Feeds:
Posts
Comments

Archive for the ‘Fungi’ Category

OurAuckland

//www.googletagmanager.com/ns.html?id=GTM-TPM76C

Invasive myrtle rust disease discovered on mainland NZ

Published: 5 May 2017

The Ministry for Primary Industries (MPI) has confirmed the presence of the myrtle rust plant disease on mainland New Zealand for first time, in Kerikeri.

MPI and Auckland Council are asking Aucklanders to keep their eyes peeled for this invasive fungus and to report it immediately if spotted.

Councillor Penny Hulse, Chair of council’s Environment and Community Committee says the find is extremely worrying and vigilance is needed.

“It’s very early days and we know that MPI are doing everything in their power to prevent the spread of this disease. Council’s biosecurity staff are standing by to assist MPI if needed.

“In the meantime we can all add to the effort by keeping myrtle rust top of mind when we are outdoors over the coming weeks and months. If you think you’ve seen it in Auckland, please call MPI straight away.”

What is myrtle rust disease?

Myrtle leaf rust is a serious fungal disease that attacks members of the myrtle family of plants.

It could have a serious impact on our native pohutukawa, manuka, kanuka and rata as well as feijoa and eucalypts, damaging or even killing them.  Myrtle rust spores are microscopic and can easily spread across large distances by wind, or via insects, birds, people, or machinery.

What does it look like?

You’re most likely to spot myrtle rust on young, soft, actively growing leaves, shoot tips and young stems, as well as flowers and fruit.

Initial symptoms are powdery, bright yellow or orange-yellow spots, or brown-grey rust pustules in the case of older infections. The rust can appear red depending on the types of spores being produced.

The fungus often causes leaves to buckle or twist and die off.

What should I do if I spot it?

Report it immediately to the Ministry for Primary Industries (MPI) on 0800 80 99 66.

Do not touch the fungus or try and take samples as this will increase the risk of it spreading. Note down its location and take photos if possible.

Visit the Ministry of Primary Industries (MPI) for more information.

Read Full Post »

TE WAHA NUI

AUT Student Journalism

Team effort to fight threatening fungal plant disease

Environment

Ashleigh Martin April 8, 2017

<!– Ashleigh Martin –>

Team effort to fight threatening fungal plant disease

Look out for yellow powdery eruptions on leaves. Photo: Supplied / M Daughtrey, Cornell University

The Ministry of Primary Industries has issued a call to arms after a fungal plant disease which could affect New Zealand native plants and our honey industry was found on Raoul Island.

The disease, myrtle rust, can be identified by bright yellow powdery eruptions on leaves and attacks various species of plant such as pōhutukawa, kānuka, mānuka and non-natives like the feijoa plant.

Amid fears the disease could spread to these shores, MPI is working with DOC and the New Zealand Defence Force to survey Raoul for it.

David Yard, MPI incident controller, said several DOC workers were going over the island, so a joint plan could be made.

“They’ve been briefed on how to minimise the risk of spreading it…because obviously the risk is if you work through an affected area, you might actually spread the disease,” Mr Yard said.

Raoul Island is 1100km away from the nearest part of the New Zealand mainland. The island is also very rocky and mountainous, making work difficult.

“We’ve been working with the Defence Force should we need to get materials, equipment and people onto the island to support DOC efforts,” Mr Yard said.

The disease can travel long distances by wind and can also be transported by insects, rain splashes and contaminated clothing.

The Wellington-based Science Media Centre quoted Dr David Teulon, director of Better Border Biosecurity, who said myrtle rust had been spreading rapidly around the world in recent years.

“If it reached mainland New Zealand, it could have a serious impact on a number of our taonga Māori plant species, such as pōhutukawa and rātā, with severe infections causing plants to die,” Dr Teulon said.

“Plants that are also important to our honey industry, such as mānuka and kānuka, could also be affected, which could severely impact on New Zealand’s annual $300 million of honey exports.”

