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Chemical crop protection affects bee reproduction over several generations

A new study from researchers at the University of California, Davis, finds that chemical crop protection not only directly affects bee health, but effects from past exposure can carry over to future generations. The study, published in the journal Proceedings of the National Academy of Sciences, suggests that bees may require multiple generations to recover from even a single application.

Bees play a critical role in agricultural ecosystems, providing pollination for many important crops. In most agricultural areas, bees may be exposed to chemical crop protection multiple times, over multiple years. Studies to date have only looked at exposure to chemical crop protection in one life stage or over one year.

“It was important for us to understand how exposure persists from one generation to the next,” said lead author Clara Stuligross, a Ph.D. candidate in ecology at UC Davis. “Our findings suggest we need to be doing more to help mitigate risks or we limit critical pollination services.”

Reproduction drops
In the study, the blue orchard bee was exposed to imidacloprid — the most commonly used neonicotinoid in California — according to amounts recommended on the label. Neonicotinoids are a class of insecticides chemically related to nicotine. Stuligross said the exposures were similar to what the bees would experience in the field. Female bees that were exposed to the insecticide as larvae had 20% fewer offspring than bees not exposed. Those bees that were exposed as larvae and as adults had 44% fewer offspring.

“We gave them one application in the first year and one in the second — that’s a pretty standard exposure. Even then, we saw strong results that added up, each exposure reducing fertility,” said Stuligross.

Populations affected
Because the impacts of insecticides tend to be additive across life stages, repeated exposure has profound implications for population growth. The research showed that bees exposed to neonicotinoids in both the first and second years resulted in a 72% lower population growth rate compared to bees not exposed at all. Neonicotinoids also persist in the environment long after application.

The study reveals how past chemical crop protection exposure can have lasting impacts, said co-author Neal Williams, professor of entomology at UC Davis. “One could draw parallels to human health where impacts early in development show up much later in life,” he said. “We just didn’t know the same was true for bees. Now we do and we need to continue to manage risks appropriately.”

For more information:
University of California Davis 
One Shields Avenue, Davis
California 95616, US
www.ucdavis.edu 

ToBRFV resistance is holding

“What we saw convinced us again that the ToBRFV resistance is holding very well”

In October 2020, Enza Zaden announced the discovery of the High Resistance gene to ToBRFV. The one and only solution to beat this devastating tomato virus.

Fast forward to today, one year later: what has happened in the past year? Where are we now? And what is yet to come? 

Martijn van Stee, Crop Breeding Manager Tomato, gives an insight into the process to create high-resistant varieties: “Since we discovered the ToBRFV high resistance gene we worked hard on introducing it in our elite parent lines. At this moment we have high-quality parent lines with the ToBRFV resistance. This helps us to make high resistance tomato varieties.”  

Check out the video here.

Trials confirm high resistance 
Besides working on the parent lines, Enza Zaden has done some extensive trials with high resistant varieties in the past year. Martijn: “We trialed the first tomato varieties already in Europe, Mexico, and the Middle East. And what we saw there really convinced us again that the ToBRFV resistance is holding very well.” 

Kees Konst, Crop Research Director, continues: “In the meantime, we started up also the seed production of the hybrids. We already have some examples of high resistance varieties in our hands.” 

Importance of high resistance to ToBRFV 
The gene that Enza Zaden has discovered provides high resistance to ToBRFV. Kees explains the importance of high resistance. “With high resistance, you will not have any problems, because there is no virus in the plant or the fruit. You keep your soil, your water, everything clean.” 

What’s next? 
Eradicating the virus remains our top priority. This is something we can only achieve together with the growers and the fresh produce industry. Martijn: “Our breeders are very busy filling the pipeline. To make more elite parent lines with resistance, to make more varieties with resistance. The solution is right around the corner.”\For more informationEnza Zaden
info@enzazaden.com
www.enzazaden.com

Publication date: Wed 1 Dec 2021

Massimo Pavan

Italy: “The summer season was a disaster due to the high temperatures and diseases”

Table tomatoes represent the most valuable vegetable and are among the most important consumer products. Massimo Pavan, an Italian expert and vice-president of Consorzio di Tutela del Pomodoro di Pachino Igp, explains how the summer was a disaster for growers. 

Now that the summer season has ended, the time has come for a winter season with table tomatoes grown in greenhouses in the Mediterranean areas, with Sicily standing out thanks to its prestigious productions.

“The summer season was a disaster due to the high temperatures and diseases. Although Tuta absoluta did not cause much trouble as it was exterminated by the high temperatures, there were other threats such as the Tomato Brown Rugose Fruit Virus. The drought that hit Sicily caused a 50% drop in production, leading to doubled production costs.”

