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EurekAlert

NEWS RELEASE 20-OCT-2022

Breakthrough in protecting bananas from Panama disease

Peer-Reviewed Publication

UNIVERSITY OF EXETER

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Exeter scientists have provided hope in the fight to control Panama disease in bananas.

Bananas are amongst the most popular fruits eaten world-wide. They are grown and eaten locally, so providing food for almost half a billion people, and banana exports generate precious income.

In the 1950s, Panama disease, caused by the fungus Fusarium oxysporum cubense Race 1, decimated the world’s bananas supply. This disaster was overcome by the introduction of a new Cavendish variety bananas. However, a new race of the fungus, known as Tropical Race 4, recently swept across the continents and through the Cavendish banana plantations. This new Panama disease threat is of particular significance as Cavendish bananas account for about 40% of world production and more than 90% of all exports. All efforts to control the disease in Cavendish bananas have, so far, failed.

In this new study, reported in the journal PLOS Pathogens, University of Exeter scientists provide hope that Panama disease can be controlled by a particular class of anti-fungal chemistries (fungicides).

Funded by the BBSRC Global Food Systems initiative (GFS), an Exeter team led by Professor Steinberg and Professor Sarah Gurr used a multi-disciplinary approach, to better understand why chemical control of Panama disease had failed. By combining expertise in cell and molecular biology, bioinformatics and plant pathology, the team revealed that all major classes of fungicides do not work against this troublesome pathogen and provide insight for the molecular reason behind this “resistance”.

Guided by this understanding, the research team discovered that a more specialised class of anti-fungal chemistries, not previously used, suppress Panama disease and maintain banana plant health in the presence of the pathogen. This discovery opens new avenues to develop efficient control strategies and provides a significant step forwards in the fight to protect this valuable crop.

Professor Steinberg, who led the molecular and cellular aspects of the work, said: “Bananas are Britain’s favourite fruit and Panama disease may ‘wipe’ them off the supermarket shelves. On top, millions of people in producer countries live on bananas. Providing an important step towards safeguarding bananas from Panama disease gives me great pride.”

Professor Sarah Gurr, the plant pathology expert who led all work on banana infection and pathogen cultivation, said: “Our success is due to an enormous amount of dedicated work over several years with co-workers with hugely disparate skills. We are highly delighted and excited by the outcome of our work and by the glimmer of hope that the beloved banana may remain as part of our daily diet.”

Professor Dan Bebber, who was not involved in the study but heads the Exeter Global Food Security programme, said: “This work has rather excitingly opened the door to development of safe and effective ways of protecting the UK’s favourite fruit by demonstrating good levels of disease control with lesser known antifungals. It also confirms that basic research has the potential to provide answers to pressing challenges in global food security.”

The University of Exeter realises the potential social impact of this study. Dr Tori Hammond, from Innovation, Impact and Business at the University of Exeter, said: “Prof Steinberg and Prof Gurr’s work has resulted in an exciting and innovative technology breaking out of the lab and towards commercialisation. The potential impact of this technology on the global bioeconomy is incredibly significant.”

The paper, published in the journal PLOS Pathogens, is entitled: “Multi-site fungicides suppress banana Panama disease, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4.”


JOURNAL

PLoS Pathogens

DOI

10.1371/journal.ppat.1010860 

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Country Matters: Tiny but brilliant creatures are better than pesticides

Ants are incredible, hard-working creatures

Ants are incredible, hard-working creatures

Joe Kennedy

August 28 2022 02:30 AM


Patiently I have watched ants for lengthy periods at their agricultural practices, endlessly busy cutting and ferrying vegetation to maintain the farms producing their fungal livelihood. Leaning over cliff top fences on Portugal’s Atlantic coast, I have looked at endless processions of insects moving along rutted tracks to disappear underground and reappear to collect more leaf fragments from a far source. Such lives of endless toil appear to be never-ending.

This leaf-cutting species works continuously to keep its fungal farms in production. The ants live on fungi that grows in their formicaries, or colonies, nurtured by leaf fragments which are further reduced by a separate team of stalk cutters before being laid out in ‘gardens’ to be tended by yet another crew.

There is careful husbandry: if a leaf source is found to be toxic, the ants promptly move to another. Source sites may be up to 300m away but, like slugs, the insects follow a scent trail laid down by the original surveyors. Individual ‘soldiers’, separate from the constantly moving lines, are on the lookout for intruders who might steal the crops. Colonies can also be raided and resident insects enslaved. Within the formicaries, reigning queen ants — who can live for up to 15 years — preside over colonies of between 100,000 and 500,000. The largest was found in Switzerland in 1977 with 300 million living in 1,200 anthills crossed by 60km of paths in the Jura Mountains.

Most of us have had unpleasant encounters with ants, red and black, in this country.

In Africa there is a species called Matabele which have remarkable human-like traits in that they save wounded comrades on termite battlefields. If an ant can stand on just one leg after a fight, it is carried off to have its wounds tended to by triage ‘doctors and nurses’ to fight another day. Prone casualties, however, are left where they fall.

A scientific report recently suggested that ‘ant power’ in crop production can be more efficient than chemicals. The ants are better at disposing of pests, thereby reducing damage and increasing yields. An analysis published in Proceedings of the Royal Society looked at 17 crops in several countries and found some ant species with proper management had similar or higher efficacy than pesticides — and at lower cost.