– See more at: http://www.tewahanui.nz/environment/team-effort-to-fight-threatening-fungal-plant-disease#sthash.vF0oxCzv.dpuf

Read Full Post »

PHYS ORG

March 23, 2017

Novel virus breaks barriers between incompatible fungi
SsMYRV4-mediated enhancement of horizontal transmission between different VCGs effectively prevents and controls Sclerotinia diseases. Credit: Wu S, et al. (2017)

Scientists have identified a virus that can weaken the ability of a fungus to avoid pairing with other incompatible fungi, according to new research published in PLOS Pathogens. By promoting fungal pairing, the virus could aid transmission of additional unrelated viruses between fungi.

Fungi, like all other organisms, can recognize foreign substances; such non-self recognition can help protect against pathogens. Some also use non-self recognition to avoid pairing and sharing genetic material with incompatible strains. The fungus Sclerotinia sclerotiorum, which infects hundreds of plant species worldwide, employs this strategy, which is known as vegetative incompatibility.

While studying S. sclerotiorum, Jiatao Xie of Huazhong Agricultural University, China, and colleagues discovered a they named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4). To better understand this novel virus, they grew infected S. sclerotiorum alongside other vegetatively incompatible strains and investigated the molecular effects.

The researchers found that SsMYRV4 decreased expression of S. sclerotiorum genes that promote vegetative incompatibility. Vegetative incompatibility is a molecular process that normally causes when two incompatible strains touch each other; in this study, Xie’s team found a reduction in the amount of cell death that normally occurs in intermingled colonies of incompatible strains.

S. sclerotiorum infected with SsMYRV4 successfully made connections with incompatible by fusing filamentous structures known as hyphae. To investigate the consequences, the scientists grew SsMYRV4-infected fungi alongside fungi infected with other unrelated viruses. They found that the unrelated viruses were able to pass through the fused hyphae, crossing between fungal pairs.

Vegetative is considered a significant obstacle to using viruses to effectively control fungal diseases. These new findings could point to a new strategy that uses SsMYRV4 to weaken barriers between fungi. They could also improve understanding of virus ecology and evolution.

Explore further: Potential biological control agents found for fungal diseases of soybean

More information: Wu S, Cheng J, Fu Y, Chen T, Jiang D, Ghabrial SA, et al. (2017) Virus-mediated suppression of host non-self recognition facilitates horizontal transmission of heterologous viruses. PLoS Pathog 13(3): e1006234. DOI: 10.1371/journal.ppat.1006234

Read more at: https://phys.org/news/2017-03-virus-barriers-incompatible-fungi.html#jCp

https://cm.g.doubleclick.net/push?client=ca-pub-0536483524803400&srn=gdn

Read Full Post »

west f p

Almond Bloom
The four main fungal diseases in almonds, which can do the most damage to the crop, are brown rot, anthracnose, shot hole, and jacket rot. All four are different and have different sensitivities to fungicides.

Cecilia Parsons | Mar 01, 2017

Warm and wet weather as the Central Valley’s almond orchards burst into bloom makes widespread fungal diseases almost a sure bet.

“If growers get behind on their control and can’t get the fungicide sprays on, they might get hammered this year,” warns Dani Lightle, University of California Cooperative Extension (UCCE) farm advisor in the Northern California counties of Glenn, Butte, and Tehama.

Lightle says, “If pathogens get a foothold and it rains through bloom and after, there may be a lot of crop damage. You can’t catch up with these diseases.”

David Doll, UCCE farm advisor at Merced County, says fungicide applications are a preventative measure, not a control. Wet conditions during this year’s bloom created a perfect environment for fungal growth.

The pathogens are always present in an orchard, Doll explains, but they need a host and the right environmental conditions. Continued warm and wet conditions during bloom can open the doors for fungal infections.

“With no fungicide applications and current conditions, significant yield losses can be expected,” Doll said. “Depending on the variety, it could be 20-30 percent.”