“Although prices were rather high during the period in question, the favorable quotations were not enough to repay the losses in absolute terms. Cherry tomatoes, with peaks of over €2/kg, settled at an average of €1.50/kg. Thus, we were not pleased with the summer of 2021, especially considering the continuous price increases of the raw materials. Prices have increased so quickly that it is difficult to quantify the actual cost index. In addition, the cost of energy and fuel has also increased in October, which affected November production.”

“The prices are currently low, as is demand in foreign markets such as Germany and Austria. Production prices hover between €0.80 and €1.20/kg with considerable Moroccan competition in the European markets. We know November is traditionally a calmer month, but this month there is a lack of consumer trust, probably due to the uncertainty caused by Covid. In addition, they are starting to be affected by the higher cost of living. Because of that, producers are not seeing increases in sales. We are currently reaching the break-even point at €1.30/kg. We are talking about presumed indexes because the situation is still unclear. After all, assessments must be made at the end of the season. Anyway, we are working at a loss below this threshold, while last year production prices were €1.10/kg.”

“What seems to be happening is a reduction of the cultivation areas destined for tomatoes, which is what occurred in Spain. It will be a physiological consequence of a trend that is difficult to manage. Competition deals with quality, and ours is unbeatable. However, the Maghreb produce has lower prices. The reasons for this difference are well known, starting with the defense tools used in Morocco, which guarantee higher yields. Another determining factor is the cost of labor which, in the north-African country, is 8 times lower than in Italy.”

“Initiatives such as that promoted by Consorzio di Tutela del Pomodoro di Pachino Igp are welcome, as they focus on the sustainability of the product as a promotional strategy. Consumers have the certainty of purchasing a product that is monitored, healthy, and with an excellent flavor, and they can count on a carbon footprint that is exceptionally low, as greenhouses are not heated and do not release CO2 into the atmosphere, unlike what happens in northern Italy and Europe.”

Publication date: Wed 1 Dec 2021

USDA Animal and Plant Health Inspection Service’s Identification Technology Program (ITP) is pleased to announce the release of the third edition of Exotic Bee ID. This tool focuses on bee families and genera that include non-native bee species that have already been introduced, or have the high potential to invade, the U.S. Exotic Bee ID is aimed primarily at individuals working at ports of entry, state departments of agriculture, or with university extension services, and non-experts with an interest in learning features that are important in the identification of native and non-native bees. The website includes fact sheets, illustrated interactive keys, a filterable image gallery, a specimen preparation guide, and much more. The third edition adds keys, fact sheets, and images for subgenera of Ceratina and Megachile.

Please find the attached PDF announcement to see an overview of ITP’s newest identification tool for PPQ and its partners. Please also feel free to forward this email or the attachment to your colleagues.

Exotic Bee ID can be accessed at: https://idtools.org/id/bees/exotic/.

Visit our website to learn more about ITP’s tools and mobile apps.

Interested in assisting ITP with tool development by being a beta reviewer for an upcoming ITP tool? We are seeking to increase our pool of beta reviewers for a variety of pest groups. Beta reviewers can be experts or non-specialists. Please contact us at itp@usda.gov.

If you did not receive this email directly from ITP, and you would like to be included in future ITP announcement emails, please send a request to itp@usda.gov.

Cheers,

Amanda

Amanda Redford

Biological Scientist | Identification Technology Program (ITP)

USDA APHIS PPQ Science & Technology (S&T)

2301 Research Blvd, Suite 108 | Fort Collins, CO 80526 | p 970-490-4477

amanda.j.redford@usda.gov | https://idtools.org

A Budding Problem: Managing Corn Earworm in Commercial Hemp Production

ENTOMOLOGY TODAY2 COMMENTS

The corn earworm (Helicoverpa zea) is an emerging pest of commercial hemp production throughout the U.S. Boring through stalks and feeding on reproductive structures, this pest presents several management challenges for hemp producers. While integrated pest management strategies for more traditional agricultural crops are established, much work is still needed to develop effective IPM for the corn earworm in hemp. Shown here is a corn earworm larva feeding on a hemp plant flower bud. (Photo originally published in Britt et al 2021, Journal of Integrated Pest Management)

By David Coyle, Ph.D.

David Coyle, Ph.D.

Cheech and Chong. The Big Lebowski. Seth Rogen. These Hollywood legends helped thrust Cannabis sativa into modern-day pop culture, making it simultaneously famous and infamous. And while the topic of C. sativa tends to elicit a range of emotions and opinions, there is no debating the fact this plant has many, many attributes and qualities.

Cannabis sativa is an annual herbaceous crop native to east Asia but is now grown worldwide and can be cultivated for a variety of purposes. Cannabis sativa is known colloquially as hemp or marijuana; these are different cultivars of the same species. The difference between hemp and marijuana is purely chemical: marijuana has a high THC (tetrahydrocannabinol, aka the intoxicating part) content, whereas the THC content in hemp, by definition, must be less than 0.3 percent. There are also some physical differences, as marijuana and hemp grown for cannabinoids have more of a bushy, horticultural crop look while hemp grown for grain or fiber appears more like a row crop, growing from a tall singular stalk.

