The long term study updated the previous evaluation of glyphosate with cancer incidence, and is part of the Agricultural Health Study (AHS), a large and important project that tracks the health of agricultural workers and their families.
Led by AHS principal investigator Laura Beane Freeman, the study results state that among 54,251 applicators studied, 44,932 (82.8 percent) used glyphosate. "Glyphosate was not statistically significantly associated with cancer at any site," the study said. For the full story, click here.
The latest innovation to join Bayer’s leading fungicide family, Prosaro XTR offers high protection for grain quality like Prosaro (retaining prothioconazole and tebuconazole), with an enhanced formula to help plants metabolize and remove stressors faster, delivering a healthier and higher yielding crop.
“At Bayer, we are committed to supporting growers in their efforts to safeguard the world’s food supply. Achieving maximum yield potential, without compromising on quality and disease control is a priority,” said James Humphris, Crop Manager, Cereals at Bayer. “Prosaro XTR delivers the high protection for grain quality that growers trust in Prosaro, in a new enhanced formulation that delivers increased yield.”
Recent Prosaro XTR trials in wheat demonstrated an impressive +2.0 bu./ac. yield advantage over the industry leading Prosaro and a +2.6 bu./ac. increase in barley. Ten years of field-scale cereal fungicide trials continue to show that application at head timing delivers the best results in terms of yield and quality.
“Prosaro XTR delivers exceptional foliar and head disease control,” said Humphris. “Application at head timing continues to offer growers the best of both worlds: protection of the flag leaf and of the head during the critical grain fill period, and peace of mind they are doing the most to protect the yield and quality of their crop.”
Prosaro XTR delivers the same performance, handling and stability attributes of the current Prosaro formulation. In addition to being registered on wheat, barley and oats, growers will be able to apply Prosaro XTR on rye, triticale and canary seed.
For more information regarding Prosaro XTR, growers are encouraged to talk to their local retailer or visit cropscience.bayer.ca/ProsaroXTR.
In an effort to shine a light on the current status of herbicide resistance in Canada, Top Crop Manager (TCM) has launched the Herbicide Use Survey!
As an industry leader providing up-to-date information and research, TCM is looking to gather input from producers across the country in order to develop a more thorough understanding of the state of herbicide resistance in Canada.
TCM’s Herbicide Use Survey will offer participants the ability to help tell the story of these important crop protection tools by having farmers like you share how herbicides are being used.
The survey takes less than 10 minutes to complete, and will ask details like soil and farm acreage, types of weeds being targeted, as well as management practices. All submissions will remain anonymous.
Those who complete the survey will be entered into a random draw for a $500 visa card! Complete the survey here.
The Herbicide Use Survey ends December 8th. Results will be collected and presented at the 2018 Herbicide Resistance Summit in Saskatoon, Sask., on February 27 and 28.
Don't forget to Sign up for the TCM E-Newsletter to stay informed.
With Climate’s analytics-based digital tools, more Canadian farmers will be able to harness their data in one connected platform to identify and more efficiently manage variability in their fields, tailoring crop inputs to optimize yield and maximize their return on every acre.
In September 2016, the company first announced the introduction of the Climate FieldView platform in Eastern Canada, where hundreds of farmers across nearly one million acres have been experiencing the value of data-driven, digital tools on their operations.
Now, farmers in Manitoba, Saskatchewan and Alberta will have the ability to use the Climate FieldView platform to uncover personalized field insights to support the many crucial decisions they make each season to enhance crop productivity.
“The Climate FieldView platform is a one-stop shop for simple field data management, helping Canadian farmers get the most out of every acre,” said Denise Hockaday, Canada business lead for The Climate Corporation. “Through the delivery of the platform’s powerful data analytics and customized field insights, farmers across Canada have the power to tailor their agronomic practices more precisely than ever before, fine tuning their action plans for the best outcome at the end of the season.”
Over the past year, the Climate FieldView platform had a strong testing effort across many farm operations in Western Canada, enabling the Climate team to further develop the platform’s compatibility with all types of farm equipment and crops, including canola and wheat, to collect and analyze field data from multiple sources.
“Part of the challenge with data is managing all of the numbers and having an adequate cloud system to store and effectively analyze the information,” said farmer D’Arcy Hilgartner of Alberta, who participated in testing the Climate FieldView platform on his operation this season. “The Climate FieldView platform instantly transfers the field data gathered from my farm equipment into my Climate FieldView account, which is especially useful during harvest season because I’m able to see where various crop inputs were used and analyze the corresponding yield. I’ve really enjoyed having this digital platform at my disposal, and I’m excited to see the positive impacts on my business this coming year.”
As Climate continues to expand its digital technologies to help more farmers access advanced agronomic insights, additional new data layers will feed the company’s unmatched R&D engine, ultimately enabling the development of valuable new features for farmers in the Climate FieldView platform.
In August 2017, the company announced the acceleration of R&D advancements through the company’s robust innovation pipeline, along with new product features and enhancements to help farmers manage their field variability more precisely than ever before.