On Feb. 1, the California Department of Pesticide Regulation approved the aerial application of fungicides in six North State counties due to the number of almond orchards inaccessible with ground spray rigs.

The exemption allows for fungicide applications in orchards with standing water. No pumping of water is allowed after the applications and the sprays must cease if a rain event is imminent.

The four main fungal diseases in almonds, which can do the most damage to the crop, are brown rot, anthracnose, shot hole, and jacket rot. All four are different and have different sensitivities to fungicides, according to Doll.

ANTHRACNOSE

Anthracnose symptoms include blossom blight and fruit infections often with spur and limb dieback. Infected flowers appear similar to brown rot strikes. Infected nuts show round, orange-colored sunken lesions on the hull with symptoms appearing about three weeks after petal fall. Nuts can be infected later in the season if conditions are favorable.

Diseased nuts become mummified but remain attached to the spur. Shoots or branches with infected nuts often die. UC Integrated Pest Management (IPM) guidelines report that all cultivars are susceptible.

Management calls for fungicide treatments beginning at 5-10 percent bloom and repeated every 10-14 days if wet weather persists. Specific materials and application rates can be found on the IPM web site.

BROWN ROT

Almond blossoms are most susceptible to brown rot when fully open. Stigma, anthers, and petals are all susceptible to brown rot infection. Gum may secrete from the base of infected flowers.

This fungus survives on twig cankers and on remaining diseased flower parts and spurs. Spores are airborne or water splashed, and infections spread rapidly in wet weather with temperatures in the mid-70s.

Timing for control should be determined by the bloom of the most seriously affected cultivar. If infections were widespread the previous year, multiple fungicide applications may be necessary.

SHOT HOLE

Symptoms of shot hole include spots on leaves, hulls, twigs, and flowers. Leaf lesions begin as tiny reddish specks. Spots on young leaves will fall out leaving a shot hole appearance. Older leaves retain the lesions.

Heavy infections can cause nutlets to drop, become distorted, or gum up. Infected trees will weaken, defoliate, and lose production.

There is a high risk of shot hole development in the spring if shot hole lesions with fruiting structures are found on leaves in the fall. Fruiting structures appear in the center of leaf lesions as small black spots, viewable with a hand lens.

Fungicide applications depend on weather conditions and the level of infection found in the fall.

JACKET ROT

Jacket rot, or green fruit rot, begins later in the bloom period when the fungus infects petals and anthers. The infection can spread to floral tubes or flower jackets causing them to wither and stick to developing nutlets. Entire nut clusters can rot if covered with the infected flower parts.

Jacket rot is not as prevalent as the three other fungal diseases and is more likely to appear in cooler weather conditions. Fungicide should be applied at full bloom to prevent jacket rot.

Lightle says targeting fungicide choices to the fungal disease of concern is vital. She encouraged use of the fungicide efficacy tables available at http://ipm.ucanr.edu/PMG/r3902111.html.

Read Full Post »

Spread of damaging wheat rust continues: new races found in Europe, Africa, Central Asia

Mediterranean particularly affected by new rust races

Photo: ©FAO/ Fazil Dusunceli

Wheat experts examine a research plot near Izmir, Turkey, affected by wheat yellow rust.

3 February 2017, Rome −  Wheat rust, a family of fungal diseases that can cause crop losses of up to 100 percent in untreated susceptible wheats, is making further advances in Europe, Africa and Asia, according to two new studies produced by scientists in collaboration with FAO.

The reports, highlighted in the journal Nature following their publication by Aarhus University and the International Maize and Wheat Improvement Center (CIMMYT), show the emergence of new races of both yellow rust and stem rust in various regions of the world in 2016.

At the same time, well-known existing rust races have spread to new countries, the studies confirm, underlining the need for early detection and action to limit major damage to wheat production, particularly in the Mediterranean basin.

