Archive for the ‘Viruses’ Category

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.”


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


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. 


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. 


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

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HLB and Canker Incidence Increasing in Brazil


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%.

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.


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.


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.


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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California’s multi-billion-dollar citrus industry faces a possible new threat after the discovery of a citrus virus in Tulare County. U.S. officials confirmed the find in a residential tree is the first-known introduction of citrus yellow vein clearing virus in the United States.

The discovery of citrus yellow vein clearing disease was announced by the USDA after California officials detected it in a routine multi-pest survey.

Todd Fitchette | Aug 23, 2022

The recent discovery of a virus in residential citrus in Tulare, Calif., marks the first time the disease has been found in the United States.

The discovery of citrus yellow vein clearing disease was announced by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) after California officials detected it in a routine multi-pest survey in non-commercial trees in the City of Tulare. The California Department of Food and Agriculture (CDFA) conducts regular inspections of residential trees in the wake of Huanglongbing (HLB) being discovered in the state, and detection of the Asian citrus psyllid (ACP), the known vector of HLB, in Tulare County several years ago.


It is unknown how the new citrus disease was introduced into the United States, or how it found its way to California, according to the public affairs firm representing the California citrus industry and CDFA on the matter. What is suspected is the disease is vectored by insects, including the citrus whitefly, green citrus aphid, melon or cotton aphid, and cowpea aphid. It is also suspected that it can spread by grafting infected material. The virus is not believed to be transmitted by seed.

The CDFA and APHIS continue to be in an information-gathering stage, according to Victoria Hornbaker, director, California Citrus Pest and Disease Prevention Program. The state is conducting an intensive delimitation survey of residential and commercial properties in the core area around the detection site. Survey activities in neighboring Fresno and Kings counties will happen in the coming months to determine extent of the virus. No mention of whether these activities will include Kern County or other known citrus producing regions in the state.

Most of California’s fresh citrus is produced in the southern San Joaquin Valley, with Tulare County leading production of navel oranges in the state. U.S. agricultural officials notified Japan and Taiwan, two important citrus trading partners with California, about the discovery. Hornbaker says the countries have not expressed concern over the find.

California citrus officials deferred comment on the find to the public relations firm. She said the most concerning issue for commercial growers currently is the reduced tree vigor that citrus trees in other countries have experienced. Information from China indicates that the virus reduces yield and fruit marketability in lemons but does not typically kill citrus trees.

Growers will likely be encouraged to implement best management practices that include sanitizing harvest equipment when moving from one grove to the next. There are said to be insecticides to help control the four insects known to vector the virus.


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  Grahame Jackson


 Sydney NSW, Australia

 For your information

 8 days ago

Soybean virus may give plant-munching bugs a boost in survival


UNIVERSITY PARK, Pa. — Most viral infections negatively affect an organism’s health, but one plant virus in particular — soybean vein necrosis orthotospovirus, often referred to as SVNV — may actually benefit a type of insect that commonly feeds on soybean plants and can transmit the virus to the plant, causing disease, according to Penn State research.

In a laboratory study, the Penn State College of Agricultural Sciences researchers found that when soybean thrips — small insects ranging from 0.03 to 0.20 inches long — were infected with SVNV, they tended to survive longer and reproduce better than thrips that were not infected.

Asifa Hameed, who led the study while completing her doctoral degree in entomology at Penn State and is now a senior scientist of entomology at Ayub Agricultural Research Institute in Multan, Pakistan, said the findings give key insight into how the virus spreads in plants and affects its insect hosts.

“In addition to prolonging the life of the insects, SVNV infection also shortened the doubling time of soybean thrip populations,” Hameed said. 


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ToBRFV project examines drain water samples, UV cell phone sanitizer, and powdered milk

“Each time we answer a ToBRFV question, three more pop up,” begins Evelien Aussems, a researcher at the ‘Proefstation voor de Groenteteel,’ a vegetable cultivation research facility in Belgium. This ToBRFV practical study – called PraKeTo – coordinator experienced this when the first year full of research concluded.

That was done in partnership with the Proefcentrum Hoogstraten, Scientia Terrae, and the East Flanders Provincial Research Center for Vegetable Production. “Growers keep asking for good hand disinfection methods and eagerly await the arrival of resistant varieties.” With the start of a new four-year research project, the research consortium will try to answer these and other pressing questions around ToBRFV.

Last week, ‘everyone that has anything to do with tomato cultivation’ gathered for an update about the ToBRFV study’s latest findings. The PraKeTo project focused on practical guidance and gathering knowledge about this virus. A group, including growers, was closely involved in the project. “As researchers, we followed up with several growers with infected plants,” says Evelien. At least 15 Belgian farms already have this virus present, while in the Netherlands, there are officially 41.

