Herbicides
Corn and soybean growers in Canada have a new tool in the fight against tough and resistant weeds. ZIDUA™ SC is a new Group 15 herbicide from BASF that contains the active ingredient pyroxasulfone.

"BASF focuses on providing Canadian growers with tools that support current and emerging resistance challenges," said Deven Esqueda, Crop Manager, Corn and Soybeans for BASF. "ZIDUA SC, backed by ten years of research, allows growers to add residual Group 15 activity to their weed management strategy and become less reliant on glyphosate."

Recently registered by the Pest Management Regulatory Agency, ZIDUA SC herbicide will be available for use in the 2018 season. ZIDUA SC is currently labelled for use in herbicide-tolerant soybeans and field corn.

ZIDUA SC is a stand-alone solution and can also be tank-mixed with glyphosate, ERAGON®LQ, MARKSMAN® or ENGENIA™ in Eastern Canada, and HEAT® LQ, ENGENIA™ or ARMEZON® in Western Canada, to provide multiple modes of action for resistance management.

Resistance has been increasing across Canada in pigweed species, including waterhemp and redroot pigweed. A study by the Canadian Journal of Plant Science states glyphosate-resistant waterhemp was first identified in Ontario in 2014. In Alberta, Group 2-resistant redroot pigweed was identied by Agriculture and Agri-Food Canada in 2010.

The residual Group 15 activity in ZIDUA SC helps to inhibit early root and shoot growth in these tough to control weeds, maximizing corn and soybean yield through the critical period for weed control. ZIDUA SC also provides flushing control of barnyard grass, crabgrass, green and yellow foxtail, common waterhemp and redroot pigweed.

For more information on ZIDUA SC herbicide, contact AgSolutions® Customer Care at 1-877-371-BASF (2273), or visit agsolutions.ca. Always read and follow label directions.
The U.S. environmental agency is considering banning sprayings of the agricultural herbicide dicamba after a set deadline next year, according to state officials advising the agency on its response to crop damage linked to the weed killer.

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 (MON.N) and DuPont which sell dicamba weed killers and soybean seeds with Monsanto’s dicamba-tolerant Xtend trait. BASF (BASFn.DE) 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 

Research trials in the U.S., and more recently at the University of Saskatchewan, are proving what’s old is new again. In this case, the use of “old” herbicides such as Avadex, Fortress and Edge are making a comeback of sorts in a weed management system that’s been dubbed “herbicide layering.”

According to Clark Brenzil, who coined the term, herbicide layering is simply utilizing two to three herbicides in sequence to tackle tough-to-control weeds and to stave off weed resistance.

Indeed, herbicide tank mixtures and/or a program that utilizes a residual product in a sequential program are now the recommended practice for delayed herbicide resistance.

“It’s a good management tool for controlling some of those weeds that may not necessarily be that responsive to one herbicide,” Brenzil notes. “Wild oats and cleavers are two great examples of this.”

But even simply switching one herbicide out for another, ie. rotating herbicides, while perhaps delaying the onset of herbicide resistance, still results in selection pressure. Today, many in the industry are starting to stress the importance of using multiple modes of action and tank mixing.

“The extension message is to use multiple modes of action together in weed control programs,” says Mike Grenier, Canadian development manager with Gowan. “But it’s not only using tank mixes – it’s using products in sequence, for instance to look at the soil residual herbicides as part of this management program.”

The idea is simple: apply different modes of action within a season – layering – and rotate chemistries through the crop rotation. As it turns out, Avadex, Edge and Fortress herbicides fit very well into this strategy.

“In our scenario, you would have Group 8, Avadex or Fortress, being soil applied either in the fall or in the early spring followed with a post-emergent program during the growing season,” Grenier notes. “So in this case of Group 1 or Group 2 product use, Avadex is the pre-emergent layer providing resistance management against wild oats.”

In trials, Gowan maintains that Avadex and Fortress can provide about 90 per cent control of wild oat, while Edge (Group 3) provides 70 to 80 per cent suppression. “Then you have a post-emergent program working on a much lower level of [weed] population, so lower selection pressure. So now we have the control level approaching close to 100 per cent.”