Wheat is a source of food and livelihoods for over 1 billion people in developing countries. Northern and Eastern Africa, the Near East, and West, Central and South Asia – which are all vulnerable to rust diseases − alone account for some 37 percent of global wheat production.

“These new, aggressive rust races have emerged at the same time that we’re working with international partners to help countries combat the existing ones, so we have to be swift and thorough in the way we approach this,” said FAO Plant Pathologist Fazil Dusunceli. “It’s more important than ever that specialists from international institutions and wheat producing countries work together to stop these diseases in their tracks −  that involves continuous surveillance, sharing data and building emergency response plans to protect their farmers and those in neighboring countries.”

Wheat rusts spread rapidly over long distances by wind. If not detected and treated on time, they can turn a healthy looking crop, only weeks away from harvest, into a tangle of yellow leaves, black stems and shriveled grains.

Fungicides can help to limit damage, but early detection and rapid action are crucial. So are integrated management strategies in the long run.

wheat_stem-rust_1Stem rust

Mediterranean most affected by new rusts

On the Italian island of Sicily, a new race of the stem rust pathogen −called TTTTF− hit several thousands of hectares of durum wheat in 2016, causing the largest stem rust outbreak that Europe has seen in decades. Experience with similar races suggests that bread wheat varieties may also be susceptible to the new race.

TTTTF is the most recently identified race of stem rust. Without proper control, researchers caution, it could soon spread over long distances along the Mediterranean basin and the Adriatic coast.

Various countries across Africa, Central Asia and Europe, meanwhile, have been battling new strains of yellow rust never before been seen in their fields.

Italy, Morocco and four Scandinavian countries have seen the emergence of an entirely new, yet-to-be-named race of yellow rust. Notably, the new race was most prevalent in Morocco and Sicily, where yellow rust until recently was considered insignificant. Preliminary analysis suggests the new race is related to a family of strains that are aggressive and better adapted to higher temperatures than most others.

Wheat farmers in Ethiopia and Uzbekistan, at the same time, have been fighting outbreaks of yellow rust AF2012, another race which reared its head in both countries in 2016 and struck a major blow to Ethiopian wheat production in particular. AF2012 was previously only found in Afghanistan, before appearing in the Horn of Africa country last year, where it affected tens of thousands of hectares of wheat.

“Preliminary assessments are worrisome, but it is still unclear what the full impact of these new races will be on different wheat varieties in the affected regions,” said Dusunceli. “That’s what research institutions across these regions will need to further investigate in the coming months.”

To offer support, FAO, in collaboration with its partners, is stepping up its efforts in training rust experts from affected countries to boost their ability to detect and manage these emerging wheat rust races.

As new races emerge, old ones continue to spread

The already established Warrior(-) race of yellow rust − which came onto scientists’ radars in Northern Europe and Turkey a few years ago −  continued its aerial march in 2016 and is now widely present in Europe and West Asia.

The Digalu (TIFTTF) race of stem rust continues to devastate wheats in Ethiopia, while the most well-known race of stem rust – the highly potent Ug99 – is now present in 13 countries. Having spread in a northward trend from East Africa to the Middle East, Ug99 has the potential to affect many wheat varieties grown worldwide as it keeps producing new variants. Most recently, it has been detected in Egypt, one of the Middle East’s most important wheat producers.

International collaboration crucial

The findings of the Aarhus study build on training sessions conducted in 2016 in collaboration between the International Center for Agricultural Research in the Dry Areas (ICARDA), Aarhus university, CIMMYT and FAO.

The training, which will be repeated this year, allows rust experts to strengthen their surveillance and management skills, coupled with surveys and collection of rust samples for tests and analysis by Aarhus University. The recently established Regional Cereal Rust Research in Izmir, Turkey, will host the training.

These efforts have been part of FAO`s four-year global wheat rust program, which facilitates regional collaborations and offers support to individual countries eager to boost their surveillance capacity.

