Produced by the International Association for the Plant Protection Sciences (IAPPS). To join IAPPS and receive the Crop Protection journal online go to: www.plantprotection.org
Intercropping allows for insect conservation without yield loss
Phys.Org
How can we halt biodiversity declines? A new study led by the Leibniz Institute for the Analysis of Biodiversity Change (LIB) shows possible solutions for agricultural landscapes. The study shows that intercropping promotes the diversity of insects and other arthropods in agriculture without affecting yields. The study has now been published in the journal Ecological Solutions and Evidence.
The Philippine Bureau of Plant Industry issued a Biosafety Permit for the Commercial Propagation of Bt cotton (GFM cry1A) developed by the Philippine Fiber Industry Development Authority (PhilFIDA). The permit was granted to PhilFIDA after completion of the biosafety evaluation and the requirements for commercial propagation based on the DOST-DA-DENR-DOH-DILG Joint Department Circular (JDC) No. 1, Series of 2021. BPI issued the permit on August 24, 2023, and announced the approval on their website.
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Bt cotton contains the Bt fusion gene, GFM cry1A, produced based on the protein template of Cry1Ab and Cry1Ac proteins from Bacillus thuringiensis. The Bt fusion gene confers resistance to bollworm infestation. Field trials have shown that this transformation leads to more harvestable bolls and reduces the use of pesticides. The increased cotton yield is projected to enhance the income of cotton farmers and provide more job opportunities, particularly the additional need for cotton pickers.
Plant viruses in the agriculture sector cause billions of dollars in losses each year. Farmers may now have a new tool in tracking these diseases.
Scientists with the Arkansas Clean Plant Center at the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, have developed a protocol that speeds up the process, lowers the cost and improves the accuracy of detecting plant viruses.
Ioannis Tzanetakis, director of the Arkansas Clean Plant Center and professor of plant virology, said a major bottleneck in detecting pathogens is the availability of positive controls to confirm a diagnosis. A positive control is a specimen known to contain the pathogen in question. Acquiring positive controls can be problematic, and their maintenance is expensive, and without them, a test cannot be validated, he said.
“This is a clear case of necessity being the mother of invention,” Tzanetakis said. “We had a new plant virus in Europe but nothing here to compare it to. What is unique about our approach is that because we are using a ‘sister’ virus as the surrogate, everything that we do pretty much mimics a natural infection and we do not need to import the infected material.”
Plant viruses cause billions of dollars of losses in agricultural crops worldwide, affecting the yield and quality of agricultural products, according to the U.S. Department of Agriculture. The emergence of novel viruses or variants through genetic evolution and spillover from reservoir host species, changes in agricultural practices, mixed infections with disease synergism, and impacts from global warming pose continuous challenges for the management of epidemics resulting from emerging plant virus diseases, the USDA reported.
The USDA has strict restrictions on the movement of plant material from outside the country, Tzanetakis said. And while there are permits for laboratories to conduct diagnostics with diseased material, the process is lengthy. So, what’s a scientist to do when time is of the essence in obtaining a positive control? Mimic it, said Tzanetakis.
A benefit of the patent-pending process, Tzanetakis noted, is that it can tell if the virus is from an unintentional contamination.
The Clean Plant Center works with plant material from all over the world, making sure plants are free from viruses. The scientists at the center provide virus “clean-up” and testing making sure that plant material is the best quality possible before providing it to nurseries, breeding companies and growers.
The Clean Plant Center receives plant samples from breeders, nurseries and growers to test for the presence of viruses. If scientists detect a potential virus, they must validate the detection by comparing the viral material from the plant with something that is known to contain the virus — either a “true” positive control or an “artificial” control. Normally, the Clean Plant Center obtains an artificial piece of DNA with the virus sequence as a positive control to amplify using polymerase chain reaction, also known as PCR, and compare to their diagnostics. But that process has major drawbacks, Tzanetakis said.
The center’s patent-pending protocol for virus-mimicking artificial positive controls, or ViMAPCs, creates an artificial positive control that acts like the target virus and allows for validation through what is considered a natural infection. Tzanetakis said for the “sister virus” to better imitate natural infection, it must belong to the same genus as the target virus.
