The late harvest in fall 2016 created more than just delays in crop removal – fields were dirty with weed growth and there was limited time for fall herbicide application. As a result, many farmers are expecting weedier fields this spring and will need to be diligent in using the best weed control strategies including pre-seed herbicides and the best in-crop solutions.

To assist farmers in what will likely be a more challenging spring battle with weeds, Dow AgroSciences has announced that the Diamond Rewards herbicide offer that was previously only available to Nexera customers will be open to all growers seeding any Roundup Ready and Clearfield canola varieties this spring.

Effectively immediately, with a minimum purchase of 240 acres (6 cases) of Eclipse, any Roundup Ready canola grower can qualify for the $2.00 per acre rebate. Similarly, with a minimum purchase of 240 acres (6 cases) of Salute, any Clearfield canola grower can qualify for the $2.00 per acre rebate.

Nexera canola growers will continue to receive the rebate with no minimum purchase requirement. Farmers must be registered for the Dow AgroSciences Diamond Rewards program and purchases must be made between December 1, 2016 and November 30, 2017 to qualify.

Click for more information on Eclipse and Salute.  
Published in Herbicides
Palmer amaranth is a nightmare of a weed, causing yield losses up to 80 percent in severely infested soybean fields. It has evolved resistance to six classes of herbicides since its discovery in the United States 100 years ago. And now, scientists have discovered it has two new tricks up its sleeve.

About a year ago, a group of researchers discovered Palmer is resistant to the herbicide class known as PPO-inhibitors, due to a mutation —known as the glycine 210 deletion — on the PPX2 gene.

“We were using a quick test that we originally developed for waterhemp to determine PPO-resistance based on that mutation. A lot of times, the test worked. But people were bringing in samples that they were fairly confident were resistant, and the mutation wasn’t showing up. We started to suspect there was another mechanism out there,” says University of Illinois molecular weed scientist Patrick Tranel.

Tranel and his colleagues decided to sequence the PPX2 gene in plants from Tennessee and Arkansas to see if they could find additional mutations. Sure enough, they found not one, but two, located on the R98 region of the gene.

“Almost all of the PPO-resistant plants we tested had either the glycine 210 deletion or one of the two new R98 mutations. None of the mutations were found in the sensitive plants we tested,” Tranel says.

Furthermore, some of the resistant plants had both the glycine 210 deletion and one of the new R98 mutations. Tranel says it is too early to say what that could mean for those plants. In fact, there is a lot left to learn about this resistance mechanism.

“We don’t know what level of resistance the new mutations confer relative to glycine 210,” Tranel says. “There are a lot of different PPO-inhibiting herbicides. Glycine 210 causes resistance to all of them, but we don’t know yet if the R98 mutations do.”

The team is now growing plants to use in follow-up experiments. Tranel hopes they will be able to determine how common the three mutations are in any given population. “That way,” he says, “when a farmer sends us a resistant plant and it doesn’t come back with the glycine 210 deletion, we will be able to tell him how likely it is that he’s dealing with another one of these mutations.”

In the meantime, other research groups or plant testing facilities could use the new genetic assay to detect the mutations in Palmer samples. Tranel hopes they will. “The more labs testing for this, the more we learn about how widespread the mutation is,” he says. 

