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GM diamondback moths

Hort week

“Self-limiting” diamondback moths trialled in US

An Oxford-based biotech firm has begun field trials of genetically modified (GM) diamondback moths that aim to control numbers of this damaging pest.

Image: Olaf Leillinger (CC-BY-SA-2.5)
Image: Olaf Leillinger (CC-BY-SA-2.5)

A non-native arrival to the US, the diamondback moth (Plutella xylostella) is the world’s most damaging agricultural pest of brassica crops, costing US farmers over $4 billion yearly in crop losses and control management. It also has a high level of resistance to conventional pesticides.

Instead the male GM moths, bred by US-owned Oxitec, pass on a self-limiting gene that prevents their female offspring from reaching adulthood.

The moths also have a fluorescent protein marker to distinguish them from wild pest moths, enabling their spread to be tracked.

The US government-approved field evaluation will be conducted at Cornell University’s New York State Agricultural Experiment Station, led by the university’s Professor Tony Shelton, an expert on sustainable agriculture.

“Importantly, this technology only targets this damaging pest species, and does not affect beneficial insects such as pollinators and biological control agents,” he said.

“Our previous greenhouse and field cage studies of this technology worked extremely well, and the evaluation will help us determine how well it works in the field.”

The earlier research was published in the journal BMC Biology.

Unusually large numbers of the moths were found in the UK last year, causing widespread damage to brassica crops.


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west f p

Don Hopkins Matt Daugherty
University of Florida plant pathologist Don Hopkins surveys vines in University of California -Riverside test plots for symptoms of Pierce’s disease.

A new biocontrol shot protects wine grapes from Pierce’s disease

In an extensive series of lab studies and in field trials at vineyards in several states including those at the University of California – Riverside, this form of biocontrol has proven effective in preventing vines from developing the disease.

Greg Northcutt | Sep 13, 2017

Although Pierce’s disease has been a threat to California vineyards since at least the 1880s, when it wiped out 40,000 acres of wine grapes in the Los Angeles Basin, there’s still no cure for it. However, Don Hopkins, a University of Florida plant pathologist, has found a way to protect uninfected vines from the disease by giving them a shot of a benign strain of the same type of bacterium that causes it.

In an extensive series of lab studies and in field trials at vineyards in several states including those at the University of California – Riverside, this form of biocontrol has proven effective in preventing vines from developing the disease, Hopkins said.

 This benign bacterial strain is part of a broader class of control agents often referred to as symbiotic control. The strain was patented in 2009 by the University of Florida, which recently licensed it for commercial development.

 

In Florida, where vineyards have long faced heavy pressure from Pierce’s disease, Vitis vinifera grape vines typically die within about three or four years after becoming infected with the disease. However, one block of Cabernet Sauvignon in a Florida vineyard remains free of Pierce’s disease symptoms 15 years after Hopkins inoculated the vines with the benign strain of the pathogen.

The disease is caused by the bacterium, Xylella fastidiosa. Growing in the xylem, the water-conducting vessels of the vine, it can kill grape vines in as little as a year or two by blocking movement of the water.

The economic cost of Pierce’s disease to California’s grape growers began rising significantly in the early 1990s, not long after arrival of the invasive glassy-winged sharpshooter, likely as eggs on nursery stock from the southeastern United States. It’s one of several members from two groups of insects – sharpshooters and spittlebugs – which can spread the disease by feeding on the xylem sap.

The glassy-winged sharpshooter is the most threatening vector because of its ability to use a much greater diversity of host plants – more than 300 different types – than the others and to achieve much higher population densities.

The glassy-winged sharpshooter was first found in Orange and Ventura counties in 1989. Since then it has spread throughout southern California and into the central part of the state, including San Luis Obispo, Santa Barbara, Santa Clara and Tulare counties. Recently, after several years of effectively controlling the glassy-winged sharpshooter, growers in some areas of the state have seen populations of the pest beginning to resurge significantly.