However, ants can also be a problem where meal bugs, aphids and whiteflies are concerned. They produce a sugary substance called honeydew to which ants are attracted and which they ‘farm’ like livestock. But researchers say alternative sugar sources may be used to distract the ants so they continue to attack the other pests.

There are more ants than any other insects in the world, about 14,000 known species, making up about half of the earth’s biomass. They are incredible creatures.

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Fall armyworms were a miss this year

ossyugioh/Getty Imageshands moving and inspecting corn plants for leaf damaged by fall armyworms

FROM THE FIELD: Damage to corn leaves in the field is a sign of fall armyworm infestation. The problem is the pest is becoming resistant to its most popular control mechanism — pyrethroids.

Research on mating disruptors may help offset growing pyrethroid resistance.

Mindy Ward | Aug 24, 2022

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Fall armyworm invasion. It is often a boom-or-bust cycle. This year was a bust, and that is good news for farmers. Still researchers know that will not always be the case, and they continue searching for ways to mitigate fall armyworm infestations, such as altering the pest’s behavior.

Last year was the biggest outbreak of fall armyworms across the U.S. in 30 years, said Kevin Rice, the former University of Missouri Extension entomologist who is now the director of the Alson H. Smith Jr. Agricultural Research and Extension Center at Virginia Tech.

“We expect that fall armyworm outbreaks may occur more often because of our milder winters,” he explained during the MU Pest Management Field Day in July.

Fall armyworms typically only overwinter in the tip of Florida and in Texas. However, researchers find that now, because of milder winters, they are overwintering in higher latitudes, but their natural enemies are not. “So they get a jump-start; they get a higher overwintering population,” Rice said.

He said farmers should beware of potentially more fall armyworm outbreaks on a more regular basis than every 30 years.

Problems with resistance

Fall armyworm is one of the fastest growing insects on earth, Rice warned. “They’re called armyworms because they move into field and devastate it like an army,” he said.

Staying ahead of them once they appear can be difficult because the larvae have a wide host range of at least 80 plants, but they prefer grasses such as corn, sorghum, bermudagrass and tall fescue. They can also feed on alfalfa, barley, oats, ryegrass, vegetables and soybeans. Armyworms tend to move quickly into new areas in large numbers.

The good news with fall armyworm is there are integrated pest management tools for control. The bad news is the pest is becoming resistant to one of those measures — pyrethroids.

kochievmv/Getty Imagesfall army worm on a corn leaf

CLOSE UP: Fall armyworms feeds on corn, leaving behind a moist sawdust-like frass near the whorl and upper leaves of the plant.

Rice noted that several states neighboring Missouri reported pyrethroid-resistant fall armyworm populations. Since females fly over thousands of miles, he added, farmers can assume those resistant genes are being passed and mixing throughout the population in surrounding states. Therefore, farmers should not be using pyrethroids for treatment of fall armyworm infestations moving forward.

While Rice is taking that tool out of the pest management toolbox, his research lab is hoping to add another control means back in.

Search for solutions

Universities such as Mizzou are working on a new management option for fall armyworms using mating disruption.

High-emission-rate “mega-dispensers” are used for sex pheromone mating disruption of moth pests. These dispensers suppress mating and reduce crop damage when deployed at very low to moderate densities. “It confuses them, and often they don’t lay eggs,” Rice noted.

The research focuses on whether these mega-dispensers work on a per-acre basis and at what levels. It is still in the “very preliminary stage,” he said, but trials were set up in Alabama and Missouri this summer. “We’re quantifying it, to see if the process works.”

Rice said these types of behavioral mechanisms might be good, viable options in the future as the industry loses chemistries to fight the fall armyworm.

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Potato blight advice: Remove badly affected areas of crop

BLIGHT

Potato blight advice: Remove badly affected areas of crop

In cases of potato crops being badly impacted with blight, growers may have no choice but to totally remove infected areas of fields.

According to Teagasc potato specialist, Dr. Stephen Kildea, fungicides may take out most of the infection for now. But residual levels of infection will only act to ensure the fast re-emergence of the disease at some future date.

“Product choice is also critically important from a blight control point of view in this type of scenario,” he explained.

“Adding cymoxinal to a blight control spray mix will work well under these conditions. It will act to give a very short lived protection. But it does allow things to be dried up.

“Crops impacted by blight must be maintained within a very tight spraying interval. And it’s very much a case of treating the whole crop, not just the patch where the initial problem had been identified.”

Potato blight control

But rather than have to physically treat outbreaks of blight, the plan from the very start should be to manage crops in ways that prevent the disease from getting a foot hold in the first place.

Commenting on the range of fungicide products available to control blight in potatoes, Kildea confirmed issues that had arisen around the efficacy of fluazinam.

This is an active ingredient, which is contained in a number of commercially available products. 

“In the trials that we have carried out over the last two years, plots sprayed with fluazinam did not receive the level of blight protection that we would have expected, Kildea said.

“The fungicide has been on the market for the past two decades. And over the years it has worked very well, particularly in end of season spray mixes.”

According to Kildea a strain of blight, 37A2, has emerged – initially in Europe, but now in Ireland. It seems to have reduced sensitivity to fluazinam.

“We picked the problem up in 2019. Samples were sent in to us from farmers.

“Trials carried out at Oak Park in 2020 and 2021 confirmed the issue, which meant that we lost a significant amount of disease control coming from it.

“The consequences of this are important. Fluazinam was a very popular blight fungicide with growers.

“Critically, it was used by commercial growers at end of season. We have lost this now. It is just too risky to use as it gave blight control across both foliage and growing tubers.”

