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Archive for the ‘Herbicides’ Category

Soil Biodiversity Under Grave Threat from Pesticides – Most Comprehensive Review Ever

Posted on May 7 2021 – 3:00pm by Sustainable Pulse« PREVIOUSNEXT »Categorized as

new study published Tuesday by the academic journal Frontiers in Environmental Science finds that pesticides widely used in American agriculture pose a grave threat to organisms that are critical to healthy soil, biodiversity and soil carbon sequestration to fight climate change. Yet those harms are not considered by U.S. regulators.

The study, by researchers at the Center for Biological Diversity, Friends of the Earth U.S. and the University of Maryland, is the largest, most comprehensive review of the impacts of agricultural pesticides on soil organisms ever conducted.

The researchers compiled data from nearly 400 studies, finding that pesticides harmed beneficial, soil-dwelling invertebrates including earthworms, ants, beetles and ground nesting bees in 71% of cases reviewed.

“It’s extremely concerning that 71% of cases show pesticides significantly harm soil invertebrates,” said Dr. Tara Cornelisse, an entomologist at the Center and co-author of the study. “Our results add to the evidence that pesticides are contributing to widespread declines of insects, like beneficial predaceous beetles and pollinating solitary bees. These troubling findings add to the urgency of reining in pesticide use.”

The findings come on the heels of a recent study published in the journal Science showing pesticide toxicity has more than doubled for many invertebrates since 2005. Despite reduced overall use of insecticides, the chemicals most commonly used today, including neonicotinoids, are increasingly toxic to beneficial insects and other invertebrates. Pesticides can linger in the soil for years or decades after they are applied, continuing to harm soil health.

The reviewed studies showed impacts on soil organisms that ranged from increased mortality to reduced reproduction, growth, cellular functions and even reduced overall species diversity. Despite these known harms, the Environmental Protection Agency does not require soil organisms to be considered in any risk analysis of pesticides. What’s more, the EPA gravely underestimates the risk of pesticides to soil health by using a species that spends its entire life aboveground — the European honeybee — to estimate harm to all soil invertebrates.

“Below the surface of fields covered with monoculture crops of corn and soybeans, pesticides are destroying the very foundations of the web of life,” said Dr. Nathan Donley, another co-author and scientist at the Center. “Study after study indicates the unchecked use of pesticides across hundreds of millions of acres each year is poisoning the organisms critical to maintaining healthy soils. But our regulators have been ignoring the harm to these important ecosystems for decades.”

Soil invertebrates provide a variety of essential ecosystem benefits such as cycling nutrients that plants need to grow, decomposing dead plants and animals so that they can nourish new life, and regulating pests and diseases. They’re also critical for the process of carbon conversion. As the idea of “regenerative agriculture” and using soil as a carbon sponge to help fight climate change gains momentum around the world, the findings of this study confirm that reducing pesticide use is a key factor in protecting the invertebrate ecosystem engineers that play a critical role in carbon sequestration in the soil.

“Pesticide companies are continually trying to greenwash their products, arguing for the use of pesticides in ‘regenerative’ or ‘climate-smart’ agriculture,” said Dr. Kendra Klein, a co-author who’s also a senior scientist at Friends of the Earth. “This research shatters that notion and demonstrates that pesticide reduction must be a key part of combatting climate change in agriculture.”

“We know that farming practices such as cover cropping and composting build healthy soil ecosystems and reduce the need for pesticides in the first place,” said co-author Dr. Aditi Dubey of the University of Maryland. “However, our farm policies continue to prop up a pesticide-intensive food system. Our results highlight the need for policies that support farmers to adopt ecological farming methods that help biodiversity flourish both in the soil and above ground.”

Background

The review paper looked at 394 published papers on the effects of pesticides on non-target invertebrates that have egg, larval or immature development in the soil. That review encompassed 275 unique species or groups of soil organisms and 284 different pesticide active ingredients or unique mixtures of pesticides.

The assessment analyzed how pesticides affected the following endpoints: mortality, abundance, richness and diversity, behavior, biochemical markers, impairment of reproduction and growth, and structural changes to the organism. This resulted in an analysis of more than 2,800 separate “cases” for analysis, measured as a change in a specific endpoint following exposure of a specific organism to a specific pesticide. It found that 71% of cases showed negative effects.

Negative effects were evident in both lab and field studies, across all studied pesticide classes, and in a wide variety of soil organisms and endpoints. Organophosphate, neonicotinoid, pyrethroid and carbamate insecticides, amide/anilide herbicides and benzimidazole and inorganic fungicides harmed soil organisms in more than 70% of cases reviewed.

Insecticides caused the most harm to nontarget invertebrates, with studies showing around 80% of tested endpoints negatively affected in ground beetles, ground nesting solitary bees, parasitic wasps, millipedes, centipedes, earthworms and springtails.

Herbicides and fungicides were especially detrimental to earthworms, nematodes and springtails.