Launched in 2015, the Climate FieldView platform is on more than 120 million acres with more than 100,000 users across the United States, Canada and Brazil. It has quickly become the most broadly connected platform in the industry and continues to expand into new global regions.
Climate FieldView Platform Offering in Western Canada
- Data Connectivity - Farmers can collect, store and visualize their field data in one easy-to-use digital platform through the Climate FieldView Drive, a device that easily streams field data directly into the Climate FieldView platform. FieldView Drive works with many tractors and combines across Canada, in addition to anhydrous applicators and air seeders, helping farmers easily collect field data for the agronomic inputs they manage throughout the season. Recently, The Climate Corporation announced a new data connectivity agreement with AGCO, providing more farmers even more options to connect their equipment to the Climate FieldView platform. In addition to the FieldView Drive, farmers can connect their field data to their Climate FieldView account through Precision Planting LLC's monitors, cloud-to-cloud connection with other agricultural software systems such as the John Deere Operations Center, and through manual file upload.
- Yield Analysis Tools - With Climate’s seed performance and analysis tools, farmers can see what worked and what didn’t at the field level or by field zone, and apply those insights to better understand field variability by quickly and easily comparing digital field maps side-by-side. Farmers can save regions of their fields in a yield-by-region report and can also save and record a field region report through enhanced drawing and note taking tools, retrieving the report at a later date for easy analysis on any portion of their field to better understand how their crops are performing.
- Advanced Field Health Imagery - Through frequent and consistent, high-quality satellite imagery, farmers can instantly visualize and analyze crop performance, helping them identify issues early, prioritize scouting and take action early to protect yield. Climate's proprietary imagery process provides consistent imagery quality and frequency by using high-resolution imagery with vegetative data from multiple images, in addition to advanced cloud identification. Farmers can also drop geo-located scouting pins on field health images and navigate back to those spots for a closer look, or share with agronomic partners.
- Seeding and Fertility Scripting - Farmers can manage their inputs to optimize yield in every part of their field with manual variable rate seed and fertility scripting tools. Through Climate’s manual seed scripting tools, farmers can easily create detailed planting plans for their fields to build a hybrid specific prescription tailored to their unique goals, saving time and improving productivity. Additionally, Climate offers a manual fertility scripting tool, enabling farmers the ability to optimize their inputs with a customized management plan for nitrogen, phosphorus, potassium and lime tailored to their unique goals.
2018 Availability and Pricing
The Climate FieldView platform is currently available for purchase in Western Canada on a per-acre basis so that farmers can begin using it on their farms in time for the 2018 growing season. To experience the complete value of the platform throughout the entire growing season, farmers should sign up for a Climate FieldView account by Jan. 1, 2018. For more information about the Climate FieldView platform and pricing, contact Climate Support at 1.888.924.7475 or visit www.climatefieldview.ca.
Click here to read more and for three top tips to make the most of this application window.
It then uses software to identify what's a plant and what's a weed and turn the sprayer on and off to target the weeds. This summer's work was the start of a five-year project, researchers are hoping to do field-scale demonstrations by year three. READ MORE
Documents seen by Reuters show how a draft of a key section of the International Agency for Research on Cancer’s (IARC) assessment of glyphosate - a report that has prompted international disputes and multi-million-dollar lawsuits - underwent significant changes and deletions before the report was finalised and made public. For the full story, click here.
Christian Willenborg, associate professor with the College of Agriculture and Bioresources at the University of Saskatchewan, initiated a small study in 2015 to collect some initial research data and find a way to lend science to the decision-making process.
“We were surprised at the announcement that some milling quality oats would not be accepted if treated with glyphosate, and frankly, this didn’t sit well with me. But there was no science on this and so we immediately established a one-season ‘look-see’ trial in 2015 at two locations near Saskatoon to compare different harvest systems and their effects on quality of milling oats,” he says. “We compared two different oat cultivars: CDC Dancer, a medium maturity cultivar, and AC Pinnacle, a later maturing cultivar. The oats were managed using typical agronomy practices, including a seeding rate of 300 seeds per square metre (seeds/m2) targeting 250 plants per square metre (plants/m2) and fertilized for a target yield of 150 bushels per acre.”
The second factor was a comparison of three different harvest systems, including swathing at the optimum timing of 35 per cent moisture, direct combined (at approximately nine per cent seed moisture content alone and direct combined with a pre-harvest glyphosate application. The pre-harvest glyphosate was applied according to label requirements at 30 per cent seed moisture content using the recommended label rate. The project compared various harvest quality parameters, as well as functional quality characteristics and residue testing across the different treatments.
Through funding from the Prairie Oat Growers Association and the Saskatchewan Agriculture Development Fund, the initial 2015 trial has been expanded into a fully funded, much larger three-year project that will involve several additional experiments.
“We gained some very good insights in the initial trial, but these very preliminary results will be compared again in this larger expanded trial over the next three years. Until we get the final results at the end of 2018, these early one-season informational highlights have to be considered very preliminary,” Willenborg says.
The 2015 preliminary results showed that, as expected, cultivar had an impact on all of the quality parameters, such as yield, plump kernels, 1,000 kernel weight and test weight. However, there was no cultivar by harvest system interaction – the effects of the harvest system were consistent regardless of which cultivar was planted.