Also Read: Enough fertiliser stocks until end of September – Dunphy

BLIGHTPOTATO BLIGHTPOTATOES

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Manage insects and other pests in rice production before they manage you

Brian Irelanddfp-ricefield-bireland (6) copy.jpg

Recently planted rice emerges in fields near Rayne, La.

Insects must be identified and managed in rice production before the effects impact a growers yield.

Brian Ireland | Jun 01, 2022

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Insects and other pests can destroy a crop at any stage, reducing yields and grower profits.  

Over the past few years, Louisiana has experienced a multitude of pests attacking the rice industry. Growers and researchers continue to be diligent in finding ways to combat the issues that arise to have a successful and productive harvest. 

Blake Wilson, a Louisiana State University field crop entomologist specializing in sugarcane and rice, works with the major pests faced by Louisiana farmers, including the invasive apple snails.  

“Pests come in waves and can destroy rice yield if not properly managed,” he said. “From armyworms and weevil in the early season to rice stink bugs in the late season.” 

The LSU Rice Research Station, located in Rayne, La., works with producers to select varieties that are resistant to pests and learn how to properly treat and control pests before they become a problem. 

Rice water weevil 

Rice water weevil is a major concern for the rice industry. According to Wilson, rice water weevil is most damaging in water seeded rice, but it also infests dry or drill-seeded rice. 

The primary treatment for controlling and preventing infestations remains to be insecticidal seed treatments, while certain practices can significantly reduce the impact on rice yield. 

“Rice water weevil can be controlled by a variety of methods,” he said. “Foliar application is less effective once the weevil larvae reach the roots.” 

Adult beetles fly into rice fields to feed on the leaves. This causes narrow scars that run lengthwise on the leaf, while this feeding rarely causes yield reduction. 

Females lay eggs at or below the water line beginning soon after a permanent flood is applied. The larvae feed on the roots, reducing plant growth and rice yields. 

Water-seeded and early flooded rice are the most susceptible to yield losses during infestations.  

“Seed dealers can apply insecticidal seed treatments before planting,” he said.  

Fall armyworm 

In 2021, Louisiana, as well as the rest of the Midsouth, experienced a major outbreak of fall armyworms.  

The armyworm is an early-season concern for rice growers. Larvae feed on the leaves of young rice plants, often resulting in the seedlings being pruned to the ground.  

Infestations typically occur on elevated areas in and around the field, where the worms can escape drowning in high water. Fall armyworms can devastate a field of rice that is too young to be flooded so scouting should occur after the germination of seedlings and continue weekly according to the LSU AgCenter. 

Since adult worms lay eggs on grasses in and around rice fields, larval infestations can be reduced by managing weedy grasses. Flooding-infested fields for a few hours can be effective under the right conditions. Parasitic wasps and pathogenic microorganisms can help reduce armyworm populations.  

“Some states had to apply for emergency approval to utilize new or different insecticides,” Wilson said concerning last year’s worm invasion.  

Rice stink bugs 

Rice stink bugs are a big threat to headed rice later in the season and can reduce yields as well as grain quality. Females lay eggs in two-row clusters on leaves, stems, and panicles.  

Nymphs and adults feed on the rice florets and suck the nutrients from developing rice grains in the early milk stage which can reduce yields. According to LSU AgCenter, the most economic losses arise from a reduction in grain quality that results from stink bugs feeding on developing kernels. 

Insecticides such as neonicotinoid Tenchu (dinotefuran)  can be used before flowering to control stink bugs. There are several insecticides available but be sure to choose the right one for that time as some cannot be applied 21-days before harvest. 

Apple snail 

Another major issue rising throughout Louisiana waterways is the invasive apple snails.  

“Apple snails have existed throughout much of south Louisiana for the last 10 to 15 years,” he said. “Over the past five years, apple snail population growth in rice and crawfish production systems has become an issue.” 

While not an insect, this pest can easily damage seedling rice in water-seeded fields. 

“These snails can be highly detrimental to crawfish production,” he said.  

Apple Snails are believed to be introduced through irrigation with infested surface water.  

“The spread of snails has been slower due to farmers using well water to fill their crawfish ponds or rice fields,” he said. “Flooding events or movement of materials or equipment from infested ponds can spread the snails into new fields.”  

Copper sulfate has been shown to be an effective treatment for apple snails but can be detrimental to aquatic life such as crawfish. 

There remains no shortage of pests. The trick is figuring out how to control all insects and other pests like invasive apple snails while maximizing yield. Remember there are individuals in the agriculture industry who specialize in identifying and controlling insects or other pests. 

TAGS: RICE

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Study Uses Carbon Black as an Alternative to Insecticides

Apr 19 2022Reviewed by Bethan Davies

The yellow fever mosquito was only found in Africa before being unintentionally introduced to the New World by the slave trade in the 16th century. It has since become an invasive species in North America due to its adaptability.

Study Uses Carbon Black as an Alternative to Insecticides.
Image Credit: Shutterstock.com/Digital Images Studio

But researchers at The Ohio State University believe they have discovered a way to eradicate the pesky population in its juvenile stages.

The current study published in the journal Insects describes how mosquitoes have evolved natural resistance to some chemical insecticides and propose carbon black, a type of carbon-based nanoparticles, or CNPs, as an alternative.

Peter Piermarini, a co-author of the study and an associate professor of entomology at Ohio State, described CNPs as “microscopic” materials made of organic elements. Emperor 1800, a tweaked version of carbon black that is commonly used to coat automobiles in black, was used in the study.

