Feeds:
Posts
Comments

Archive for the ‘Weeds’ Category

VA Tech logo

Invasive plants have surprising ability to pioneer new continents and climates, Virginia Tech researchers discover

December 4, 2017

Velvetleaf plant
Velvetleaf represents one of the many invasive plant species that was tested by Dan Atwater and Jacob Barney.

Virginia Tech scientists have discovered that invasive plant species are essentially able to change in order to thrive on new continents and in different types of climates, challenging the assumption that species occupy the same environment in native and invasive ranges.

It’s no secret that globalization, aided by climate change, is helping invasive species gain a foothold across the planet, but it was something of a surprise to Virginia Tech researchers just how mutable these invaders are.

The study, by Jacob Barney, an associate professor in the College of Agriculture and Life Sciences’ Department of Plant Pathology, Physiology, and Weed Science, and Dan Atwater, a lecturer in the Department of Biological Sciences at North Carolina State University and Barney’s former post-doctoral advisee, was published Dec. 4 in Nature Ecology and Evolution, a new online journal.

Two Virginia Tech researchers
Dan Atwater, left, and Jacob Barney examined 815 terrestrial plant species from every continent, along with millions of occurrence points, and compared models in the largest global invasive species study to date.

“This is important for both changing how we think about species and where they grow,” said Barney, who is also a fellow in the Fralin Life Science Institute and an affiliate of the Global Change Center. “The findings also change our ability to predict where they will grow and how they may respond in a changing climate. This could be a game-changer for invasive species risk assessment and conservation.”

Atwater used data compiled by undergraduate Carissa Ervine, also an author on the paper, to test a long-held assumption in ecology – that the climate limitations of plants do not change, which means we can predict where they will grow. Small studies supported this supposition. However, the Virginia Tech researchers blew this assumption away by testing more than 800 species using new models developed by Atwater and Barney.

“Some people would say that invasive species have different distributions in a new climate. But we found they are occupying a wider range of new climates,” said Atwater. “Species are changing in their ecology when they move from one continent to another. We should expect species to change, possibly permanently, when they cross continents.”

The results have major consequences for applying environmental niche models to assess the risk of invasive species and for predicting species’ responses to climate change. Species capable of changing their ecology and the climates they call home may pose a challenge to researchers using native range data to forecast the distribution of invasive species.

The driver behind the study was a desire to forecast the future distribution of invasive species, which pose a serious threat to human, environmental, and economic health. The researchers began by posing the question: Do invasive species occupy the same climate in invasive range that they do in their native range? To find out, they compared native and invasive species.

Barney and Atwater examined 815 terrestrial plant species from every continent, along with millions of occurrence points, or locations where the plants have been known to occur, and compared models in the largest global invasive species study to date. They found evidence of climatic niche shifts in all of the 815 plant species introduced across five continents. A climatic niche refers to the set of climates in which a species has a stable or growing population.

Generally, their findings suggest that niche shifts reflect changes in climate availability at the continent scale and were the largest in long-lived and cultivated species. If species move to a warmer continent, for instance, they tend to shift toward occupying warmer climates. In short, cultivated plants with long lifespans are particularly adept at making themselves home in new climates.

“There are not only implications for predicting where invasive species will occur, there are management repercussions as well,” said Barney. “As an example, for certain species we use biocontrol, introducing one organism to control another, an approach that may not be effective or safe if the targeted species undergoes ecological change. When we do climate modeling, we assume the climate niche may be the same when it may not be. So, there are a broad range of implications in a broad range of fields.”

Barney raised another concern.

“By cultivating species — bending them for agricultural or ornamental purposes and selecting for traits, such as cold-hardiness, we push them into environments they would not have occupied,” he said. “Those selection pressures in breeding, plus the environments we put them in, may exaggerate this change. Short-lived species, for example, go into dryer climates. So the take home is that different species’ traits influence the direction of a niche shift.”

Once Atwater and Barney understand these drivers more fully, they hope to be able to predict how the geographic range of an invasive species will increase in order to pinpoint areas likely to be invaded.

“The other piece layered onto this is the assumption that the climate is stable, which is not the case,” said Atwater. “We have also relied on the assumption that a species is a species and its ecological tendencies remain constant. This too is not the case. Species vary in space and time. They behave differently on different continents and in different climates. Consequently, the concept of a species climatic niche is less stable and less clearly defined.”

With food production, human health, ecosystem resilience, and biodiversity at stake as global invasions outpace our ability to respond, a greater understanding of climatic niche shifts is critical to future attempts to forecast species dynamics, according to the researchers.