“The harvest system did have an impact on several of the quality parameters, however the preliminary results did not show any negative effects of a pre-harvest glyphosate application,” Willenborg explains. “In terms of yield, swathing resulted in a 15 to 18 per cent yield reduction compared to direct harvest, however some of that reduction may be a function of our plot harvesting equipment, and this may be different with field-scale grower systems. The direct harvested plots, with and without a pre-harvest glyphosate treatment, had virtually equal yield. Swathing produced the highest test weight, with direct harvest plus pre-harvest glyphosate equal to the swathing treatment; direct harvest with no glyphosate had a significant lower test weight.”
The swathing treatment also produced the highest percentage of thin kernels, with direct harvest and no glyphosate intermediate and the lowest percentage of thin kernels with direct harvest plus glyphosate treatment. On the other hand, the percentage of plump kernels was the same in both direct harvest treatments, but slightly lower for the swathing treatment. Overall, the pre-harvest glyphosate reduced the percentage of thin kernels in the sample, which is a benefit for growers.
“For the initial and longer term project, we partnered with Dr. Nancy Ames at Agriculture and Agri-Food Canada to compare the functional aspects of the oat cultivars under the different treatments,” Willenborg says. “Her preliminary functional test results were similar to the seed quality results, with no major impacts on functional quality among the treatments. For the glyphosate testing, we partnered with Dr. Sheryl Tittlemier at the Canadian Grain Commission to develop a glyphosate residue test for oat. Her initial test results from the 2015 treatments showed that the direct harvest plus pre-harvest glyphosate treatment did have very small levels of residues at four [parts per million], which is well below the MRL threshold levels in North America. We will continue to use this test for the larger project.”
The expanded three-year study will include the same harvest treatments, with some additional trials assessing seeding rate and stand uniformity. Stand uniformity is related to the question of whether or not additional tillers in the stand may be a factor with potential glyphosate issues. The three harvest treatments will also be compared at a range of different moisture contents, from 10, 20, 30, 40, 50 and 60 per cent at the time of swathing, or direct harvest alone and direct harvest plus pre-harvest glyphosate.
Willenborg will also be investigating alternative cultural and herbicide combinations for managing perennial weeds in oat. The full analysis and final project results will be available in 2019, including seed quality and functional analysis.
“So far it doesn’t appear that glyphosate is having an adverse effect on oat seed quality or functionality, and if anything is showing a small quality benefit to having glyphosate applied prior to harvest,” Willenborg says. “The key is to follow the label directions for pre-harvest application and make sure the crop is at 30 per cent moisture or lower, which corresponds roughly to the hard dough stage of development. All of our research treatments have been completed according to the label, but once you get off label in terms of timing we don’t know what will happen with glyphosate residues.
“For example, in some of our earlier work with lentil, the results were fine as long as label directions were followed, but as soon as application got off label in terms of timing and at higher moisture content, [that’s] where problems with quality and MRLs showed up. We expect that may be similar to oat, which is often harvested late in the season, when growers are between a rock and a hard place, with frost or heavy rains threatening harvest.”
Although it can be a challenge to apply glyphosate at the proper timing, there can be serious consequences due to not adhering to the label timing. Always follow the label, and check with your grain buyer about the acceptance of all pre-harvest and other product use and MRLs for all crops, including oats.
Setting a cut-off date, possibly sometime in the first half of 2018, would aim to protect plants vulnerable to dicamba, after growers across the U.S. farm belt reported the chemical drifted from where it was sprayed this summer, damaging millions of acres of soybeans and other crops.
A ban could hurt sales by Monsanto Co ( ) and DuPont which sell dicamba weed killers and soybean seeds with Monsanto’s dicamba-tolerant Xtend trait. BASF ( ) also sells a dicamba herbicide.
It is not yet known how damage attributed to the herbicides, used on Xtend soybeans and cotton, will affect yields of soybeans unable to withstand dicamba because the crops have not been harvested.
The Environmental Protection Agency (EPA) discussed a deadline for next year’s sprayings on a call with state officials last month that addressed steps the agency could take to prevent a repeat of the damage, four participants on the call told Reuters.
It was the latest of at least three conference calls the EPA has held with state regulators and experts since late July dedicated to dicamba-related crop damage and the first to focus on how to respond to the problem, participants said.
A cut-off date for usage in spring or early summer could protect vulnerable plants by only allowing farmers to spray fields before soybeans emerge from the ground, according to weed and pesticide specialists.
Monsanto spokeswoman Christi Dixon told Reuters on Aug. 23, the day of the last EPA call, that the agency had not indicated it planned to prohibit sprayings of dicamba herbicides on soybeans that had emerged. That action “would not be warranted,” she said.
The EPA had no immediate comment.
EPA officials on the last call made clear that it would be unacceptable to see the same extent of crop damage again next year, according to Andrew Thostenson, a pesticide specialist for North Dakota State University who participated in the call.
They said “there needed to be some significant changes for the use rules if we’re going to maintain it in 2018,” he said about dicamba usage.
