No Room for Error in Weed Control Programs for ’22
In the 30-plus years that Bill Johnson has been a weed scientist, he has never been more nervous on behalf of the American farmer for what they’re going to face this season.
“We’ve always had herbicides to clean up mistakes. My big concern is we don’t get out of that mindset this year, we get the seed in the ground, and then we don’t have good herbicides to spray,” Johnson, Professor of Weed Science at Purdue University tells CropLife® magazine in early March.
Throughout his county meeting season in Indiana, he has asked growers to raise their hand if they have herbicides on their farm. While more hands have gone up as the season has progressed, the situation is less than ideal. “Still less than two-thirds have the inventory they need on their farm,” he says. “I’m concerned that well over half don’t have Plan B.”
Even with the price of glyphosate being four times what it was a year ago, the fact that it works on so many grasses, and that it works so much faster than something like clethodim or soy or Accent in corn makes finding alternatives tricky, he says. “There aren’t good second choices.”
Many individuals along the ag value chain we met at the 2022 Commodity Classic in New Orleans the following week echoed Johnson’s comments.
“We’re going to be short (on bulk chemicals) — there’s no way around it,” Tom Wood, General Manager at Belchim Crop Protection, told CropLife at the company’s booth on the trade show floor. “We talk to customers about how our products fit in different programs,” including its Tough selective herbicide (active ingredient: pyridate), which it started stocking heavily in the third quarter last year anticipating the current situation.
That product will be in ample supply, but for others, it could be a different story — for post-patent stock from India, he expects to see delays into the end of March or April.
“One of the major challenges in the three months ahead will be knowing the bias in your supply chain,” he says. Dual-country sourcing for nearly every raw material and formulating locally where it makes sense financially — including in the U.S. — are strategies Belchim uses to shorten supply chain and cut down on logistics risk, he explains.
Michael Kenty, Product Specialist with Helena Agri-Enterprises based in Memphis, tells CropLife that while there are plenty of options to control primary weeds and insects, “this is a year where we’re starting to tell our customers we can’t guarantee you’ll get what you want. You may want (Roundup) PowerMax, and you may only get 80% of the PowerMax you want, and we will have to provide another alternative to glyphosate if you need it. I think every retailer is dealing with that.”
Will Mangen, Agriculture Technology Specialist with WinField United, points out that research has shown in any given glyphosate application, on average, one-third of the amount applied makes it to the target. Making the most of that application with the proper adjuvants and preemergence herbicides will be crucial to getting the most out of every drop.
“There’s no room for error,” he says of this season. “Our position would be you plan for Plan A. You have to make sure you have B, C, and D, and be up front with customers.”
Pete Eure, Syngenta Technical Product Lead, drove home the point about leading with solid agronomics: Start off with clean fields, come out with a strong preemergence or residual herbicide, and then follow with an overlapping post-emerge, thereby reducing the need for subsequent foliar products.
He points to the cost of neglecting early weed season management: “You can see about a 1% reduction in yield per day when you allow weeds to sit in field and compete with your soybean crop, beyond the period of critical weed control.” He explains that not using a strong pre-residual can result in early season yield competition, that “we may not think is reducing yield but it’s holding our crop back, it’s stunting the crop, it’s reducing photosynthetic potential, and it’s ultimately minimizing our yield potential.
“I think understanding the value there is really key for folks that are considering preemerge products in soybean, and for those that aren’t, they need to understand the risk and cost associated with that. In a year like this year with $15 to $16 beans, protecting that investment is really key,” he adds.
In addition, Eure notes that with growers planting earlier, in cooler wet conditions, they are using lower plant populations to save on seed costs. As a result, use of some products can stunt the crop early in season, reducing stands slightly, and slowing the crop taking off in season. “Anything that we do to not get crop off to bad start, we negate the early planting benefit, and your whole purpose is maximizing yields,” he tells CropLife. “We want to drive that message that if we’re going to use a strong pre-residual up front, let’s use one that’s safe as well, so you maximize your yield potential because of that early planting.”
In soybean, rely on effective residual herbicides pre- and postemergence as much as possible, Kevin Bradley, Professor, Plant Sciences at the University of Missouri wrote on March 1.
“Because of our problems with resistant waterhemp and Palmer amaranth, this is really something I hope that our farmers are already familiar with and practicing, regardless of any potential herbicide shortages,” Bradley noted, adding, “Also because of our problems with these resistant weed species, soybean is a crop where a potential shortage of glufosinate might hurt the most. If used correctly, glufosinate is still a herbicide that works on the pigweed species in most Missouri soybean fields. With that in mind, I would save all the glufosinate you have for post-emergence use in Enlist soybean (preferably with Enlist One), or for post-emergence use in Liberty Link, Liberty Link GT27, or XtendFlex soybean.”
For pre applications in corn, Prashant Jha, Associate Professor and Extension Weed Specialist with the Department of Agronomy at Iowa State University, recommends a combination of products containing herbicide group (HG) 5, 15, and 27 to achieve foliar and residual control of grass and broadleaf weeds. Herbicides containing active ingredients such as S-metolachlor (HG 15), acetochlor (HG15), pyroxasulfone (HG 15), or isoxaflutole (HG 27) have very good activity on foxtail species (giant, green, or yellow). Addition of atrazine (HG 5) will enhance activity on broadleaves such as waterhemp and giant ragweed, according to Jha.
For post applications in corn, herbicide programs based on HG 27 such as Impact, Laudis, or Shieldex will be essential to achieve broadspectrum weed control. Jha added that Group 2 herbicides like Accent (nicosulfuron) can substitute for grass control in corn, and Revulin/Realm Q, which contains rimsulfuron (for grasses) and mesotrione (for broadleaves) is another option that can be used for broadspectrum weed control in corn. Atrazine should be added to these products to enhance the foliar and residual activity (needed for late-emerging waterhemp) at the post-application timing, he noted.
On the importance of adjuvants, Council of Producers and Distributors of Agrotechnology (CPDA) offers suggestions to mitigate challenges herbicide shortages impose on growers. The right adjuvant package maximizes glyphosate efficiency by using lower labeled rates, adjusting for optimum droplet sizes, spray timing, with the use of surfactants, water conditioners, and drift and deposition agents, CPDA says.
“At Nutrien Ag Solutions, we are confident in our ability to meet customer needs because of our business relationships with the world’s largest suppliers and the personal relationships between agronomists and their individual grower customers,” says David C. Elser, Senior Vice President, Retail North America at Nutrien Ag Solutions and CPDA member. “Our crop consultants have the ability to recommend a wide variety of products including adjuvant packages to help deliver solutions meeting very specific needs.”
Dr. Bryan Young, Purdue University Professor of Weed Science adds, “The lower labeled use rate of glyphosate will kill most non-resistant annual weeds when applied with additional non-ionic surfactant, ammonium sulfate, drift and deposition agents and proper application. We need to actively manage 2022 glyphosate supplies to stretch covered acres.”
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