Studies find an added bonus
Led by Christian Willenborg, weed scientists at the University of Saskatchewan (U of S) have been conducting research to determine if herbicide layering proves beneficial. “We have some good information in peas and some really good information in canola,” says Eric Johnson, U of S research assistant. “Graduate student Ian Epp’s research in canola showed some benefits, even with Roundup Ready canola, to be using clomazone pre-emergent to improve cleavers control.”

In the studies on cleavers weed control in canola, the researchers used three different modes of action – applying clomazone pre-emergent, then followed by either Clearfield, Roundup or Liberty tank mixed with quinclorac. “Even with the Roundup system, which is already pretty effective on cleavers, we found that using three different modes of action provided weed control benefits, and some yield benefits which totally surprised us,” Johnson notes. (See Fig. 1.)

The team also did studies on managing Group 2 resistant cleavers in field pea. “What we found was that if we put a pre-emergent down, that suppressed the cleavers somewhat. But then we came in and followed with a post-emergent, and we ended up with better than 80 per cent control.” (See Fig. 2.)

Going forward, the U of S is starting some work on managing Group 2-resistant wild mustard and Group 2-resistant kochia in lentil.

The big picture
Brenzil says herbicide layering has some merit for everyone. “What the U of S research has found is that if you have control taking place right at the point where the weed is germinating [with the pre-emergent], you’re going to get better yield response out of your crop, rather than waiting for the three- or four-leaf stage when there’s already been some competitive effect of that weed on that crop,” he notes.

“By having a soil active, even if it’s not doing a fantastic job of controlling the weeds, it’s suppressing the influence of those weeds on that crop, and you’re getting a bit of a yield bump by having herbicide in the soil along with your foliar product that’s coming a little later.”

An added bonus, Brenzil adds, is that by using a herbicide layering program, you’re making a pre-emptive strike against herbicide resistance. “It’s a good management tool for controlling some of those weeds that may not necessarily be that responsive to one herbicide for effective management, such as wild oats and cleavers.”

At the Herbicide Resistance Summit held March 2 in Saskatoon, Jason Norsworthy made a comment about the “treadmill” of using one weed chemistry and the very real threat of developing herbicide resistance as a result. Brenzil explains: “If you use one chemistry to death and then you allow your weed populations to get very high again, then you’re just starting from square one to select for the next Group that you’ll overuse, and so on and so on, until you paint yourself into a corner and there are no herbicide options left. At this point, the only management option left will be seeding the field to a forage crop and cut for hay until the seedbank is exhausted.”

With herbicide layering, “If you’ve got your soil active products on the ground, then you come in with your foliar and you’ve got a mix of two foliars that could still control that same weed – now you have three active in there of different families,” he adds. “You avoid that overuse and you don’t allow selection pressure to accumulate.”

 WTCJune16 Herbicide layering



This story originally appeared in the June 2016 issue of Top Crop Manager West.
With the confirmation of glyphosate-resistant (Group 9) kochia across the Prairies, a renewed focus on best chemfallow management practices is needed.
Using several herbicides with multiple modes of effective action are essential in combatting resistance, minimizing the weed seedbank and preparing fields for success. A planned herbicide program using multiple modes of action is the best strategy for these tough-to-control weeds.

An herbicide that offers multiple modes of action to help manage a variety of broadleaf weeds that can also be used in various tank-mixes to control glyphosate-resistant species will help address the challenges of weed resistance in both the current and future growing seasons. 

For example, last year, a group of growers in Eastern Canada tested Armezon PRO, a new Group 15 and Group 27 herbicide. With a wide application window from early post-emergence to the eight-leaf stage in glyphosate-tolerant corn and the ability to easily tank-mix with additional products, growers were able to customize their weed management to meet their needs. When tank-mixed with atrazine in glyphosate-tolerant corn, Armezon PRO provides four modes of action.

Customizing weed management strategies is especially useful when weather prevents getting into the field for a pre-emergent application.
Managing problem weeds with multiple modes of action provides residual activity, reducing the weed seedbank and setting up fields for the next season. 
Premier Tech, an international leader in active ingredients for sustainable agriculture and horticulture, will take the lead in the final steps to bring to full scale the manufacturing and commercialization of a selective bioherbicide. In January, the Horticulture and Agriculture Group signed a license agreement with Agriculture and Agri-Food Canada (AAFC) to finalize the development and commercialization of a product formulated from an indigenous fungus (Phoma macrostoma).