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Combine old with new for resistant weed management

TAGS: HERBICIDEHERBICIDE RESISTANT WEEDSAdam Hixon, BASFadam-hixson-pigweed-glyphosate.jpgSignificant pigweed infestation remains in this field after two applications of glyphosate.Getting back to the basics is critical to managing herbicide resistant weeds.

Ron Smith | Apr 19, 2021

Weeds resistant to herbicides are a way of life for farmers, one more concern to complicate an already complex production system.

But options exist not only to manage resistance but also to reduce the size of the weed seed bank.https://82ae8ac4f4c5904dfe4704d0077ebf4f.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

“Resistance is here to stay,” said Adam Hixson, BASF technical service representative for Texas, Oklahoma, and New Mexico, during a recent media update on managing herbicide resistant weeds in the Southwest.

swfp-shelley-huguley-adam-hixon-profile.jpgAdam Hixson, BASF technical service representative for Texas, Oklahoma, and New Mexico. (Photo by Shelley E. Huguley)

“We’ve heard the expression, ‘out with the old and in with the new,’” Hixson said. “I want to change that to ‘in with the old and in with the new.’”

Back to basics

Getting back to basics, he said, is crucial to managing herbicide resistant weeds. He called on Texas A&M AgriLife Professor and Extension Weed Specialist Pete Dotray to put the problem in perspective.

“According to the International Survey of Herbicide Resistant Weeds, we have eight resistant weed species in Texas,” Dotray said. “The first case of resistance in the state was noted 30 years ago, but in the last 10 years, glyphosate resistance has created a lot of concern.”

Dotray said Roundup resistant Palmer amaranth, also known as pigweed and carelessweed, was first identified on the Texas High Plains about 10 years ago, later than in some Mid-South and Southeastern states. He believes a key to that late arrival was that High Plains farmers never abandoned residual herbicides, especially the yellow herbicides like Treflan and Prowl.

shelley-huguley-dotray-profile.jpgTexas A&M AgriLife Professor and Extension Weed Specialist Pete Dotray (Photo by Shelley E.Huguley)

Overuse of Roundup, using the same chemistry over and over, and use of fewer herbicide and tillage inputs provided an open door for the increase in resistant weed populations, Dotray said. “Resistant weeds were likely already out there in extremely low numbers.”

Palmer amaranth resistance has complicated weed management, Hixson added. “We’ve seen multiple applications of glyphosate at labeled rates fail to control Palmer amaranth.”

He said remedies include manual control, such as hoeing, which is expensive and time-consuming. “Also, we’re always looking for that next ‘shiny object’ that will solve the problem.”

Shiny things have been scarce in recent years, however, so Hixson offers a different option. “We need to use what we have today, but use it in a more calculated, knowledge-based approach. We have to get back to the fundamentals of weed control.”

Year-round effort

He and Dotray agree that successful weed control strategies do not focus solely on in-season herbicide applications. “Good weed management has to be a well-planned, year-round venture,” Hixson said.

Weed identification is a priority. “It’s important to identify the weeds and to understand fully the biology. Know when specific weed species are most vulnerable.”

He explained that Kochia, sometimes “a huge problem and resistant to several herbicides,” emerges early in the spring and typically has only one flush. An effective residual herbicide, applied at the right time, will take care of most Kochia issues.

Palmer amaranth, however, emerges from early in the season well into fall and requires a season-long management program.

Dotray said Palmer seed that emerge late in the season remain a threat to replenish the seed bank and create problems for the next crop year.

“We’ve looked at the abundance of seed one plant can produce,” he said. “Palmer that emerges early produces as many as 500,000 to 600,000 seed, maybe more, per plant. That’s a lot of seed. But a Palmer plant that emerges in August will still produce as many as 20,000 seed, also a lot. As late as September, emerging plants will produce 2,000 seed, and still hundreds by October. Even plants that emerge as late as November can produce some viable seeds.”

“Leaving just one plant,” Hixson said, “may add to the weed seed bank, a key factor for the next season. One seed per square inch represents more than 6 million seeds per acre.” So, next season’s weed control should start before this season ends.

Good news

Dotray said recent research shows a bit of good news about the longevity of Palmer seed. Studies have shown that some weed seed will retain viability for as long as 120 years.

“We had no good answer for how long Palmer seed remain viable, so five years ago we set up a test to see. We buried Palmer seed at various depths across the state.”

They uncover them at intervals, beginning at six months, again at 12 months, and yearly after that. Based on data from the first 48 months of the research, “Palmer seed viability begins to decline significantly after 12 months. Those findings were the same across all locations and at all depths. A second study initiated in 2018 has shown the same results so far,” Dotray said.

“The good news is that a farmer who does a good job of managing Palmer amaranth effectively with a systematic program can get them down to a manageable level in a short time.”

That system should include late applications to prevent escapes, he said.

Knowledge is key

Hixson said an effective weed management program also depends on knowing not only the weed species vulnerabilities but also the interactions of soils and chemistry.

He said using herbicides with multiple, effective modes of action should be a critical part of weed management

“But also understand the properties of the herbicides and how they respond to different conditions, including soil types and moisture. Soil leaching properties will affect herbicide efficacy,” he said. “Also, the more water soluble a product is, the deeper it will move into the soil profile. Less soluble usually means more soil binding.”