 

—      Written by Amy Painter

Contact:

 

Read Full Post »

BCPC News

Aussie scientists develop microwave device that kills weeds instantly

Source: Xinhua| 2017-11-22 08:53:32|Editor: pengying

SYDNEY, Nov. 22 (Xinhua) — Australian scientists on an experimental farm have developed a revolutionary method of killing weeds using microwaves.

Graham Brodie, a food and agriculture lecturer at the University of Melbourne’s agricultural campus, an experimental farm in Dookie, 226 km north of Melbourne, has developed the method of using trailer-mounted microwave generators to combat weeds.

A bank of four microwave generators, approximately double the power of an average microwave oven, is put on the back of the trailer which is then driven over the weeds, killing them immediately.

The generators “cook” the weeds from the inside, just as a microwave oven does with food, leaving them wilted and dead rather than burned or shrivelled.

The range of radiation is limited to between two and three centimeters, enough to kill the weeds while making the device safe to operate.

“It kills the plants almost instantaneously,” Brodie told the university’s internal publication on Wednesday.

“The big gain is that we can kill weeds without herbicides, so we don’t have to worry about weeds that are now evolving chemical resistances, and it kills the seeds left in the soil too so the weeds don’t grow back.

“It can also be done in any weather, it isn’t a fire hazard, and farmers can sow their crops immediately instead of having to wait for the herbicide to clear.”

The device could save the Australian agricultural industry more than 3 billion U.S. dollars which is spent by farmers on herbicides every year.

Testing of Brodie’s device found that it was marginally more expensive than using herbicides but had added benefits such being longer lasting, enriching soil and killing pests such as snails, fungi and parasites.

Brodie said the microwaves did kill worms that were within five centimeters of the surface but deeper-lying worms were unharmed.

The device has been patented and will be subjected to a large-scale trial

 

Read Full Post »

The Country

Two rust fungi that are very welcome

Entomologist Jenny Dymock with a Cable Bay lantana plant showing the damage done by a biocontrol fungus.
Entomologist Jenny Dymock with a Cable Bay lantana plant showing the damage done by a biocontrol fungus.

The discovery of myrtle rust in a Kerikeri nursery earlier this year sparked a dramatic but probably futile bid by the Ministry of Primary Industries to contain and destroy it, but not all rusts are equal.

Two rust fungi that attack Lantana camara have not only been welcomed – they were deliberately introduced, and according to Cable Bay-based entomologist Jenny Dymock, one is beginning to have a noticeable impact on the pest plant in Northland.

The Environmental Protection Authority approved the release of Puccinia lantanae and Prospodium tuberculatum to control lantana in 2012. Both were released in Northland (the Whangaroa, Doubtless Bay, Awanui and Kohukohu areas) in autumn.

Dr Dymock, who works with the Northland Regional Council, said they worked by restricting the growth rate and fruit and leaf production of lantana, one of the world’s most invasive weeds.

While Puccinia lantanae (a blister rust) did not appear to have established itself in Northland yet, the leaf rust Prospodium tuberculatum was beginning to have a big impact on lantana populations, as evidenced by the number of plants with dead or dying branches.

Lantana was a serious problem in Northland, where it formed dense thickets that invaded a wide variety of areas, from native and exotic forests to domestic gardens, roadsides, sand dunes, quarries and wasteland, Dr Dymock said.

Typically a low, scrambling shrub with small, colourful flowers, lantana could be poisonous to people and grazing stock. It had thorny stems, strong-smelling leaves, especially when crushed, and produced fruit that was attractive to birds, which then spread its seeds to uninfested sites.

The NRC was behind the original application to the EPA to import the rusts, part of a growing number of host-specific weapons in the council’s biocontrol arsenal.

She was delighted to see the rust, native to Brazil, making a noticeable dent in the local lantana population. Surprisingly, it appeared to be most effective in late winter, which she attributed to wetter conditions.

“Many people will be unaware that we have a range of more than two dozen biological control agents already in use in Northland, with even more likely to be available in the future,” Dr Dymock added.

“Biological control is the use of naturally-occurring enemies and diseases to control pests and weeds. A cost-effective and environmentally-friendly method of pest control, it’s not designed to eradicate a species; instead it aims to keep populations at low levels.”

As well as fungi and bacteria, biological control tools included an “army” of insects, some of which targeted other insects, and even tiny internal parasites.

The process from lowly insect or fungus to biological control agent was a painstaking, lengthy and initially costly one, however.