State regulators and university specialists from Arkansas, Missouri, Illinois, Iowa and North Dakota are pressuring the EPA to decide soon on rules guiding usage because farmers will make planting decisions for next spring over the next several months.
Tighter usage limits could discourage cash-strapped growers from buying Monsanto’s more expensive dicamba-resistant Xtend soybean seeds. Dicamba-tolerant soybeans cost about $64 a bag, compared with about $28 a bag for Monsanto’s Roundup Ready soybeans and about $50 a bag for soybeans resistant to Bayer’s Liberty herbicide.
Already, a task force in Arkansas has advised the state to bar dicamba sprayings after April 15 next year, which would prevent most farmers there from using dicamba on Xtend soybeans after they emerge.
Arkansas previously blocked sales of Monsanto’s dicamba herbicide, XtendiMax with VaporGrip, in the state.
“If the EPA imposed a April 15 cut-off date for dicamba spraying, that would be catastrophic for Xtend - it invalidates the entire point of planting it,” said Jonas Oxgaard, analyst for investment management firm Bernstein.
Monsanto has projected its Xtend crop system would return a $5 to $10 premium per acre over soybeans with glyphosate resistance alone, creating a $400-$800 million opportunity for the company once the seeds are planted on an expected 80 million acres in the United States, according to Oxgaard.
By 2019, Monsanto predicts U.S. farmers will plant Xtend soybeans on 55 million acres, or more than 60 percent of the total planted this year. READ MORE
Fertilizer Canada is proud to announce the signing of a Memorandum of Understanding with the Agricultural Research & Extension Council of Alberta (ARECA) that includes integration of 4R Nutrient Stewardship (Right Source @ Right Rate, Right Time, Right Place®) into the province's Environmental Farm Plan (EFP). This agreement marks a significant milestone on Fertilizer Canada's journey to create truly sustainable and climate-smart agriculture in Canada.
"We are pleased that ARECA has officially recognized 4R Nutrient Stewardship as a best practice for nutrient management on Alberta farms," said Garth Whyte, President and CEO of Fertilizer Canada. "By encouraging farmers across the province to use fertilizer effectively, Alberta is joining the front lines in the fight against climate change and ensuring their place among the world's leaders in sustainable agriculture."
"ARECA is a long-time supporter and promoter of 4R Nutrient Stewardship," said Janette McDonald, Executive Director. "There is no doubt this formalized partnership with Fertilizer Canada will aid us in expanding awareness of the program as a best practice for nutrient management planning."
4R Nutrient Stewardship is a science-based nutrient management system that is universally applicable yet locally focused. By applying the right source of fertilizer at the right rate, the right time and the right place, farmers can ensure nutrients are efficiently taken up by their crops and are not lost to air, water or soil. This increases crop productivity and reduces unwanted environmental impacts.
Managed by ARECA, the province's EFP self-assessment process encourages producers to assess and identify environmental risks on their farms and take action to improve their practices.
"While Alberta's EFPs already include a section on nutrient risks, adding information about the positive long-term benefits of 4R Nutrient Stewardship will expand awareness among the province's farmers," said Paul Watson, EFP Director at ARECA.
As growers in Alberta adopt 4R Nutrient Stewardship under the Alberta EFP, the acres they manage will be counted under Fertilizer Canada's 4R Designation program, which tracks the amount of Canadian farmland using 4R Nutrient Stewardship to boost productivity and conserve resources. Fertilizer Canada aims to capture 20 million 4R acres by 2020 – representing 25 per cent of Canadian farmland – to demonstrate to the world the commitment Canada's agriculture sector has made to adopt climate-smart and sustainable farm practices.
To learn more about 4R Nutrient Stewardship and the benefits it offers, visit www.fertilizercanada.ca
Learn more about the Alberta Environmental Farm Plan and the benefits it offers by visiting www.AlbertaEFP.com
Tractors delivered participants to more than 10 sites at the 23rd annual Southwest Crop Diagnostic Day. The event, which took place July 5 and 6, saw agronomists, producers and industry professionals visiting stations across the University of Guelph’s Ridgetown campus to learn about new research and the implications for crops in Ontario.
Here’s a sampling of some of the topics covered.
Albert Tenuta [Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)] and Dave Hooker [University of Guelph – Ridgetown (UGR)] took producers through a few different plot sites and discussed planting corn and soybeans in a cover crop. Although cover crops help with soil organic matter, erosion and moisture control, it’s often best to terminate a cover crop in a dry year.
Peter Sikkema and Darren Robinson (both from UGR) tested participants on herbicide injury in both corn and soybean, respectively. Producers saw first-hand the symptoms caused by new and common herbicides.
Peter Sikkema holding a corn plant injured by herbicides.
Chris Brown (OMAFRA) and Doug Young (UGR) did a smoke bomb demo to highlight soil pores and offered tips for managing water movement through soil. Producers were reminded that soil pores (which include macropores, mesopores and micropores) are impacted by different issues such as soil properties (texture, pH), cultivation (tile drainage, crop rotations), external loads (tillage and compaction) and natural processes (biological activity, frost).