He said different soil types — changes in clay content, sand, organic matter level — all may affect herbicide activity.

He said in situations with good moisture, a product like Zidua could be the best option. “In dryland or subsurface drip irrigation conditions, Outlook would be ideal.”Adam Hixon, BASFadam-hixson-timely-applications.jpg

Timely applications, with overlapping residuals (Prowl H2O herbicide followed by Outlook herbicide), along with an effective postemergence herbicide (Engenia herbicide), provide exceptional control of Palmer amaranth.

They key is understanding the weed, the environment, and the herbicide properties, then using the proper material for the target weed under those specific conditions.

Timing and coverage

He added that application timing and coverage also matter.

“Also remember, the cottonseed trait package you plant determines the herbicides you can use.”

“Using residual herbicides, identifying weeds and understanding the difference in solubility and where a product fits best based on soil and moisture are critical to a systems approach to weed management,” Dotray added.

In response to a question about new dicamba labels, Hixson said BASF would not veer from the requirements established by the federal label in Texas, Oklahoma, and New Mexico

Dotray noted that the new registrations come with some significant changes, including bigger buffers, volatility reduction adjuvant requirements and application timing.

“Also, last year some states used 24-C exemptions to alter some regulations. So far this year, states that have applied for a 24-C have been denied.”

Hixson announced that BASF does have one “shiny object” in the pipeline, a new seed trait with tolerance to four herbicides –GLIXTP, pending regulatory approval. He anticipates introduction in 2023, with potentially more availability in 2024.

In the meantime, he said, “Old chemistry still has value.”

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What have we learned about kochia management?

TAGS: MANAGEMENTPhoto courtesy of Nevin LawrenceKochia in a continuous corn field after four years of ALS-inhibiting herbicideKOCHIA CONTROL: Kochia is a tough weed to beat, and it can cause real trouble in crops if it is not controlled. In this photo, you can see the kochia pressure in a continuous corn field after four years of using an ALS-inhibiting herbicide.Extension Crop Connection: Kochia remains a tough weed, but integrated weed management can help win the battle.

Nevin Lawrence | Apr 12, 2021

Kochia remains one of the most challenging weeds to control in western Nebraska. Kochia can be resistant to Group 5 (atrazine), Group 2 (imazamox), Group 9 (glyphosate) and Group 4 (dicamba) herbicides in western Nebraska.

While there are still many herbicides available to irrigated corn growers, those who grow dry beans and sugarbeets have few options because of crop rotation restrictions. When a grower runs out of herbicide options, what can they do?

IWM to the rescue

Integrated weed management is often discussed as the solution. A simple definition of IWM is the strategic use of all the tools a farmer has available, including herbicides, tillage, crop selection, crop rotation, cover crops and other cultural practices.

Does IWM actually work? In 2014, a study was established in Scottsbluff, Neb., to find out. The study ran for four years, concluding in 2017. The goal of this study was to use IWM to target kochia in an irrigated crop rotation.

Each site was established by seeding a mix of kochia biotypes of which 95% were susceptible to Group 2 (ALS-inhibiting herbicides) and 5% were resistant to Group 2 herbicides. The seed mixture used created a “low level” of resistance in the seed bank, which simulates the early stages of herbicide-resistance development.

3 strategies

There were three IWM strategies, including the use of tillage, crop rotation and herbicide strategy. The tillage strategy used two different treatments — minimal tillage or intensive tillage.

Four crop rotations were established — four years of continuous corn; a corn-sugarbeet-corn-sugarbeet rotation; a corn-sugarbeet-corn-dry bean rotation; and finally, a small grain-sugarbeet-corn-dry bean rotation.

The final strategy was herbicide use, with three different treatments. This included a Group 2 herbicide-only treatment, where only herbicides that wouldn’t control the resistant kochia were applied every single year.

Table shows Kochia density per square yard on various crops after 4 yearsAnother was a herbicide mode-of-action rotation, where a Group 2-alternative herbicide rotation and herbicide effective for Group 2-resistant kochia were used every other year. In corn for example, the effective herbicide was a tank mixture of glyphosate and dicamba.

The last treatment was mixing MOAs, where an effective herbicide treatment was mixed with a Group 2 herbicide each year. For the rotation herbicide treatment, in 2014 and 2016, the alternative herbicide was used, and in 2015 and 2017, the Group 2 herbicide was used.

Results are in

After four years, kochia density ranged from as low as 0 to 40 kochia plants per square yard, with seed production as high as 8,000 seeds per square yard. Yield reduction was significant — sugarbeet and dry bean plots experienced total yield loss, and corn yield was reduced from 200 to 60 bushels per acre from the highest kochia densities. Wheat, however, was not greatly affected by kochia competition, always yielding between 55 to 60 bushels.

So, what worked in reducing kochia numbers over four years? The obvious winner was using herbicide mixtures, with low kochia density observed regardless of tillage system or crop rotation.