Hemp became a legal crop with the passage of the 2018 Farm Bill (the Farm Bill is now called the Plant Protection Act, or PPA 7721). This action was significant, as it was the first time hemp was legally differentiated from marijuana. While the law placed restrictions on its production and use, the legalization of industrial hemp (as it is known) led to several pilot production programs being initiated.

Since industrial hemp had not been cultivated in the U.S. before, pest management in this new crop was an area in dire need of research. Several well-known pests present challenges to hemp cultivation, including the corn earworm (Helicoverpa zea). An article published in September in the Journal of Integrated Pest Management highlights what we do and don’t know about H. zea management in industrial hemp. I spoke with the lead author, Kadie Britt, Ph.D., postdoctoral scholar at the University of California, Riverside, about challenges and opportunities associated with this well-known corn (and now hemp) pest.

Coyle: Do you think hemp will take off? I mean, do we even have the infrastructure to support this industry?

The corn earworm (Helicoverpa zea) is an emerging pest of commercial hemp production throughout the U.S. Boring through stalks and feeding on reproductive structures, this pest presents several management challenges for hemp producers. While integrated pest management strategies for more traditional agricultural crops are established, much work is still needed to develop effective IPM for the corn earworm in hemp. Shown here is a corn earworm larva that has tunneled into a hemp plant stem. (Photo originally published in Britt et al 2021, Journal of Integrated Pest Management)

Britt: Yes and no. There is a market, but there’s already too much planted acreage, and the market is saturated. 2019 was a big year after legalization in 2018, and some growers still have that material in their barns as of summer 2021. Hemp is very useful, and there’s a very positive long-term future with this crop in terms of grain and fiber. The fiber can be used for many things, including plastics, clothes, rope, and a bunch of other things. The grain can be used as a food (think Whole Foods fancy spices section) and has very beneficial fatty acids. Unfortunately, we still see too much cannabinoid and not enough grain or fiber acreage.

Regarding management, is it fair to say there are more questions than answers at this point?

Yes! Every answer seems to lead to more questions. Can we sample for pests in hemp as we do in other row crops? Yes, sampling is similar, but with nuances. For instance, pheromone traps don’t seem to be effective, so we’ll have to develop something else. The takeaway is that it’s difficult to rely solely on chemical control, and the best thing we can do or recommend at this point is to watch for eggs and larvae and to initiate spray applications with a product legal for use in hemp. Weekly spraying can be effective but targets only corn earworm—a more IPM-friendly approach is needed, but first we need to know more about the system.

What are the biggest management challenges for industrial hemp?

There are so many! Pest management is a huge challenge, but growers need to be able to successfully produce the crop first. Right now, there’s a lack of infrastructure for the crop as a whole. Industrial hemp is a legitimate alternative to many products; anything from fabric to plastic can be made from hemp. Some companies are building processing facilities, machinery, and all the other infrastructure necessary for a new crop. Having properly labeled pesticides available is a challenge, as industrial hemp probably won’t garner the attention of huge chemical companies, but smaller, newer biopesticide companies may be more willing, as will those that focus on specialty crops.

Any final thoughts?

Yes, the industry is new and emerging, and we have to realize that federal legalization of high-THC cannabis will likely happen at one point. The work we do now will only help prepare us for that time. Cannabis is here to stay, and pest susceptibility greatly increases when the crop is grown in a monoculture type of production. Commercial acreages are different than backyard growing operations. Any information we get now will only help future C. sativa growers, regardless of the final product.

Read More

Pest Management Needs and Limitations for Corn Earworm (Lepidoptera: Noctuidae), an Emergent Key Pest of Hemp in the United States

Journal of Integrated Pest Management

David Coyle, Ph.D., is an assistant professor in the Department of Forestry and Environmental Conservation at Clemson University. Twitter/Instagram/TikTok: @drdavecoyle. Email: dcoyle@clemson.edu.

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July 24, 2020 Research NewsCannabis sativaCorn EarwormDave CoyleHelicoverpa zeahempintegrated pest managementJournal of Integrated Pest ManagementKadie Britt

DECEMBER 1, 2021

Resolute scientific work could eliminate wheat disease within 40 years

by Lauren Quinn, University of Illinois at Urbana-Champaign

wheat
Credit: CC0 Public Domain

Wheat and barley growers know the devastating effects of Fusarium head blight, or scab. The widespread fungal disease contaminates grain with toxins that cause illness in livestock and humans, and can render worthless an entire harvest. As Fusarium epidemics began to worsen across the eastern U.S. in the 1990s and beyond, fewer and fewer farmers were willing to risk planting wheat.