Joanna Follings and Anne Verhallen (both from OMAFRA) talked cover crop seeding rates and options for growers. They highlighted research that indicates underseeding red clover into winter wheat leads to an increase of 10 bushels per acre (bu/ac) for corn and five bu/ac in soybean.
One of the plots of red clover planted at UGR.
There’s also a nitrogen credit of 85 pounds per acre. Follings offered tips for seeding, since the biggest challenge with red clover is establishment. (A uniform stand of three to four plants per square foot is the minimum number to be considered a good stand.)
Another session offered an overview of trapping technology, scouting tips and management strategies for Western bean cutworm presented by Christina DiFonzo (Michigan State University), Tracey Baute (OMAFRA) and Art Schaafsma (UGR).
The Z Trap is one of the newest Western bean cutworm traps on the market.
When scouting, DiFonzo says to look at 100 plants (10 plants in 10 different areas, or 20 plants in five areas) every five days when crop is in the pre- to full tassel stages. The threshold to spray is an accumulation of five per cent of plants with Western bean cutworm egg masses or small larvae over a two to three week period.
Dave Bilyea (UGR) covered some lesser-known but potentially problematic weeds for Ontario agriculture. Some of the weeds highlighted include annual bluegrass (which competes with young plants and is tolerant to glyphosate) and dog strangling vine. There aren’t many reports of this vine yet, but it’s very competitive and is toxic to insects and animals, affecting ecology. Another weed to watch is wild parsnip, which makes skin UV-sensitive and results in burns similar to those caused by giant hogweed. With scouring rush (also known as snakegrass), part of the challenge is that the plant has no leaves for contact with any herbicides producers might spray.
Dave Bilyea explains the similarities between Northern willowherb and goldenrod.
Bilyea reminded growers that they can send in weeds for herbicide-resistance testing free of charge.
Jake Munroe and Horst Bohner (both of OMAFRA) focused on fertilizing soybeans: deficiency symptoms, strategies and new research demonstrating the importance of phosphorus in soybean. 4R nutrient stewardship was also highlighted using the Phosphorus Loss Assessment Tool for Ontario (PLATO).
Ben Rosser (OMAFRA) and Peter Johnson from Real Agriculture had participants digging up corn plants from a variety of plots to discuss the effects of planting dates, depth and staging.
Peter Johnson from Real Agriculture discussing the stages of corn development.
Hail damage in corn was also discussed using the example of a corn plant damaged just a couple of weeks ago. Although the farmer growing the corn in question thought he should plant something else, there was still new growth in the corn and so he was advised to leave the crop; he would likely only suffer a five per cent yield loss from the hail damage.
Jason Deveau and Mike Cowbrough (both of OMAFRA) highlighted the importance of sprayer clean out and compared two different systems: triple rinsing and continuous rinsing.
Deveau and Cowbrough explaining how a continuous rinse system works.
Growers walked through soybean and tomato plots and saw the level of injury caused when equipment isn’t properly rinsed between spray applications. Although triple rinsing is effective, it takes three times longer to do; the continuous rinse system is not only faster, but also limits operator exposure. The current challenge is adding the pump on the sprayer equipment due to challenges with the computer operating systems.
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Where are we in terms of integrated disease management (IDM)? What is IDM all about? Principally it’s about trying to make sure we use all the tools in the toolbox, integrating genetic resistance with chemical fungicides, cultural control and overall crop agronomy. When we sow the crop and how we look after it with nitrogen can profoundly affect how much disease pressure we’re under.
Getting it just right is never going to be easy. What’s happened in Australia? Before 2002, there wasn’t a huge amount of fungicide usage because it’s a much less responsive environment. Then we had an “exotic incursion.” Stripe rust came in from North America, probably on a grower’s boots. That changed the pendulum, from a dependence on genetic resistance to a reliance on fungicides, because, overnight, a huge proportion of all of the germplasm in Australia became susceptible to stripe rust.
Meanwhile in Europe, there was a totally different swing of the pendulum. It was inspired by a new set of varieties, in this case semi-dwarf varieties. With the new cultivars and more nitrogen, crops stayed greener for longer. Suddenly yields increased enormously in the ’70s. Higher yields and longer growing seasons in Europe drove growers to apply more and more fungicide. If you go to Europe now, it’s all about T1, T2 and T3 – Timing 1, Timing 2, Timing 3 with fungicides as a fixed part of crop agronomy. Up until 2005 in Europe, the pendulum had swung very much to the fungicide side of the IDM pendulum.
However, that’s all changed. In Europe, the profound driver for change has been fungicide resistance. Fungicide resistance influences everything that a European grower now does with fungicides. If there’s one thing that I think is really important to take on, it is that fungicide resistance – if it’s not affecting you now, it will be shortly unless you can moderate your use of fungicides.
What’s gradually happened over time is that we’ve got better products with greater activity, but at the same time fewer products based on limited modes of action. There are fewer products that are more and more environmentally benign, but at the same time at greater risk of resistance development. In other words, we’ve moved from multi-site fungicides that killed the fungus in many different ways to single-site fungicides that do less damage in the environment but actually are much more vulnerable to resistance.
