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Archive for the ‘Viruses’ Category

Remote-sensing models to combat Banana bunchy top virus in Africa

The IITA–CGIAR team has published a method using drones and satellite imager-based remote sensing approaches for mapping banana farms to guide surveillance for the detection and mapping of the banana bunchy top virus spread and support data-informed decision-making on virus containment strategies in sub-Saharan Africa.

The study, Banana Mapping in Heterogenous Smallholder Farming Systems Using High-Resolution Remote Sensing Imagery and Machine Learning Models with Implications for Banana Bunchy Top Disease Surveillance, was published in the peer-reviewed, open access Remote Sensing journal.

BBTV has emerged as a major threat to banana production in sub-Saharan Africa. The virus infection results in severe dwarfing (bunching) of the shoots and cessation of fruit production, denting the food and income security of smallholder farmers.

Source: iita.org

Publication date: Mon 16 Jan 2023

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 EPPO Reporting Service no. 11 – 2022  Num. article: 2022/244

First record of sweet potato chlorotic stunt virus in the Netherlands

The NPPO of the Netherlands recently informed the EPPO Secretariat of the first finding of sweet potato chlorotic stunt virus (Crinivirus, SPCSV – EU Annexes) in sweet potato (Ipomoea batatas) plants on its territory. SPCSV was found in September 2022 in two open fields in Noord-Brabant province (11.83 and 4.72 ha) and one in Limburg province (0.5 ha). The official survey was part of the Euphresco project ‘Phytosanitary risks of newly introduced crops’ (PRONC). Tracing back investigations to the origin of the finding showed that the sweet potato slips used for planting originated from a company in another EU Member State. Sweet potato is a new crop in the Netherlands. During the survey, plants with and without virus symptoms were sampled and tested. SPCSV was identified in several plants with virus-like symptoms (e.g. vein banding, discoloration, rings, dots). Additionally, in several of these symptomatic plants a second, non-EU listed, virus was identified: sweet potato virus G (Potyvirus, SPVG00). The mixed infection may have increased the severity of the observed symptoms.

Official phytosanitary measures have been taken. The companies have to report to the NPPO when all tubers of the Ipomoea batatas plants have been harvested and the total quantity thereof. All infected lots should be stored in a traceable manner, separately from other harvested lots. Only sales for consumption/industry are allowed, otherwise the lots have to be destroyed. The companies should report when the infected lots are sold or destroyed. The lots must be sold/destroyed before 31 March 2023. 

The pest status of sweet potato chlorotic stunt virus in the Netherlands is officially declared as: Transient, actionable, under eradication.

Sources

NPPO of the Netherlands (2022-10). https://english.nvwa.nl/topics/pest-reporting/pest-reports

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Virus Undercuts Fungus’s Attacks on Wheat

USDA Agricultural Research Service sent this bulletin at 11/29/2022 10:05 AM EST

View as a webpageARS News ServiceARS News
ServiceFusarium head blight on wheat
A “mycovirus” could help stop the Fusarium head blight fungus from contaminating wheat grains and giving them a ghastly bleached appearance (shown at right).Virus Undercuts Fungus’s Attacks on Wheat
For media inquiries contact: Jan Suszkiw, (202) 734-1176