Despite the fact that CNPs are a comparatively new scientific development, they have been regarded as a crucial tool for controlling various insect and pest infestations, according to Piermarini.

If we can learn more about how carbon black works and how to use it safely, we could design a commercially available nanoparticle that is highly effective against insecticide-resistant mosquitoes.

Peter Piermarini, Study Co-Author and Associate Professor, Entomology, The Ohio State University

The yellow fever mosquito, also known as Aedes aegypti, is a mosquito species that spread diseases such as dengue fever, Zika virus and chikungunya fever. Adults rarely fly more than a few hundred meters from where they appear, but their abundance allows diseases to spread at a steady rate, killing tens of thousands of people each year and hospitalizing hundreds of thousands more.

Related Stories

As a result, the mosquito is regarded as one of the most lethal animals on the planet. The goal of this research was to determine how toxic these nanomaterials might be to mosquito larvae or the insect’s immature form.

Not all mosquitos are interested in making blood their next meal. Male mosquitoes consume flower nectar, while female mosquitoes consume both flower nectar and blood to provide enough protein for their eggs to grow.

Female mosquitoes revert back to standing pools of water, such as birdbaths or lakes, to lay their eggs. These larvae will stay in the water for about a week after hatching until they reach adulthood and take flight.

To see if Emperor 1800 could stop this process, investigators used two distinct strains of yellow fever mosquitos in the laboratory, one that was extremely susceptible to chemical insecticides and the other that was extremely resistant.

The researchers introduced the carbon black nanomaterials to the water during the early stages of the mosquito’s life cycle and checked in 48 hours later. They were thus able to ascertain that CNPs kill mosquito larvae both efficiently and swiftly.

Given the properties of carbon black, it has the most potential for killing larvae because it can be suspended in water,” Piermarini adds.

The observations revealed that the material was accumulated on the mosquito larvae’s abdomen, head and even in its gut. This indicates that the larvae were consuming smaller particles of carbon black.

Our hypothesis is that these materials may be physically obstructing their ability to perform basic biological functions. It could be blocking their digestion, or might be interfering with their ability to breathe.

Peter Piermarini, Study Co-Author and Associate Professor, Entomology, The Ohio State University

Piermarini, on the other hand, found one thing particularly surprising.

Carbon black appeared to be equally toxic to larvae of insecticide-susceptible and insecticide-resistant mosquitoes when suspended in water at first, but the longer it was suspended in water before being treated, the more toxic it became. For insecticide-resistant larvae, it became more toxic.

When you first apply the CNP solution it has similar toxicity against both strainsBut when you let the suspension age for a few weeks, it tends to become more potent against the resistant strain of mosquitoes.

Peter Piermarini, Study Co-Author and Associate Professor, Entomology, The Ohio State University

Although the researchers were unable to pinpoint the cause of the time-lapsed deaths, they concluded that using these new nanomaterials as a preventive treatment on mosquito breeding grounds could be extremely effective in controlling the species.

Carbon black, however, must undergo extensive testing before it can be used by the general public, according to Piermarini, to ensure that it will not harm humans or the environment as a whole.

Erick Martinez Rodriguez, a visiting scholar in the Ohio State Entomology Graduate program, Parker Evans, a former Ph.D. student in the Ohio State Translational Plant Sciences Graduate Program, and Megha Kalsi, a former postdoctoral researcher in entomology, were co-authors of the paper. Ohio State’s College of Food, Agricultural, and Environmental Sciences, as well as Vaylenx LLC, funded this research.

Disease Spreading Mosquito

Disease Spreading Mosquito. Video Credit: The Ohio State University.

Journal Reference:

Rodríguez, E. J. M., et al. (2022) Larvicidal Activity of Carbon Black against the Yellow Fever Mosquito Aedes aegyptiInsectsdoi.org/10.3390/insects13030307.

Source: https://www.osu.edu/

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MARCH 2, 2022

Can amino acid also be developed as pesticide against plant viruses?

by Higher Education Press

Can amino acid also be developed as pesticide against plant viruses?
Credit: Hongjian Song, Qingmin Wang

Plant viruses create a great variety of harm. Virus disease pandemics and epidemics are estimated to have a global economic impact in the tens of billions of dollars. At present, there are not many effective and satisfactory varieties of anti-plant virus agents in practical use, and especially few therapeutic agents.

https://70cbbc045c672bb983a1214d7cd647c1.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

In the face of the harm viruses cause to agricultural production, it is necessary to develop environmentally friendly anti-plant virus drugs. It is increasingly important, and a growing research focus, to find drug candidates from natural products. Natural products possess many of the properties that can make them useful drug candidates, including structural diversity, specificity and novel modes of action. However, natural products also have some disadvantages, such as limited compound availability, high structural complexity and poor drug-likeness. Therefore, pesticide creation based on natural products has become an important direction of green pesticide creation.

Tryptophan is one of the essential amino acids and the biosynthetic precursor of many alkaloids. Prof. Qingmin Wang and Dr. Hongjian Song from Nankai University previously found that tryptophan, the biosynthesis precursor of Peganum harmala alkaloids, and its derivatives have anti-TMV activity both in vitro and in vivo. Further exploration of this led to the identification of NK0238 as a highly effective agent for the prevention and control of diseases caused by plant viruses, but the existing routes are unsuitable for its large-scale synthesis.