The PraKeTo discussion drew a full house

Drain water samples
One of the study’s focal points was monitoring via drain water. The idea is that virus detection should be possible before symptoms of infection become visible on the plants and fruit. “Taking drain water samples gives you a better, broader picture than sampling per plant. Then, you’d either have to take samples from all the plants, which is impractical, or you’d have to sample the ‘right’ plants. That’s not so easy to determine, especially at the onset of an outbreak.”

The grower group specifically requested the study, says Evelien. “If a grower hasn’t yet had an outbreak, we can successfully detect the virus in the drain water, and well in time. But what happens to the virus concentrations in the drain water of growers whose plants are already infected?” she had to wonder.

Nine growers already had this virus in their greenhouse, so researchers took bi-weekly drain water samples. They did so after the growers had cleared the greenhouse and, after a time, resumed planting according to all the relevant regulations. “We wanted to get an idea of how the virus concentration in the water evolves in a new crop, with or without a new outbreak. The virus did indeed return to some of the sites, while others were declared virus-free by the Federal Agency for the Safety of the Food Chain (FASFC) six months post-planting.”

This study showed that virus residue can remain in the drain water. “It is thus important not to draw conclusions based on a single water sample. You must monitor the virus concentrations trend over a longer period,” explains Evelien.

ToBRFV contamination leads to poorly colored tomatoes

Distinguishing active and inactive virus
The four-year research project has now begun. Researchers from Proefstation voor de Groenteteelt, Proefcentrum Hoogstraten, and  Scientia Terrae want to further investigate their findings. The researchers also want to further examine the virus residue to determine whether the virus is still active or not.

The B2B project, which stands for ‘Beheersing van ToBRFV op de Belgische tomatenbedrijven’ (‘Controlling ToBRFV on Belgian tomato farms’) allows researchers to do this further research. One of this ongoing study’s goals is to be able to distinguish inactive from active (infectious) viruses. “We learned that, after an outbreak, this virus is present all over. Much of this is probably residue that’s no longer infectious. Clarity about that can give growers a little more peace of mind.”

Researchers will also try to “get to know the virus better,” says Aussems. “We want to use monitoring on farms to do things like map symptom expression, determine the incubation period, and learn more about the spread of the virus. With a new virus, there’s always much to learn.”

Cell phone decontamination
Cell phones were a second major focus of the PraKeTo project. Everyone has one these days, including in the greenhouse. ToBRFV is known to be very tenacious and can survive on surfaces for a long time. So, the thinking is that it can be on phones, too, thus necessitating decontamination methods to be sought there.

“We’ve been researching UV decontamination. We got the idea for that from an experiment. In it, we touched a ToBRFV-infected plant with our hands, then sent a message on our cell phones. We then checked to see how much virus was on the phone. We were shocked to see the sky-high levels of virus concentration,” admits Evelien.

Thus, the search was on to find a way to disinfect cell phones. An American company, PhoneSoap, had developed a technique for this purpose. Evelien describes it as “a box in which you place your phone, where it is hit, on all sides, with UV light. After 15 minutes of exposure, the phone was virus-free.” Growers found this to be too long and thus asked that they try shorter exposures too. “However, five minutes of exposure and disinfection proved too short.”

It is up to each grower, but the best solution would be to keep your cell phone out of the greenhouse, the researcher points out. “Even if you disinfect your cell phone when going into the greenhouse, there’s still a risk, especially if you start using that phone intensively in the greenhouse. Growers, who struggle to ban phones in the greenhouse, can disinfect them. We do that at our test facility station. If you have sufficient time, UV light might be better for your phone’s lifespan than chemicals.”

Powdered milk
The researchers found that disinfecting your hands is a recurring topic among growers, as it was last week. After presenting the year’s first research results, the audience already had new questions. “We even looked at powdered milk as a hand disinfectant. It’s harmless to your skin and is widely used by growers,” says Evelien.

They tested, for example, skimmed powdered milk from the local supermarket. “We dipped our hands in a 5% milk powder solution. After a single dip, we tried to re-infect a plant, and the powdered milk seems to work well.” It is not as straightforward as that, though, and Evelien cautions against drawing hasty conclusions.

The milk powder (temporarily) encapsulates the virus but does not break it down. “After some time, especially at 15 immersions, the powdered milk was teeming with virus concentrations,” she explains. The researchers thus advise growers to replace the powdered milk very regularly. “Otherwise, it becomes a major source of contamination.”

Looking ahead
The new four-year project consists of five so-called work packages. Also, the new study explicitly seeks to connect with other research institutions doing ToBRFV investigations. For example, the European Virtigation project has close links with countries like Israel, where the virus emerged before reaching northwestern Europe.

“Above all, we don’t want to duplicate research,” Aussems points out. Not all five work packages will start simultaneously. The researchers, along with industry stakeholders, including growers, will review the study direction biannually. “It’s vital that what we’re investigating continues connecting to what growers want in practice.”