“The NRC typically spends at least $80,000 a year on biological control work, and is part of a national group that collectively spends more than $600,000 on this annually,” she said.

Signs of an introduced rust fungus at work on a lantana leaf.
Signs of an introduced rust fungus at work on a lantana leaf.

The first step in finding a biocontrol agent was a survey of the target’s natural enemies, in New Zealand and/or overseas. If no natural enemies were found in New Zealand, potentially suitable overseas candidates from areas with a climate matching Northland’s had to be extensively tested in a secure quarantine facility to determine whether they would attack any native New Zealand species, or any species that was of economic value.

“Only when researchers are confident the potential biocontrol agent attacks just the target species alone is an application for release from quarantine made to the EPA, followed by consultation with the public and stakeholders,” she said.

It could take years to progress from beginning an initial hunt for a biological control agent to approval of its release.

Anyone who was interested in learning more about biocontrol in Northland should visit www.nrc.govt.nz/biologicalcontrol.

Northland Age

Read Full Post »

icbc China.png

cspp-logo-copy1

FIRST INTERNATIONAL CONGRESS OF BIOLOGICAL CONTROL

The first International Congress of Biological Control will be held in Beijing, China, May 14-16, 2018.

The purpose of the congress is to strengthen communication and cooperation between researchers investigating biological control techniques of insect pests, invasive weeds and plant diseases, and to promote the global development of biological control technology and industry. The theme of this conference is: Biological Control for a Healthy Planet with a sub-theme of Interdisciplinary Biological Control.

This congress, hosted jointly by Chinese Academy of Agricultural Sciences (CAAS), China Society of Plant Protection (CSPP) and International Organization for Biological Control (IOBC) will cover a wide range of biological control topics regarding insect pests, invasive weeds and plant diseases. The organizing committee has invited many excellent scientists to attend the congress and more excellent investigators are joining the congress. We are confident that you will enjoy the congress in Beijing, China’s beautiful and historic capital city and discuss new developments and future directions of biological control with scientists around the world. It is our great honor to welcome you to the First International Congress of Biological Control.

The conference will include three sessions: plenary lectures, invited talks, poster session and the exhibition of new technologies and products. Topics will include, but no limited to, the following:

  • Integration of the various classes of biological control
  • Biological control of plant diseases, insect pests and weeds
  • Biological control as a means of preserving biodiversity
  • The impact of climate change on biological control
  • Risk assessment and biosafety for biological control
  • Industrial policy and market development of biological control
  • Socio-economic impacts and capacity building for biological control
  • Current status and uptake of biological control in the Belt and Road countries

Committee Chairs

Scientific Committee Chairs Organizing Committee Chairs Local Working Group Leader
WU Kongming (CAAS) TANG Huajun (CAAS) QIU Dewen (CAAS)
George Heimpel (IOBC) Barbara Barratt (IOBC)  

 Program outline

May 14, 2018:AM: plenary lectures; PM: Session presentations

May 15, 2018: AM: plenary lectures; PM: visit Modern Agricultural Exhibition

May 16, 2018: Session presentations and closing speech

Registration and Accommodation

You can register online or fill in the preliminary registration form and send it to us by E-mail. We have selected international hotels for participants. Please make your hotel choices and send to us when you register.

For more detailed information about registration and accommodation, please refer to our website.

http://www.canevent.com/customPage/customPagePreview?pageId=43612&eventId=10003226

Contact Persons

Qiu Dewen (CAAS) Gao Yulin (IOBC)
Email: qiudewen@caas.cn Email: gaoyulin@caas.cn
   

Read Full Post »

Scoop Regional

Independent News

Rust fungus proving value in battle against lantana

04 October, 2017

Rust fungus proving value in battle against lantana

A rust fungus introduced to New Zealand two years ago to wage biological war against ‘Lantana camara’ is starting to have a noticeable impact on the pest plant in Northland.

Entomologist Jenny Dymock says the Environmental Protection Authority (EPA) approved the release of two rust fungi – Puccinia lantanae andProspodium tuberculatum – to control lantana in April 2012, with both subsequently released in Northland in 2015.

Cable Bay-based Dr Dymock, who works with the Northland Regional Council (NRC), says the fungi were released in the Whangaroa, Doubtless Bay, Awanui and Kohukohu areas in autumn two years ago.

The rusts work by reducing the growth rate and fruit and leaf production of lantana plants, one of the world’s most invasive weeds.

While Puccinia lantanae (a blister rust) did not appear to have established itself in Northland yet, in contrast the leaf rust Prospodium tuberculatum was beginning to have a big impact on local lantana populations, as evidenced by the number of lantana with dead and dying branches.