But the battle to eliminate Fusarium head blight never went away. Public breeding programs, with support from the USDA-supported Wheat and Barley Scab Initiative, have been doggedly tweaking soft red winter wheat lines in hopes of achieving greater resistance to the disease.

In a new analysis, University of Illinois researchers say those efforts have paid off. Over the past 20 years, critical resistance metrics have improved significantly. And, they say, if breeding efforts continue, vulnerability to Fusarium head blight could be eliminated within 40 years.

“I don’t think anybody realizes it’s possible we could eliminate Fusarium head blight as a problem. Forty years sounds like a long time, but by the time I’m retired, the threat of disease could be gone. That would make a huge difference,” says Jessica Rutkoski, assistant professor in the Department of Crop Sciences at Illinois and co-author on the new paper.

Rutkoski and her colleagues examined 20 years of data from nine university breeding programs spanning 40 locations in the eastern U.S. That’s a whopping 1,068 wheat genotypes.

In each year and each location, researchers inoculated wheat plants with Fusarium spores. They evaluated both test entries (novel wheat lines) and check cultivars (standard across all locations and years) for various resistance traits. The long-term check cultivars act as a kind of barometer, accounting for agronomic practices and environmental factors.

The researchers looked at disease incidence, severity, Fusarium-damaged kernels, and deoxynivalenol (also known as Vomitoxin) content—the main toxin of concern in Fusarium-contaminated grain. And over 20 years and 1,068 lines, all the resistance traits improved.

“The genetic gain in disease resistance was significant for each of those four traits. Most importantly, we saw a 0.11 parts-per-million decrease in deoxynivalenol per year. Just to see any significant favorable trend is really good,” Rutkoski says. “It basically shows that everyone’s making progress, and that the investment in public breeding programs is paying off.”

Rutkoski says breeders have thrown nearly every technique at wheat to try to improve resistance to Fusarium head blight. It’s a tough nut to crack because resistance is controlled by multiple interacting genes.

“It’s quantitative resistance. There isn’t just one gene that’s going to solve it. On the breeding side, people have looked at exotic sources of resistance, such as Chinese lines that have high resistance. Then they’ll map the genes and introgress them,” Rutkoski says. “That’s been successful to some degree, but those genes tend to be associated with unfavorable traits, like lower yield. So, there have been issues.”

When Rutkoski analyzed the impact of germplasm introductions from Chinese wheat lines, they weren’t responsible for boosting resistance. In other words, progress over the past 20 years was mostly due to breeders exploiting native resistance—the locally adapted wheat‘s inherent genetic capacity to resist disease—rather than introducing resistance from exotic sources.

That’s not to say novel genetic sources of resistance don’t have their place. Rutkoski notes it’s important to try to identify major-effect genes because often they can help breeders achieve their goals faster.

Ultimately, Rutkoski hopes her results justify and encourage investments in public breeding programs.

“Nobody really notices the progress that’s being made. I think there’s some skepticism and suspicion that breeding isn’t that important. Or people think we need to focus more on genome editing or finding more exotic sources of resistance,” she says. “A lot of public breeding programs are getting shut down, and we risk losing all that progress. So, I was gratified to show that the improvement is very consistent over time. And if you just stick to this kind of strategy, you will have guaranteed results. It’s not risky.”

The article is published in Plant Disease.


Explore furtherScientists discover a protein that naturally enhances wheat resistance to head scab


More information: Rupesh Gaire et al, Genetic trends in Fusarium head blight resistance due to 20 years of winter wheat breeding and cooperative testing in the Northern US., Plant Disease (2021). DOI: 10.1094/PDIS-04-21-0891-SRProvided by University of Illinois at Urbana-Champaign

DECEMBER 1, 2021

Resolute scientific work could eliminate wheat disease within 40 years

by Lauren Quinn, University of Illinois at Urbana-Champaign

wheat
Credit: CC0 Public Domain

Wheat and barley growers know the devastating effects of Fusarium head blight, or scab. The widespread fungal disease contaminates grain with toxins that cause illness in livestock and humans, and can render worthless an entire harvest. As Fusarium epidemics began to worsen across the eastern U.S. in the 1990s and beyond, fewer and fewer farmers were willing to risk planting wheat.

But the battle to eliminate Fusarium head blight never went away. Public breeding programs, with support from the USDA-supported Wheat and Barley Scab Initiative, have been doggedly tweaking soft red winter wheat lines in hopes of achieving greater resistance to the disease.

In a new analysis, University of Illinois researchers say those efforts have paid off. Over the past 20 years, critical resistance metrics have improved significantly. And, they say, if breeding efforts continue, vulnerability to Fusarium head blight could be eliminated within 40 years.

“I don’t think anybody realizes it’s possible we could eliminate Fusarium head blight as a problem. Forty years sounds like a long time, but by the time I’m retired, the threat of disease could be gone. That would make a huge difference,” says Jessica Rutkoski, assistant professor in the Department of Crop Sciences at Illinois and co-author on the new paper.