Hopkins discovered the benign strain of Xylella fastidiosa in an elderberry bush as part of his initial research on the bacterium. During several years of lab testing in the early 1990s, he found that, by introducing this benign bacterial strain into very young vines and then exposing them to the pathogenic strain, most vines did not develop Pierce’s disease.

In the lab, Hopkins treated the very young vines by placing a drop of the benign bacterial suspension on the stems. Then, he punctured the vines with a needle, which allowed the bacteria to be taken up in the xylem. Two weeks later he used this approach to inject these same vines with the pathogenic strain. In most cases, the vines treated with the biocontrol did not show symptoms of Pierce’s disease.

Meanwhile, others vines, which did not receive the biocontrol treatment, were injected with the pathogen. Most of them later developed Pierce’s disease.

Hopkins then repeated these trials under actual field conditions in a Florida vineyard. “The biocontrol turned out to be more effective at preventing the disease in the vineyard than it was in the greenhouse,” Hopkins says.

Next followed vineyard trials involving a number of different wine grape varieties in Florida as well as in Georgia and California. Vines that were not inoculated with the benign strain of the bacterium often developed symptoms of Pierce’s disease in one to six months.

“Usually, in new plantings, we can see a difference in the health of treated and non-treated vines within from six months to three years,” Hopkins says.

Meanwhile, most of the inoculated vines remained free of the disease throughout the five- to six-year-length of the studies.

“We don’t know how this benign strain of the bacterium works to protect the vine,” he says. “Somehow it doesn’t allow the pathogen to build up in large enough numbers to block the xylem.”

Results of the UC-Riverside vineyard trials with Cabernet Sauvignon and Pinot Noir, which began in 2012, have been similar to those in Florida and Georgia.

“As of last year, we had not lost any treated vines to Pierce’s disease, and the growth, vigor and production of most of these vines remained really good,” Hopkins said. “However, several untreated vines died from the disease. Also, some of the treated vines were showing symptoms of the disease by the end of the trial. Either they didn’t get inoculated properly or the pathogen overcame the benign strain of the bacterium. But, that’s to be expected. As with any type of biocontrol, treatment is not 100 percent effective.”

Hopkins notes some of the other findings in this research:

  • Early on he and his colleagues noticed the benign bacterium doesn’t colonize young vines much past the 10th or 12th internode. The colony of the pathogenic strain, on the other hand, continues to advance through the plant as the vine grows. Still, the biocontrol induces resistance to Pierce’s disease beyond the area which it colonizes.
  • The benign strain of the bacterium multiplies at a much lower rate than the pathogenic strain. In fact, Hopkins notes, the population of the strain of benign bacterium in the vine is 100-fold smaller than the pathogenic strain and does not build up populations in the grape plant that will cause symptoms.

Hopkins says that, while this treatment can prevent most of the vineyard from becoming infected with Pierce’s disease, it won’t cure vines that have already been infected with it. “If a mature grape vine is coming down with Pierce’s disease, this biocontrol treatment is not going to prevent the disease from developing and, eventually, killing the vine,” he says.

While stress can make Pierce’s disease symptoms more severe, the benign strain has provided control compared to the untreated in all conditions, including drought, other diseases, and insect pressure.

Ideally, the best use of this benign bacterium would be to treat very young vines while they’re still in a greenhouse or transplant house before they are transplanted in the field, Hopkins says. Inoculating the small individual vines while on benches is much easier than in a vineyard. Plus, it minimizes the risk of newly planted vines from contracting Pierce’s disease before they are treated.

The ability of this benign form of the bacterium to protect vines for the long term are promising, he adds.

“Originally, we thought vines would have to be inoculated with the biocontrol every year or two for the treatment to remain effective,” Hopkins says. “But, we’ve been surprised. Some of the data indicate that one treatment might protect the vines for life. Normally, as long as a biocontrol strain survives, it continues to provide good protection. In this case, one treatment and, maybe, a booster later, should be enough to prevent infection with Pierce’s disease.”