Lantana is a serious problem in Northland, where it forms dense thickets that invade a wide variety of areas from native and exotic forests to domestic gardens, roadsides, sand dunes, quarries and wasteland.

Typically a low, scrambling shrub with small, colourful flowers, lantana can be poisonous to people and grazing stock. It has thorny stems, strong-smelling leaves, especially if they’re crushed, and produces fruit that’s attractive to birds, which then spread its seeds to uninfested sites.

Dr Dymock says the NRC was behind the original application to the EPA to import the rusts, part of a growing number of host-specific weapons in the council’s biocontrol arsenal.

She says it’s great to see the rust – a native of Brazil – making a noticeable dent in the local lantana population. Surprisingly, in Northland it appears to be damaging lantana especially well during late winter, something Dr Dymock attributes to the wetter conditions.

“Many people will be unaware that we have a range of more than two dozen biological control agents already in use in Northland, with even more likely to be available in the future.”

Biological control is the use of naturally-occurring enemies and diseases to control pests and weeds. A cost-effective and environmentally-friendly method of pest control, it’s not designed to eradicate a species; instead it aims to keep populations at low levels.

Dr Dymock says as well as fungi and bacteria, other biological control tools include an army of insects – including some which target other insects – and even tiny internal parasites.

However, she says the process from lowly insect or fungus to biological control agent is a painstaking, lengthy and initially costly one.

“The NRC typically spends at least $80,000 a year on biological control work and is part of a national group that collectively spends more than $600,000 on this annually.”

She says the first step in finding biocontrol agents is a survey of the natural enemies of the target weed or pest either here in New Zealand and/or overseas.

If no natural enemies of a target weed or pest are found in New Zealand then

potentially suitable overseas candidates from areas with a climate matching Northland’s must be extensively tested in a secure quarantine facility to determine whether they will attack any native New Zealand species or any species that is of economic value.

“Only when researchers are confident the potential biocontrol agent attacks just the target species alone, an application for release from quarantine is made to the EPA, followed by consultation with the public and stakeholders.”

Dr Dymock says it can take years from when an initial hunt for a biological control agent begins to when approval for its release is finally given.

She says those interested in learning more about biocontrol in Northland should visit www.nrc.govt.nz/biologicalcontrol

Read Full Post »

agweek

 

Grand Forks, ND

70°

<!–

–>

The impact of dicamba drift on fields won’t be known until soybean harvest begins. (Michelle Rook/Special to Agweek)

Yield impact of dicamba injury unknown, label changes possible in SD

HURON, S.D. — The South Dakota Department of Agriculture fielded dozens of dicamba injury complaints from off-target drift this season, and they’re still taking input from farmers to determine the total number of acres hit. State officials are looking at possible label changes for spraying dicamba on Xtend soybeans next year, but a lot of that hinges on what farmers find in the fields this fall.

Farmers that had some or widespread cupping in soybeans this season may not know the full production impact until harvest.

 “The combine will tell, we don’t know,” says Reno Brueggeman, who farms near Miller, S.D. “Nobody knows. It’s one of those things that nobody’s seen before. Maybe nothing is going to come of it, maybe there won’t be any yield loss, but nobody knows.”

South Dakota Secretary of Agriculture Mike Jaspers agrees about the unknowns.

“For the most part I don’t think we’re going to know until harvest gets here,” he says. “Fortunately, we do have the technology of yield monitors and things on the majority of farms, so I think that will help.”

Agronomists are looking at past research on the yield impact of dicamba on soybeans for clues. “The real key was, as long as the growing point wasn’t hurt, it was felt that beans will be fine and recover,” says Paul Johnson, South Dakota State University Extension weed specialist.

 However, he says most of the research was done 40 years ago and the application timing was different then. “The difference is now we are spraying it a month later than we did before, and we really don’t know how those effects will compare the same or not,” Johnson says. “In a lot of cases, maybe we were pushing the window on the application timing, because once we go past the last week of June, we’re going to start flowering and it is just labeled for R1.”

 

Once more is known on yield impact, then state officials in South Dakota can determine label changes for 2018.

“I think we definitely will see changes in the labeling,” Jaspers says. “In South Dakota we did a one-year, restricted label which will expire in December, so virtually it’s done as the application season is done for this year, so we would have to reassess that label anyway. I’m looking at maybe restricting the time of day to try to get away from those inversion issues, or maybe have a restriction as far as growth stage or calendar date, so we don’t get into the hotter portions of the growing season.”