Rutkoski and her colleagues examined 20 years of data from nine university breeding programs spanning 40 locations in the eastern U.S. That’s a whopping 1,068 wheat genotypes.

In each year and each location, researchers inoculated wheat plants with Fusarium spores. They evaluated both test entries (novel wheat lines) and check cultivars (standard across all locations and years) for various resistance traits. The long-term check cultivars act as a kind of barometer, accounting for agronomic practices and environmental factors.

The researchers looked at disease incidence, severity, Fusarium-damaged kernels, and deoxynivalenol (also known as Vomitoxin) content—the main toxin of concern in Fusarium-contaminated grain. And over 20 years and 1,068 lines, all the resistance traits improved.

“The genetic gain in disease resistance was significant for each of those four traits. Most importantly, we saw a 0.11 parts-per-million decrease in deoxynivalenol per year. Just to see any significant favorable trend is really good,” Rutkoski says. “It basically shows that everyone’s making progress, and that the investment in public breeding programs is paying off.”

Rutkoski says breeders have thrown nearly every technique at wheat to try to improve resistance to Fusarium head blight. It’s a tough nut to crack because resistance is controlled by multiple interacting genes.

“It’s quantitative resistance. There isn’t just one gene that’s going to solve it. On the breeding side, people have looked at exotic sources of resistance, such as Chinese lines that have high resistance. Then they’ll map the genes and introgress them,” Rutkoski says. “That’s been successful to some degree, but those genes tend to be associated with unfavorable traits, like lower yield. So, there have been issues.”

When Rutkoski analyzed the impact of germplasm introductions from Chinese wheat lines, they weren’t responsible for boosting resistance. In other words, progress over the past 20 years was mostly due to breeders exploiting native resistance—the locally adapted wheat‘s inherent genetic capacity to resist disease—rather than introducing resistance from exotic sources.

That’s not to say novel genetic sources of resistance don’t have their place. Rutkoski notes it’s important to try to identify major-effect genes because often they can help breeders achieve their goals faster.

Ultimately, Rutkoski hopes her results justify and encourage investments in public breeding programs.

“Nobody really notices the progress that’s being made. I think there’s some skepticism and suspicion that breeding isn’t that important. Or people think we need to focus more on genome editing or finding more exotic sources of resistance,” she says. “A lot of public breeding programs are getting shut down, and we risk losing all that progress. So, I was gratified to show that the improvement is very consistent over time. And if you just stick to this kind of strategy, you will have guaranteed results. It’s not risky.”

The article is published in Plant Disease.


Explore furtherScientists discover a protein that naturally enhances wheat resistance to head scab


More information: Rupesh Gaire et al, Genetic trends in Fusarium head blight resistance due to 20 years of winter wheat breeding and cooperative testing in the Northern US., Plant Disease (2021). DOI: 10.1094/PDIS-04-21-0891-SRProvided by University of Illinois at Urbana-Champaign

NOVEMBER 19, 2021

Loss of tree species has cumulative impact on biodiversity

by British Ecological Society

Loss of tree species has cumulative impact on biodiversity
Atlantic oak woodlands on the west coast of Scotland. Credit Ruth Mitchell

Diseases affecting different UK tree species have been shown to have a multiplying effect on the loss of associated biodiversity, according to new research published in the Journal of Ecology by James Hutton Institute scientists and partners in the UK and Portugal. The research team reveals that the decline of ash and oak trees may affect more species than just the ones that only use oak and ash as their habitat.

In the UK, the common ash hosts 45 species that are only found on ash trees, and sessile and pedunculate oaks host 326 species that are only found on oak trees. However, if both tree species were to be lost, the number of species at risk is 512 due to an additional 141 species that only use oak and ash.

Lead author of the study Dr. Ruth Mitchell, an ecologist within the James Hutton Institute’s Ecological Sciences department, said that “When a plant pest or pathogen kills a plant, particularly when it results in the wide-spread loss of one plant species, it also impacts on those species such as insects, mosses, lichens, mammals, birds and fungi that use that plant species for feeding, for nesting or as a living space.”

“The impact of plant pests and pathogens on associated biodiversity is rarely considered when risk assessments for plant pests and pathogens new to the UK are made.”

“This work shows that such impacts may be considerable, particularly if multiple host plants are lost that support the same biodiversity, as is the case with the number of different diseases currently impacting the UK’s trees.”

Loss of tree species has cumulative impact on biodiversity
Dead oak tree due to acute oak decline. Credit Ruth Mitchell

Many species use ash, oak and other tree species and thus should be resilient to the loss of ash and oak as they can use other tree species.

However, when the researchers looked at 24 mixed ash and oak woodlands within the UK, they found that only 21% of the sites were able to continue to support species that use ash and oak if ash and oak were lost. This was because the other tree species that would support this biodiversity were not present at the site, although the site conditions were often suitable for them to grow.