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Scoop

 

Honshu White Admiral versus Japanese Honeysuckle

Honshu White Admiral versus Japanese Honeysuckle

 

Greater Wellington’s biosecurity guardians get on top of most pest plants, but there are times when we have to enlist nature to help us tip the scales in our favour.

And so it is with the fight against the Japanese Honeysuckle, a highly invasive vine that climbs over and smothers most plants, causing canopy collapse and allowing the invasion of more species of weeds. It thrives in a variety of habitats such as shrub lands, forest margins, coastal areas, river systems and wetland margins and is widespread around our region.

Enter the Honshu White Admiral butterfly, a biocontrol agent Greater Wellington Regional Council hopes will stop its spread and bring the light back into woodland canopies.

The butterflies will be used in the front line of efforts to control Japanese Honeysuckle, providing a cost-effective, easy to manage approach to what is becoming in some areas a major challenge to the health of our bush.

“We released around 100 butterflies in April 2017 to control an infestation in the Akatarawa ranges,” says Greater WellingtonBiosecurity Officer (Pest Plants) s Kieran McLean. “The butterfly’s offspring, during their caterpillar stage, will eat their way through the plant’s foliage. If the numbers are large enough they can defoliate the honeysuckle without damaging the host plant. Hopefully the caterpillars are out there now eating their way through honeysuckle leaves.”

The black, white and brown butterfly us quite small: its wingspan is only 6cm. It lives for only one month but during that time lays around 200 eggs. As the caterpillars hibernate in cold weather, the Honshu white admiral is usually seen in warmer months.

Development from an egg to an adult butterfly can occur in as little as eight weeks at warm temperatures. Egg to caterpillar takes about one week. After about six weeks the caterpillar is fully grown and it then sheds its skin to form a light green and brown pupal case suspended from the plant. One week later it emerges as a butterfly.

Extensive research is undertaken before a biocontrol agent, such as the Honshu White Admiral Moth, is introduced. In New Zealand where biocontrol agents have been introduced follow up surveys have been undertaken to check for non-target damage.

So far Landcare Research has reported that 20 invertebrate agents and five fungal agents (including three self-introduced species) have been surveyed and results have provided additional assurance that current best practice host-testing is a good indicator of what will happen in the field. Non-target attack was generally absent, even when some might have been expected

It will take several years until we know if the population of butterflies has been successfully established and if they are effective at damaging the Japanese honeysuckle. Follow up research on their impact will take place this summer, though it will take several seasons to properly assess their performance.

Using biocontrol agents is just one of the ways Greater Wellington’s biosecurity officials work to keep the region free of pest plants and pest animals.

 

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Radio Parharaha

English

EU proposes to enlarge list of invasive species

The European Union is poposing to extend its list of invasive plants and animals, some of which have been intensively spreading in the Czech Republic in recent years.

Red-eared terrapin, photo: Magnus Manske, CC BY 2.0

Red-eared terrapin, photo: Magnus Manske, CC BY 2.0

Red-eared terrapin, spiny-cheek crayfish or Persian hogweed – these are just some of the numerous invasive species which have been introduced to Europe in recent decades, presenting a danger to the local environment. The European Union is now proposing to extend its list of alien species, some of which have been intensively spreading in the Czech Republic.

In the summer of 2016, the European Commission took an important step in fighting alien species, adopting a list of 37 invasive plants and animals that require joint action across the whole of Europe. Another twelve species were added to the list in August this year and the European Union is already working on another update.

The Czech Republic belongs among EU member states worst hit by invasive plants and animals. Jan Šíma, Director of the Department of Species Protection at the Ministry of the Environment lists some of the main offenders:

“In the case of plants, such as hogweed or Asian knotweed, we try to limit their occurrence, either by chopping the plants or by eradicating them with herbicides.

