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2017/065 First reports of a new bacterial leaf blight of rice caused by Pantoea anana and Pantoea stewartii in Benin and Togo

In Benin, surveys were carried out from 2011 to 2015 in rice fields to assess the importance of bacterial leaf blight caused by Xanthomonas oryzae pv. oryzae (EPPO A1 List). Symptomatic leaf samples were collected and tested. As all isolates gave negative results in a multiplex PCR test for X. oryzae, further studies were conducted and revealed the presence of bacteria belonging to the genus Pantoea. Molecular and pathogenicity tests (to fulfill Koch’s postulates) confirmed that the bacteria which had been isolated from rice leaves were P. ananatis and P. stewartii (EPPO A2 List). It is noted that symptoms were  observed in all surveyed localities (14 sites) with a disease incidence varying from 30 to 100%. In Togo, surveys were also carried out in 2013 and 2014 in the main rice-growing regions (Kovié and Kpalimé) to evaluate the prevalence of plant-pathogenic bacteria. Rice leaves showing characteristic symptoms of bacterial leaf blight were collected and tested. Similarly, the bacteria which were isolated from rice leaves and grains were shown to be P. ananatis and P. stewartii. According to the authors, this is the first time that P. ananatis and P. stewartii species are found causing a leaf blight disease on rice crops in Benin and Togo. According to the EPPO Secretariat this is also the first time that P. stewartii is reported from Africa.

Source: Kini K, Agnimonhan R, Afolabi O, Milan B, Soglonou B, Gbogbo V, Koebnik R, Silué D (2017) First report of a new bacterial leaf blight of rice caused by Pantoea ananatis and Pantoea stewartii in Benin. Plant Disease 101(1), p 242. Kini K, Agnimonhan R, Afolabi O, Soglonou B, Silué D, Koebnik R (2017) First report of a new bacterial leaf blight of rice caused by Pantoea ananatis and Pantoea stewartii in Togo. Plant Disease 101(1), 241-242.

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From Pestnet

USDA releases proposals to fight citrus greening & diamondback moths

In the past two weeks, USDA’s Animal and Plant Health Inspection Service (APHIS) has released documents on proposals to release two genetically modified (GM) organisms: diamondback moths and a virus designed to control the citrus greening disease attacking the citrus industry.

DB moth

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

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Kiwi bacteriosis control now a reality

The international Journal of Plant Disease and Protection finally published the research financed by MIPAAF and coordinated by Prof. Giorgio M. Balestra which saw the cooperation between the Department of Agricultural Sciences (DAFNE) of Università della Tuscia and the Department of Life Sciences and Biotechnology (SVeB) of the University of Ferrara

Title: “Microparticles containing gallic and ellagic acids for the biological control of bacterial diseases of kiwifruit plants

Authors: Antonio Rossetti, Angelo Mazzaglia, Massimo Muganu, Marco Paolocci, Maddalena Sguizzato, Elisabetta Esposito, Rita Cortesi, Giorgio Mariano Balestra.

It is a lengthy study that demonstrates how it is possible to use vegetable substances to monitor the different phytopathogenic bacteria that cause much worry in all the areas growing Actinidia spp..

The cultivation of actinidia to produce kiwis has become increasingly important in Italy as well as in various areas around the world. At the same time, however, bacterial diseases are affecting its cultivation. The most dangerous is without doubt the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Pss) Takikawa et al., also known as Psa, which damages all vegetative organs.

Serious damage is caused also by the drop in temperatures in spring, as is the case this year, associated with other two bacteria – Pseudomonas syringae pv. syringae (Pv) van Hall, responsible for floral bud necrosis and Pseudomonas viridiflava (Burkholder) Dowson, the bacterial blight which affects leaves and floral organs.

In Italy, prevention is carried out by using copper salts as well as a biological control agent (B. a. subsp. plantarum ceppo D747) during blossoming. Other areas outside the EU employ antibiotics with serious repercussions on the environment and leading to the development of antibiotic-resistant bacteria strains.

This study assessed the effectiveness of gallic and ellagic acids, i.e. natural substances that are easily attainable from many vegetable tissues and with high anti-microbial properties.

These natural, active principles proved effective as pure substances both in the lab and in vivo (greenhouses, then open-field actinidia orchards naturally affected by Pss, Pv and Psa).The vegetable active principles significantly reduced the various bacterial populations as well as the damage caused both through artificial contamination and by using them on orchards naturally affected by Pss, Pv and Psa.

In association with the intrinsic activities, the active principles proved particularly effective when employed through micro-formulations in micro-capsules, thus preventing alterations (physical-chemical) and enabling a controlled release of the principles over two weeks protecting all vegetable organs.