The article, “Two new PPX2 mutations associated with resistance to PPO-inhibiting herbicides in Amaranthus palmeri,” is published in Pest Management Science. The work was supported by a grant from the USDA’s National Institute of Food and Agriculture.
Published in Corporate News
Just over 20 years ago, researchers initiated the first bioherbicide research and development program in the country at Agriculture and Agri-Food Canada (AAFC) in Saskatoon. Led by Karen Bailey (who recently retired), the program has made significant advancements in bioherbicide development for horticulture and turf crops, and more recently, promising solutions for agriculture. Bioherbicide product development is a welcome addition to the integrated weed management toolbox for crop production. Biopesticides are classified as “reduced-risk” products by the Pest Management Regulatory Agency (PMRA).
Published in Herbicides
Harvest weed seed control is a last-ditch line of defence against herbicide-resistant weeds in Australia and one many producers there would rather not have to deploy in the field.
Published in Harvesting
In 2013, two University of Guelph weed scientists began collaborating on alternatives to herbicides for weed control. The report, by Francois Tardif and Mike Cowbrough, was released in 2016.
Published in Weeds
Glyphosate-resistant (GR) waterhemp was first found in Ontario in 2014, but it already has a foothold in three counties in the southwest of the province. Fortunately, Peter Sikkema’s research group at the University of Guelph’s Ridgetown Campus has made a good start on finding effective options for controlling this challenging weed.
Published in Weeds
Originally from Asia, woolly cupgrass has been in the United States since about the 1950s and has caused problems in field crops across the corn belt. This annual grassy weed was first found in Canada in 2000, when it was discovered in Quebec. Since then, government agencies and producers have been working to prevent the weed from getting out of hand, and researchers have been learning about the weed and its management under Canadian conditions.
Published in Weeds
Another weed control tool bites the dust. A field in southwest Saskatchewan was confirmed to have Group 4-resistant kochia in the fall of 2015. The durum field had been sprayed with OcTTain herbicide (2,4-D and fluroxypyr; both Group 4 active ingredients) and it had little effect on the kochia population.
Published in Weeds
Glyphosate, the key ingredient in Monsanto Co's Roundup herbicide, should not be classified as a substance causing cancer, the European Chemical Agency concluded on Wednesday, potentially paving the way for its license renewal in the EU. | READ MORE
Published in Corporate News
Mississauga, ON – Corn growers in Eastern Canada now have a new tool for fast and hassle-free weed control. DuPont Crop Protection announced that approval has been granted for registration of DuPont Destra IS herbicide.

Destra IS is a post-emergence corn herbicide with one-pass broad-spectrum knockdown and residual control, and adds two additional modes-of-action to a glyphosate tolerant system – there’s also residual control and multiple modes of action. The herbicide will allow growers to control hard-to-kill broadleaf and grassy weeds and to keep corn weed-free during the critical weed-free period.

Destra IS has a wide window of application, allowing growers to apply up to the eight-leaf stage, with excellent crop safety and a broader geography, including short season areas. It offers a smaller, easy-to-handle package and compact dry formulation, and is the only dry mesotrione formulation on the market. It offers a faster pour and bottle cleanout.

Fore more information visit Dupont.ca
Published in Herbicides
The key to controlling tufted vetch in soybeans is to try to maximize control in all crops in the rotation and in all kinds of windows. That’s the advice of Mike Cowbrough, weed management specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). He has been investigating options for tufted vetch control for about 14 years so he knows just how difficult this weed is to conquer.
Published in Weeds
Full registration of the imidazolinone-tolerant (IMI-tolerant) chickpea system with recommended chickpea varieties and registered Solo herbicide is imminent. Two IMI-tolerant chickpea varieties – CDC Alma (Kabuli-type) and CDC Cory (Desi-type) – have already been developed. The Prairie Pesticide Minor Use Consortium has submitted the application for Solo herbicide use on IMI-tolerant chickpea to the Pesticide Management Regulatory Agency (PMRA) and registration could be received in early 2017.  
Published in Pulses
Weed control challenges are becoming even more difficult as the number of herbicide-resistant weeds in pulse crops continues to grow. With more than 60 unique cases of herbicide resistance identified in Canada and some weeds developing resistance to key pulse herbicides such as Pursuit (imazethapyr, Group 2) and Solo (imazamox, Group 2), the challenges will become even more daunting in the future.
Published in Weeds
A new factsheet from the Weed Science Society of America is now available for free download, exploring research of weed seed longevity. It highlights the unique ways weed seeds can travel (earthworms can collect and move them into their burrows), their viability (moth mullein seeds buried in 1879 were able to germinate more than 130 years later), ways they can be eliminated (carabid beetles can consume large quantities of weed seeds that drop to the soil) and more. Download the factsheet here and visit www.wssa.net for more information.
Published in Weeds
Bayer has announced the launch of Luxxur, a new wheat herbicide for controlling tough weeds, including wild oats and perennials.
Published in Corporate News
Dow AgroSciences plans to debut a new spring wheat and barley herbicide to help producers combat their most difficult annual and perennial broadleaf weeds.
Published in Corporate News

The Canadian Weed Science Society (CWSS) recently honoured several individuals for their extraordinary contributions to the field of weed science. The awards were presented during the organization’s 70th annual meeting, held this year in Moncton, N.B.