But what if good herbicides are not available? Including wheat in the rotation helped tremendously, even when an ALS herbicide was used every year. In the sugarbeet-corn and sugarbeet-corn-dry bean rotation, kochia density was reduced from near 40 plants every square yard down to only seven, even when using an herbicide that didn’t work.

Wheat, in irrigated systems, is great at reducing kochia emergence early in the season. Although this study didn’t consider wheat as a cover crop, a similar benefit may be observed by using any small grain — wheat, barley, oats, rye or triticale — as a cover crop preceding other crops. Small grains close rows quickly and smother early plants before they have a chance to emerge in the spring.

Lawrence is a Nebraska Extension weed management specialist.

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John Deere using machine learning to reduce herbicide use

Melody Labinsky

Melody Labinsky@MelodyLabinsky4 Mar 2021, 4:30 p.m.On Farm

John Deere Australia and New Zealand managing director Luke Chandler spoke at the Rural Press Club of Queensland last week.

 John Deere Australia and New Zealand managing director Luke Chandler spoke at the Rural Press Club of Queensland last week.Aa

Machine learning technology is set to reduce herbicide use by up to 80 per cent, according to John Deere’s Australia and New Zealand managing director Luke Chandler.

Mr Chandler said this would be achieved by moving from a whole-of-field approach to a plant-by-plant management strategy.

He said global agriculture was at an inflection point and technological developments would help drive productivity.

Farmers across the world have been chasing economies of scale and the company’s focus had been on building bigger, faster and stronger machinery to meet that growth, he said.

“That’s still important but as we shift towards this next frontier of agriculture, we really see machinery being driven by automation, easier to use, more precise types of technologies.”

In 2017, John Deere acquired Silicon Valley company Blue River Technology for US$305 million.

By using Blue River’s deep learning algorithms and artificial intelligence programming and embedding it on the “hard iron of John Deere machines”, the company hopes to take agriculture’s productivity to the next level.

Mr Chandler spoke about the company’s focus on innovation and how it can help farmers grow the food and fibre sector at the Rural Press Club of Queensland last week.

“While you might hear a lot about ag tech being a new industry, it’s not new for us and it’s not new for us in Australia,” he said.

Mr Chandler pointed to the role of cotton and grains farmers in northern NSW in helping to develop GPS and yield mapping technology, which has become a major part of precision agriculture, and is used around the world.

John Deere has grown from its humble beginnings in Illinois 184 years ago, into one of the world’s largest agricultural machinery manufacturers.

Together with dealerships, the company employs 4500 people across Australia and New Zealand.

John Deere is also looking to bring its total number of tech apprentices to 1200, predominately in rural and regional communities.
SHARETWEETAa

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Sustainable Pulse

US EPA Evaluation Finds Glyphosate Likely to Injure or Kill 93% of Endangered Species

Posted on Nov 28 2020 – 3:21pm by Sustainable Pulse« PREVIOUS| Categorized as

The Environmental Protection Agency released a draft biological evaluation on Wednesday finding that glyphosate is likely to injure or kill 93% of the plants and animals protected under the Endangered Species Act.

Endangered Species

The long-anticipated draft biological evaluation released by the agency’s pesticide office found that 1,676 endangered species are likely to be harmed by glyphosate, the active ingredient in Roundup and the world’s most-used pesticide.

The draft biological opinion also found that glyphosate adversely modifies critical habitat for 759 endangered species, or 96% of all species for which critical habitat has been designated.

“The hideous impacts of glyphosate on the nation’s most endangered species are impossible to ignore now,” said Lori Ann Burd, environmental health director at the Center for Biological Diversity. “Glyphosate use is so widespread that even the EPA’s notoriously industry-friendly pesticide office had to conclude that there are hardly any endangered species that can manage to evade its toxic impacts.”

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Hundreds of millions of pounds of glyphosate are used each year in the United States, mostly in agriculture but also on lawns, gardens, landscaping, roadsides, schoolyards, national forests, rangelands, power lines and more.

According to the EPA, 280 million pounds of glyphosate are used just in agriculture, and glyphosate is sprayed on 298 million acres of crop land each year. Eighty-four percent of glyphosate pounds applied in agriculture are applied to soy, corn and cotton, commodity crops that are genetically engineered to tolerate being drenched with quantities of glyphosate that would normally kill a plant.

Glyphosate is also widely used in oats, wheat, pulses, fruit and vegetable production.

“If we want to stop the extinction of amazing creatures like monarch butterflies, we need the EPA to take action to stop the out-of-control spraying of deadly poisons,” Burd continued.

The EPA has, for decades, steadfastly refused to comply with its obligation under the Endangered Species Act to assess the harms of pesticides to protected plants and animals. But it was finally forced to do this evaluation under the terms of a 2016 legal agreement with the Center for Biological Diversity.

Emails obtained in litigation brought against Monsanto/Bayer by cancer victims and their families have uncovered a disturbingly cozy relationship between the agency and the company on matters involving the glyphosate risk assessment.

In one example, when the U.S. Department of Health and Human Services announced it would be reviewing glyphosate’s safety, an EPA official assured Monsanto he would work to thwart the review, saying, “If I can kill this, I should get a medal.” The Health and Human Services review was delayed for three years.on.”