“The virus-mimicking artificial positive control allows the center to create an artificial positive control that not only mimics the titre and tropism of the target virus, but also is cheap and rapid compared to the currently available artificial positive controls,” said Shivani Singh, a co-inventor of the technology and program associate for the center.
Titre is the concentration of a substance in solution – in this case the concentration of virus in the plant – and tropism refers to the distribution of the virus within the plant. A positive control considered to have a “natural infection” allows for a more accurate comparison to the diagnostic than a synthetic piece of DNA, Tzanetakis added.
“With just a piece of DNA, you don’t really know if the virus you are testing for has the same titre in the tissue,” Tzanetakis explained. “Some viruses hide in the roots, and they are barely detectable in the leaves and vice versa. We have developed a protocol that is as close to natural infection as you can get unless you have the actual infection of the target virus.”
The protocol was also designed so the ViMAPC control is easily differentiated from a true infection.
“The way that we use this protocol, we can easily identify if a positive result is due to an infection in the plant or a lab-based contamination from our controls, because the controls always have a different size than what the targets will be,” Tzanetakis said, referring to gel electrophoresis, which separates DNA by size.
The newly developed approach takes less than five days to implement whereas alternatives normally take several weeks. The strategy, Tzanetakis said, is straightforward and can be done by laboratories that use polymerase chain reaction-based diagnostics. The process could also have the potential to accurately confirm viruses that impact humans, he said.
Tzanetakis said they use widely available viruses as surrogates to the ones they are targeting, and the protocol limits the need to move viral tissue across international borders.
Corteva launches breakthrough innovation to control crop-damaging nematodes, protect soil health
Indianapolis, Indiana, USA September 13, 2023
Award-winning chemistry Reklemel™ active is latest addition to company’s portfolio of sustainable innovation
Plant-parasitic nematodes are microscopic organisms found in soil that feed on the roots of plants. Because they are notoriously difficult for farmers to identify and control, plant-parasitic nematodes represent a significant constraint to the delivery of global food security, causing damage estimated at or exceeding $80 billion per year.1
To address this significant, global challenge, Corteva (NYSE: CTVA) has launched Reklemel™ active, a new nematicide to help protect a wide variety of food and row crops from plant-parasitic nematode damage without disrupting the healthy balance of beneficial organisms in soil. Reklemel active was discovered and developed by Corteva and is the result of more than a decade of research and investment.
“The future of global farming – and our ability to feed a growing population – rests on innovation. Reklemel demonstrates how Corteva deploys innovation to help farmers meet critical challenges to feed the world,” said Robert King, Executive Vice President, Crop Protection Business, Corteva Agriscience.
Reklemel received a Reduced Risk designation from the U.S. Environmental Protection Agency (EPA) due to the product’s ability to selectively target plant-parasitic nematodes, its lower use rates than older nematicides, and its highly favorable environmental and toxicological profile as compared to alternatives. Reklemel is one of the first new active ingredients to be registered under EPA’s updated policy incorporating Endangered Species Act assessments into the pesticide registration process.
Reklemel also received the National Association of Manufacturers’ Sustainability and the Circular Economy Award in recognition that it, through lower use-rates, enables the potential to avoid more than 500M Kg of CO2 – equivalent emissions over the next five years.2
Salibro™ nematicide with Reklemel™ active will be available in the United States, India and Mexico beginning in late 2023, and is currently available for sale in Canada and Australia. Additional registrations are planned globally, including in the European Union, subject to regulatory approvals.
Reklemel is the latest advance brought to market by Corteva to help farmers increase yields, meet climate and other challenges, and ultimately strengthen global food security. Corteva invests nearly $4 million every single day in research and development. In 2022, the company launched more than 180 new crop protection products globally and advanced nine new active ingredients in its R&D pipeline.
About Reklemel
Reklemel active can be applied pre-plant, at-plant or in-crop and protects a wide range of annual and perennial crop groups, including fruiting vegetables, cucurbits, root and tuber vegetables, fruits and nuts, field row crops, small fruits, and berries. Farmers who use Reklemel active in combination with cultural, mechanical, and biological management practices as part of an Integrated Pest Management strategy can increase yield potential and reduce quality losses associated with plant-parasitic nematode damage, reduce environmental impact compared to many alternative nematicides, and help preserve beneficial organisms critical to soil health.