What is clear, however, is that the researchers have not yet solved the ToBRFV puzzle. The test facility itself became infected last year. “We’ve seen what a huge effect such an infection has. We’re fully committed to finding answers to the many questions.”

“Every day, we get asked, ‘Is this allowed?’, ‘Is that allowed?’ It is a ferocious virus that greatly affects plants and fruits. In the coming years, we want to gather new knowledge about the virus, results with new – resistant or not – varieties, prevention management, and an integrated, post-outbreak approach,” concludes Evelien.

For more information:
Evelien Aussems
Proefstation voor de Groenteteelt
Email: evelien.aussems@proefstation.be
Website: www.proefstation.be

Publication date: Wed 14 Sep 2022

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Disease-resistant GM cassava promises to be game-changer for Kenya


AUGUST 15, 2022


At the Kenya Agricultural and Livestock Research Organization (KALRO) center in Mtwapa, Kenya, scientist Paul Kuria uproots two sets of cassava tubers exposed to the devastating cassava brown streak disease (CBSD).

One of the plants is a conventional cassava variety that has no immunity to the disease. The second has been genetically modified (GM) to resist the disease. Kuria punctiliously slices each of the tubers open, and the difference between the two is stark — like night and day.

The conventional tuber looks emaciated and is punctured with brownish, unsavory spots dotting the entire circumference of its flesh. The GM tuber, on the other hand, is the picture of good health. Its skin is flawless and firm, and its flesh has an impeccable, white lustre.

CBSD is considered one of the world’s most dangerous plant diseases due to its significant impact on food and economic security. Cassava varieties that are resistant to the disease could considerably improve the crop’s ability to feed Africa while generating income for smallholder farmers.

In severe cases, the disease can lead to 100 percent yield loss. As noted by KALRO and its partners, cassava resistant to CBSD is in high demand by farmers where the crop is grown.

Meeting that demand has been an elusive target for plant breeders. But through modern biotechnology, a collaborative effort known as the VIRCA project has developed CBSD-resistant cassava line 4046. It has the potential to prevent 90 percent of crop damage, thus improving the yield and marketability of cassava roots.

“We used genetic engineering and produced an improved cassava,” Professor Douglas Miano, the lead scientist in the project, told journalists and farmers who toured the KALRO grounds in Mtwapa in early August.

“It’s the first GM cassava in the world, and Kenya is leading in this production,” Miano said.

The VIRCA (Virus Resistant Cassava for Africa) project was conceived in 2005 with the aim of solving the viral diseases that suppress cassava yields and reduce farmer incomes in East Africa. It brings together KALRO, the National Agricultural Research Organization (NARO) of Uganda and the Donald Danforth Plant Science Centre (DDPSC) in the United States.

“We have two main diseases affecting cassava production — CBSD and cassava mosaic disease,” Miano explained. “Cassava mosaic disease affects the leaves of the crop. The net effect is a reduction in the amount of cassava that is produced. CBSD, on the other hand, destroys the roots and affects the tuber.”

Scientists Paul Kuria displays GM disease-resistant cassava (left) vs cassava infected with CBSD. Photo: Joseph Maina

Dr. Catherine Taracha, a Kenyan who is on the project’s leadership team, said that plant viruses create a huge challenge for farmers.

“Cassava productivity is significantly hampered by viral diseases, and so we sought to develop a cassava line that would resist the viruses and thereby improve farmers’ livelihoods by boosting productivity and earnings from the crop,” Taracha said.

Because the line is yet to be approved for commercial release, the work is being carried out in regulated confined field trial conditions. If and when Kenya’s National Biosafety Authority approves line 4046 for the market, the new CBSD-resistant varieties would undergo normal government variety assessment and registration by regulators before being distributed to farmers.

The scientists further assure that CBSD-resistant cassava varieties are no different than their conventional equivalents — aside from their ability to resist CBSD.

“Due to the ability to resist CBSD, these varieties will be more productive with better quantity and quality of root yields,” Miano said.. “This will translate to greater demand and more profits for farmers.”

In addition, CBSD-resistant cassava line 4046 will produce disease-free planting material and thereby contribute to long-term sustainability of the cassava crop.

There will be no technology fee associated with line 4046, scientists say, implying that cassava stakes and cuttings will cost about the same as other highly valued cassava varieties.

Cuttings from CBSD-resistant cassava can be replanted in the same way farmers replant conventional cassava. They can also be grown with other crops because cultivation practices are the same as for conventional varieties.

The developers have further assured that CBSD-resistant cassava line is safe for the environment and biodiversity.

“We have developed the GM cassava up to the point where we have conducted all the safety studies and demonstrated that it is safe as food, feed and to the environment,” Miano said.

The general public and key stakeholders have been involved in the project, and it is anticipated that farmers and communities will be involved in selecting the best CBSD-resistant cassava varieties for their needs.