November 29, 2022 A naturally occurring virus co-discovered by Agricultural Research Service (ARS) and university scientists may offer a way to undermine a costly fungal threat to wheat, barley and other small-grain crops.The fungus, Fusarium graminearum, is the chief culprit behind a disease called Fusarium head blight, or “scab.” Unchecked with fungicides or other measures, scab diminishes the yield and quality of the crops’ grain. Under wet, humid conditions, the scab fungus can release a toxin called deoxynivalenol (a.k.a., “vomitoxin”) that can contaminate the grain, reducing its point-of-sale value or leading to outright rejection depending on end use.Now, however, a team of scientists with the ARS Application Technology Research Unit in Wooster, Ohio, and South Dakota State University in Brookings (SDSU) has discovered a strain of a fungal virus, or “mycovirus,” that disables the scab fungus’s vomitoxin-making machinery.In nature, the mycovirus, a species called Fusarium graminearaum Vg1, infects the scab fungus to replicate and spread. But the new mycovirus strain, dubbed F. graminearum Vg1-SD4, takes such attacks a step further by stopping the scab fungus from making vomitoxin—a fortuitous benefit for wheat plants.Indeed, in laboratory and greenhouse experiments, cultures of the scab fungus that had been infected with the mycovirus strain grew slower than non-infected cultures and produced no vomitoxin in the grain of susceptible potted wheat plants. In contrast, the grain of wheat plants exposed to mycovirus-free cultures of scab contained 18 ppm of vomitoxin, a byproduct of the fungus’s metabolism that can be harmful to livestock and human health.ARS molecular biologist Shin-Yi Lee Marzano and her collaborators discovered the mycovirus strain after sequencing its genomic makeup and noticing slight differences from its “parent” species, FgVg1, which had been maintained in a live culture of the scab fungus and known to science for about a decade.Marzano cautioned that their research—reported in the July 2022 issue of Microorganisms—is still in its early stages. However, with further study, the mycovirus strain could prove useful as a biological control agent that could be formulated and sprayed onto susceptible wheat varieties or other small-grain crops. That, in turn, could potentially offer growers another tool to use in avoiding costly losses to scab and its contamination of grain destined for livestock and human consumption.  Marzano collaborated on the mycovirus strain research with Bimal Paudel and Yang Yen—both with SDSU’s Department of Biology and Microbiology—and Connar Pedersen (formerly SDSU and now ARS).The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.Interested in reading more about ARS research? Visit our news archiveU.S. DEPARTMENT OF AGRICULTURE
Agricultural Research Service

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Rijk Zwaan launches ToBRFV-resistant tomato varieties

The Tomato Brown Rugose Fruit Virus or ToBRFV has been causing major economic losses in tomato cultivation worldwide. Rijk Zwaan’s team of researchers found new ToBRFV-resistant genetics .

HR ToBRFV – Rugose Defense
Soon after this discovery, breeders started to develop resistant varieties in all worldwide breeding programs and extensively tested these varieties internally as well as with growers to assess their agronomic value. Rijk Zwaan now offers growers the best-performing hybrids under the Rugose Defense label, including mini plum, cherry TOV, cocktail, and medium TOV tomato varieties.

Compatible with all commercial rootstocks
Rijk Zwaan tomato varieties with high resistance to ToBRFV are compatible with all commercially available rootstocks. Trials have shown that rootstock variety Suzuka RZ performs strongly in combination with both susceptible and resistant tomato varieties.

Contact for more information
In the coming period, Rijk Zwaan will continue to introduce new varieties suitable for high-tech and protected cultivation. Rijk Zwaan would like to thank all growers who supported the company in testing the first HR resistant tomatoes for high-tech cultivation. Keen to know more? Visit Rijk Zwaan’s local Rugose Defense page.

For more information:
Rijk Zwaan
info@rijkzwaan.com
www.rijkzwaan.com

Publication date: Tue 6 Dec 2022

   

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Growers can use a test kit to detect ToBRFV before plants even shows signs

Knowing, for sure, that your crop is infected before the plants show signs. Growers have wanted that since the Tomato brown rugose fruit virus (TOBRFV) reared its ugly head. And preferably quickly, too. This summer, the Dutch company Spark Radar launched a grower test kit for that. Growers can use it to detect, with high reliability and within three hours, whether their crop is contaminated.

According to Spark Rader’s co-founder, Rogier van der Voort, its virus test’s reliability and sensitivity can well well-compared to that of a PCR test. “However, you don’t have to send our test’s samples to a service lab. That saves considerable time – crucial when detecting and containing a possible outbreak.”

When the COVID-19 pandemic broke out, he and Bas Rutjens, who founded Spark Genetics, put their heads together. That company has been supporting breeding companies with genetics issues since 2018. “When the pandemic began, the laboratory had to partially close. We started asking ourselves how we could offer the market something that was much needed. That had to be a reliable, sensitive pathogen test that anyone could perform on-site,” says Rogier.

Testing before symptoms show
The test works pre-symptomatically, meaning you can test for the virus’ presence early. Rogier draws a parallel with COVID-19. “You can now do a self-test for that. But, that’s an antigen test you use when you’re already showing symptoms.” In the case of the coronavirus, for example, a runny nose.