Reklemel is one of the first new active ingredients to be registered under EPA’s updated policy incorporating Endangered Species Act assessments into the pesticide registration process. As part of these assessments, EPA evaluates the potential effects of labeled uses of a pesticide on listed species and their habitats, and initiates ESA consultation with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, as appropriate. EPA’s work to establish and implement this new process is an important step toward regulatory certainty for farmers and others who rely on important pesticide technology, while also helping protect listed species and their habitats.
The 2023 BCPC Weeds Review marks 60 years of sharing experiences of weed control challenges and successes. To highlight this landmark, the organisers have asked some speakers to explore influences, changes and successes over the past 60 years which will also inform future needs.
Please find about 10 minutes to provide your experiences on weed control in your career to date, and to help highlight emerging priorities. The survey (which may be shared with colleagues) will be open until 15 October and is accessible via the ONLINE SURVEY LINK or by scanning the QR code below. It is suitable PCs and mobile devices. Thank you.
We welcome your reflections in this. The survey outcomes will provide a topic of discussion at the BCPC Weeds Review on 2 November.
Edited by Dr Manuele Tamo and posted to the IAPPS website, the IAPPS Newsletter is subsequently published in the journal – Crop Protection, the Official Journal of IAPPS under a contract between IAPPS and Elsevier Science.
We welcome submissions of new articles, letters, and other items of plant protection interest, particularly from IAPPS members but also from other individuals and organizations. Address correspondence and information to:
Dr. Manuele Tamo, Editor IAPPS Newsletter Biological Control Center for Africa, IITA-Benin 08 B.P. 0932 Tri Postal, Cotonou, Republic of Benin
Downy mildew (DM; Plasmopara viticola) is amongst the most severe fungal diseases in viticulture and the reason for the majority of fungicide applications. To reduce synthetic and copper-based fungicides, there is an urgent need for natural alternatives, which are being increasingly tested by the industry and the research community. However, their mode of action remains unclear. Therefore, our study aimed to investigate the transcriptomic changes induced by oregano essential oil vapour (OEOV) in DM-infected grapevines. OEOV was applied at different time points before and after DM infection to differentiate between a priming effect and a direct effect. Both pre-DM treatment with OEOV and post-infection treatment resulted in a significant reduction in DM sporulation. RNA-seq, followed by differential gene expression and weighted gene co-expression network analysis, identified co-expressed gene modules associated with secondary metabolism, pathogen recognition and response. Surprisingly, the molecular mechanisms underlying the efficiency of OEOV against DM appear to be independent of stilbene synthesis, and instead involve genes from a putative signalling pathway that has yet to be characterized. This study enhances our understanding of the molecular regulation of innate plant immunity and provides new insights into the mode of action of alternative natural antifungal agents.
Genetic cluster in root fungus found to be the “on/off” switch for disease-causing behavior:
Switching from harmful to helpful fungi
Mold and diseases caused by fungi can greatly impact the shelf life of fruits and vegetables. However, some fungi benefit their hosts by aiding plant survival. Colletotrichum tofieldiae (Ct) is a root mold that typically supports continued plant development even when the plant is starved of phosphorus, an important nutrient for photosynthesis and growth. Researchers studied a unique pathogenic strain of the fungi called Ct3, which conversely inhibits plant growth. By comparing the beneficial and harmful Ct strains, they found that activation of a single fungal secondary metabolism gene cluster determined the negative impact of the fungus on the host plant. When the cluster was disrupted, either genetically or by a change in environment, the fungi’s behavior changed from inhibiting growth to promoting it. Understanding mechanisms like this could help us reduce food waste by harnessing the beneficial role fungi can have on food.
When your fresh strawberries go fuzzy with mold, or grapes turn gray and shrivel at the bottom of the fruit bowl, it’s always a bit disappointing and unpleasant. The culprit is typically a disease-causing fungus called Botrytis, which devastates food crops globally and is easily spread by wind and soil. However, there are many fungi that have a less destructive relationship with their host plants, even forming partnerships that can help the plant to thrive. Promoting the beneficial traits of fungi and suppressing undesirable outcomes (like moldy fruit) would greatly aid global food security and help reduce a huge amount of food waste.