Cassava roots and leaves are the nutritionally valuable parts of the plant. The tuber is rich in gluten-free carbohydrates while the leaves provide vitamins A and C, minerals and protein. In addition to its nourishing properties, stakeholders have also identified cassava’s potential to spur Kenya’s industrial growth.

“Cassava is an important food crop, but we can also use it to industrialize in Kenya,” Miano asserted. “However, we have not yet been able to achieve this as a country.”

Miano identified starch as a potential cassava product that the country can leverage to advance its industrial growth. It is also projected that the improved cassava can protect farmers from devastating losses of this important food crop and contribute to the creation of thousands of jobs along the value chain due to the crop’s use as animal feed.

The scientists note that modern biotechnology is by far the best option to incorporate CBSD resistance in cassava cultivars carrying farmer-preferred characteristics. Similar approaches have been used to confer resistance to plant viruses and have been authorized by regulatory bodies around the world, including virus-resistant pawpaw, squash and beans.

Image: Scientist Paul Kuria displays cassava infected with cassava brown streak disease (left) and a GM variety that resists the devastating disease. Photo: Joseph Maina


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Breeder develops disease-resistant snack cucumbers varieties

“Developing varieties with resistances takes time but it’s an important role we play as plant breeders”

Rijk Zwaan is taking innovation to new heights in snack cucumbers by focusing on high wire varieties with the combination of Powdery Mildew (PM) and Cucumber Green Mottled Mosaic Virus (CGMMV) resistance. This is the latest development in the company’s ever-growing range of flavorsome snack cucumbers in various sizes and colors, all with the best possible resistances to help growers harvest a healthy crop.

Snack varieties with resistances to CGMMV and Powdery Mildew (PM)
Since introducing Quarto RZ – one of the first varieties of snack cucumber – in 2005, Rijk Zwaan has worked with growers and listened to consumers to breed new varieties that are not only agronomically sound and productive, but also delicious and visually appealing. “Developing varieties with resistances takes time but it’s an important role we play as plant breeders,” says Marcel van Koppen, a Dutch-based crop specialist at Rijk Zwaan. “Growers face pressure from a number of diseases such as mildew as well as viruses that can have serious consequences for crop viability. In 2019, we enhanced the snack cucumber range with the introduction of Quayal RZ as a PM-resistant version of Qwerty RZ. We’ve now taken our range to the next level once again by asking our breeders to develop snack cucumber varieties with a combination of PM and CGMMV resistances. This will be a significant improvement for growers and other value chain partners.”

Innovating the snack cucumber category for consumers
It is important to keep the segment fresh and exciting, since more than 35% of consumers in some markets eat snack cucumbers. One of Rijk Zwaan’s new varieties is Quirk RZ, a unique bi-coloured ‘baby apple’ snack cucumber with a sweet taste and good shelf life. Additionally the company has made further improvements in the smaller cucumber segment, resulting in the development of one-bites as well as a white-skinned variety which looks very striking in snack cucumber medleys. 

The future is sky
Rijk Zwaan continuously conducts research into new cucumber varieties, important resistances and technical characteristics. From generation to generation, the company maintains an ongoing dialogue with growers to anticipate new challenges in changing cultivation conditions, such as high wire. That’s why most of the company’s current varieties are suitable for both umbrella and high wire systems. “The future is the sky,” they say.

For more information:
Rijk Zwaan

Publication date: Wed 10 Aug 2022

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From PestNet


Source: New Vision [summ. Mod.DHA, edited]

The latest research by the National Agricultural Research Organisation (NARO) has revealed that banana bunchy top disease is set to affect the entire country. It was first reported in the Northern region and has now spread to the Western region. It is being speculated that the virus could have originated from the neighbouring Democratic Republic of Congo.

The Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) is setting up surveillance systems to monitor the spread of the virus, so that management measures can be taken before it spreads further. MAAIF stressed the need to collaborate and support regional efforts toward emerging pests and diseases, since Uganda imports plants and plant products.

[Byline: Juliet Waiswa, Violet Nabatanzi]

Communicated by:
[_Banana bunchy top virus_ (BBTV) is the type member of the genus _Babuvirus_ (family Nanoviridae). It affects only _Musa_ species and hybrids. BBTV causes one of the most serious diseases of these crops with symptoms of chlorosis, stunting, and death of the host plant. The virus is spreading in Africa, Australasia, and the Pacific Islands.

BBTV is transmitted by the banana aphid _Pentalonia nigronervosa_ in a persistent manner. Infectious insects may be spread on plant material or by air currents. The virus is also spread with infected suckers but cannot be transmitted by mechanical means (such as cutting tools). Disease management is extremely difficult and may include vector control, removal of inoculum, use of clean planting material, as well as frequent scouting for new outbreaks. Eradication of established BBTV from a planting or natural cluster of plants is considered impossible; the only option is to kill off all plants in the group. Tolerant varieties can be used to enable some crop production in infected areas, but these cultivars may still support virus replication and thus serve as pathogen reservoirs.

