As most growers and industry stakeholders have heard by now, reports of shortages of glyphosate and glufosinate have become common since late 2021. They’ve led to bulletins of price increases of 100 to 300 per cent for glyphosate in some areas, and recommendations for how to manage their herbicide programs for 2022.
One reason for the reduced supply in North America is due to the effect of Hurricane Ida late last summer. Another is the availability of herbicide active ingredients from China. Whatever the reason, retailers in Eastern Canada are having a tough time acquiring their usual supplies of glyphosate, leading to concerns that some growers may try to hoard the herbicide, which can only serve to drive prices higher.
One input retailer in central Ontario received its allotment of glyphosate last December, and it was significantly less than expected. The agronomy staff developed recommendations for lower-rate applications (using Roundup’s 540 g/L product) in the 0.7 to 0.8 L/ac. range, instead of 1.0 or 1.5 or even 2.0 L/ac. Recommendations are based on plot tests which determined the lower rates would reduce glyphosate use by 38 per cent while covering the same number of acres.
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In addition to reducing rates, the staff advised growers to use a newer, more effective water conditioner. Tank mixing with another active ingredient is also recommended, as are the usual practices: selecting the right nozzles, the right water volumes, starting when weeds are small and tank mixing glyphosate for residual weed control.
Several weed scientists and specialists have repeatedly stated it’s still possible to get excellent weed control with existing products, even against resistant biotypes of Canada fleabane and waterhemp.
Advice from advisors
Three advisors provided their insights into how growers can better manage weeds with less product:
Jonathan Zettler, Fieldwalker Agronomy
Although the current situation is unfortunate, it could push growers to revisit products they haven’t looked at recently, working to determine the cost/benefit to their weed spectrum, says Jonathan Zettler, a certified crop advisor (CCA). Herbicide-resistant Canada fleabane was an eye-opener for some consultants and farmers that Roundup-only systems maybe aren’t the answer. Instead of what’s doing what’s simple, they will have to expand their familiarity with all options available.
“Glyphosate is still a very effective herbicide, so if you start to back off rates or not apply it, you’d better understand your weed spectrum and the limitations of the herbicide you’re considering,” Zettler says. “There are some farmers and advisors who may only know the Roundup systems and need to learn more conventional chemistries as a result.”
The biggest challenge in shifting away from glyphosate is its efficacy on in-crop grassy weeds in corn. In soybeans, post-emerge glyphosate still provides broadleaf weed control at a cost-effective rate. Where there aren’t as many options is with spring or fall burn-down applications, depending on recropping restrictions and weed spectrum. That’s where glyphosate remains a key component.
“So yes, there are some options, in both corn and soybeans, where putting together a strong pre-emerge program up front is perhaps the best course of action for annual weed control,” says Zettler. “Understand that the best return on investment in weed control is typically the herbicide that’s the most effective at controlling the biggest yield-robber in your weed spectrum.”
For identity-preserved and non-GMO soybean or edible bean growers, there are also crop quality concerns such as eastern nightshade. Zettler says determining the most effective product to protect yield and operational efficiency is important, not just calculating the cost of production. He suggests some producers may not understand the impacts of weed stage and density on their cost of production.
Zettler says there were signs last year with shortages or delays on winter wheat herbicides and he believes farmers and their retail channels were primed to consider more proactive ways of heading off expected issues.
“Some growers didn’t change their rates when the formulations changed from 1.0 to 0.67 L/ac. as the standard rate of control. Maybe this is an opportunity for some operations to do some finessing of the rates they’re spraying.”
Colin Smith, Andermatt Canada
For Smith, weed management during short supply of one particular herbicide is not a complex issue. Yes, growers should understand the weed spectrum on their land and yes, knowing the price point of chemistries is vital. But too often, growers and agronomists go for the cheapest option and sacrifice the better choice for control, possibly allowing a key yield robber to escape, negating any savings in input costs.
“More growers need to understand the mode of action along with the growth characteristics of target weeds,” says Smith, Andermatt’s sales and marketing manager. “This understanding should determine the best configuration for application, such as water rate, nozzle selection and nozzle placement. There are some new nozzles and configurations that could have significant impact on control, especially if we revert to chemistries that require more contact with the target.”
As for the wealth of suitable alternatives for effective weed management, Smith notes there is some reluctance in using older products which may require more tank mixing or different application timing. The simplicity of using glyphosate-tolerant crop technologies is what growers and agronomists have become accustomed to with one- or two-pass single chemistry. And that has to change. Smith likens it to understanding the value of the cost of production.
“I would like to see more growers look at true COP per bushel,” he says. “Spreading costs over more acres doesn’t mean COP is decreasing, especially if yields are not as robust. I’ve worked with growers who have had higher equipment, fertilizer and crop protection costs per acre but their cost per bushel produced is significantly lower.”
Smith adds that reducing label rates is a reasonable expectation, depending on weed pressure. But reducing rates below the label specifications presents a challenge, as the label is viewed as a legal document in Canada. Those with accreditation are expected to follow the label or face a potential loss of their credentials (growers can apply lower rates if they believe it’s reasonable). Smith’s experience showed a short-term benefit to reducing label rates, but it also meant higher costs as weed pressure increased in subsequent crops.
“The key is for growers to realize there are no magic conventional or biological products that will directly replace all current inputs that are in limited supply,” he says. “Biologicals require the support of technical expertise, the same as all products, so growers understand how a biological product works … farmers have become reluctant to integrate this group of products due to past history — they tend to be over-promised with no technical support.”
In time, the reluctance will disappear as more growers have success with integrating these products into the appropriate applications.
Paul Sullivan, PT Sullivan Agro
Trying to keep things simple is a common refrain across Eastern Canada. One-pass weed control is the wish of growers and custom spray operators, says Paul Sullivan of PT Sullivan Agro. His recommendation for getting around any glyphosate shortage is a strong pre-emerge program with a full rate of a herbicide like Acuron (with rates that are soil-texture specific). With that, he says, there’s little need to respray glyphosate in-crop.
“In corn, Halex has been a mainstay for a lot of Ontario acres,” says Sullivan. “A soil-applied herbicide like Integrity or Engarde can be applied pre-emerge, but they are part of a two-pass program, due to the timing and impact of weather. But definitely, there are several options using varying chemistries.”
The cost of poor weed control — as emphasized by Peter Sikkema of University of Guelph’s Ridgetown Campus — comes in yield losses. In corn or soybeans, those can range in the 30 to 40 bu./ac. range, which can be considerable anytime but especially when commodity prices are relatively high.
When discussions turn to cutting rates, Sullivan believes a lot of growers apply a rate appropriate to the weed size and type. Scouting and timing of application become very important but must be done with greater consideration for weed spectrum and weed sizes in any field.
“Weeds will always evolve — they just do that,” he adds. “If you use less of a residual herbicide program, you’ll start to get pigweed or smooth crabgrass coming through.”