“Plant-associated fungi show varied infection lifestyles ranging from mutualistic (beneficial) to pathogenic (harmful) depending on the host environment. However, the mechanisms by which these microbes transit along these different lifestyles remain poorly understood,” said Associate Professor Kei Hiruma from the Graduate School of Arts and Sciences at the University of Tokyo. “We analyzed genetic information from varied strains of a root fungus called Colletotrichum tofieldiae using comparative transcriptomic analysis, which enabled us to study differences in gene expression between each strain. Surprisingly, we found that a single fungal secondary metabolism gene cluster, called ABA-BOT, solely determines whether the fungus exhibits pathogenic or mutualistic traits toward the host plant.”
Colletotrichum tofieldae is a fungus that typically benefits plants when they suffer a phosphorus deficiency, helping them thrive despite the lack of this vital nutrient. It has even been shown to increase the growth and yield of economically important crops such as maize and tomatoes. In this study, the multi-institutional team used thale cress as the host plant and sourced six strains of Ct from different geographical locations to infect it with. Five strains significantly promoted plant growth, as expected, but a sixth — called Ct3 — was found to suppress nutrient uptake, inhibiting plant growth and leading to symptoms of disease. So, what caused this drastic change?
“We identified two key points: First, on the fungal side, that Ct3 activates the ABA-BOT biosynthesis gene cluster; and second, on the plant side, that Ct3 induces the host plant’s ABA signaling pathways, through which the fungus inhibits plant growth,” explained Hiruma. The researchers found that both pathogenic and mutualistic strains of Colletotrichum tofieldae contain the ABA-BOT gene cluster, but mutualistic strains did not express it, i.e., the genes were not activated. The discovery came as a surprise, as conventionally pathogens and mutualists were thought to have distinct characteristics, but these findings suggest that they are more intricately related.
When the gene cluster was disrupted, either at a genetic level or by changing the plant’s environment, the Ct3 was rendered nonpathogenic and even became beneficial to the host, promoting root growth. Although further study is needed, it appears that the ABA-BOT gene cluster may contribute to pathogenesis in diverse fungi beyond the Ct species. For example, it may be involved in the pathogenesis of the Botrytis, which afflicts our household fruit and vegetables. “If we gain a comprehensive understanding of the regulatory mechanisms governing the fungal secondary metabolism gene cluster, we can devise a method to selectively suppress potential pathogenesis in otherwise beneficial fungi, optimizing their utilization in agriculture and harnessing the full potential of the microbial diversity naturally present in soil ecosystems,” said Hiruma.
“I have come to realize that even pathogens can exhibit nonharmful characteristics during a significant portion of their life cycles. In fact, I am beginning to contemplate the possibility that what we traditionally refer to as pathogens may actually function as beneficial microbes under other conditions.”
IAPPS members and other visitors to the IAPPS website will see that Google translate has recently been added, enabling non-English speaking visitors to read most of the material on the site in their local language. Whenever possible, our intention will be to post new material on the website as html, allowing for local language translation.
To access this translation facility, click on the “Translate” button and choose the relevant flag symbol associated with your local language. Note: a list of languages at the bottom of the screen provides an alternative means of selecting a language.
While making most of the current information on the website available to visitors with limited English, this translation facility offers a broader service to plant protection worldwide. Three examples, that can be accessed via http://www.plantprotection.org – Resources – Education and Training, illustrate this point:
“A Brief History of Plant Protection”, was initially posted on the “Education and Training/Plant Protection Stories” section of the IAPPS website, as two English language pdf documents.
Starting with the early beginnings in subsistence agriculture, we examine various case studies that illustrate the many economic, technical, social, and regulatory factors that have influenced the development, effectiveness and problems associated with modern plant protection strategies. This plant protection story is now available as a website document, that allows users to take advantage of Google translate to view the tutorial in their own language.
“A Review of Digital Identification Tools for Plant Biosecurity”, a publication involving 11 experts from 6 countries, has recently been posted on the IAPPS site. It is freely available as an English pdf version as well as a website version, which can be translated into any of the Google languages and made available to a much wider audience.
“A series of digital pathway keys for identifying insects and spiders found in rice in West Africa”(see IAPPS Newsletter January 2023) has now been converted from English to French by Dr Souleymane Nacro (IAPPS West Africa Board member). Dr Nacro used Google translate to initially convert the keys to French, then checked and edited this initial translation, using appropriate French taxonomic terms. This French version of the digital keys will be made freely available on the same IAPPS site.