There are 2 groups of BBTV isolates from different regions: the South Pacific group (including Australia, Burundi, Egypt, Fiji, India, Tonga, and Western Samoa) and the Asian group (including Philippines, Taiwan, Viet Nam). The mean sequence difference between the 2 groups has been reported as approximately 10% (see link below). This is thought to suggest that the virus has spread after the initial movement of its hosts from the Indo-Malayan region, where edible _Musa_ species originated, to Africa and the Americas.

BBTV is closely related to _Abaca bunchy top virus_ (ABTV) reported from some areas of SE Asia (ProMED post 20191215.6842101). ABTV and BBTV cause the same disease symptoms in both banana and abaca (_M. textilis_).

In Africa, BBTV is thought to be present currently in around 16 countries (e.g. ProMED post 20211117.8699734). The virus is also endangering the diversity of banana varieties and landraces which are predominantly grown by farmers because they are well adapted to local conditions.

The Consultative Group for International Agricultural Research (CGIAR) through its International Institute of Tropical Agriculture (IITA), together with a number of international research institutions and stakeholders, have established an alliance to address the issue in the region and develop practical measures for BBTD control (see links below).

Undiagnosed diseases of banana have been reported recently several times from western Uganda (ProMED posts 20220511.8703185, 20210908.8655572, 20210601.8413562). It is feasible that some of these may have already been due to the spreading BBTV now confirmed by NARO above.

http://www.nationsonline.org/maps/uganda-political-map.jpg, and
http://en.wikipedia.org/wiki/Districts_of_Uganda (regions & districts)
Africa (overview):

Bunchy top symptoms on banana:
http://www.iucngisd.org/gisd/image/ecology/infected_fruits5.jpg, and
Bunchy top photo galleries:
http://www.ctahr.hawaii.edu/banana/leaves_bunchy.asp (whole plants),
http://www.ctahr.hawaii.edu/banana/morse_code.asp (leaves),
http://www.ctahr.hawaii.edu/banana/deformed_fruits.asp (fruits), and
http://www.ctahr.hawaii.edu/banana/closeup_photos.asp (banana aphids)

Information on BBTV:
https://www.cabi.org/isc/datasheet/8161, and
BBTV description and genetic groups:
ABTV description and characterisation:
Information on genus _Babuvirus_:
Virus taxonomy via:
Information on the banana aphid:
BBTD Alliance:
https://www.iita.org/news-item/international-multi-stakeholder-alliance-continue-to-tackle-banana-bunchy-top-disease-in-africa/ and via
– Mod.DHA]

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Jerome Kabiriba a Makerere University researcher from National Agricultural Research Organization (Photos by Juliet Waiswa)

By Juliet Waiswa and Violet Nabatanzi
Journalists @New Vision

#Banana virus#National Agricultural Research Organization (NARO-Mak)#Arua


Scientists have expressed fears that a new banana virus may affect the country in the next three years.

The latest research by the National Agricultural Research Organization (NARO-Mak) has revealed that the virus which was first reported in Arua district is likely to affect West Nile region.

Presenting the study findings at Golden Trip hotel during a meeting on plant pest surveillance, notification and emergency response in Uganda Jerome Kabiriba a Makerere University researcher from the NARO said “The virus forms small bunches out of the banana clusters which stops the crop from producing a bunch,”

The country according to Kabiriba is likely to lose $1.5b (approximately sh5.4trillion) because banana farming generates money in the hands of many people who sell and depend on the food for their income.

The commissioner for crop inspection and certification at the Ministry of Agriculture Animal Industry and Fisheries (MAAIF) Paul Mwambu 

The disease known as banana bunchy affects the banana bunches by entering the plant and stopping it from forming bunches.

Banana bunchy top disease is the most serious virus disease of bananas worldwide. Diseased plants rarely produce fruit and when they do, the fruit is stunted and twisted. However, in the rare scenario that the diseased plant does produce fruit that reaches maturity, it is edible

Kabiriba also revealed that last month, cases of the disease were reported in Kasese district in the Mpondwe. He raised fears that the disease might spread to neighbouring districts of Kamwenge and Kitagwenda if not controlled. Mpondwe is in the Rwenzori Mountains in Kasese District, the town is at the border with the Democratic Republic of the Congo (DRC).

How is it spread

According to experts, the disease is spread by transporting of banana suckers, bananas and other products from banana plantations. Kabiriba said the virus could have been spread from the Democratic Republic of Congo (DRC) entering into Arua.

“If the virus reaches the main banana growing areas of Buganda and Ankole we will be heavily affected, he revealed,’’ he said

As a ministry, we are going to put up surveillance systems to monitor the spread of the pest since they affect our regional markets.