Fungicide insensitivity and resistance
Fungicide insensitivity and resistance has occurred principally in two ways. In Europe in the late 1990s and early 2000s, strobilurins, such as pyraclostrobin and azoxystrobin, came along with the biggest media hype since glyphosate. However, after only three to four years, the pathogen causing powdery mildew and then Septoria tritici (now Zymoseptoria tritici) in wheat developed resistance to stobilurins, and that’s been a real challenge ever since. In two to three years, the strobilurins went from being the best products to control foliar diseases in broad acre cereals to products that wouldn’t work against Septoria, a disease that is widespread in northwest Europe. I think that’s when attitudes really changed and people started asking the question, “Is there a different way to control disease?”
We’re in our infancy with fungicide resistance issues in Australia. We can see it in the field with powdery mildew in barley. Our triazole fungicides such as Tilt (propiconazole), Folicur (tebuconazole), Proline (prothioconazole), Prosaro (prothioconazole and tebuconazole co-formulated) don’t work as effectively to control powdery mildew. With Septoria, we’re not yet seeing reduced activity in the field, but the samples are showing insensitivity in the laboratory, so there is increasing threat that we will see resistance to fungicides in the field.
Europe and triazole use
What has happened in Europe with the triazoles over the last 20 years is that triazole fungicides have gradually become less effective against key diseases, firstly not working as effectively in the lab and then gradually being noted to be less effective in the field. That’s why with triazoles I think it’s important to talk about “fungicide insensitivity” and not “fungicide resistance.”
For example, it’s taken 20 years of exposing the Septoria pathogen population to the triazoles for them to become less effective. They still have activity but are now only 60 to 70 per cent effective when it used to be 90 to 100 per cent. So in Europe the triazoles and the strobilurins become less effective and ineffective for key diseases in a similar time period, but the triazoles had been gradually degrading in their effectiveness over time.
Therefore with the terminology we use, I think it’s important to recognize we really have three basic modes of action that we use in broad acre cereal disease control – triazoles, strobilurins, and the new SDHIs [succinate dehydrogenase inhibitors].
With the triazoles I think it is probably more appropriate to call it “insensitivity” rather than resistance, since if you say to a grower, “It’s resistant,” the tendency is to think that it won’t work when in reality it is still partially effective.
With regard to the SDHIs, they’re not actually that new since the family of chemistry has been around for 40 years. But a new branch of SDHI chemistry is now taking Europe by storm, as the strobilurins now have less application because of resistance in key pathogens. But after only three years of commercial use with these new SDHIs, resistance is developing quickly in the net blotch and Septoria pathogens.
It’s really important to recognize that fungicide resistance is changing the way in which growers and advisors elsewhere in the world manage their cereal crops. In Australia, growers and advisors are just beginning on that resistance journey. You’ve already had some exposure in Canada to the fact that the strobilurins are at high risk of resistance development in the pathogen. It begs the question, “What can you do about it?”
Click here for part two: The importance of multiple modes of action and linking pathology with crop physiology.
Importance of multiple modes of action
I’m horrified to hear that you can apply straight strobilurin fungicide to your crops, since there’s no other mode of action in the application to protect you from pathogen mutants that might be strobilurin resistant. If you went back to when the strobilurins were breaking down to Ascochyta in some of your pulse crops, it’s worth asking yourself, wouldn’t it have been better to have been using them in combination with other older multi-site fungicides in order to give the strobilurins a degree of protection?
What’s now happening in Europe is that there’s a lot of dependence on the triazole fungicides since there is widespread resistance amongst a number of pathogens to strobilurins and increasingly to SDHIs. However it’s not the same with all pathogens. For example, the rusts – stripe rust, leaf rust – seem particularly stable. But with the necrotrophic diseases such as Septoria, such as net blotch, such as scald, populations are shifting. That stated, the triazoles remain the backbone of disease management programs all over the world.
It’s actually becoming more complicated for advisors in Europe. What’s happening is that different regions in Europe have different pathogen populations that are differentially susceptible to triazoles. What researchers are finding is that the triazole that works best in one area of Europe might not be the triazole that works best in another.
Now I know what you’re thinking: aren’t triazoles all from the same family of chemistry with the same mode of action? That’s where the resistance to these molecules is more complicated. For example, in one region, Folicur might not work very well on the Septoria pathogen, but a Tilt still does a reasonable job, depending on the history of fungicide use. Somewhere else in Europe, the exact reverse might be happening.
In Europe, they’ve set up a project called EuroWheat with 26 trials all across Europe examining triazole fungicides and their activity against key diseases, looking at not only what’s happening in the field in terms of foliar control, but then taking samples for lab analysis. It’s revealing that the pathogen is adapting in different regions differently, depending on what fungicides have been used, particularly the Septoria population.
We are now beginning to see the same thing with Septoria in Australia. Some products that are effective on the mainland of Australia don’t work well in Tasmania.
What can we do to protect fungicides going forward? We can minimize our use of them. Pick the best adapted, highest yielding, and most resistant varieties we can use. Such a choice might enable you to use just one fungicide application instead of two applications. In some parts of the world, there are guidelines advising using that active ingredient just once in a growing season. But probably the strongest message that comes out around the different regions of the world is the one about mixing different modes of action in cereal crops.