Jaspers encourages farmers to report damage and yield results to help them with that decision-making process.

“We’re definitely hoping that people will continue to report to the Department of Ag,” he says. “Right on our website there’s a link to a dicamba reporting page.”

Jaspers is also confident they’ll require the product manufacturers to do more education with farmers and applicators before the next growing season.

“In South Dakota we required a lot of education on their part — to come and do a lot of training and education of the applicators. I’m pretty confident that will be one of the key issues right there,” he says.

On the federal level, the Environmental Protection Agency is working with herbicide companies and manufacturers to decide if they will impose other label or application changes.

“I’d be surprised if we won’t see some modifications on the state level,” says Johnson.

The other lingering question is if a farmer proves there was a yield loss, will crop insurance cover that loss? Brueggeman, who is also an agent, says no.

“Crop insurance has to be a natural loss, natural cause of disaster. Your farm liability insurance is going to have to step in on this,” he says.

Despite that, Brueggeman says a large number of farmers are gearing up to plant Xtend soybeans again in 2018 because of the excellent weed control they get, especially on resistant weeds like kochia and waterhemp. He says the technology is not going away.

“There’s a lot of people who are mad and it’s understandable, but I hope they have an open mind. We can get through this point,” he says.

Read Full Post »

Cornell Chronicle

Beneficial soil bacteria face a weed-killing threat from above

Blaine Friedlander

Media Contact

Lindsey Hadlock

As farmers battle in their above-ground war on weeds, they may inadvertently create underground casualties – unintentionally attacking the beneficial bacteria that help crops guard against enemy fungus.

Cornell researchers have found an agricultural conflict: negative consequences of the weed-killing herbicide glyphosate on Pseudomonas, a soil-friendly bacteria.

“Beneficial Pseudomonas in the soil can help crops thrive. They can produce plant-stimulating hormones to promote plant growth and antifungals to defeat problematic fungi – such as Pythium and Fusarium – found in agricultural soil, but previous studies reported that the abundance of beneficial bacteria decreased when the herbicide glyphosate seeps underground,” said Ludmilla Aristilde, assistant professor of biological and environmental engineering. “Our study seeks to understand why this happens.”

Soil bacteria require their proteins – composed of amino acids – and their metabolism to support cellular growth and the production of important metabolites to sustain their underground fight. But glyphosate applied to crops can drain into the soil and disrupt the molecular factories in the bacterial cells in some species, interfering with their metabolic and amino acid machinery.

The new findings show that glyphosate does not target the amino acid production and metabolic gadgetry equally among the Pseudomonas species. For example, when Pseudomonas protegens, a bacteria used as a biocontrol agent for cereal crops, and Pseudomonas fluorescens, used as a fungus biocontrol for fruit trees, were exposed to varying glyphosate concentrations, the researchers noted no ill effects. However, in two species of Pseudomonas putida, used in soil fungus control for corn and other crops, the bacteria had notably stunted growth, said Aristilde, who is a faculty fellow at Cornell’s Atkinson Center for a Sustainable Future.

“Thus, if a farmer is using Pseudomonas fluorescens as a biocontrol, then it is probably okay to use glyphosate,” Aristilde said. “But if the farmer uses Pseudomonas putida to control the fungus in the soil, then glyphosate is more likely to prevent the bacteria from doing its job.”

The study offers molecular details for why glyphosate adverse effects on Pseudomonas are species-specific. “That’s actually good news because – as a society – we will likely not stop using herbicide completely,” said Aristilde. “If that is the case, farmers need to know which beneficial soil biocontrol they’re using can be susceptible. If they’re using a strain that is susceptible and conflicting with their herbicide application, then it is a problem. That’s the bottom line.”

Aristilde will present this research to farmers and agricultural professionals Nov. 14 at the Agriculture, Food & Environmental Systems In-Service training hosted in Ithaca by Cornell Cooperative Extension.

Glyphosate-Induced Specific and Widespread Perturbations in the Metabolome of Soil Pseudomonas Species” was published in Frontiers of Environmental Science in June 2017. Co-authors are Michael Reed ’17; graduate student Rebecca Wilkes; Tracy Youngster, M.S. ’17; Matthew Kukurugya, M.S. ’17; Valerie Katz ’18; and Clayton Sasaki ’18. The research was funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture; the National Science Foundation; and the Academic Venture Fund at Cornell’s Atkinson Center for a Sustainable Future.


Story Contacts

Blaine Friedlander

Read Full Post »

Older Posts »