“Alien animal species can be captured and their population gradually reduced. But in some cases, nothing can be done but prevent the animals from getting to our country.

“Once they are here, it is often too late, especially in the case of aquatic species, which are very difficult to remove from their environment. So in this case it is essential to prevent their further spreading.”

Many of the plants and animals recently added to the EU list of dangerous invasive species, such as hogweed, have caused significant damage to the Czech environment. Jan Šíma outlines some of the newly added species:

'Tree of heaven', photo: Luis Fernández García L. Fdez., CC BY-SA 2.1 es

Tree of heaven’, photo: Luis Fernández García L. Fdez., CC BY-SA 2.1 es

“Among the plants, it is the hogweed, or the so-called Policeman’s Helmet. Among animals, it is the raccoon dog, a predator, which has been devastating populations of small animals and birds.”

“And then there are some less problematic species, such as Nile goose, which has started to occasionally nest on our territory, or the muskrat, which creates more problems in the warmer regions of Europe, where its populations are stronger. But even here the muskrat can cause damage, for instance to flood protections on dams.”

Among the species proposed to be added to the EU list of invasive plants and animals is the so-called tree of heaven, a deciduous tree from Asia, which has been intensively spreading across the Czech Republic in recent years.

The tree grows very quickly and can rapidly out-compete native trees and shrubs. The sap and wet sawdust of this tree can also trigger allergic reactions in some people.

Another newcomer to the list could be the American mink, a predator with a devastating impact on local river wildlife, affecting both fish and water birds.

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Video: How insect-resistant Bt GMO eggplant rescued Bangladesh’s staple crop

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[Editor’s note: Pamela Ronald is plant pathologist and geneticist. She is a professor in the Genome Center and the Department of Plant Pathology at the University of California Davis.]

Eggplants are the most important vegetable crop in Bangladesh, India. Serious pests in the region have the ability to destroy an entire eggplant crop, so farmers fight back by heavily spraying insecticide. Many of these insecticides are unregulated and very dangerous, resulting in illness and death to those who come in contact with the chemicals. Pamela Ronald explains in this episode of Startalk (a podcast hosted by Neil deGrasse Tyson) how Bangladeshi and Cornell scientists teamed together to fight pests by developing GMO eggplants.


The GLP aggregated and excerpted this article to reflect the diversity of news, opinion and analysis. Read full, original post: Genetic engineering saved the Bangladeshi eggplant industry

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Scientists Unlock Secrets of Photosynthesis

Photosynthesis is one of the most important biological processes in the world. It works by using photosynthetic reaction centers (RC) — specialized membrane proteins — which collect the energy from light and use it to pump electrons across a biological membrane from one cellular electron carrier to another, resulting in the conversion of electromagnetic into chemical energy, which can be used by organisms.

A team of scientists from Arizona State University (ASU) and Pennsylvania State University has taken a step closer to unlocking the secrets of photosynthesis. The research team believes that the first reaction center was simpler than the versions available today. In terms of the protein structure, it was a homodimer — that is, two copies of the same polypeptide came together to form a symmetric structure. The reaction centers whose structures we know are all heterodimers in which this inherent symmetry has been broken, although at their heart they still retain the vestiges of the original symmetric architecture.

The research showed the first homodimeric RC structure and it sheds light in several ways on what the ancestral RC may have looked like. The overall architecture of the protein is very similar to photosystems of plants and cyanobacteria and the RC of the purple sulfur bacteria.

More details are available at ASU Now.

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Field days show Ugandan farmers hope in disease-resistant varieties

By Allison Floyd
University of Georgia, Peanut & Mycotoxin Innovation Lab

Planting an unimproved variety of peanut in Uganda was a recipe for disaster this year. Groundnut rosette disease (GRD), an aphid-borne virus that causes mottling and affects much of sub-Saharan Africa, took 80% to 100% of the yield in some fields planted with a traditional variety.

