says finding another infection in Auckland so soon after last week’s detection is disappointing but also expected.

“While myrtle rust has been relatively dormant over the winter months we have been expecting new infections to be identified as the weather warms up and the fungus begins to release spores again.

“We are now considering what this new find means to the future management of the fungus. It may well mean that we have to review our tactics and prepare for a longer term approach to managing it in partnership with others including local authorities, iwi, plant production industry and interested individuals.

“We’ll be keeping people informed about any decisions and will provide the most up to date information about best practice in fighting this disease,” Dr Duthie says.

Myrtle rust has previously been found in Taranaki, Te Puke, Waikato and Northland, and just last week, in Auckland for the first time.

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.

MPI receives application for new strain of rabbit virus

The Ministry for Primary Industries has received an application to approve the use of Rabbit Haemorrhagic Virus Disease RHDV1 –K5 for pest rabbit management.

RHDV (Czech strain) already exists in New Zealand, after it was introduced in 1997. This 2017 application is for a Korean strain that isn’t currently found here.

The ministry has notified the application under the Agricultural Compound Veterinary and Medicines Act and will consider any submissions before making a decision on the data that have been submitted in support of the registration.

The consultation closes on December 14.

The ministry will consider benefits of the release to the agricultural sector, as well as identification and management of risks to animal welfare, agricultural impacts, trade and public health matters associated with the virus. This will include consideration of the risks posed to non-target animals such as pet rabbits.

“The strain of RHDV that already exists in New Zealand has a vaccine which is being used to protect against the new strain in other countries,” says Allan Kinsella, the ministry’s Director Systems Audit, Assurance and Monitoring.

“As part of MPI’s assessment we will be considering evidence of protection against the new strain.”

Any new strain that is released, propagated, and sold also needs to be approved under the Biosecurity Act.

RHDV1-K5 strain will be approved only if it meets the requirements under the Agricultural Compound Veterinary and Medicines Act and Biosecurity Acts.

The Canterbury Regional Council has made the application. The intent is to introduce the strain nationally.