“We need to manage these pests before they go too far so we are going to send our surveillance teams to go on ground,” Mwambu said

In Malawi three years ago the disease affected banana plantation which lead to losses that forced farmers into maize growing. In some parts of Asia, the diseases also affected the banana plantations in 2020 destroying most of the plantations of farmers. Cases of banana bacterial wilt at its peak were reported in early 2000.

The State Minister of Agriculture and Animal Industries Fred Bwino , in his speech read for him by the commissioner for crop inspection and certification at the Ministry of Agriculture Animal Industry and Fisheries (MAAIF) Paul Mwambu said, “As a ministry, we are going to put up surveillance systems to monitor the spread of the pest since they affect our regional markets.

We need to manage these pests before they go too far so we are going to send our surveillance teams to go on the ground,”

He called for a need to collaborate and support regional efforts toward emerging pests and diseases.

“Without Timely response to emerging pests and diseases the agro-industrialization agenda will negatively be affected as key sectors like Coffee, Maize, Banana, and diary, are threatened by emerging and endemic pests. Regional collaboration is also key,’’ he said

Uganda imports plants and plant products worth over $479m (about sh1.7 trillion) and exports more than $660m (approximately sh2.4 trillion) to different markets globally.


Symptom severity will vary from one banana variety to another. Dark green streaks on petioles and midribs called morse codes. Dark green streaks on the underside of the leaves Chlorotic leaf margins

Severe stunting with short and narrow leaves leading to a rosette-like or bunchy and choked appearance No bunches or bunches fail to fill up

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Soil Health and Pest Management: Challenges in the European Union



Jackie Pucci of AgriBusiness Global sat down with Dr. Arben Myrta, Corporate Development Manager with Certis Belchim B.V., based in Italy, to discuss developments in soil health and pest management solutions at the company and wider trends he is witnessing in the space.

Dr Arben Myrta, Certis Belchim B.V.
Quality produce with good soil pest management
Damage by Fusarium wilt in melon
Destroyed tomato plants from the attack of Meloidogyne spp.
Damaged roots of tomato by the nematode Meloidogyne spp.
Nematode damage in carrots from Meloidogyne spp.

Can you talk about some of the key developments in ‘soil health management’ in agriculture and what is driving adoption in Europe?

Soil health in its broad scientific definition considers its capacity, thanks to biotic and abiotic components, to function as a vital living ecosystem to sustain plants and animals. A soil may be healthy in terms of the functioning of its eco-system but not necessarily for crop production. In agriculture, good soil pest management remains a cornerstone for the quantity and quality of production at farm level. When farmers cultivate the same plants for a long time in the same soil without crop rotations or other agronomic measures, the soil starts to evidence nutritional and phytopathological problems for the plants. This is more evident in horticulture, and particularly, in protected crops in Europe, where this problem is of major importance.

In the past, in Europe, soil pest management in horticulture was mostly covered by chemical fumigation, lead first by methyl bromide (MB). MB was later globally banned for depleting the ozone layer, while other fumigants, which were intended to replace it, were not approved during the regulatory renewal process, thus creating a gap between the farmers’ needs and the possibilities to have adequate solutions for their cropping.  Meanwhile, in the last decades there has also been huge progress in research and technology, developing more effective biorational soil products (beneficial microorganisms, such as fungi, bacteria, etc.., plant extracts, etc..) and increased public awareness around human health and the environment, followed by more restrictive legislation on the use of chemicals in agriculture.

Driven by the legislation and the general attention of society on the use of plant protection products in agriculture, the industry has been proactive in looking for new solutions with safer tox and eco-tox profile, focusing on biorational products, whose number, as new plant protection products for the control of soil-borne pests and diseases, is continuously increasing in the EU.

How important do you see soil health and soil pest management in the complete picture of agricultural productivity, and how has that view changed?

Soil health and good soil pest management practices in crop production have always been considered important. In Europe, the level of attention and knowledge on this topic has been higher among professionals and farmers working in horticulture, the ornamentals industry, nurseries and particularly protected crops, basically everywhere where long crop rotations are not easily practiced, and pest-infested soils become a big problem for the farmers.

The rapid banning or limitation of several traditional synthetic products used to control soil pests raised the question for field advisors and farmers of how to deal with soil problems in the new situation. In recent years European farmers have been facing particular difficulties in controlling plant-parasitic nematodes.

Biorational products available today in EU countries represent a very good tool for the management of several soil pests in many crops and targets, but are still not sufficiently effective to guarantee full satisfaction to the growers in important crops like protected fruiting vegetables, strawberry, carrots, potato, ornamentals, etc., which explains why ‘emergency uses’ are still granted at EU country level following the request of grower associations to cover the needs of their farmers. The continuous increase in the numbers of new biorational products in the future, and particularly the innovative formulations that will follow, will be of paramount importance for their role in soil pest management.