The authors suggest that in risk assessments, higher impact scores should be given to pests and pathogens affecting hosts occurring with other host plant species already impacted by pests and pathogens.

The work provides further support for a major theme in recent guidance on sustainable forestry, which advocates that species diversity of multipurpose and conservation woodlands should be increased to enhance their resilience.

Dr. Mitchell added that “current pest and pathogen risk assessment approaches that ignore the cumulative, cascading effects shown in this study may allow an insidious, mostly overlooked, driver of biodiversity loss to continue.”

Defra Chief Plant Health Officer, Professor Nicola Spence, commented that “this work reiterates the importance of protecting our native trees. It confirms that the value of our interconnected ecosystems is often more than may immediately meet the eye, and the importance of intelligent woodland management plans to support resilience. Such combinatorial analysis is beneficial to our understanding and further development of available ‘toolkit’.”


Explore furtherResilience of vertebrate animals in rapid decline due to manmade threats


More information: Ruth J. Mitchell et al, Cumulative impact assessments of multiple host species loss from plant diseases show disproportionate reductions in associated biodiversity, Journal of Ecology (2021). DOI: 10.1111/1365-2745.13798Journal information:Journal of EcologyProvided by British Ecological Society

Over the past two years, locusts have ravaged swathes of East Africa. But the cure for the problem may also have dire consequences

THE WEEK STAFF19 NOV 2021

A farmer walking through a swarm of locusts

A farmer walking through a swarm of locusts in Meru, Kenya, on 9 February 2021

Yasuyoshi Chiba/AFP via Getty Images

Most of the time, the desert locust, Schistocerca gregaria, is an innocuous grasshopper: a green or brown short-winged insect that lives a solitary life in the deserts of Africa, Arabia and Asia. But in certain conditions – when there’s lots of moisture and vegetation flourishes – these locusts enter a “gregarious phase”, and undergo a remarkable transformation.

Their brains change, they turn yellow and black, and their wings grow. Most importantly, they become attracted to each other and start joining together in swarms which can reach a density of 15 million insects per square mile, and travel up to 90 miles in a day. Since late 2019, vast clouds of these locusts have devastated parts of the Horn of Africa, devouring crops and pasture, triggering a huge operation to track and kill them.

Where did the locusts come from?

In 2018, two unusual cyclones – linked to climate change – deposited rain in the remote Empty Quarter of the Arabian peninsula, which led to an 8,000-fold increase in locust numbers there.

In 2019, strong winds blew the growing swarms first into Yemen, then across the Red Sea into Somalia, Ethiopia, Eritrea and Kenya, where their populations were further boosted by a wet autumn, and a cyclone in Somalia – paving the way for a major emergency last year. Billions of the insects swept on, into Uganda, South Sudan and Tanzania, going on to affect a total of 23 countries, from Sudan to Iran to Pakistan.

How big were the plagues?

In Kenya, they were the worst in 70 years. When they arrived in East Africa, witnesses said it was “like an umbrella had covered the sky”. “The first swarms we saw were massive – three or four kilometres wide and a thousand metres deep,” Mark Taylor, a farmer in the Laikipia region of northern Kenya, told The Sunday Times.

A swarm of desert locusts

A swarm of desert locusts pictured after an aircraft sprayed pesticide in Meru, Kenya

Yasuyoshi Chiba/AFP via Getty Images

When the locusts settled on trees, there were “so many of them that branches broke under the weight”. Locust swarms can vary from less than one square kilometre to several hundred square kilometres. There can be at least 40 million and sometimes as many as 80 million locust adults in each square kilometre. One swarm in northern Kenya was reported to have reached 2,400 square kilometres in size – an area the size of Luxembourg.

How bad was the damage?

Locusts eat their body weight in food every day; a small swarm covering one square kilometre can eat the same amount as 35,000 people. So when they descended on East Africa, vast swathes of vegetation were consumed within minutes. “They attacked everything,” says Mark Taylor. “Fifty-four hectares [133 acres] were destroyed just like that.”