It also helps countries act swiftly to control outbreaks before they turn into epidemics and cause major damage to food security. But further research, particularly into breeding resistant varieties, and national response plans need to be backed by adequate resources.

FAO, CIMMYT, ICARDA and Aarhus University are working together as members of the Borlaug Global Rust Initiative (BGRI).

Read Full Post »

IBIS daily digest

Morning Agclips

WHEAT DISEASE …

Found in Europe, Africa, Central Asia; Mediterranean particularly impacted

Wheat experts examine a research plot near Izmir, Turkey, affected by wheat yellow rust. (Courtesy Photo)

 

ROME — Wheat rust, a family of fungal diseases that can cause crop losses of up to 100 percent in untreated susceptible wheats, is making further advances in Europe, Africa and Asia, according to two new studies produced by scientists in collaboration with FAO.

The reports, highlighted in the journal Nature following their publication by Aarhus University and the International Maize and Wheat Improvement Center (CIMMYT), show the emergence of new races of both yellow rust and stem rust in various regions of the world in 2016.

At the same time, well-known existing rust races have spread to new countries, the studies confirm, underlining the need for early detection and action to limit major damage to wheat production, particularly in the Mediterranean basin.

Wheat is a source of food and livelihoods for over 1 billion people in developing countries. Northern and Eastern Africa, the Near East, and West, Central and South Asia – which are all vulnerable to rust diseases − alone account for some 37 percent of global wheat production.

“These new, aggressive rust races have emerged at the same time that we’re working with international partners to help countries combat the existing ones, so we have to be swift and thorough in the way we approach this,” said FAO Plant Pathologist Fazil Dusunceli. “It’s more important than ever that specialists from international institutions and wheat producing countries work together to stop these diseases in their tracks −  that involves continuous surveillance, sharing data and building emergency response plans to protect their farmers and those in neighboring countries.”

Wheat rusts spread rapidly over long distances by wind. If not detected and treated on time, they can turn a healthy looking crop, only weeks away from harvest, into a tangle of yellow leaves, black stems and shriveled grains.

Fungicides can help to limit damage, but early detection and rapid action are crucial. So are integrated management strategies in the long run.

Mediterranean most affected by new rusts

On the Italian island of Sicily, a new race of the stem rust pathogen −called TTTTF− hit several thousands of hectares of durum wheat in 2016, causing the largest stem rust outbreak that Europe has seen in decades. Experience with similar races suggests that bread wheat varieties may also be susceptible to the new race.

TTTTF is the most recently identified race of stem rust. Without proper control, researchers caution, it could soon spread over long distances along the Mediterranean basin and the Adriatic coast.

Various countries across Africa, Central Asia and Europe, meanwhile, have been battling new strains of yellow rust never before been seen in their fields.

Italy, Morocco and four Scandinavian countries have seen the emergence of an entirely new, yet-to-be-named race of yellow rust. Notably, the new race was most prevalent in Morocco and Sicily, where yellow rust until recently was considered insignificant. Preliminary analysis suggests the new race is related to a family of strains that are aggressive and better adapted to higher temperatures than most others.

Wheat farmers in Ethiopia and Uzbekistan, at the same time, have been fighting outbreaks of yellow rust AF2012, another race which reared its head in both countries in 2016 and struck a major blow to Ethiopian wheat production in particular. AF2012 was previously only found in Afghanistan, before appearing in the Horn of Africa country last year, where it affected tens of thousands of hectares of wheat.

“Preliminary assessments are worrisome, but it is still unclear what the full impact of these new races will be on different wheat varieties in the affected regions,” said Dusunceli. “That’s what research institutions across these regions will need to further investigate in the coming months.”

To offer support, FAO, in collaboration with its partners, is stepping up its efforts in training rust experts from affected countries to boost their ability to detect and manage these emerging wheat rust races.

