Mite might trim old man’s beard

A gall mite may be introduced to New Zealand to control the pervasive weed old man’s beard, if an application to the Environmental Protection Authority (EPA) succeeds.

The weed forms dense, permanent masses with heavy layered stems that smother and collapse underlying vegetation.

Heavy infestations prevent regeneration, leading to loss of native species in affected areas. This can open vegetation to invasion by other weeds.

Old man’s beard can also scramble over the ground, destroying low-growing plant communities on riverbanks, and in coastal and other sensitive habitats.”

“It colonises open forests, forest margins, shrublands, riversides, cliffs, bushtracks and hedgerows. It is also a troublesome urban weed. The vines can extend as far as 20 metres,” ,” says Dr Clark Ehlers, EPA senior advisor New Organisms.

Horizons Regional Council has applied to the authority to introduce the gall mite, Aceria vitalbae, on behalf of the National Biocontrol Collective, comprised of 14 regional councils and the Department of Conservation.

While old man’s beard, Clematis vitalba, is a member of the Ranunculaceae family, of which there are nine native Clematis species and four native genera in the same subfamily, laboratory tests and overseas experience suggest the gall mite is unlikely to colonise other species of Clematis.

Manaaki Whenua – Landcare Research  is the science provider for the application, and consulted widely before choosing six exotic Clematis species or hybrids for host range testing at the University of Belgrade in Serbia.

According to the applicant, the results suggest that the gall mite is expected to effectively colonise only old man’s beard in New Zealand. Occasional galls may be expected on exotic, non-target Clematis species, but the presence of low numbers of mites is unlikely to cause them damage.

The application says that old man’s beard causes environmental damage throughout most of New Zealand, often in distant or inaccessible areas of high conservation value. Most infestations go unmanaged.

Biological control by the gall mite could provide a safe and sustainable alternative to mechanical and chemical methods of control, the applicant says. The gall mite could also disperse to isolated infestations that are inaccessible, or unknown to land owners. It would persist from year to year.

“Adult gall mites are less than one millimetre long,” Dr Ehlers notes. “They do not fly, but disperse on the wind. They attack old man’s beard by sucking out plant juices and creating tumour-like galls on leaves and shoots. This often leads to the death of that part of the plant.”

The applicant notes that successful biological control of the weed would mean reduced costs for regional councils, the Department of Conservation and other land owners. Five regional councils recently estimated they spend approximately $760,000 per year to fight old man’s beard.

Public submissions on this application open on Wednesday 18 July 2018 and close at 5pm on 29 August 2018.

View application details and information

Source:  Environmental Protection Authority


Rabbit virus is working as expected – the science behind RHDV1-K5 explained

Manaaki Whenua Landcare Research has released an update on its monitoring of the spread of the Rabbit Haemorrhagic Virus Disease (RHDV1-K5), which regional councils began releasing several weeks ago.

Following extensive overseas research, RHDV1-K5 was released at more than 150 sites across New Zealand as a longer-term biocontrol for pest rabbit management.

Manaaki Whenua Landcare Research is leading the science behind the virus. Since the release, research teams have been intensely monitoring sites, to study the impact of the virus and how well it is establishing.

‘So first thing we wanted to know was whether the virus was killing rabbits within 5 km’s of our release sites and that seems to be the case – so far we’ve detected the RHDV1-K5 from carcasses at all of the research sites,’ says Landcare Research Lead Researcher Dr Janine Duckworth.

The Ministry for Primary Industries approved applications for the importation and release of the RHDV1-K5, to help reduce the significant environmental and agricultural impacts caused by wild rabbits.

The virus is a Korean variant of a virus that was illegally released in New Zealand in 1997. But questions have been asked as to why every farmer is not seeing dramatic numbers of dead rabbits on their property.

The answer is simple, Dr Duckworth says. It was never expected to act that way.

RHDV1-K5 is expected to improve rabbit knockdown by up to 40% above the current strain and results will vary with the location and the number of susceptible animals within the population.

“One of the major differences with this virus release is the rabbits have already seen RHDV type viruses and have built up some antibodies against them, so it’s not going to see the huge 80-90% die off that we saw back in 1997, but it will be more effective over time,” she said.

“When you use a biocide it only affects the rabbits that eat the virus and then they die within one to two weeks. With a natural spread, the infection builds much more gradually but we see a longer period of infection. It will be six to eight weeks that the virus will still be slowly spreading through a rabbit population and we want to see this virus establish and be here long term as a new biocontrol agent.”

Now the research focus is on finding out how quickly the virus is moving away from the release sites through natural spread to infect nearby rabbit populations.