Fellow Award (sponsored by CWSS)
CWSS presented the Fellow Award – its highest recognition – to Eric Johnson, who was until recently a researcher employed by Agriculture and Agri-Food Canada in Scott, Sask. Johnson now works at the University of Saskatchewan. He is recognized internationally for his research on weed management, including his work on mechanical and chemical weed control. He is also active in the areas of organic production systems and cropping systems/agronomy. Johnson has been an author or coauthor on more than 80 peer-reviewed publications, seven book chapters, and multiple conference proceedings. He has maintained an active collaboration with the University of Saskatchewan where has taught a pesticides course, given more than 30 guest lectures, and has served on the supervisory committees of several MSc students. He has also served in various capacities within the CWSS/SCM, including as a board member for over 10 years, and as president in 2015. 

Excellence in Weed Science Award (sponsored by Dow AgroSciences)
CWSS honored Dr. Robert Gulden, an associate professor with the University of Manitoba in Winnipeg. Gulden's research focuses on weed biology and management. Dr. Gulden has served on the board of directors for CWSS/SCM and currently serves as an associate editor for the Canadian Journal of Plant Science. Gulden has published more than 60 peer-reviewed manuscripts, several monographs and book chapters, and supervised or co-supervised nine graduate students. In addition, he has received multiple awards for teaching excellence at the University of Manitoba.

Excellence in Weed Extension Award (sponsored by Valent)
CWSS honored Dr. Peter Sikkema, who has been involved in applied weed research and extension in field crops for the past 20 years at the University of Guelph, Ridgetown Campus. Sikkema has published more than 250 manuscripts in various national and international peer-reviewed scientific journals. He has presented more than 450 oral extension presentations in the province of Ontario, more than 50 extension poster presentations, written more than 70 popular extension articles, conducted more than 325 extension/research tours of weed management plots and has obtained more than 137 minor-use registrations through the Pest Management Regulatory Agency. He has also served in various capacities within the CWSS/SCM, including as president in 2011.

Outstanding Industry Member Award (sponsored by CWSS)
CWSS honored Al McFadden, research scientist with Dow AgroSciences, based in Guelph, Canada. McFadden has a strong track record of interaction with CWSS, CropLife Canada, and the Ontario Weed Committee (OWC), through various presentations at various scientific meetings. Al has served as the industry representative on the CWSS Board of Directors, the Ontario Provincial Council Chair of the Technical and Education and National Biology sub-committees of CropLife Canada, and was the industry representative for the Ontario Weed Committee. In addition to the various presentations he has given at various scientific society meetings, his name appears in peer-reviewed journal manuscripts based on his willingness to involve himself in graduate student training.

Presidential Award (sponsored by CWSS)
CWSS honored Dr. Rory Degenhardt, research scientist with Dow AgroSciences, based in Edmonton. His primary responsibilities are as biology team leader for Canadian Cereal Herbicides. Degenhardt has published several peer-reviewed manuscripts, and has served as principal biologist for discovery of herbicides such as Arylex, as well as for nitrogen stabilizers. He has a strong track record of interaction with CWSS since becoming a member in 2002, including his most recent appointment as local arrangements chair for the CWSS annual meeting held in Edmonton in 2015. Degenhardt played a key role in the co-ordination of this meeting, and his strong leadership abilities were a tremendous asset to the society and to the local arrangements committee. He remains an active member of the CWSS. 

Student Scholarships and Travel Awards

Travel Award for PhD student (sponsored by Monsanto) was presented to Charles Geddes from the University of Manitoba. Geddes' research covers optimization methods in canola to reduce populations of volunteer canola in subsequent soybean crops. He works under the direction of Dr. Rob Gulden.

Travel Award for a M.Sc. student (sponsored by Monsanto) was presented to Moria Petruic from the University of Saskatchewan. Petruic's work focuses on expanding weed management options in flax. She works under the direction of Dr. Christian Willenborg.