One of the ToBRFV’s symptoms is spots on the fruit or signs on leaves. “Antigen tests, however, aren’t as reliable as PCR tests, and their lower sensitivity means they don’t work pre-symptomatically. You can also only test two to three plants at once,” Rogier explains.

Leaf material
Currently, growers can test 60 plants at a time using Spark Radar test kits. Testing can be done in three ways. “We started with leaf samples. A piece of leaf the size of a fingernail is enough. Growers collect the leaf sample in a bag we provide, and once collected, testing can begin.”

The test kits include the test material and hardware so that growers can run the tests themselves. “We’ve developed equipment to read the tests. We use magnetic and sensing racks for that. The magnetic rack lets us extract the virus from the sample, which helps ensure our tests’ high sensitivity,” Van der Voort continues.


A part of the test kit. The white container is lined with magnets. Detection is done using a different rack.

Surface and water tests
Growers, however, prefer to test more than just leaf material. “There’s plenty of market demand for swab tests too, which allows for testing for the presence of the virus on things like carts or blades. It’s like the cotton swab you use in your throat and nose when doing a COVID-19 self-test.”

They developed a third testing protocol for water. “Growers can test for the ToBRFV in, say, their drainage system,” Rogier elaborates. These last two testing methods are currently in their final market introduction stages. “We’re fully in the testing phase for these new applications and are using trial feedback to make the swab and water test kits are durable as possible.” The company plans to market these two testing kits in December commercially.

International
Spark Radar also wants to start offering the kits internationally, and this fledgling company has taken the first steps toward that. “A large North American party has been using our test for several months. They want to deploy it more widely during the next harvest period. We have a commitment from a Dutch party with overseas farms too. They want to use our tests outside the Netherlands,” states Rogier.

A virus test must be reliable. The test kits, thus, include a clear manual (you can also watch an online video). For now, it is in Dutch and English, but the company wants to include other languages as well. “We’re currently focusing on producing the tests. We’ve gained new clients after presenting the test at a recent event.”

Testing for other pathogens
ToBRFV is undoubtedly receiving global attention. That begs the question: Does Spark Radar have the clout to help growers combat this virus? Spark Radar’s co-founder thinks so. “We were recently chosen to participate in the Foodvalley and government investment fund, InvestNL’s Fast Lane program. We had to give an answer to what’s needed to become even more influential, scale up and maintain our test’s current and projected speed.”

That speed does not only apply to the ToBRFV but to other plant viruses, bacteria, and fungi. Spark Radar is also working on a test kit for cucumber fur virus and Pepino mosaic virus in tomatoes. “Those will be similar tests to the ToBRFV ones,” concludes Rogier.

For more information:
Rogier van der Voort
Spark Radar
8 Padualaan
3584 CH, Utrecht, NL
Email: rogier@sparkgenetics.com 
Email: info@sparkradar.bio 
Website: www.sparkradar.bio

Publication date: Fri 25 Nov 2022

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Bonwell: the multi-fruited mini cucumber with high resistance to CGMMV

In ‘The future is sky’ series, we show that shared entrepreneurship is of paramount importance. Blake Fischer, Head Grower at JEM Farms, discusses the partnership between JEM Farms and Rijk Zwaan in this second video. “It’s always great to have another set of eyes looking at your crop and pointing things out that we can all learn from”, says Blake Fischer.

Furthermore, JEM Farms shared their experiences with our high CGMMV resistant mini-cucumber variety, Bonwell. Curious to learn more about ‘The future is sky’ series or Bonwell?

Publication date: Mon 14 Nov 2022

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Plan to eliminate ToBRFV published

The Nederlandse Voedsel- en Warenautoriteit (Dutch Food and Consumer Product Safety Authority) has published a plan of action to eliminate the persistent Tomato Brown Rugose Fruit Virus at an infected cultivation site.

According to the latest official figures as of 1 June 2022, 41 growers in the Netherlands are infected. By far, the most infections are in the municipality of Westland. A total of 57 growers have faced infection since the first outbreak in mid-2019. Only 12 growers managed to eliminate the virus, of which another two had to deal with a new virus introduction regardless.