SMART researchers develop method for early detection of bacterial infection in crops

Novel Raman Spectroscopy-based method enables early detection and quantification of pathogens in plants, which can impact plant disease management and agricultural industry Peer-Reviewed Publication

EurekAlert

SINGAPORE-MIT ALLIANCE FOR RESEARCH AND TECHNOLOGY (SMART)PrintEmail App

Rapid detection of bacterial infection in leafy vegetable Choy Sum
IMAGE: RAPID DETECTION OF BACTERIAL INFECTION (XANTHOMONAS CAMPESTRIS PV. CAMPESTRIS (XCC)) IN LEAFY VEGETABLE CHOY SUM USING QUANTITATIVE RAMAN SPECTROSCOPY-BASED ALGORITHM. ON THE RIGHT, THE INFECTION RESPONSE INDEX IS SHOWN, WHICH CAN AID FARMERS TO IDENTIFY INFECTIONS AND TAKE ACTION. view more CREDIT: SINGAPORE-MIT ALLIANCE FOR RESEARCH AND TECHNOLOGY (SMART)

Researchers from the Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP) Interdisciplinary Research Group (IRG) of Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore and their local collaborators from Temasek Life Sciences Laboratory (TLL), have developed a rapid Raman spectroscopy-based method for the detection and quantification of early bacterial infection in crops. The Raman spectral biomarkers and diagnostic algorithm enable the non-invasive and early diagnosis of bacterial infections in crop plants, which can be critical for the progress of plant disease management and agricultural productivity.

Facing an increasing demand for global food supply and security, there is a growing need to improve agricultural production systems and increase crop productivity to overcome this challenge. Globally, bacterial pathogen infection in crop plants is one of the major contributors to agricultural yield losses. Climate change also adds to the problem by accelerating the spread of plant diseases. Hence, developing methods for rapid and early detection of pathogen-infected crops is important to improve plant disease management and reduce crop loss.

The breakthrough by SMART and TLL researchers offers a faster and more accurate method to detect bacterial infection in crop plants at an earlier stage, as compared to existing techniques. The team explained their research in a paper titled “Rapid detection and quantification of plant innate immunity response using Raman spectroscopy” published in the prestigious journal Frontiers in Plant Science.

“The early detection of pathogen-infected crop plants is a significant step to improve plant disease management,” says DiSTAP co-lead Principal Investigator Professor, TLL Deputy Chairman, and co-corresponding author, Chua Nam Hai. “It will allow the fast and selective removal of pathogen load and curb the further spread of disease to other neighbouring crops.”

Traditionally, plant diseases diagnosis involves a simple visual inspection of plants for disease symptoms and severity. “Visual inspection methods are often ineffective as disease symptoms usually manifest only at relatively later stages of infection when the pathogen load is already high, and reparative measures are limited. Hence, new methods are required for rapid and early detection of bacterial infection. The idea would be akin to having medical tests to identify human diseases at an early stage, instead of waiting for visual symptoms to show so that early intervention or treatment can be applied,” says DiSTAP Principal Investigator, MIT Professor, and co-corresponding author, Rajeev Ram.

While existing techniques, such as current molecular detection methods, can detect bacterial infection in plants, they are often limited in their use. Molecular detection methods largely depend on the availability of pathogen-specific gene sequences or antibodies to identify bacterial infection in crops; the implementation is also time-consuming and non-adaptable for on-site field application due to its high cost and bulky equipment required, making it impractical for use in agricultural farms.

“At DiSTAP, we have developed a quantitative Raman spectroscopy-based algorithm that can help farmers to identify bacterial infection rapidly. The developed diagnostic algorithm makes use of Raman spectral biomarkers and can be easily implemented in cloud-based computing and prediction platforms. It is more effective than existing techniques as it enables accurate identification and early detection of bacterial infection, both of which are crucial to saving crop plants that would otherwise be destroyed,” explained Dr Gajendra Pratap Singh, Scientific Director and Principal Investigator at DiSTAP, and co-lead author.

A portable Raman system can be used in agricultural farms and provides farmers with an accurate and simple yes or no response when used to test for the presence of bacterial infections in crop plants. The development of this rapid and non-invasive method will improve plant disease management and have a transformative impact on agricultural farms by efficiently reducing agricultural yield loss and increasing productivity.

“Using the diagnostic algorithm method, we experimented on several edible plants such as Choy Sum,” says DiSTAP and TLL Principal Investigator and co-corresponding author Dr Rajani Sarojam. “The results showed that the Raman spectroscopy-based method can swiftly detect and quantify innate immunity response in plants infected with bacterial pathogens. We believe that this technology will be beneficial for agricultural farms to increase their productivity by reducing their yield loss due to plant diseases.”

The researchers are currently working on the development of high-throughput, custom-made portable or hand-held Raman spectrometers that will allow Raman spectral analysis to be quickly and easily performed on field-grown crops.

The development and discovery of the diagnostic algorithm and Raman spectral biomarkers were done by SMART and TLL. TLL also confirmed and validated the detection method through mutant plants. The research is carried out by SMART and supported by the National Research Foundation of Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) programme.


JOURNAL

Frontiers in Plant Science

DOI

10.3389/fpls.2021.746586 

ARTICLE TITLE

Rapid Detection and Quantification of Plant Innate Immunity Response Using Raman Spectroscopy

ARTICLE PUBLICATION DATE

21-Oct-2021

Disclaimer: AAAS and EurekAlert! are not r

SCN: What you can do to fight soybeans’ top yield robber

DFP Staffsoybean fieldRotating SCN-resistant sources of resistance is an active management strategy advised by the SCN Coalition, but easier said than done for Midsouth growers.”We’re seeing bushels upon bushels of soybeans lost.”