They optimized a route for two-step synthesis of this virucide candidate. The optimized route provides a solid foundation for its large-scale synthesis and subsequent efficacy and toxicity studies. Field experiment results showed that it had good effect on multiple plant viruses. The oral toxicity in rats was mild, and it had no effect on the safety of birds, fish or bees. The study entitled “Route development, antiviral studies, field evaluation and toxicity of an antiviral plant protectant NK0238” is published on the Journal of Frontiers of Agricultural Science and Engineering in 2022.

In this study, a two-step synthetic route for the antiviral plant protectant, NK0238, was developed. By this route, NK0238 can be obtained in 94% yield and nearly 97% HPLC purity. Compared with the previously reported routes, this route has the advantages of high atom economy, high yield and operational simplicity. In addition, it can be used for the preparation of more than 40 g of NK0238 in a single batch. After completing the process optimization, an in-depth study of antiviral activity in greenhouse and field experiments and toxicity tests were conducted. NK0238 exhibited a broad antiviral spectrum, in field experiments, the activities of NK0238 against TMV, pepper virus, panax notoginseng virus Y, gladiolus mosaic virus, banana bunchy top virus were equal to or higher than amino-oligosaccharins and moroxydine hydrochloride-copper acetate. The results of ecotoxicological testing showed that the compound was not harmful to birds, fish, bees and silkworms, its excellent activity and safety make NK0238 a promising drug candidate for further development.


Explore further

Novel synthetic process for the core structure of the fungal antiviral agent neoechinulin B and its derivatives


More information: Wentao Xu et al, Route Development, Antiviral Studies, Field Evaluation And Toxicity Of An Antiviral Plant Protectant Nk0238, Frontiers of Agricultural Science and Engineering (2021). DOI: 10.15302/J-FASE-2021390

Provided by Higher Education Press

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Growing Rice Alongside Aquatic Life Reduces Need for Pesticides

 Paige Bennett

 Feb 24, 2022 13:56PM ESTFOOD

A local carp living with rice plants

A local carp living with rice plants in the co-culture experiment. Lufeng Zhao (CC BY 4.0)

While rice is an important staple in global diets, rice cultivation and production are not so eco-friendly. Most rice agriculture relies on pesticides and chemical fertilizers for higher yields and less issues with insects and weeds. Now, researchers have found a way to minimize pesticide use for rice fields, instead using aquatic animals to help stifle weeds and improve crop yields.

Conventional farming involves planting large monocultures, or fields of the same crop. That makes each crop vulnerable to pests and weeds, which could wipe out most of one field. As such, farmers use pesticides to prevent weeds, pests, and diseases from taking over the crops and to boost yields.

But some farmers are testing ways to grow their crops while using natural methods to keep away pests and weeds.

“One example includes farmers experimenting with growing aquatic animals in rice paddies,” said Liang Guo, study author and postdoctoral fellow at the College of Life Sciences at Zhejiang University in Hangzhou, China. “Learning more about how these animals contribute to rice paddy ecosystems could help with producing rice in a more sustainable way.”

The research, published in eLife, analyzes three experiments and four years of study. In each experiment, the study authors considered rice grown alone or alongside carp, mitten crabs, or softshell turtles. According to the study, growing rice alongside these aquatic animals helped prevent weed growth. 

The animals also improved decomposition of organic matter and ultimately provided better yields compared to the rice that was grown alone. The researchers found yields that were 8.7% to 12.1% higher than the control crop grown without the aquatic animals.

Lufeng Zhao, author of the study and a Ph.D. student at the College of Life Sciences at Zhejiang University, added that the nitrogen levels in the soil remained stable with the aquatic animals present, so less chemical fertilizers were needed for the rice. The animals were given feed, but they scavenged for up to half of their diet. In turn, the rice plants absorbed 13% to 35% of nitrogen from leftover feed that the animals didn’t eat.

“These results enhance our understanding of the roles of animals in agricultural ecosystems, and support the view that growing crops alongside animals has a number of benefits,” said Xin Chen, co-senior author of the study and an ecology professor at Zhejiang University. “In terms of rice production, adding aquatic animals to paddies may increase farmers’ profits as they can sell both the animals and the rice, spend less on fertilizer and pesticides, and charge more for sustainably grown products.”

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Farmers are overusing insecticide-coated seeds, with mounting harmful effects on nature

Published: February 22, 2022 8.41am EST

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  1. John F. TookerProfessor of Entomology and Extension Specialist, Penn State

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John F. Tooker receives funding from the United States Department of Agriculture and the Pennsylvania Soybean Promotion Board.

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Planting season for corn and soybeans across the U.S. will begin as soon as March in Southern states and then move north. As farmers plant, they will deploy vast quantities of insecticides into the environment, without ever spraying a drop.

Almost every field corn seed planted this year in the United States will be coated with neonicotinoids, the most widely used class of insecticides in the world. So will seeds for about half of U.S. soybeans and nearly all cotton, along with other crops. By my estimate, based on acres planted in 2021, neonicotinoids will be deployed across at least 150 million acres of cropland – an area about the size of Texas.

Neonicotinoids, among the most effective insecticides ever developed, are able to kill insects at concentrations that often are just a few parts per billion. That’s equivalent to a pinch of salt in 10 tons of potato chips. Compared with older classes of insecticides, they appear to be relatively less toxic to vertebrates, especially mammals.

But over the past decade, scientists and conservation advocates have cited a growing body of evidence indicating that neonicotinoids are harmful to bees. Researchers also say these insecticides may affect wildlifeincluding birds that eat the coated seeds.