So think about fungicides as part of that integrated disease management package – use them, but don’t overuse them.
Across Europe at the moment, the new SDHIs are entering the market already mixed and formulated with a triazole in order to ensure the use of two modes of action in a fungicide application. “Make sure that you’re mixing different modes of action” is the strongest message that comes out of the scientific studies on fungicide resistance and it’s the one key take-home that I can give you. If you’re not mixing, ask why not.
There is one area that is important to clarify and that is with regard to fungicide rate and resistance. I don’t believe that there’s a lot of scientific evidence in the literature that suggests keeping fungicide rates high is a good anti-resistance strategy. Generally it is with herbicides, but I’m not sure that evidence exists for fungicides. Frank van den Bosch from Rothamsted in the U.K. did a literature search on 46 different fungicide studies and found there were more studies showing that increasing fungicide rate increased resistance selection pressure than the reverse. I think it’s more appropriate that we consider fungicide rate as an efficacy message, not a resistance message: i.e. what rate of fungicide is appropriate to obtain the best economic outcome. There are other things, like mixing our active ingredients with different modes of action, which are far more important in resistance management than considering fungicide rates.
Linking pathology with crop physiology
The other factor that is really important is linking our knowledge of pathology with crop physiology. Fungicides don’t only kill a disease, they keep plant leaves greener for longer, providing soil water is available to express the benefit of the disease free leaves. The upper leaves of the cereal crop canopy, particularly the top four, affect the ability of a plant to produce yield. In Australia, disease management strategies based on fungicides are particularly dependent on the presence of soil water to express the benefit of a fungicide both in terms of yield response and economic return.
One of the things from Europe that I think they have right is that they talk all the time about “What are the key parts of the plant to protect from disease?” If you’re growing a cereal crop, what do the individual leaves on that cereal crop contribute to yield? That’s an incredibly important part of any strategy using a fungicide. We use fungicides to make money, not just control disease, and what’s been really good in Europe is actually characterizing which parts of the plant are best to protect from disease.
When it comes to thinking about fungicides, don’t only think about the disease. The time of disease onset in the crop will determine to which leaves fungicides are applied. In Europe, set development timings trigger the questions. “Do we have the disease? Are the conditions conducive for the disease? What’s this crop going to yield?” These are key questions that link the effect of the disease with the physiology of the crop.
I think the key message when it comes to thinking about using fungicides as part of an integrated disease management package is to recognize that they’re not very effective at protecting tissue that’s not emerged at the time of application. Other than reducing overall inoculum in the crop, fungicides only directly protect the leaves and plant structures that are emerged at the time of application, so you need to target the most important leaves that contribute to yield.
The interaction of crop disease development and crop physiology is now a target for an Australian modelling team. In summary, it’s important to look at disease development and crop development together.
I’d like to finish off with a reference to future developments. The Magnetic Induction Cycler (MIC) is about the size of a four-litre pail. From leaf samples using MIC, you can determine the genetic makeup of the pathogen population, determining not only the presence of genetic mutations that might affect fungicide performance but also the frequency of the population with that mutation. In the future this technology will assist the advisor in making the right product choice for individual paddocks. That technology moving forward could be linked with automated spore traps informing us when pathogen spores are moving into the paddock, their genetic makeup and how that’s going to affect product choice.
Lastly, I believe RNA interference technology has the potential to produce the next phase of environmentally-friendly fungicides. The technology is based on short segments of nucleotide that are absorbed into the plant and pathogen, and which can switch off the RNA messenger before it can synthesize the proteins for fungal development in that plant. It is very specific technology and offers some great potential for disease management in the future.
Photo courtesy of Gary Peng.
There are three important things that can lead to an infection:
· there’s residue to harbour the pathogen inoculum
· you need to have early infection to get into the stem
· insect damage may help the infection to occur more severely.
The disease was very prevalent in the late ’80s, early ’90s. Then we introduced some resistant varieties in the early ’90s, which brought down the occurrence for many years. Partially that was resistance bred into varieties, but we also had three- or four-year rotations. That was a big part of the whole management effectiveness.
In the last five to six years, the disease incidence has been creeping back up to 20 to 25 per cent in Alberta and Manitoba, and about 10 per cent in Saskatchewan. However, the average severity remained below level 1 (light). Research by Sheau-Fang Hwang in Alberta indicates that in most years, this level of severity could result in a yield loss of about two to eight per cent on a susceptible variety. But from a trade perspective, our trading partners want to see the disease level trend going down.
Why the upward trend?
The first reason for an increase in blackleg incidence is likely the change of the pathogen population, which is adapting to the resistant varieties. The pathogen population may be becoming more virulent or with a greater proportion of virulent isolates in it.
Plant breeders have used major gene resistance to control the disease. The resistant gene blocks the infection by the pathogen carrying the corresponding avirulence gene. For example, an Rlm3 resistant gene would block the pathogen with avirulence AvrLm3 gene (abbreviated to Av3). It might be like a lock-and-key, but for some reason, over time, the Av gene may change and the resistant gene may not be able to recognize it.