Ginger Rowsey | Dec 02, 2021

Soybean cyst nematode continues to rank as the top yield robber of soybeans in the U.S. and Canada and it’s showing no signs of stopping. Since 2017 SCN has continued to move into new areas, and, according to experts is becoming harder to control. 

“We’re seeing bushels upon bushels of soybeans lost. The biggest challenge is yield loss can occur in the absence of symptoms. We’ve observed yield loss of up to 30% in fields that looked fine,” said Kaitlyn Bissonnette, Extension specialist with the University of Missouri. Bissonnette was speaking at a Grow in the Know SCN webinar, sponsored by the SCN Coalition and BASF. https://31ff83a5596d5b2313020cd4368ba0f3.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

In addition to SCN expanding to new geographic areas, there is evidence these nematodes are also adapting to PI 88788 — the most common source of SCN resistance that is available in about 95% of SCN-resistant varieties. In Tennessee, for example, the SCN Coalition reports that 93% of fields planted to soybean varieties with PI 88788 sources of resistance have seen SCN numbers increase more than 10%. 

“This elevated reproduction tells us these sources are no longer as resistant as they once were,” said Bissonnette. 

Rotating sources of resistance 

Rotating sources of resistance would slow SCN’s growing tolerance to one source. The problem for Midsouth growers is there are few desirable alternatives to PI 88788. Peking is the second most widely used source of SCN resistance, but it is not a major player in southern soybean genetics. A search of seed companies’ websites revealed Peking resistance could only be found commercially available in maturity groups earlier than MG3.  

Expanding the sources of SCN resistance is not an easy task. Public soybean breeders have spent years working with SCN resistance breeding lines other than PI 88788. Unfortunately, breeding resistance genes from those other sources — such as Peking and Hartwig — into elite varieties has been challenging. 

Vince Pantalone, soybean breeder with the University of Tennessee said Hartwig resistance is the better option for the South. This year, UT’s breeding program released TN14-5021, which Pantalone says contains multiple SCN resistance as well as resistance to many southern plant pathogens. Other universities, such as University of Illinois and University of Nebraska have also developed cultivars with the Hartwig resistance source. 

If growers can only get soybeans with PI 88788 resistance, the SCN Coalition recommends rotating different varieties of soybeans with PI 88788 because not all PI 88788 varieties are the same. 

“Ideally, we’d like growers to rotate among several different modes of action of SCN resistance,” said Melissa Mitchum, University of Georgia molecular nematologist. “That’s what we’re working to provide.”  

More resistance genes on the way 

However, Mitchum says there are additional resistance genes that haven’t been used yet in commercial soybean varieties. “We’ve only utilized Rhg1 and Rhg4, and that’s what you see in growers’ fields, but we can breed with other sources to introduce other resistance genes.” 

Mitchum is working closely with soybean breeders to investigate other sources of resistance. “We’ve already found new genes and gene combinations that are different from Rhg1b in PI 88788 and the Rhg1a/Rhg4 combination in Peking to help fight back against virulent SCN.”  

SCN research 

For several years, checkoff-funded researchers have been working to identify novel types of nematode resistance. Advances in technology, such as the ability to clone resistance genes and the development of precise molecular markers, have allowed university soybean breeders to speed up the process of getting resistant cultivars out to commercial breeders.   

“Today, we can quickly test more soybean germplasm for nematode resistance,” Mitchum explains. “We’re also looking at which genes we should combine, which genes we shouldn’t, and the best rotation strategies for different modes of action.”   

The goal is to get more SCN-resistant modes of action on the market for farmers and protect existing SCNresistance sources. “We want to keep PI 88788 in the toolbox and offer growers other options to protect their soybean yields,” Mitchum says.  

Beyond variety selection 

Beyond variety selection, crop rotation is still effective within reason, according to Bissonnette.  

“We can’t get rid of this through crop rotation alone, but cultural practices like that along with planting certain species of cover crops and improving weed management can help,” she said.  

“Growers could also consider using SCN seed treatments, especially where SCN populations have gotten out of control,” she added. Results from an SCN Coaltion survey showed the number of growers using nematode protectant seed treatments has almost doubled over the past five years. 

“Soil testing will always be the first step in SCN management. Those results will give you a better idea of how intensively to manage, but it’s much easier to keep counts down than reduce high numbers,” Bissonnette said. “The most important steps will be selecting resistant varieties and using different resistance sources. If that’s not an option for you, at least rotate varieties within PI 88788.”  

Learn more 

To learn more about the checkoff-funded research that’s focused on bringing new tools to soybean growers in the fight against parasitic nematodes, watch the Research Collection of “Let’s Talk Todes” videos.