Over nearly ten years, the federal department invested millions of dollars in research on this fungus and its compounds (macrocidins), which can eliminate broadleaved weeds, particularly dandelions. This breakthrough discovery has been patented in several countries and is commercially registered in the U.S. and Canada.
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.  
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).
Gowan Canada has added volunteer canola to the Permit WG Herbicide label in time for spring 2017.

Permit is registered for pre-emergent and post-emergent use in dry beans, and post-emergent use only in corn. Data generated by independent contract researchers has consistently shown high levels of extended residual control of volunteer canola from both pre and post-emergent applications.

For more information on Permit for volunteer canola, growers are urged to contact their local retailer.
New herbicide product registrations and label updates continue to bring more choice to farmers, with multiple modes of action to manage weed infestations and herbicide resistance. The following product information has been provided to Top Crop Manager by the manufacturers.
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
SASKATOON – Western Canadian corn growers now have a new tool to remove early season weed pressure to help maximize yield and profits in corn. DuPont Crop Protection has announced that approval has been granted for registration of DuPont Sortan IS herbicide.

DuPont Sortan IS herbicide will allow growers to control tough, yield robbing weeds, such as volunteer Roundup Ready canola, wild buckwheat, redroot pigweed (including triazine-resistant biotypes), lamb's-quarters, green foxtail, barnyard grass, and quackgrass, to keep corn weed-free to maximize yield and profits.

An additional mode of action to glyphosate, Sortan IS offers application flexibility – it can be applied pre-emergent or post-emergent, and provides extended control throughout the critical weed free period. For optimum weed control, it is recommended that Sortan IS be tank-mixed with glyphosate herbicide at 900 g ai/ha for control of additional weeds.

Sortan IS will be available at local retailers in Western Canada for the 2017 season.

For more information, visit dupont.ca
Lentil and canola growers in Western Canada have new options for burndown weed control with new herbicide updates from Nufarm Agriculture Inc. Valtera is now approved for a fall application prior to seeding lentils (large green and small red types).

Valtera (Group 14) is a distinct mode of action that can be used as part of a fall burndown program for residual weed control where lentils will be planted the following crop season. Valtera controls a range of broadleaf weeds including pigweed, lamb’s-quarters, seedling dandelion, kochia and chickweed, and suppression of green foxtail and volunteer canola. Valtera re-activates with moisture to deliver residual control that lasts for four to six weeks in the spring. Valtera is also registered for spring or fall pre-seed burndown and residual control in chickpeas, field peas, soybeans and spring wheat. Visit nufarm.ca for more info.
Axter Agroscience has improved the performance of CropBooster with the addition of specific organic acids and micronutrients to create CropBooster 2.0. These modifications generate a significant yield increase.

CropBooster 2.0 in the herbicide tank mix produced an average yield increase of 3.3 bushels of wheat per acre in multiple field trials. In these same experiments, CropBooster 2.0 performed better than the original CropBooster with a higher yield increase.

By allowing crop plants to restart growth or to continue growing more quickly, CropBooster 2.0 is also proven to increase yields without reducing weed control.

Click here for more information.

FMC of Canada has announced a new expanded label for Authority 480 herbicide. The new label features more registered weeds and additional crops, according to a press release.

The weeds include eastern black nightshade, a particularly troublesome weed for identity preserved (IP) soybeans, and common waterhemp – the newest glyphosate-resistant weed in Eastern Canada. There are 13 weeds on the new expanded label, such as red root pigweed, lamb’s-quarters, wild buckwheat, eastern black nightshade, common waterhemp, yellow woodsorrel, common groundsel, cleavers (suppression), Powell pigweed and common purslane.

Authority offers a new group 14 weed control option for group 2 and glyphosate resistant weeds. 

Several new specialty horticulture crops have also been added to the Authority herbicide label, including chickpeas, field pea, flax and sunflowers. 

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