“RHDV spreads either from rabbit to rabbit contact, contact of rabbits with feces from an infected rabbit, or from bedding material,” Dr Duckworth said.

“But it also spreads across the land much faster than it could by rabbit to rabbit contact, and what we believe is that it’s the flies that are carrying the virus from one area to another.”

Ongoing monitoring and research is continuing with the project. Spotlight night counts of rabbit populations are underway and are expected to be completed in a few weeks’ time.

You can find out more about the RHDV1-K5 virus  HERE.

Source: Manaaki Whenua Landcare Research

Two moths would hound the horehound weed but herbalists oppose their importation

Picture of horehound plume moth

Two moths may be imported to combat the horehound weed, which a recent survey estimates is costing New Zealand dryland farmers almost $7 million a year.

The Environmental Protection Authority is considering an application from a collective of affected farmers – the Horehound Biocontrol Group – to introduce the horehound plume moth and horehound clearwing moth to attack this invasive weed.

It is calling for public submissions.

The application is supported by the Ministry for Primary Industries’ sustainable farming fund.

But the horehound weed is highly valued as a medicinal herb, and is harvested for that purpose. A literature review suggests the plant may be beneficial in the treatment of respiratory disorders, diabetes, inflammatory disorders and a wide range of other conditions.

Successful biological control would adversely affect the value of the medicinal harvest.

The applicant notes that the New Zealand Association of Medical Herbalists and the Herb Federation of New Zealand both oppose the proposed biological control programme.

The applicant also emphasises that the horehound weed is a serious threat to the viability of some farms. It establishes strongly in hill and high-country lucerne forage crops and is exceptionally hard to control.

Herbicide treatments aimed at the horehound weed are said to be highly detrimental to lucerne, and may do more harm than good.

The two moths attack horehound weed in different ways, and have been released successfully in Australia. The larvae of the plume moth feed on horehound leaves, while those of the clearwing moth feed in the roots.

The Horehound Biocontrol Group says that experimental evidence suggests neither moth will persist in or damage any native plant or desirable ornamental plant. Both feed on a narrow range of plants in their native Europe, and this was confirmed in Australia prior to their introduction, it says.

Public submissions on this application open on 29 May 2018 and close on ­­­­­11 July 2018.

Find out more about the application and make a submission

Source: Environmental Protection Authority

Pea weevil programme is on track to eradicate the pest

The Ministry for Primary Industries and the pea-growing industry are on track to eradicate the pest insect pea weevil from New Zealand.

The pest was first discovered in the Wairarapa in 2016 and has been subject to an eradication programme since then.

“Our trapping programme found only 15 pea weevils from 2 neighbouring sites this season. That is significantly down on the 1,735 pea weevils which were found across 11 sites last season. MPI response manager Nicky Fitzgibbon said.

“It’s encouraging progress. We think that is largely due to the Controlled Area Notice currently in place which restricts the growing of peas in the Wairarapa up to Pahiatua. We intend to maintain these restrictions until we are confident that we can eradicate the pest from New Zealand”.

“We understand the restrictions have had an impact on the pea growing industry and wider Wairarapa community and MPI would like to recognise their efforts and support.”

Growers had shown a great deal of flexibility by finding alternate crops to plant while the ministry has been working to get rid of this pest, Ms Fitzgibbon said.

This support had been critical in the success of the programme so far.

A Controlled Area Notice issued by the ministry indicates where peas can’t be grown (all Wairarapa including Pahiatua) and restricts the movement of pea seed and pea straw within, and in and out of the area.

You can find more about pea weevils HERE.

Source: Ministry for Primary Industries


EPA meets its stakeholders

The Environmental Protection Authority today posted news of its “inaugural stakeholder event” last Thursday.  Eugenie Sage, Associate Minister for the Environment, was guest of honour.

More than 60 key stakeholders and partners attended. The aim was to share with them key elements of our work, and to discuss the ways the authority can work together to ensure New Zealand and New Zealanders remain protected.

Authority chief executive Allan Freeth told them:

“Science moves fast, so we need to too. We’ve formed a dedicated hazardous substance reassessments team to make sure we can act quickly on new information.”

Ms Sage addressed the meeting on the government’s commitment to ensuring the safe management of hazardous substances.

Presentations given by Dr Freeth and the authority’s board chair, Kerry Prendergast, are available HERE.

The authority says it envisages this will become a regular event as part of its commitment “to customer centricity and engagement”.

Source: Environmental Protection Authority



Fruitless sex is collapsing codling moth populations

A pilot programme to collapse the population of one of New Zealand’s most harmful apple pests, the codling moth, has produced spectacular results, Plant & Food Research reports.