Travel Award for a M.Sc. student (sponsored by Syngenta) was presented to Felix Marsan-Pelletier from Laval University. Marsan-Pelletier’s work focuses on herbicide resistance in wild oat and common ragweed. He works under the direction of Dr. Anne Vanasse.

Travel Award for a M.Sc. student (sponsored by Dow AgroSciences) was presented to Taiga Cholette from the University of Guelph. Ms. Cholette's work focuses on the interaction between cover crops and herbicides. She works under the direction of Dr. Peter Sikkema and Dr. Darren Robinson.

Travel Award for a M.Sc. student (sponsored by CWSS) was presented to Meghan Grguric from the University of Guelph. Grguric’s work focuses on management of giant hogweed in Ontario. She works under the direction of Dr. Francois Tardif and Mike Cowbrough.

Travel Award for a M.Sc. student (sponsored by CWSS) was presented to Mike Schryver from the University of Guelph. Schryver's work focuses on the distribution and control of glyphosate-resistant waterhemp. He works under the direction of Dr. Peter Sikkema and Dr. Darren Robinson.

Published in Corporate News
Throwing some dirt over the new seedling weeds in your rows isn’t necessarily the end of the story. They could come back, depending on the weed, the tool and the approach you take, according to two weed scientists.

Mechanical weed control, using some form of tillage, still has an important role in weed control in Eastern Canada. Generally, though, it isn’t getting much attention from weed science – as compared to research with herbicides.

South of Lake Ontario, Charles Mohler, a senior weed research associate at Cornell University in Ithaca, N.Y., recently completed semi-basic ecological research on the ability of five annual weed seedlings to recover from burial.

That work has some direct implications for shallow tillage in rows after planting for growers in Ontario and Eastern Canada, says Mike Cowbrough, the field crops weed management specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs, in Guelph, Ont.

Most Ontario corn still has some tillage for weed control, although the form can vary, Cowbrough says.

“Tillage is very much crop specific. The majority of corn has either a single pass or double pass. The vast majority of wheat acres are no-till, and soybeans probably fall somewhere in the middle for weed control,” he says.

As for the weeds, common lamb’s-quarter is the most significant annual weed in Ontario, being both abundant and very competitive. Pigweeds (redroot and green), common ragweed, green, yellow and giant foxtails and velvetleaf also are common annuals. Among perennial weeds, perennial sowthistle is most abundant, he says.

“There’s no question that tillage is a critical component of weed management. However, species react in different ways, so the best strategy varies with the weed species,” Cowbrough says.

Basic science
In mid-state New York, with agricultural climate and soils similar to Ontario, Mohler chose to investigate how well five species could recover from burial. The five were common lamb’s-quarters, Powell amaranth (or green pigweed), velvetleaf, giant foxtail and barnyard grass.

Greenhouse experiments began in 2006 and ended with field experiments in 2013.

Farmers have three basic ways to kill a seedling weed with tillage: burial, dismemberment and uprooting.

Mohler says, “Burying seedlings is a very effective way to kill them, but you’ve got to get them completely buried. When we cultivate corn or soybean, we throw four or five inches of soil into the row. You can bury some pretty good-sized seedlings with that much soil.”

In practice, however, burial may not work out. The trials in New York, with more than 35,000 weed seedlings, revealed:
•    Recovery often exceeds 50 per cent if a small portion of a seedling is left exposed.
•    Recovery from complete burial (by two centimetres of soil) ranges from zero to 24 per cent, but recovery greater than five per cent is rare.
•    No seedlings recover from four cm of complete burial.
•    Large-seeded species tend to recover from complete burial better than small-seeded species.
•    If the soil remains dry after burial, the recovery rate is low or may even be zero.
•    Small seedlings are easier to kill by burial, with less soil.

In a controlled greenhouse setting, weed seedbeds were watered daily at first. After burial, some received no water; some were watered immediately after burial and some had daily watering for up to two weeks.

“In one experiment, we got re-emergence of seven seedlings out of thousands that were buried. In another experiment, we watered every day and something like 12 per cent of the velvetleaf re-emerged. Recovery of other species was lower,” Mohler says.

Among the five weeds, generally, velvetleaf was the most successful at recovery.