A second, but important obstacle, is the generally limited knowledge on soil components (including its fertility and capacity to suppress pests by beneficial microorganisms) and the correct use of the biorational products, which cannot be expected to be effective quickly or be used as solo products, as the ‘old’ chemicals were. They should be seen more in programs with other soil management solutions, as recommended by the integrated production guidelines. Here, a further important obstacle is the lack of an effective public extension service to advise farmers, which is limited or totally lacking in many European Countries.

Everybody in the EU is now convinced that soil management in the future will rely on biorational and integrated solutions, but the question is how to reach this objective gradually, being pragmatic and reliable, balancing the environmental, economic and agricultural perspective. Legislation always steers the direction of progress but should be carefully considering the real product capabilities to make it happen in a short time and not focusing on ‘emergency situations’ as has now been the case for more than a decade.

What are some of the perceptions, either correct or incorrect, and other challenges you are dealing with in the region with respect to products for soil health?

This market has seen a rapid change from chemistry to biorational solutions, but in the meantime is facing a lot of challenges in order to meet the expectations of the farmers for quantity and quality of produce. This topic is widely discussed in dedicated scientific forums like that of the International Society of Horticultural Sciences, of which the last International Symposium on Soil and Substrate Disinfestation was held in 2018 in Crete, Greece. A dedicated round table was organized with soil experts to discuss the important challenges faced by the European growers due to the lack of plant protection solutions for an effective control of several soil pests, most of all nematodes. I participated in that round table discussion, whose main conclusions were the following concerns, considered as target actions for the scientific community:

  • the farmer needs various tools for soil disinfestation (SD) in the light of the limited current arsenal of SD tools;
  • the lengthy and unpredictable European registration process (sometimes more than 10 years from dossier submission to the first national approval) of new plant protection products (including biorational) and the cautious approach of EU regulation, as well as restrictions imposed, has led to a reduction of active ingredients available in the past years;
  • a more effective and faster evaluation system is needed, especially for naturally occurring and low risk products (biological, plant extracts, etc.). That is, all products which are essential for Integrated Pest Management (IPM) programs;
  • following the implementation of Regulation EC 1107/2009, the only tool available to fill the gaps in local production systems is Art. 53 of the above-mentioned Regulation, which provides “derogations” for exceptional authorizations of plant protection products. Such authorizations increased exponentially in the last years, indicating that existing solutions in the European market are not considered sufficient;
  • the above-mentioned EU Regulation has a high socio-economic impact on various production systems in Europe and a Spanish case shows clearly the importance of maintaining a sustainable agricultural activity in local communities that, in the case of protected crops area, includes 13% of the active population employed in agriculture;
  • several European agricultural sectors are affected as the EU authority is allowing increased importation from extra-EU countries, considered unfair competition due to their more flexible registration system for plant protection products than that of the EU;
  • reduced capacity of soil pest research, where experts are retired and not being replaced, alongside weak, or in many areas non-existent, extension services together are causing the loss of soil knowledge and good advice for our farmers. Today, soil diagnosis is frequently completely lacking or insufficient before any soil pest and crop management decisions are taken.

The clear message from the scientific experts at that meeting was that these issues must be correctly addressed at all levels of stakeholders, in such a way that all available tools, including sustainable use of soil disinfestation, may be used in a combined IPM system to allow sustainable production in Europe.

What are some of the most exciting developments at Certis Belchim in soil health and pest management?

Since the establishment of Certis Europe in 2001, we have focused on soil pest and disease management. In 2003, Certis built the first CleanStart program providing integrated solutions for sustainable soil management, combining cultural, biological and chemical approaches. After more than a decade, in the mid-2010s, the CleanStart integrated approach started combining biological and chemical inputs with agronomic services (training to farmers and field advisors, soil pest diagnosis support for partner farms and stewardship product advice for applicators and/or farmers) to provide sustainable soil management for the future, aligned with the principles of the Sustainable Use of pesticides as per the EU Directive. All these activities were carried out successfully thanks to a wide international network created with many research institutes across Europe on soil pest management topics. This approach facilitated our participation in soil research projects funded also by the EU. Thanks to this experience we have been able to prepare and share many publications and communications, in particular the coordination for several years of an International Newsletter on Soil Pest Management (CleanStart).

Last year we were also granted a SMART Expertise funding from the Welsh Government, which is co-founded by Certis, in a research project lead by Swansea University, with Certis Belchim B.V. the industry partner, alongside major Welsh growers, Maelor Forest Nurseries Ltd and Puffin Produce Ltd. This project, now ongoing, looks to develop new and innovative products to control soil pests, primarily nematodes.

Thanks to this team involvement on soil topics, our present soil portfolio includes several biorational solutions such as Trichoderma spp. (TriSoil), Bacillus spp. (Valcure), garlic extract (NemGuard), etc. and this is continuously increasing through our research and development pipeline. With the soil biorational products we have developed a good knowledge not only on the products, but also in their interaction with biotic and abiotic soil components and with other similar products.