As new races emerge, old ones continue to spread

The already established Warrior(-) race of yellow rust − which came onto scientists’ radars in Northern Europe and Turkey a few years ago −  continued its aerial march in 2016 and is now widely present in Europe and West Asia.

The Digalu (TIFTTF) race of stem rust continues to devastate wheats in Ethiopia, while the most well-known race of stem rust – the highly potent Ug99 – is now present in 13 countries. Having spread in a northward trend from East Africa to the Middle East, Ug99 has the potential to affect many wheat varieties grown worldwide as it keeps producing new variants. Most recently, it has been detected in Egypt, one of the Middle East’s most important wheat producers.

International collaboration crucial

The findings of the Aarhus study build on training sessions conducted in 2016 in collaboration between the International Center for Agricultural Research in the Dry Areas (ICARDA), Aarhus university, CIMMYT and FAO.

The training, which will be repeated this year, allows rust experts to strengthen their surveillance and management skills, coupled with surveys and collection of rust samples for tests and analysis by Aarhus University. The recently established Regional Cereal Rust Research in Izmir, Turkey, will host the training.

These efforts have been part of FAO`s four-year global wheat rust program, which facilitates regional collaborations and offers support to individual countries eager to boost their surveillance capacity.

It also helps countries act swiftly to control outbreaks before they turn into epidemics and cause major damage to food security. But further research, particularly into breeding resistant varieties, and national response plans need to be backed by adequate resources.

FAO, CIMMYT, ICARDA and Aarhus University are working together as members of the Borlaug Global Rust Initiative (BGRI).

–FAO

– See more at: https://www.morningagclips.com/spread-of-damaging-wheat-rust-continues/#sthash.xFba0wMD.dpuf

Read Full Post »

Weird year for Sicilian citrus fruit

“Citrus fruit production this year is quite low, especially for oranges. Producers not only had to deal with the CTV-Citrus Tristeza Virus, but also with a whole lot of other factors – mild temperatures during the past winters, lower blossoming, wider yield alternance. In addition, it rained a lot in September,” reports Corrado Vigo, agronomist and President of the Ordine dei Dottori Agronomi e dei Dottori Forestali in Catania.

For what concerns the rain/drought, Vigo explains that “I have noticed these events are cyclical, they occur every 10-11 years. What is weird is that this cycle coincides with the Sun cycle. We are expecting some more rain in December as well.”

In addition to the weather conditions, there is a series of fungi, pathogens and Phytophthora that, with the temperatures registered so far, spread. “For example, the persistent rain in September triggered Phytophthora citrophthora, which led to a loss of fruit. In addition, in October, there was a late attack of Ceratitis capitata“.

There are a lot of drops of yet unripe oranges as well as a lot of mouldy fruit on the trees. The areas of Scordia, Lentini, Palagonia and Mineo were affected by dessicating wind, which damaged both the fruit and the leaves. “We already expected a drop in volumes, but now they will be even lower.”

Varietal innovation
“There are very few innovative varieties. Producers are looking to replace the trees (especially because of the Citrus Tristeza Virus), but costs are high. The last PSR call for bids, for example, ended in 2012 and the new one hasn’t opened yet. If we consider that, last year, oranges sold at 4 cents, we can see how it might be difficult to end the year positively, let alone make investments.”

We must also keep in mind that orchard response times are slow. “We are talking about seven/eight years for a full production cycle. Another problem is the availability of plants. In Sicily, we generate around 1.5/2 million plants. To reconvert the areas affected, 24-25 million plants are needed and it would take 12-13 years.”

Competition
“Just like every year, our citrus fruit is available on the market as well as oranges from Spain and grapefruit from Israel, for example.”
“I keep thinking about the French, who only buy produce made in France before anything else. Only then do they look for something foreign. In Italy, it seems as if we welcome foreign produce.”

Contacts:
Corrado Vigo
Email: corrado@vigo.it
Web: www.vigo.it

 

Publication date: 12/8/2016

Read Full Post »

Older Posts »