Earlier this year, relying on confidential industry research, the EPA reapproved glyphosate. The EPA’s assessment contradicts a 2015 World Health Organization analysis of published research that determined glyphosate is a probable carcinogen.

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Delta f perss

 

Adam-Famoso-01-DFP-BRobb Brad Robb
Dr. Adam Famoso, talks to rice growers about the latest breeding efforts from the scientists and researchers at the LSU AgCenter in Rayne, La., during its recent rice field day.

New LSU rice breeding strategies include genetic markers

Dr. Adam Famoso provides insight into what growers are learning about Provisia Rice System during its first year of commercial availability.

Brad Robb | Jul 23, 2018

The LSU AgCenter has a long history of rice breeding success. At its recent field day at the H. Rouse Caffey Rice Research Station in Rayne, La., area rice farmers heard the latest performance data on the Clearfield Rice Production System, the Provisia Rice System, and what growers can expect from both systems and their impact on the future U.S. rice production.

One presentation was given by Dr. Adam Famoso, who joined the staff of the H. Rouse Caffey Rice Research Station in May 2015. Famoso is not only developing breeding strategies for the station, he is also carrying the breeding program into the next generation of breeding technology, including the use of genetic markers.

He has begun incorporating DNA marker-based selection by genotyping the rice varieties of the future through DNA analysis prior to the standard field testing. “We are working to build upon the strong breeding foundation in place at the LSU AgCenter by integrating molecular tools to accelerate the release of the best varietal lines for our growers,” says Famoso.

Breeding Traits

Famoso provided some insight into what growers are learning about Provisia Rice System — the first herbicide-tolerant system released since the Clearfield Production System was released 15 years ago — during its first year of commercial availability.

“It always takes a few steps in the breeding process to increase the performance of the new herbicide-resistant varieties when the technology is being incorporated from unadapted material, as we work to get them to the point where our adapted varieties are today,” says Famoso.

“We have to look for specific traits in thousands of lines and select for things such as maturity, height, and grain quality to increase a variety’s commercial value to a producer. That’s what had to be done with PVL01.”

Despite being a little lower yielding than the varieties released under the Clearfield designation, PVL01 is exhibiting some excellent qualities like low chalk and a nice long grain.

“Similar to the Clearfield varieties when they were first released, we expected a little yield drag,” adds Famoso. “After 10 years of breeding though, the Clearfield varieties are the highest-yielding on the market today.”

Another Provisia

Famoso and the rest of the scientists have been analyzing data from another Provisia line, PVL108. It has improved characteristics over PVL01 like better milling and yield.

“In addition to having very low chalk, PVL108 has shown a 10 percent yield advantage over PVL01 in three years of statewide testing,” says Famoso. “That is pretty significant.”

PVL108 is maturing a week earlier than PVL01 — a trait which Louisiana rice producers prefer, especially now that hurricane season has begun. “The earlier we can get a rice variety to mature, the less risk our growers will have to assume toward the end of the year,” says Famoso.

Although longer-maturing varieties typically yield more, in the balance of all things, farmers in the line of fire from hurricanes know earlier is better.

While PVL108 has some yield and earliness advantages, it is 2 inches taller than PVL01. Shorter plant height is preferred to reduce the risk of lodging. PVL108 also has a shorter grain than PVL01.

“One positive aspect of PVL01 is its long grain, although PVL108 is classified as a long grain variety, its grain length is slightly shorter than PVL01,” explains Famoso.

Seed increase

In the interests of time, efforts are under way to begin the necessary seed increase and purification for PVL108. “We started with a seed increase in Puerto Rico over the winter. We brought back 50 pounds of seed and planted it on 5 acres at 10 pounds an acre here at the research station,” explains Famoso.

“If we decide to move forward with this variety, we should have a good bit of seed available for seed production next year, and in producers’ fields for the 2020 growing season.”

Famoso knows the disease resistance in PVL108 is not as active as it is in CL153, but there are some materials currently in early-stage testing that are showing not only an improvement in yield, but also a much-improved resistance to blast.

“It’s our intention to release a new variety every two to three years that will chip away at some of the limitations we are seeing in these current Provisia varieties,” adds Famoso. “I’d like to see them perform up to the levels of the Clearfield varieties as quickly as possible.”

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UK: Herbicide resistance

Weeds out of control

Herbicides can no longer control the weeds that threaten crop productivity and food security in the UK because the plants have evolved resistance, and future control must depend on management strategies that reduce reliance on chemicals.

A nationwide epidemiological assessment of the factors that are driving the abundance and spread of the major agricultural weed, black-grass, was the focus of collaborative work led by the University of Sheffield, with Rothamsted Research and the Zoological Society of London.

The team mapped the density of black-grass populations across 70 farms in England, collecting seed from 132 fields. They also collected historical management data for all fields to address the question “which management factors are driving black-grass abundance and herbicide resistance?” Their findings are published in Nature Ecology & Evolution.