Each week thousands of sterile codling moths are being released into Central Hawke’s Bay apple orchards to mate with the local population. Critically, no progeny are produced from these relationships, although the sterile moths have the same drive to mate.

By overwhelming the local codling moth population with the sterile moths, imported from a production facility in Canada, the wild moth populations have collapsed.

Of particular importance to the programme is the method for releasing the sterile insects. An unmanned aerial vehicle (UAV), following GPS coordinates, is fitted with special pods that release 20,000 sterile moths over 100 hectares of orchard during a flight of just 10 minutes.

These releases mean there may be up to 200 sterile moths for every fertile moth present in the treated orchards.

“We’ve seen dramatic results across the 400 hectares of Central Hawke’s Bay orchards treated with these sterile moths, up to 98% reduction of the wild moth populations,” says Plant & Food Research scientist Dr Jim Walker.

“Within two seasons we expect the codling moth population will be eliminated from these orchards.”

Plant & Food Research Science Group Leader Professor Max Suckling says this organically accepted technique can help eradicate a major pest for apple growers, particularly when used in combination with other mating disruption techniques that many growers already use.

Tim Herman, Technical Manager of New Zealand Apples & Pears, says the New Zealand apple and pear industry is always looking for new and innovative ways to control codling moth to reduce the use of insecticides.

“We already produce fruit with very low residues, but this research will add to our already sustainable programme of codling moth control and help maintain our ranking as the most competitive apple and pear industry in the world.”

It is believed that the same method has the potential to prove effective for eradicating other insect pests, such as Queensland fruit fly, if the species became established in New Zealand.

Click HERE to see a video of the UAV in action

Source: Plant & Food Research

Researchers are poised to win the race against rust diseases

A joint US and Australian research team has generated the first haplotype-resolved genome sequences for the rust fungi causing oat crown rust and wheat stripe rust diseases, two of the most destructive pathogens in oat and wheat, respectively.

After using the latest genome sequencing technologies to understand how rust fungi adapt to overcome resistance in crop varieties, scientists from the University of Minnesota, the USDA-ARS Cereal Disease Laboratory, the Australian National University, Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Sydney are releasing results with two publications in mBio, a journal by the American Society of Microbiology.

The work was announced (here) by the University of Minnesota.

“Like humans, rust fungi contain two copies of each chromosome, which makes their genetics much more complicated than other types of fungi,” said Assistant Professor Melania Figueroa from the University of Minnesota. Figueroa co-led the sequencing effort for the oat crown rust fungus P. coronata f. sp. avenae along with Shahryar Kianian, research leader at the USDA-ARS Cereal Disease Laboratory and adjunct professor at the University of Minnesota.

“A key advance of this work is that for the first time, separate genome assemblies were generated reflecting both of the two chromosome copies in the rust.”

In parallel, Postdoctoral Fellow Benjamin Schwessinger and Professor John Rathjen at the Australian National University applied similar approaches to develop an improved genome assembly of the stripe rust fungus, P. striiformis f. sp. tritici. By working together the two teams were able to combine their techniques and knowledge to achieve these breakthroughs much more rapidly than by working alone.

These studies represent a breakthrough in plant pathology as they now show how genetic diversity between the two chromosome copies can influence the emergence of new virulent pathogen strains.

Both studies uncovered a surprisingly high level of diversity between the two copies, suggesting that such variation likely serves as the basis to rapidly evolve new rust strains.

“Reports from growers facing yield losses due to oat crown rust occur during most cropping seasons and the genome assemblies of this pathogen will help us understand the evolution of this pathogen and means to develop more resistant crops,” said Kianian, who coordinates annual rust surveys in the US in order to monitor the pathogen population in oat growing areas.

The oat crown rust genomics study compared two strains from North Carolina and South Dakota with different virulent profiles which were obtained in 2012 as part of the routine USDA-ARS Rust Surveys.

The first author of this publication, Marisa Miller, is the awardee of a prestigious USDA-NIFA Postdoctoral Fellow and recently embarked on a study comparing the genomic composition of oat crown rust strains collected in 1990 and 2015.

“In the last 25 years the population of oat crown rust has gained additional virulences, and we would like to understand how this has occurred. Miller’s work is essential to answering this question,” commented Figueroa.

“Oat crown rust is one of the most rapidly evolving rust pathogens,” explained University of Minnesota Adjunct Professor Peter Dodds of CSIRO Agriculture and Food. “So this work will really help understand how new rust diseases like the highly destructive Ug99 race of wheat stem rust can overcome resistance in crops.”

The publications describing the work in the oat crown rust and wheat stripe rust pathogens, both released in the current issue of mBio, will serve as a framework for future studies of virulence evolution in these pathogens as well as for applying similar approaches to the rust fungi causing many other major crop diseases.