Our new company, Certis Belchim, in the future will continue to be particularly interested in this market segment and will be focusing mostly on biorational products. Our plans mainly encompass: (i) label extension to more crops and targets for the existing products; (ii) development and registration of new active ingredients for the control of soil borne pathogens, insects and nematodes; (iii) development of innovative formulations for soil use with focus on slow-release; (iv) field validation of effective programs with bio-solutions and other control methods.

In all these research and development activities, supported by the long experience we have in such topics, we are looking to generate our own IP solutions for soil pest management.

How have you seen this space evolve over the past of years, and what are you expecting the next years will bring?

From a technical perspective, we expect the nematode problems to increase globally in the future. This is due in part to the gradual global increase in average temperature, now recorded over recent decades, which will allow the most damaging nematodes, Meloidogyne spp., to establish at higher elevation and higher latitudes while in areas already infested, they will develop for a longer damaging period of time, thus leading to larger nematode soil population densities by the end of the crop cycle and, in turn, to greater damage to the succeeding crops.

From a regulatory perspective in Europe, if the approval process for new effective nematicides is not shortened and remains as restrictive as today, less effective solutions will be available, and there will be more reductions in rates and crops on which their use is permitted (e.g. not every year). This again will certainly lead to an increase in the severity of the nematodes that in many areas could be overlooked.

From a quarantine perspective, the globalization of trade has facilitated the introduction into Europe of new damaging nematodes and diseases and pests in general, events which are expected to increase in the future. The most critical situation can occur in protected and nursery crops, and for the production of healthy propagating material of annual crops, such as potato seed, bulbs and seeds of bulbous plant crops, including flowers, strawberry runners, woody nursery plants, of both crop and ornamental plants, and in all crops for which quarantine issues must be considered, especially when seeds, bulbs and any kind of plant propagating material are to be exported out of the EU.

The expectation is also that positive results will come from public research (more focus on resources is needed) and private industry where work is ongoing to bring to the market new biorational solutions and innovative methods with higher efficacy in controlling soil pests and to fulfill the increasing needs of this market. However, this will only be realized if regulatory hurdles are reduced in the EU, for example for low risk biorational solutions.

How are external factors (e.g., soaring input costs) impacting the adoption of these products?

Today agriculture and plant protection products, like the whole economy, are affected by higher prices due to the increased cost of energy and raw materials globally. Considering that the costs in agricultural production are already high and sometimes, those of soil pest control are not applicable for several crops, any further increase in production costs may lead to the abandonment of effective solutions, resulting in additional increase in the complexities of soil problems on our farms. This trend, if allowed to persist, will severely affect our agricultural sector.

This said, there will also be a potential increase in the new solutions entering the market in the coming years, which will face higher costs during development and the registration process as well.

From a technical perspective, the only way to reduce such risks is to support farmers with the right knowledge on how to use new soil products correctly (dose rate, timing and method of application, etc..) and increase cost effectiveness.

Can you share highlights of research and case studies that your company has conducted with respect to soil health?

Our company has been involved in many research and market studies dedicated to the soil pest management sector. The last important one was ‘Sustainability of European vegetable and strawberry production in relation to fumigation practices,’ prepared by a European team of independent soil experts. The aim of the study was to understand technically the role and economic impact of chemical soil fumigation in key European areas of vegetable and strawberry production. Three cases of representative crops were investigated: strawberries, solanaceous/cucurbitaceous crops cultivated under protected conditions and carrots as a relevant open field crop.

The study concluded that vegetable production is a key agricultural sector in Europe: including high-value crops like solanaceous and cucurbitaceous crops produced under protected conditions (tomatoes, peppers, aubergines, courgettes, cucumbers and melons), carrots and strawberries, the production value at farmer level is €12.5 billion; the cultivated area involved is roughly 330,000 ha. The importance of these crops is even greater when the entire food value chain, in economic and social terms, is also considered.

High standards in terms of food quality/safety and certificated production, along with affordable consumer prices and consistent availability across the seasons are demanded of European vegetable production and, as a consequence, are the drivers for the growers who have to protect such crops effectively and economically. The growers face very significant issues deriving from soil-borne pests, which are the key limiting factor to achieving quality and economically sustainable yields. As strongly indicated by farmers and crop experts, among the soil-borne pests, nematodes present the most impactful and frequent challenges.

According to the survey carried out in key EU countries (Spain, Italy, France, Belgium,…), the most common soil management practices for vegetable crops and strawberries are: chemical fumigation, crop rotation, resistant cultivars and rootstocks, followed by soil-less systems, non-fumigant treatments, soil solarization, biological products, organic soil amendments, catch and cover crops.

This shows clearly that soil pest management today and in the near future will rely on IPM systems combining and rotating different management practices, with a different degree of implementation depending on the cropping system.

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