In Belgium, at least 15 growers have already faced an infection.

View the elimination plan published by the NVWA here.

Publication date: Wed 26 Oct 2022

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HLB and Canker Incidence Increasing in Brazil

 SEPTEMBER 27, 2022 BRAZIL DISEASES

The average incidence of HLB rose from 22.37% in 2021 to 24.42% in 2022 in Brazil’s citrus belt, an annual survey by Fundecitrus shows. That’s an increase of 9.16%.

HLB
Inadequate psyllid control is a major reason that HLB is on the rise in Brazil.

In the regions of Brotas, Limeira and Porto Ferreira, where the incidence was already high in previous years, HLB increased to even more worrying levels of 49.41%, 70.72% and 74.05%, respectively. HLB is also commonly called greening disease.

“We are seeing the disease grow at a worrying speed,” said Fundecitrus General Manager Juliano Ayres. “However … the results obtained in properties in regions that have registered a decline or stabilization of the disease reinforce our confidence that the measures to combat greening are effective. This has always been the way and always will be, until we manage to reach plants resistant to the disease. However, we need more efforts” to control HLB.

REASONS FOR HLB INCREASE

Fundecitrus reported that most regions have a favorable climate for HLB. Additionally, most regions have a high density of orchards and a large number of medium and small properties. Those factors make it difficult to coordinate joint actions for the regional management of the disease.

Most importantly though, Fundecitrus stated, in most orchards in production, diseased trees are not being eliminated, and control of HLB-spreading psyllids has been inadequate. Inefficient spraying has also contributed to the increase in HLB.

“This work has not been done with the necessary frequency, especially in the sprouting seasons,” said Fundecitrus researcher Renato Bassanezi. “Failures in spray coverage have also been observed, mainly at the top of the canopy of adult trees and in dense orchards.”

Also impairing the effectiveness of psyllid control is the repetitive use of insecticides from the pyrethroid group without adequate rotation with insecticides with other modes of action, Fundecitrus stated. That has led to the detection of psyllid resistance to the pyrethroid group in some places.

BIG JUMP IN CANKER

The Fundecitrus survey also showed growth in the incidence of canker in orchards. According to the new survey, the disease is present in 18.77% of the trees, an increase of 74.44%.

Canker accounts for just 0.21% of fruit drop across the citrus belt. The low rate is related to studies carried out by Fundecitrus that adjust the use of copper in the management of the disease. That adjustment doesn’t impact the effectiveness of the treatment and generates savings of 56% in the amount of product used per hectare.

CVC REMAINS LOW

The incidence of CVC remains low throughout Brazil’s citrus industry, with an incidence of just 0.80% in 2022. About 20 years ago, the disease was present in 46% of the trees. The significant reduction is mainly due to the evolution of research and management practices disseminated by Fundecitrus.

Source: Fundecitrus

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Hazera launches ToBRFV resistant varieties in Mexico

After having announced the pipeline of its ToBRFV-resistant varieties, Hazera launched its first resistant varieties for the Mexican market and showcased them at EXPO AgroAlimentaria Guanajuato 2022 in Mexico.

ToBRFV is very noticeable in Mexico, and growers have been faced with diminished yields and battered fruit. ToBRFV is a huge problem for tomato production, affecting the yield and fruit quality, with coloring issues and brown spots on fruits directly impacting the marketable yield.

Since ToBRFV hit tomato growers worldwide, Hazera’s R&D team has been working for several years to find varieties capable of giving an effective level of ToBRFV resistance without compromising the yield and fruit quality. “These efforts included in-depth trials in many locations, under different conditions on a global scale, to confirm that we are able to provide solutions, with the right balance between performance and ToBRFV protection,” according to Alejandro Szechtman, Hazera’s Portfolio Marketing Director.

Canelo, one of Hazera’s tomato varieties with resistance to ToBRFV, is an indeterminate Roma type with a vigorous plant that maintains a balanced yield under adverse environmental conditions due to its wide array of resistances. “Through vast trialing of Canelo in most regions of Mexico, including San Luis Potosi, Baja California, Michoacan, Sinaloa, and Coahuila, Canelo provides high yield, excellent fruit quality, good maturation with an intense red color, as well as excellent firmness, maintaining L and XL sizes with average weights of 150 to 160 grams throughout the production cycle”, according to Javier Angulo- Product Development Manager, Mexico.