“At Rothamsted, we used glasshouse bioassays to determine that 80% of sampled populations were highly resistant to all herbicides that can be used for selective black-grass control in a wheat crop,” says Paul Neve, a weed biologist and leader of Rothamsted’s strategic programme, Smart Crop Protection.

“Field monitoring indicated that the level of resistance to herbicides was correlated with population density, indicating that resistance is a major driver for black-grass population expansion in England,” notes Neve.

He adds: “We found that the extent of herbicide resistance was primarily dictated by the historical intensity of herbicide use, and that no other management factors had been successful in modifying this resistance risk.”

The research team also surveyed farmers about their use of herbicides, and about how much their different approaches cost them. The team found that the increased weed densities lead to higher herbicide costs and lower crop yields, resulting in significant losses of profit.

Increasing resistance is linked to the number of herbicide applications, and mixing different chemicals or applying them cyclically did not prevent resistance developing, the team report.

Current industry advice urgently needs to change to reflect this, the researchers conclude. They recommend that farmers switch to weed-management strategies that rely less on herbicides, as it is inevitable that weeds will overcome even new agents.

Read the paper: The factors driving evolved herbicide resistance at a national scale.

Article source: Rothamsted Research.

Image credit: Rothamsted Research

 

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Cornell Chronicle

Beneficial soil bacteria face a weed-killing threat from above

Blaine Friedlander

Media Contact

Lindsey Hadlock

As farmers battle in their above-ground war on weeds, they may inadvertently create underground casualties – unintentionally attacking the beneficial bacteria that help crops guard against enemy fungus.

Cornell researchers have found an agricultural conflict: negative consequences of the weed-killing herbicide glyphosate on Pseudomonas, a soil-friendly bacteria.

“Beneficial Pseudomonas in the soil can help crops thrive. They can produce plant-stimulating hormones to promote plant growth and antifungals to defeat problematic fungi – such as Pythium and Fusarium – found in agricultural soil, but previous studies reported that the abundance of beneficial bacteria decreased when the herbicide glyphosate seeps underground,” said Ludmilla Aristilde, assistant professor of biological and environmental engineering. “Our study seeks to understand why this happens.”

Soil bacteria require their proteins – composed of amino acids – and their metabolism to support cellular growth and the production of important metabolites to sustain their underground fight. But glyphosate applied to crops can drain into the soil and disrupt the molecular factories in the bacterial cells in some species, interfering with their metabolic and amino acid machinery.

The new findings show that glyphosate does not target the amino acid production and metabolic gadgetry equally among the Pseudomonas species. For example, when Pseudomonas protegens, a bacteria used as a biocontrol agent for cereal crops, and Pseudomonas fluorescens, used as a fungus biocontrol for fruit trees, were exposed to varying glyphosate concentrations, the researchers noted no ill effects. However, in two species of Pseudomonas putida, used in soil fungus control for corn and other crops, the bacteria had notably stunted growth, said Aristilde, who is a faculty fellow at Cornell’s Atkinson Center for a Sustainable Future.

“Thus, if a farmer is using Pseudomonas fluorescens as a biocontrol, then it is probably okay to use glyphosate,” Aristilde said. “But if the farmer uses Pseudomonas putida to control the fungus in the soil, then glyphosate is more likely to prevent the bacteria from doing its job.”

The study offers molecular details for why glyphosate adverse effects on Pseudomonas are species-specific. “That’s actually good news because – as a society – we will likely not stop using herbicide completely,” said Aristilde. “If that is the case, farmers need to know which beneficial soil biocontrol they’re using can be susceptible. If they’re using a strain that is susceptible and conflicting with their herbicide application, then it is a problem. That’s the bottom line.”

Aristilde will present this research to farmers and agricultural professionals Nov. 14 at the Agriculture, Food & Environmental Systems In-Service training hosted in Ithaca by Cornell Cooperative Extension.

Glyphosate-Induced Specific and Widespread Perturbations in the Metabolome of Soil Pseudomonas Species” was published in Frontiers of Environmental Science in June 2017. Co-authors are Michael Reed ’17; graduate student Rebecca Wilkes; Tracy Youngster, M.S. ’17; Matthew Kukurugya, M.S. ’17; Valerie Katz ’18; and Clayton Sasaki ’18. The research was funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture; the National Science Foundation; and the Academic Venture Fund at Cornell’s Atkinson Center for a Sustainable Future.


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Blaine Friedlander

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  • Bloomberg

Pesticide ‘Drifting’ Wreaks Havoc Across U.S. Crops

Photographer: Daniel Acker/Bloomberg

Pesticide ‘Drifting’ Wreaks Havoc Across U.S. Crops

‎August‎ ‎1‎, ‎2017‎ ‎4‎:‎04‎ ‎PM‎ ‎CDT ‎August‎ ‎2‎, ‎2017‎ ‎9‎:‎58‎ ‎AM‎ ‎CDT
  • Missouri, Tennessee, Arkansas have placed curbs on dicamba use
  • At least 2.5 million soy acres are impacted, researcher says

Larry Martin in Illinois says he’s never seen anything like it in his 35 years of farming. Arkansas soybean grower Joe McLemore says he faces the loss of his life savings.