In addition, the activity of these formulations on both plant development and final production was also assessed. All parameters showed how these micro-formulations do not affect plant development (the plants treated with micro-capsules had a higher chlorophyll content in the leaves and the fruits, though with the same size and Brix level, were more compact).

The results obtained with this study represent a significant contribution towards the attainment of formulations that can successfully counter dangerous micro-organisms like those affecting actinidia with a sustainable/organic approach.

Reducing the use of copper salts to protect crops is a process dictated by the EU. As of January 2018, further reductions of Cu++ will be introduced, thus valid alternatives must be found.

This study suggests how gallic and ellagic acids, when formulated together in microformulations, can be successfully employed in sustainable/organic defence strategies against pathologies like those currently affecting actinidia.

The active principles and technology used in this research constitute an important base, as what described can be applied to different pathogens/ crops, thus reducing the use of chemicals and therefore chemical residue.

Additional studies are currently being carried out concerning organic nano-formulations for the protection of different crops both in the fields and during the storage and commercialisation stages. They aim at a further reduction of the (natural) active principles used, at a prolonged controlled release and at making it so that formulations can penetrate fruit/plants and target the pathogen.

For further information:
Prof. Giorgio M. Balestra
DAFNE (Department for Agriculture, Forestry, Nature and Energy)
University of Tuscia
Via S. Camillo de Lellis
01100 Viterbo
Tel.: (+39) 0761 357474
Cell.: (+39) 333 4246404
Fax: (+39) 0761 357473
Email: balestra@unitus.it
Web: www.unitus.it
Skype: giorba5618
Personal page: www.dafne.unitus.it/web/interna.asp?idPag=1118

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Plant disease patterns offer clues about climate change

By Tim Sandle     May 20, 2017 in Environment

General atmospheric models provide an indicator of climate change. More sensitive models are needed to understand what is happening on ground level, however. One way to do this, new research highlights, is by tacking the spread of plant pathogens.

The research focuses on understanding climate change on agroecosystems (the ecology of agriculture). This is specifically thorough charting the effects of temperature change upon leafhopper vector behavior, which relates to the spread of Pierce’s disease on grapevines. The headline finding from the research is that global warming exacerbates the disease symptoms seen with infected grapevines.

Pierce’s disease is caused by a bacterium called Xylella fastidiosa. The disease is endemic in northern California, being spread by the blue-green sharpshooter, which only attacks grapevines. Vines become damaged through the bacterium causing a gel to form in the xylem tissue of the vine. This prevents water from being drawn through the vine. In terms of symptoms, the leaves become slightly yellow or red along margins in white and red varieties. This is followed by fruit clusters shriveling or becoming raisin-like.

The new connections have been made based on a mix of biology field work together with a mathematical model. The study has been led by University of California, Riverside entomologist Dr. Matthew Daugherty. The factors considered in the research included the type of disease, the insect vector, and temperature. The research shows how rising temperatures led to variable effects in relation to vectors of diseases (in this case, insects spreading plant diseases).

The data indicates while global warming increases the types of disease symptoms seen with infected grapevines there could also be a limit to the extent that the insects that spread the disease will function under the higher temperatures. This is because the insects do not like feeding on vines that show extensive signs of the disease. In other words, the infections that grape vines contract might become worse but the rate of infection may slowdown.

As Dr. Daugherty explains: “Because the leafhopper vectors of the Pierce’s disease pathogen avoid feeding on diseased vines, pathogen spread declined over time at higher temperatures.” In this sense climate change introduces both a negative effect (a more virulent pathogen) and a positive effect (a reduction in vine infections).

The research is published in the journal Phytobiomes, with the research paper titled “Conflicting Effects of Climate and Vector Behavior on the Spread of a Plant Pathogen.”

Read more: http://www.digitaljournal.com/news/environment/plant-disease-patterns-offer-clues-about-climate-change/article/493107#ixzz4hqAfynmq

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Cucumber green mottle mosaic virus could have entered Queensland through imported seeds – ABC News (Australian Broadcasting Corporation)

//4654321.fls.doubleclick.net/activityi;src=4654321;type=abcne0;cat=abcne000;ord=4463444923102;~oref=http%3A%2F%2Fwww.abc.net.au%2Fnews%2F2017-05-04%2Fcucumber-green-mottle-mosaic-virus-imported-seed-biosecurity-qld%2F8494354?

Ccucumber green mottle virus could have entered Queensland through imported seeds

 

Posted 3 May 2017, 3:18pmWed 3 May 2017, 3:18pm

Biosecurity authorities are trying to figure out how a fruit and vegetable rotting disease broke out in Queensland, but have initial suspicions it was through imported seed.

Farmers from the Bundaberg region are angry cucumber green mottle mosaic virus (CGMMV) has recently been discovered on five local properties, owned by two growers.