My colleague, Randy Kutcher, looked at the change in pathogen populations in 2007 when he looked at the avirulent gene prevalence on the Prairies. In his work looking at 800 isolates of L. maculans, the percentage of Av2 and Av6 genes were very high in the population, and the others at more moderate to low levels. Further work in 2010 and 2011 with Dilantha Fernando at the University of Manitoba found the picture had changed quite a bit. The presence of the Av3 and Av9 genes had decreased quite a bit, but at the same time Av7 seemed to be increasing quite a bit. That means the Rlm3 gene would be less likely to be effective across the Prairies because the Av3 gene had changed mostly to the virulent type. The Rlm3 gene was first introduced back in early 1990s and has been used for over 20 years.
Other research in Fernando’s lab also looked at what resistant genes are present in 206 varieties/breeding lines in Western Canada. The resistance gene that was predominantly found was Rlm3 in around 70 per cent of the varieties/breeding lines. There was also a bit of Rlm1 detected as well. Overall, the diversity of R genes is still quite limited in the germplasm tested. The important message is that Rlm3 is not going to remain effective on the Prairies because the corresponding Av3 gene is already fairly low in the pathogen population.
However, when we looked at field data in Alberta and Manitoba, while the occurrence of other Av genes was high, disease levels ranged widely. This told us there was something else going on, which we called non-specific resistance in our varieties, although the effect was definitely less than the major gene resistance.
We further investigated this non-specific resistance in our varieties. We tested commercial varieties with a pathogen without a corresponding Av gene so any resistance observed would be due to non-specific gene resistance. Almost all the varieties had a slightly smaller amount of the disease on inoculated cotyledons than the susceptible Westar. At the same time, it’s a totally different kind of resistance reaction as opposed to the major gene resistance. It would not stop the infection completely – it just slowed it down a little bit, and on some varieties, substantially.
A further look at three of those varieties found the progress of plant mortality originated from cotyledon or petiole inoculation was somehow reduced, but varied between the varieties. Using a fluorescent protein gene labeled isolate, photography was able to show the reduced spread of the pathogen in the cotyledon compared to the susceptible Westar variety.
If you can slow down the movement from the cotyledon via the petiole into the stem, there may not be enough of the pathogen getting into the stem before the cotyledons drop off. This is one of the reasons that non-race-specific resistance works in some of those varieties we have.
Photo courtesy of Gary Peng.
Click here for part two: management strategies
This article is a summary of the presentation “Managing blackleg of canola in Western Canada,” delivered by Dr. Gary Peng, Agriculture and Agri-Food Canada, Saskatoon, at the Field Crop Disease Summit, Feb. 21-22, 2017. Click here to download the full presentation.
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The study, “Agricultural Landscape and Pesticide Effects on Honey Bee Biological Traits,” which was published in a recent issue of the Journal of Economic Entomology, evaluated the impacts of row-crop agriculture, including the traditional use of pesticides, on honeybee health. Results indicated that hive health was positively correlated to the presence of agriculture. According to the study, colonies in a non-agricultural area struggled to find adequate food resources and produced fewer offspring.
“We’re not saying that pesticides are not a factor in honeybee health. There were a few events during the season where insecticide applications caused the death of some foraging bees,” says Mohamed Alburaki, lead author and post-doctoral fellow with the University of Tennessee Department of Entomology and Plant Pathology (EPP). “However, our study suggests that the benefits of better nutrition sources and nectar yields found in agricultural areas outweigh the risks of exposure to agricultural pesticides.”
According to the study, hives located in areas with high to moderate agricultural vegetation grew faster and larger than those in low or non-agricultural areas. Researchers suggest the greater population sizes enabled better colony thermoregulation in these hives, as well.
Meanwhile, bees located in a non-agricultural environment were challenged to find food. Although fewer pesticide contaminants were reported in these areas, the landscape did not provide sustainable forage. In fact, during the observations, two colonies in the non-agricultural areas collapsed due to starvation.
Disruptions and fluctuations in brood rearing were also more notable in a non-agricultural environment. Interestingly, brood production was highest in the location that exhibited a more evenly distributed mix of agricultural production, forests and urban activity.
“One possible explanation for this finding could be the elevated urban activity in this location,” says Alburaki. “Ornamental plantings around homes or businesses, or backyard gardens are examples of urban activity that increase the diversity of pollen in an area. Greater pollen diversity has been credited with enhancing colony development.”
Researchers also evaluated trapped pollen from each colony for pesticide residues. Low concentrations of fungicides, herbicides and insecticides were identified, but at levels well below the lethal dose for honey bees. Imidacloprid was the only neonicotinoid detected, also at sub-lethal levels.
Agricultural pesticides, particularly neonicotinoids, are considered by some to be a key factor in declining honeybee populations. The UTIA study found that higher exposure to pesticides in agricultural environments did not result in measurable impacts on colony productivity.
This study was supported in part by the U.S. Department of Agriculture’s Agricultural Research Service Pest Management Program.
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