Canelo is a very productive variety, ideal for growing in a net house or greenhouse. Additionally, with its ToBRFV resistance, Canelo is able to serve the Mexican grower as an effective tool to face the highly infectious virus, which is supported by local growers, who claim that “Canelo is a very strong and healthy plant with outstanding high fruit quality.”

Looking forward, “Hazera is continuing its efforts to provide effective varieties to better cope with ToBRFV on a global scale and, in Mexico, will launch several new varieties, including the up and coming new Indeterminate Grape Tomato, ‘Pendragon,’ a variety that combines ToBRFV IR resistance with high yield, long shelf life, and good taste, following our commitment to provide growers varieties with the optimal balance between protection and performance,” says Alejandro Szechtman.

For more information:
Hazera 
info@hazera.com
www.hazera.com    

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Viruses devastate Salinas Valley lettuce

Richard Smith/UCwfp_INSV_submitted-4476.jpg

Salinas Valley lettuce exhibiting symptoms of INSV infection. The summer lettuce crop in California was significantly impacted by plant diseases caused by insect feeding and soil-borne pathogens. This led to a short supply of lettuce for U.S. markets and record-high prices.

Growers tallying their losses as consumer prices rise.

Todd Fitchette | Nov 09, 2022

Salinas Valley lettuce growers are tallying their losses from a set of plant viruses that continue to increase in frequency and intensity across the region.

“It was a disaster as we wrapped up the year,” said Salinas Valley lettuce grower Mark Pisoni. “I’ve seen 20-acre fields without a single head of lettuce harvested.”

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As knowledge of the widespread outbreak spread, lettuce growers in the low desert of southern California and southwest Arizona planted lettuce earlier than normal. Some of those lettuce crops are being harvested this week as growers try to capture record-high lettuce prices. The U.S. Department of Agriculture reports iceberg prices above $90 per box, with romaine prices trailing that by a few dollars per box.

What caused this?

Laboratory tests of lettuce plants point to Impatiens necrotic spot virus (INSV) and Pythium wilt, according to Steven Koike, director, TriCal Diagnostics in Hollister, Calif. Koike admits that disease diagnosis can be confusing in that the symptoms resemble each other. This can make it difficult to determine the primary cause of death for the lettuce plant.

The two pathogens largely responsible for the lettuce deaths happen independently, but one may encourage the other. Mary Zischke, facilitator for the INSV and Pythium task force with the Grower Shipper Association in Salinas, said INSV seems to be the trigger Pythium wilt as plant stress increases.

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First plant disease detection found in California; quarantine in place

Steve Angeles | TFC News California

Posted at Oct 27 2022 12:14 PM

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HLB on young tree

In Southern California, state agriculture officials are expanding a citrus plant quarantine in Los Angeles county after the citrus disease Huanglongbing (HLB) was detected in Pomona. 

Asian citrus psyllid

The plant disease is not harmful to people or animals but can greatly affect citrus plants. HLB is spread from plant to plant by the Asian citrus psyllid. Once a tree is infected it cannot be cured. 

ACP

According to the Citrus Pest & Disease program’s press release, a citrus plant quarantine is in place throughout portions of Los Angeles, Orange, Riverside, San Bernardino and San Diego counties. To further limit the spread of the pest that can carry HLB, there are additional quarantines in place that make it illegal to bring citrus fruit or plant material into California from other states or countries. 

The new quarantine map can be found at https://www.cdfa.ca.gov/citrus/pests_diseases/hlb/regulation.html.

Yellowing leaves

All citrus trees including, lemons, oranges, and limes can be affected by HLB.

While an outbreak of HLB could impact local citrus industries, backyard gardeners also need to be cautious. 

An estimated 60% of California homeowners own citrus trees, and a popular one among Filipino homes, is calamansi. 

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Read More:  Huanglongbing   HLB   Asian Citrus Psyllid   ACP   plant disease   quarantine   TFC News  

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