CGMMV causes internal rot and discolouration in some cucurbit family fruit and vegetables, and its discovery comes months after an outbreak of white spot disease decimated the aquaculture industry in south-east Queensland.

Biosecurity Queensland spokesman Mike Ashton said the virus was not harmful to humans, but could ravage parts of the agriculture industry if a widespread outbreak occurs.

He said there was a possibility the virus was brought onto the infected farms by imported seeds.

That is considering the businesses operate independently and do not share personnel and equipment.

“That kind of increases the risk that perhaps it was seed that was the source of the introduction,” he said.

“It’s highly unlikely that we’ll ever be able to pinpoint exactly how it got introduced.”

“We’re certainly doing tracing investigations to try and identify the source.”

Farmers like Gino Marcon are angry there has been an outbreak of another virus, and are switching to less risky crops.

Mr Marcon normally grows a wide range of vegetables on his farm, but this year, he is only growing tomatoes to avoid CGMMV.

“We’ve actually stopped growing cucumbers, we’ve sort of got a wait-and-see attitude at the moment,” Mr Marcon said.

“We’re a bit worried that the disease may affect our zucchini production, so we’ve switched over to 100 per cent tomato production in our greenhouses.”

He blamed biosecurity authorities for the outbreak.

“We’ve lost confidence in the system and that’s the biosecurity system,” Mr Marcon said.

“We think it’s not broken, it’s shredded to bits. It’s simply not working.

“I think the whole system needs to be overhauled, we’re not getting value for money for the money being allocated to biosecurity.

“[Politicians] need to look long and hard at the whole system and change it.”

Mr Ashton rejects the allegation that the system has failed.

“We have managed to restrict the disease to a very small number of properties in Queensland,” he said.

“Unlike the Northern Territory and increasingly so in Western Australia where the disease has become quite established.”

There have been previous outbreaks of CGMMV in the Territory and WA, and an isolated case at Charters Towers in North Queensland in 2015.

Biosecurity Queensland hope the Charters Towers farm will be declared clear of the virus later this year.

The Federal Agriculture Department introduced mandatory imported seed testing to try and combat CGMMV in 2014.

In a statement, the department said it uses a sample size more than four times the size (9,400 seeds) than that used internationally (2,000).

It said that gave a high level of confidence in the results.

Topics: pest-management, rural, quarantine, crop-harvesting, agricultural-policy, vegetables, activism-and-lobbying, agricultural-crops, fruit, fruits, bundaberg-4670, qld

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The spread of pests and pathogens that damage plant life could cost global agriculture $540 billion a year, according to a report published on Thursday. The report, released by the Royal Botanic Gardens (RBG) at Kew in London, said that an increase in international trade and travel had left flora facing rising threats from invasive […]

via Pests and pathogens could cost agriculture billions — The Plantwise Blog

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Black Rot Disease Affecting Cabbage Growing Season

Posted: May 04, 2017 6:33 PM CDT Thursday, May 4, 2017 7:33 PM EDTUpdated: May 04, 2017 6:33 PM CDT Thursday, May 4, 2017 7:33 PM EDT

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NEAR EDINBURG – Many Rio Grande Valley farmers are trying to recoup their losses after the black rot disease invaded their cabbage crops.

Edinburg farmer Tommy Hanka’s company, Tommy Hanka Farms, grows cabbage as well as other cool season vegetables in a 1,000-acre farm land.

Hanka said the recent record heat was terrible news for farmers.

“Well, it affected me on my green cabbage and red cabbage. I had some black rot issues. I ended plowing under over 75 percent… It was just not marketable. It was a real disaster, a real train wreck this year,” he said.

Hanka said farmers and the local economy are affected when there is a bad growing season.

“The box companies don’t get paid, the trucking companies don’t get paid because there is no product to move. There’s no produce to sell. We just can’t employ these guys because there is no work,” he said.

Texas A&M AgriLife Extensions vegetable specialist Juan Anciso said other farmers also saw big losses this growing season.

He said about half of the 3,000 acres of cabbage planted this season was lost due to black rot.

“Warm weather – for example for bacteria – it increases their reproduction rate so you have more bacteria,” he said. “And we have had a serious problem with black rot, which is a bacterial pathogen in cabbage. It’s a disease that has been around since cabbage has been around. But we haven’t had these problems since the 1980s.”

Anciso explained black rot enters through the leaves and causes them to turn black and brown, making the cabbage unsellable.

But Hanka said although this year’s season was extremely tough he’s not giving up.

“Let’s move on. We are going to stick to the game plan. We are going to do the same thing we did this year. We are going to be here next year…. It’s only going to get better,” he said.

Anciso said Texas AgriLife will continue to look for black rot resistant strains of cabbage. He said farmers will then be better equipped to turn a profit during unusually warm season.

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