They’re among farmers across the U.S. suffering from a pesticide “drifting” across from neighboring fields onto their crops, leaving behind a trail of damage. Although not a new problem, it’s re-emerged with a vengeance this year. At least 2.5 million acres (1 million hectares) have been damaged in this growing season through mid-July, according to estimates from Kevin Bradley, a professor of plant sciences at the University of Missouri.

Dicamba, the offending herbicide, is produced by seed and crop-chemical giants Monsanto Co., DuPont Co. and BASF SE. It’s been around for decades, but in recent years it gained a new lease of life after the companies developed new dicamba-resistant soybean and cotton seeds, allowing farmers to spray crops later in the growing process.

Dicamba is fine if you’re growing those genetically modified varieties, but not if you’re cultivating others and the chemical wafts over from another farm. The situation is so bad that states including Missouri, Arkansas, and Tennessee have placed restrictions on dicamba use at various times during the summer.

Martin, a third-generation farmer, says an 80-acre soybean field of his has been damaged by dicamba. McLemore, who started out on his own eight years ago, after two decades working on someone else’s farm, says 800 of his 1,026 acres of soybeans have suffered damage.

Stunted, Wrinkled

“I’m not really trying to whine or anything, but it’s my life savings on the line every year,” he said by phone.

 McLemore is among a group of growers that have filed a lawsuit in a federal court in Missouri against BASF, Dupont and Monsanto for compensation. Monsanto spokeswoman Christi Dixon said the suit is without merit, while BASF spokeswoman Odessa Hines said it’s reviewing the claim. Dupont spokeswoman Laura Svec said the company hasn’t seen the lawsuit and so can’t comment on it.

Non-resistant crops are left stunted with wrinkled leaves after coming into contact with dicamba. Frustratingly, there’s no way to gauge the impact of yield until the fall harvest, farmers and researchers say. And it’s not always clear where the chemical might have come from — McLemore says that, in his case, he can’t be sure. That leaves farmers angry but also unsure whether to blame neighbors or herbicide manufacturers, said Aaron Hager, a weed scientist at the University of Illinois.

Farmers planted 20 million acres of dicamba-resistant soybeans and 5 million acres for cotton this year, executives at St. Louis-based Monsanto said in a telephone interview Monday. The company attributes the drifting problem to farmers using illegal, off-label products that are more volatile — and thus more prone to drift — than the latest versions of dicamba. They may also be cleaning or using their spraying equipment incorrectly, or applying dicamba when it’s windy, said Robb Fraley, executive vice president and chief technology officer.

Monsanto, which is being acquired by Germany’s Bayer AG, says employees are out in the fields talking to farmers about the problem. Fraley said farmers want better weed-control tools, such as dicamba product, and that the company will learn lessons from what’s happened this season. “There’s always a few challenges in launching new technology,” he said.

Germany’s BASF referred questions on dicamba to a recording of a July 19 media briefing that cited possible explanations for drifting similar to those outlined by Monsanto.

“This year thousands of growers have used these products properly and successfully meeting their challenges with resistant weeds and productivity,” said Svec at DuPont, which has a supply agreement with Monsanto for the herbicide.

The Environmental Protection Agency says it’s reviewing the situation.

“EPA is very concerned about the recent reports of crop damage related to the use of dicamba in Missouri, Arkansas and other states,” an EPA spokesperson said in an emailed statement. “We are working with the states and the registrants to better understand the issue. We are reviewing the current use restrictions on the labels for these dicamba formulations in light of the incidents that have been reported this year.”

While farmers typically look to federal crop insurance for a myriad of issues, problems with dicamba aren’t covered, according to the Risk Management Agency. Country Financial, a farm insurer, based in Bloomington, Illinois, has seen an increase in the number of dicamba-related inquiries, said company spokeswoman Alexandrea Williams. Martin, the Illinois farmer, says he’s not confident his insurance coverage will pay out.

“This is the craziest thing I’ve ever seen,” he said in a telephone interview. “You know you’re going to have a loss of income.”

— With assistance by Jeff Wilson

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2 PPOresistant pigweeds confirmed in Arkansas Tennessee MidSouth weed specialists have been warning that pigweeds ndash already often resistant to multiple chemistries ndash were in danger of developing resistance to PPO chemistry Those warnings have proven prophetic

The resistance treadmill – how do we get off?

Weed scientists say we can’t keep replacing one resistant herbicide with another.

Forrest Laws | May 12, 2017

How long will it take Palmer amaranth to become resistant to the new formulations of dicamba and 2,4-D that have been approved to be applied over the top of dicamba- and 2,4-D-tolerant cotton and soybeans?

That depends on what growers do to protect the new technologies, according to Bob Scott, a University of Arkansas Extension weed scientist and a speaker at the Pigposium 3 herbicide resistance meeting in Forrest City, Ark.