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In response to these concerns, Connecticut, Maryland, Vermont, Massachusetts, Maine and New Jersey have enacted laws limiting use of neonicotinoid insecticides. Other states are considering similar measures. Consumer and environmental advocates are also suing to force the U.S. Environmental Protection Agency to regulate coated seeds more tightly.

As an applied insect ecologist and extension specialist who works with farmers on pest control, I believe U.S. farmers are using these insecticides far more heavily than necessary, with mounting harm to ecosystems. Moreover, our ongoing research indicates that using farming strategies that foster beneficial, predatory insects can greatly decrease reliance on insecticides.https://cdn.knightlab.com/libs/juxtapose/latest/embed/index.html?uid=c74b20ca-8eb2-11ec-a554-13fc6baea232Use of imidacloprid, a common neonicotinoid, increased dramatically from 1994 to 2019 (move slider to compare years).

Insecticides on seeds

Most neonicotinoids in the U.S. are used as coatings on seeds for field crops like corn and soybeans. They protect against a relatively small suite of secondary insect pests – that is, not the main pests that typically damage crops. National companies or seed suppliers apply these coatings so that when farmers buy seeds they just have to plant them. As a result, surveys of farmers indicate that about 40% are unaware that insecticides are on their seeds.

The share of corn and soybean acreage planted with neonicotinoid-coated seeds has increased dramatically since 2004. From 2011 to 2014, the amount of neonicotinoids applied to corn doubled. Unfortunately, in 2015 the federal government stopped collecting data used to make these estimates.

Unlike most insecticides, neonicotinoids are water soluble. This means that when a seedling grows from a treated seed, its roots can absorb some of the insecticide that coated the seed. This can protect the seedling for a limited time from certain insects.

But only a small fraction of the insecticide applied to seeds actually enters seedlings. For example, corn seedlings take up only about 2%, and the insecticide persists in the plant for only two to three weeks. The critical question: Where does the rest go?

Treated and untreated seeds on a black background
Soybean seeds treated with neonicotinoids (dyed blue to alert users to the presence of pesticide) and treated corn seeds (dyed red) versus untreated seeds. Ian Grettenberger/PennState University, CC BY-ND

Pervading the environment

One answer is that leftover insecticide not taken up by plants can easily wash into nearby waterways. Neonicotinoids from seed coatings are now polluting streams and rivers across the U.S.

Studies show that neonicotinoids are poisoning and killing aquatic invertebrates that are vital food sources for fish, birds and other wildlife. Recent research has connected use of neonicotinoids with declines in the abundance and diversity of birds and the collapse of a commercial fishery in Japan.

Neonicotinoids also can strongly influence pest and predator populations in crop fields. In a 2015 study, colleagues and I found that use of coated soybean seeds reduced crop yields by poisoning insect predators that usually kill slugs, which cause serious damage in mid-Atlantic corn and soybeans fields. Subsequently, we found that neonicotinoids can decrease populations of insect predators in crop fields by 15% to 20%.

Recently we found that these insecticides can contaminate honeydew, a sugary fluid that aphids and other common sucking insects excrete when they feed on plant sap. Many beneficial insects, such as predators and parasitic wasps, feed on honeydew and may be poisoned or killed by neonicotinoids.

Slugs, shown here on a soybean plant, are unaffected by neonicotinoids but can transmit the insecticides to beetles that are important slug predators. Nick Sloff/Penn State UniversityCC BY-ND

Are neonicotinoids essential?

Neonicotinoid advocates point to reports – often funded by industry – that argue that these products provide value to field crop agriculture and farmers. However, these sources typically assume that insecticides of some type are needed on every acre of corn and soybeans. Therefore, their value calculations rest on comparing neonicotinoid seed coatings with the cost of other available insecticides.

Recent field studies, however, demonstrate that neonicotinoid-coated seeds provide limited insect control because target pest populations tend to be scarce and treating fields for them yields little benefit.

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Does this mean that the U.S. should follow the European Union’s lead and ban neonicotinoids or adopt strict limits like those enacted in New Jersey?

As I see it, neonicotinoids can provide good value in controlling critical pest species, particularly in vegetable and fruit production, and managing invasive species like the spotted lanternfly. However, I believe the time has come to rein in their use as seed coatings in field crops like corn and soybeans, where they are providing little benefit and where the scale of their use is causing the most critical environmental problems.

https://platform.twitter.com/embed/Tweet.html?creatorScreenName=jftooker&dnt=false&embedId=twitter-widget-

Instead, I believe agricultural companies should promote, and farmers should use, integrated pest management, a strategy for sustainable insect control that is based on using insecticides only when they are economically justified. Recent research at Penn State and elsewhere reaffirms that integrated pest management can control pests in corn and other crops without reducing harvests.

Concerns about neonicotinoid-coated seeds are mounting as research reveals more routes of exposure to beneficial animals and effects on creatures they are not designed to kill. Agricultural companies have done little to address these issues and seem more committed than ever to selling coated seeds. Farmers often have very limited choice if they want to plant uncoated seeds.

Scientists are sounding the alarm about rising extinction rates worldwide, and research indicates that neonicotinoids are contributing to insect declines and creating more toxic agricultural lands. I believe it’s time to consider regulatory options to curb the ongoing abuse of neonicotinoid-coated seeds.

This is an update of an article originally published on June 26, 2018.