The final experiment purposely left a small, consistent fraction of leaf area exposed while burying the rest of the seedling, including the growing point, with two cm of soil.

Despite almost complete burial, more than 35 per cent of seedlings recovered in every species. In most cases, more than 50 per cent recovered. Velvetleaf and giant foxtail recovery was 60 to 80 per cent.

That’s the basic science.
Mohler says, “I try to teach, don’t run through a field without thinking about what you’re doing. You need to target the kind of damage you’re trying to inflict. That depends on the soil conditions, the weather conditions, what your implement can do and how you set it up to use it.”

Applied science
In practice, Cowbrough says, effective tillage needs strategy as well as complete weed burial.

First, there’s a need to distinguish perennial from annual weed control. In-crop tillage is better suited for annual weeds in most cases.

Cowbrough says, “Doing a shallow primary tillage pass in spring on dandelions is good eye-candy for a couple weeks, but that’s all. For effective perennial weed control, you really have to get rid of the entire root or the plants can grow back.”

Some annuals, such as eastern black nightshade, germinate very late. Those weeds arise too late for effective in-crop tillage. Canada fleabane is a common annual weed in Ontario and often glyphosate-resistant.

“Tillage is very good at controlling Canada fleabane, if it is aggressive and early. It has to be effective enough to knock the soil off the roots so the fleabane has zero chance of recovery,” Cowbrough says.  

The second point is about timing. Secondary roots develop as the fleabane gets beyond seedling stage.

“Secondary roots hold soil, too. Tillage may uproot the plant but it can eventually recover and grow again as long as it has some secondary roots holding onto soil,” he says.

For ragweed control, there are strategy variations. For an infestation of common ragweed, the best strategy is complete burial.

“You want to bury the common ragweed seed. The deeper you bury it, the less likely it is to germinate,” he says.

But giant ragweed is different, including glyphosate-resistant giant ragweed.

“The best strategy is to leave the seed of giant ragweed on the surface in a no-till environment,” Cowbrough says. “That seed is prone to predation and degradation, and it’s unable to germinate without a bit of disturbance along with moisture and light. Tillage is not an asset for managing that species of ragweed.”

However, if conditions were right and last year’s giant ragweed seed got what it needed, it is likely to be up very early and in huge numbers of seedlings ahead of planting. If you go in with a tillage implement to knock down those giant ragweed seedlings ahead of planting, it is just as effective as a chemical burndown.

Generally, Cowbrough says, tillage tools can be pretty effective at weed management if they are used appropriately.

In the days after a burndown, light disturbance may be enough for burying and controlling weed seedlings that emerge.  

The disc hiller can bury more advanced weeds ahead of planting.  

And, after crop emergence, a treatment with the sweeps on a row crop cultivator can throw a lot of soil within the rows to bury and destroy seedling annuals.

To wrap it all up, Cowbrough offers this advice:

•    Determine the one or two most prominent species to control.
•    Pick the tillage tool that’s best for that job. No one tool will address all the situations.
•    If there’s opportunity, adjust the tool to its best advantages.
Published in Weed Management
Arbuscular mycorrhizal fungi (AMF) are among the most common and ubiquitous soil microorganisms in almost all soil systems. They contribute to nitrogen and phosphorus absorption and translocation, alleviation of water stress, resistance to soil-borne pathogens and improvement of soil structure. Several studies have reported organic farming systems tend to have more diverse AMF communities.
Published in Soil
The year 2017 will mark the 60th anniversary of the discovery of the first known herbicide-resistant weeds in 1957 — a spreading dayflower found in a Hawaiian sugarcane field and a wild carrot variety found in Ontario, both which showed resistance to up to five times the normal usage dosage of synthetic auxin herbicides.

In the past six decades since these discoveries, weed scientists have documented more than 250 weed species with some form of herbicide resistance. These span 23 of the known 26 herbicide modes of action and impact 86 different crops across 66 different countries. As a result, the cost of weed control across the nation’s crop fields has tripled in recent years as growers are being forced to employ more herbicides per season, increase application frequency, and spend more on fuel costs to achieve some measure of control. | READ MORE
Published in Weeds
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