“If we follow on the resistance path that we’ve been following, and we just come in here and add dicamba to take care of this problem (PPO inhibitor resistance), what do you think is going to happen?” Dr. Scott asked. “We’re just going to add to our list of resistant weeds. We’re going to add dicamba to the growing list of resistance.”

Dr. Scott traced the history of the development of herbicide resistance in Palmer amaranth or pigweed in soybeans, beginning with Prowl and Treflan in the 1980s, the ALS herbicides such as Scepter in the 1990s, glyphosate in the 2000s and

the PPO inhibitor herbicides such as Reflex and Flexstar since 2010.Extension weed scientists at the University of Arkansas have already demonstrated how quickly resistance could develop to dicamba, the active ingredient in the new Xtendimax, Engenia and FeXapan herbicide formulations.

Three generations

“We proved this in a laboratory where this particular population of pigweed in just three selections using sub-lethal doses was not controlled with 16 ounces of dicamba,” Dr. Scott noted. “So we just proved that it can happen if we don’t do something to address herbicide resistance, and we’re not proactive in managing this from Day one.”

He had some words of warning about glufosinate or Liberty, which is one of the few remaining herbicides that can be applied postemergence to control pigweed – in Liberty Link cotton and soybeans.

“The last herbicide that’s put on the field is where the selection pressure occurs,” he said. “I had somebody ask me the other day about planting Liberty Link beans and putting Prefix or Zidua down and using Liberty post. But that last application they’ve been putting out has always been Liberty post, right?

“So they said ‘Is that a good enough reason to rotate to Xtend beans?’ and I said ‘absolutely.’ It’s a good reason to rotate chemistry. If it’s been working, change it. We have to rotate to change that last selection pressure that goes on that field.”

Farmers in northeast Arkansas have about a 50 percent chance of encountering resistance to PPO inhibitor herbicides in their fields in 2017, according to Jason Norsworthy, professor of weed science at the University of Arkansas and one of the organizers of the Pigposium.

Multiple resistance

But some growers are having to deal with Palmer amaranth populations that are not only resistant to PPO inhibitors but to three other groups of herbicides, as well, said Dr. Norsworthy, who holds the Elms Farming Chair of Weed Science at the U of A.

“In 2015, this field near Gregory in Woodruff County was found to contain resistance not only to the PPO inhibitor or Group 14 herbicides, but also to the ALS chemistries (Group 2), the dinitroanilines, things like Treflan and Prowl (Group 3), and Roundup (glyphosate – Group 9,” he said, referring to a field overgrown with pigweed.

“This was actually a conventional soybean field. Bob Scott did research in this field in 2015. And when you take a look at this population, we’re unable to grow Roundup Ready or conventional soybeans in this field because there is no effective postemergence option for the control of a pigweed population that has PPO resistance as well as glyphosate resistance.”

Weed scientists have now documented resistance in Palmer amaranth to the PPO inhibitor class of herbicides in seven states – Arkansas, Mississippi, Tennessee, Missouri, Illinois, Kentucky and Indiana. Norsworthy said 19 counties in Arkansas have confirmed PPO resistance.

“If you had any Palmer amaranth in one of your fields at harvest in 2016, you have better than a 50 percent chance that you have PPO-resistant Palmer in your fields,” said Dr. Norsworthy. “Folks, this is spreading, and it is spreading no different than what we saw with glyphosate. We are quickly losing one of the mainstays, especially in soybeans, from a weed control standpoint.”

Better than 50 percent

He displayed a slide of a bench top containing plants from about 40 different populations of Palmer amaranth. The plants were sprayed with 1.5 pints of Flexstar when they were about 1-inch tall.

“Anything you see that is still alive on this bench top (40 to 50 percent of the plants) would be resistant to the PPO chemistry,” he said. “Research has been conducted that shows the resistance mechanism is very similar to what you see in waterhemp in the Midwest. However, there are other PPO resistance mechanisms in this population that are much more resistant to the PPO chemistry than in some of the other pigweeds out there like waterhemp.”

Dr. Scott said that once resistance occurs that herbicide is lost to producers whether it’s glyphosate, Treflan or Flexstar.

“There’s no fitness penalty for the most part,” he said. “Some resistances have fitness penalties – the weed is damaged by the herbicide so it’s less competitive – but in pigweed it just seems to make it stronger the more resistant it gets.”

The threat of multiple resistance or resistance to more than one class of chemistry is frightening, Scott says. “I’ve had people calling me wanting to know where they can buy a good hoe, and that’s not my idea of weed science.”

Change it if it’s working

He said overlapping residual herbicides, rotating chemistries – even when the current herbicide is working – and using cultural practices will all be needed to preserve any new chemistries or traits growers may get in the years ahead. And growers need to treat the new traits – Xtend, Enlist and the new Balance trait that is expected to be approved in the near future – as if they were new herbicide chemistries.

Dr., Scott also called on herbicide manufacturers to help growers “do the right thing” economically when it comes to helping growers avoid overusing the currently available herbicide tools.

To read more about herbicide resistance-fighting efforts, click on http://www.deltafarmpress.com/cotton/odds-not-arkansas-growers-favor-ppo-herbicides-2017

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