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Minimizing Further Insect Pest Invasions in Africa

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Esther Ngumbi

Jun 20, 2018

Photo: Tamzin Byrne/ICIPE

This was written by Esther Ngumbi, and appeared on Sci Dev Net

USAID recently offered prize money for the best digital tools that can be used to help combat the fall armyworm (FAW), an invasive pest that has spread across Africa. The winners will be announced in the coming months.
 
Identified in over 35 African countries since 2016, the FAW is expected to continue to spread, threatening food security and agricultural trade in African countries.

Map of areas affected by Fall Armyworm (as of January 2018)


Map of areas affected by Fall Armyworm (as of January 2018) Credit: FAO

But this is not the first invasive pest the African continent is dealing with. Just a few years ago, African smallholder farmers battled the invasive South American tomato moth, Tuta absoluta. According to recent research, five invasive insect pests including T. absoluta cost the African continent US$ 1.1 billion every year.
 
Around the world, invasive pests are causing US$ 540 billion in economic losses to agriculture each year despite the fact that many countries are doing their best to prevent insect invasions now and into the future.
 

Tackling invasive pests reactively

To deal with invasive insects, African countries assisted by other stakeholders, including aid agencies such as USAID, research institutions such as the International Center for Insect Physiology and Ecology, the Center for Agriculture and Bioscience International (CABI, the parent organization of SciDev.Net) and the United Nations Food and Agriculture Organization (UN FAO) have repeatedly taken a reactive rather than a proactive approach in tackling the invasive pests only after they have established a foothold and caused considerable damage.
 
Ghana, for example, established a National Taskforce to control and manage FAW after the worms had invaded local fields. This taskforce mandate includes sensitizing farmers and making them aware of the symptoms of armyworm attacks so they can report infestations to authorities and undertake research aimed at finding short and long term solutions to combat the spread of FAW.

“While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem.”

Esther Ngumbi, University of Illinois

Malawi’s government prioritized the use of pesticides as an immediate and short-term strategy to fight the FAW after many of their smallholder farmers lost crops to this invasive insect. Further, the government intensified training and awareness campaigns about this pest and installed pheromone traps to help monitor the spread only after the pest had established a foothold.
 
The FAO, a leader in the efforts to deal with invasive pests in Africa, has spearheaded many efforts including bringing together experts from the Americas, Africa and other regions to share and update each other on FAW. The FAO has launched a mobile phone app to be used as an early warning system tool. But again, many of these efforts happened after the first detection of the FAW.
 
While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem. How can aid agencies such as USAID, UN FAO and other development partners that are currently spending billions to fight the invasive FAW help Africa to take the necessary steps to ensure that it is better prepared to deal with invasive insects now and into the future?
 

Anticipate and prepare

Recent research predicts that threats from invasive insects will continue to increase with African countries expected to be the most vulnerable. African governments must anticipate and prepare for such invasions using already available resources.
 
Early this year, CABI launched invasive species Horizon Scanning Tool (beta), a tool that allows countries to identify potential invasive species. This online and open source tool supported by United States Department of Agriculture and the UK Department for International Development allows countries to generate a list of invasive species that are absent from their countries at the moment but present in “source areas,” which may be relevant because they are neighboring countries, linked by trade and transport routes, or share similar climates. Doing so could allow African countries to prepare action plans that can be quickly rolled out when potential invaders actually arrive.
 

Learn from other regions

Africa can learn from other regions that have comprehensive plans on dealing with invasive insects and countries that have gone through similar invasions. The United States and Australia are examples of countries that have comprehensive plans on preventing and dealing with insect invasions, while Brazil has gone through its own FAW invasion.

“African governments must learn to be proactive rather than reactive in dealing with invasive insects.”

Esther Ngumbi, University of Illinois

Through workshops and training programs that help bring experts together, African countries can learn how to prevent and deal with future insect invasions. Moreover, key actors should help organize more workshops and training programs to enable African experts to learn from their counterparts overseas. At the same time, the manuals, and all the information exchanged and learned during such workshops, could be stored in online repositories that can be accessed by all African countries.   
 

Strengthen African pest surveillance

A recent Feed the Future funded technical brief, which I helped to write, looked at the strength of existing African plant protection regulatory frameworks by examining eight indicators including the existence of a specified government agency mandated with the task of carrying out pest surveillance.
 
It reveals that many African countries have weak plant protection regulatory systems and that many governments do not carry out routine pest surveillance which involves the collection, recording, analysis, interpretation and timely dissemination of information about the presence, prevalence and distribution of pests.
 
The International Plant Protection Convention offers a comprehensive document that can help African countries to design pest surveillance programs. Also, the convention offers other guiding documents that can be used by African countries to strengthen their plant protection frameworks. African countries can use these available documents to strengthen national and regional pest surveillance abilities.
 

Set up emergency funds

Invasive insects know no borders. Thus, African countries must work together. At the same time, given the rapid spread of invasive insect outbreaks, the African continent must set up an emergency fund that can easily be tapped when insects invade. In dealing with the recent FAW invasion, it was evident that individual African countries and the continent did not have an emergency financing plan. This must change.

By anticipating potential invasive insects and learning from countries that have comprehensive national plant protection frameworks, Africa can be prepared for the next insect invasion. African governments must learn to be proactive rather than reactive in dealing with invasive insects.
 
Doing so will help safeguard Africa’s agriculture and protect the meaningful gains made in agricultural development. Time is ripe.
 