Australia still has opportunity to eradicate varroa mites
Varroa mites have recently reached Australia, detected at the Port of Newcastle in New South Wales last year. If they establish here, there would be significant implications for agricultural food security, as honey bees are heavily relied on for the pollination of many crops.
However, while Australia is the last continent to be invaded by the mite, it has an opportunity to be the first to eradicate it. Previous invasions of varroa have been successfully eradicated before establishing, but this time, varroa circumvented the biosecurity surveillance near Newcastle and spread locally.
The New South Wales Department of Primary Industries has been contact-tracing and culling hives in contaminated areas, and the spread has been slow so far. Australia has large populations of feral honey bees, which could potentially act as a reservoir for varroa and are much harder to trace and control, so the department is tackling this with a wild honey bee baiting program.
Orange juice prices are expected to rise further in the US after a bacterial disease and extreme weather intensified by global heating ravaged this season’s crop of the citrus fruit.Last year Florida, which produces more than 90% of the US’s orange juice supply, was hit by Hurricane Ian, Hurricane Nicole and freezing conditionsin quick succession, devastating orange producers in the Sunshine State.
Producers also battled anincurable citrus greening diseasethat is spread by an invasive insect, rendering fruit unusable. Most infected trees die within a few years, and some producerstold the Financial Timesthey were giving up farming and selling their land.Industry figures said US orange production would reach its lowest level for more than a century.
And futures prices forfrozen concentrated orange juiceon the Intercontinental Exchange, the global benchmark which is strongly linked to production in Florida, have roughly doubled in the last year to more than $3 a pound and could rise further, prompting warnings that prices are set to surge further on the shelves.Matt Joyner, chief executive ofFloridaCitrus Mutual, a grower trade association, said: “At its height, our industry was doing about 244m boxes of oranges. This season we ended up with just under 16m boxes.“You can see that is a very dramatic decline as a result of this disease and multiple weather events that really hammered our industry. Supply and demand dictates that with such a reduced crop, there will be upwards pressure on prices.”
A worker collects oranges at an orchard in Arcadia, Florida, 14 March 2023.Photograph: Chandan Khanna/AFP/Getty Images
Joyner told the Guardian that about 10% of Florida’s orange trees were lost in last year’s hurricanes. Hurricane Ian, one of the worst storms in US history, was worsened by the climate crisis, accordingto scientific analysis. The storm hit 152,000 hectares (375,000 acres) of citrus groves in Florida – nearly all of the 162,000 hectares of groves – causing $675m in damages,according to Florida Citrus Mutual’s assessment of the 2022-23 season published last month.Joyner said: “You would like to think there’s more than can be done to prepare for hurricanes and massive flooding events but there’s really little we can do, from a production standpoint, to combat Mother Nature.”Jack Scoville, a broker at Chicago-based Price Futures Group, said the environmental impact on orange production would filter through to retailers in the coming months, likely raising prices even further. He said the climate crisis was having an increasing impact on orange production around the world.
“I am not going to blame the situation in Florida exclusively [on climate change] but there is that factor,” he said. “In Brazil, the number one exporter of oranges and orange juice, they are experiencing heat right now that’s being blamed on climate change. When you look at orange production in other states of the US like California and Texas, they are both states that have been extremely hot.
“You look at Europe. Spain and Italy are both pretty big producers of oranges. Some Asian countries are pretty big producers, too. Climate change definitely has a part to play in this.”Spain, Portugal, France and Italy are alltaking measures to stop the spreadof the bacteriaCandidatus liberibacterthat causes citrus greening, also known as yellow dragon disease.The impact of extreme weather on food production is one of the major risks of global heating, with coffee, olives and rice among some of the crops affected.Find moreage of extinction coverage here, and follow biodiversity reportersPhoebe WestonandPatrick Greenfieldon Twitter for all the latest news and features
Damage caused by gray mold. Botrytis cinerea is one of the most damaging fungal pathogens, affecting many different agricultural crops and plants before and after harvesting, leading to plant loss and food waste. ©Kira_Yan, Envato Elements
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