The difficult season made farmers even more interested in two recent field-day events held in Uganda, where they could see the results coming from fields planted with improved varieties resistant to GRD.

Farmers check out peanut-growing guides at one of two recent Field Day trainings in Uganda.

One woman, a farmer named Adong Christine borrowed $7,000 from a bank and planted 20 acres with a local variety. At the end of the season, she harvested just two bags of peanuts (from a potential 400 bags) and could not repay the loan.

“There had been an outcry of big losses as most of the capital were borrowed from loan institutions. This event showcasing improved groundnut varieties therefore was timely as it restored hopes and enhanced adoption,” organizers said.

David Okello, the head of Uganda’s national groundnut research program and a leading scientist on PMIL’s breeding project, is behind many of the varieties. Based at the National Semi-Arid Resources Research Institute (NaSARRI) in Serere District, Okello works to create varieties that are high yielding, resistant to drought and GRD, and to educate farmers about practices that will give them more success with their peanut crop.

Peanuts are a traditional crop in Uganda and much of sub-Saharan Africa, are high-protein and valuable as a cash crop. Still, GRD is a persistent problem that stunts the growth of otherwise healthy plants and can destroy a crop if the disease strikes early enough in the season before flowering.

A woman farmer picks up some bags of seed at Field Days in the Nwoya District of Uganda. At the end of a particularly bad season for disease, many farmers made the investment to buy small bags of improved seed.

At one of two field days, 61 farmers, researchers and representatives of local government visited a 5.6-acre plot planted with three varieties bred for their resistance to GRD and leaf-spot, Serenut 9T (Aber), Serenut 14R and Serenut 5R. While participants could see for themselves the success of the varieties, farmers in the Loyo Kwo group, who are using the new varieties, explained their agronomic practices, where they get seed and how NaSARRI trainings helped improve their results.

“Heart breaking and sad testimonies came from the farmers growing local varieties,” Okello said. “The Loyo Kwo group members, on the other hand, were boasting of bumper harvests, higher income and improved livelihoods that they are experiencing from adopting the improved groundnut varieties,” Okello  said

Uganda Field DaysLeoora Okidi (centre) shows her approval of the high yield of Serenut 11T, an improved variety during a Field Day in August 2017 in the Kiteny Pader District of Uganda.

 

Farmers were able to buy small packs of .5 kg to 3 kg., and the NaSARRI team delivered 45 kgs of Serenut 8R (Achieng), a large-seeded red variety that had been previously promised.

In a second field day, farmers spent part of a religious holiday – the Assumption of the Virgin Mary to Heaven – visiting test plots, learning about improved production practices and visiting a farm where the owner planted Serenut 5R and Serenut 11T alongside the local Red Beauty variety.

Uganda Field Days crowdA crowd of farmers fan out over a field at a recent Field Days event comparing the yield and disease resistance of improved lines and varieties over the traditional, unimproved types, which have been ravaged by rosette disease this year.

 

The farmer, Leonora Okidi, planted 2 of her 5 acres with an improved variety, and the other 3 acres with the local variety. She abandoned the local variety after the first weeding since most of the plants had been severely attacked by the rosette virus.

In a good year, she is able to feed and educate her 11 own children and support 25 others from her groundnut operation, which is part of a women-led group called Pur Lonyo or “Farming is Wealth,” she said.

Okidi first connected with Okello through her son, who he mentored in his diploma and bachelor’s degree studies and still supervises in his current master’s degree studies. She offered land to host demonstration plots and participatory variety trials and co-funded the operations using her family labour.

“The superiority of our improved lines and varieties over her local varieties caught her attention and (Okidi) quickly adopted these improved varieties and has become a model research farmer in the village,” Okello said. “Through this effort our improved varieties adoption rates has increased and we are closely working with her women group to upscale these successes, improve their livelihoods and increase varieties adoption.”

– Published Sept. 1, 2017

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