Esther Ngumbi is a distinguished postdoctoral researcher with the Department of Entomology at the US-based University of Illinois at Urbana Champaign, a World Policy Institute Senior Fellow, Aspen Institute New Voices Food Security Fellow and a Clinton Global University Initiative Agriculture Commitments Mentor and Ambassador. She can be contacted at enn0002@tigermail.auburn.edu 
 
This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk. 
 

References

[1] USAID: Fall Armyworm Tech Prize (USAID, 2018). 
[2] Briefing note on FAO actions on fall armyworm in Africa (UN FAO, 31 January 2018) 
[3] Corin F. Pratt and others  Economic impacts of invasive alien species on African smallholder livelihoods (Global Food Security, vol 14, September 2017).
[4] Abigail Barker Plant health-state of research (Kew Royal Botanic gardens, 2017).
[5] US Embassy in Lilongwe United States assists Malawi to combat fall armyworm. (US Embassy, 13 February 2018).
[6] Joseph Opoku Gakpo Fall armyworm invasion spreads to Ghana (Cornell Alliance for Science, 19 May 2017). 
[7] Kimberly Keeton Malawi’s new reality: Fall armyworm is here to stay (IFPRI, 26 February 2018).
[8] Malawi’s farmers resort to home-made repellents to combat armyworms (Reuters, 2018). 
[9] Fall Armyworm (UN FAO, 2018). 
[10] FAO launches mobile application to support fight against Fall Armyworm in Africa (UN FAO, 14 March 2018).
[11] Dean R. Paini and others Global threat to agriculture from invasive species (Proceedings of the National Academy of Sciences of the United States of America, 5 July 2016).
[12] CABI launches invasive species Horizon Scanning Tool (CABI, 2018).
[13] United States Department of Agriculture Animal and Plant Health Inspection Service(USDA APHIS, 2018).
[14] Australia Government Department of Agriculture and Water Resources (Australia Government, 2018).
[15] Plant protection EBA data in action technical brief (USAID FEED THE FUTURE, 26 January 2018).
[16] Guidelines for surveillance (International Plant Protection Convention, 2016)FILED UNDER:AGRICULTURAL PRODUCTIVITYMARKETS AND TRADEPOLICY AND GOVERNANCERESILIENCE

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Honeydew contaminated with systemic insecticides threatens beneficial insects

Neonicotinoids and other systemic insecticides can contaminate honeydew, which is an important food source for beneficial insects in the agroecosystems, according to an international team of researchers.

John Tooker, professor of entomology in Penn State’s College of Agricultural Sciences, was part of the multidisciplinary team that conducted a review of the scientific literature, concluding that systemic insecticides in honeydew are a serious concern, particularly in large-acreage crops that commonly are treated with these products.

Honeydew is the excretion product of sap-sucking insects such as aphids, mealybugs, whiteflies, and psyllids, Tooker explained.

“This rich carbohydrate source is a common food for many beneficial insects, including pollinators, such as bees and flies, and some natural enemies of pests, such as ants, wasps, and beetles,” he said. “Honeydew often is more abundant than nectar in agroecosystems.”

In their review, the researchers cited a 2019 study published in the Proceedings of the National Academy of Sciences by some of the co-authors, who found that honeydew represents a novel route of exposure to neonicotinoids, the most widely used group of systemic insecticides in the world. These insecticides often are applied in the form of seed coatings, and as a plant germinates and grows, the insecticide in its sap kills pest insects that feed on it.

As part of the 2019 study, the scientists conducted chemical analyses of honeydew excreted by insects feeding on sap from plants treated with neonicotinoids. They found clear evidence that this honeydew was contaminated and toxic to beneficial insects such as parasitic wasps and pollinating hoverflies, which died within a few days of consuming the contaminated honeydew.

The study was the subject of industry skepticism because it was conducted under laboratory conditions that may not exist in the field. Subsequently, members of the research team conducted a two-year field study — published recently in Environmental Pollution — which found that neonicotinoids from soybean plants grown from neonicotinoid-coated seeds reached honeydew excreted by soybean aphid 30-40 days after the seeds were sown.

“Continued work by our consortium, and studies published by other researchers, have revealed that the phenomenon is widespread, occurring in several species of plants and honeydew producers and with several systemic insecticides with various modes of action and modes of application,” said co-author Miguel Calvo-Agudo, of the Instituto Valenciano de Investigaciones Agrarias in Valencia, Spain. “As a result, many beneficial insect species are at risk of being exposed to neonicotinoids via contaminated honeydew.”

Resistant insect species 
The research team’s summary, published recently in Biological Reviews, analyzed relevant information from the fields of plant and insect physiology, toxicology, and ecology to identify the systemic insecticides that are more likely to reach honeydew and those insect species that are more likely to excrete contaminated honeydew.

For example, the authors raise serious concerns about invasive sap-sucking insect species that are resistant or tolerant to systemic insecticides and infest large-acreage crops — such as corn, wheat, rice and barley — that are commonly treated with systemic insecticides. These crops represent more than 50% of the worldwide harvest area, and honeydew is the main carbohydrate source in these crops for beneficial insects.

This review study can raise awareness among integrated pest management programs and environmental protection agencies that regulate the use of systemic insecticides, the researchers noted. Among their conclusions is a recommendation that agencies restrict the use of highly water-soluble systemic insecticides that are persistent in the environment and those that have a broad-spectrum activity to avoid nontarget impacts on beneficial insects through honeydew and other avenues of exposure.For more information:
PennState University
www.news.psu.edu

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